To The Point - Bushings

Jun 3, 2013 at 21:07
Jun 3, 2013
by Mike Kazimer  
 
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Bushings are an oft-overlooked component of modern mountain bikes, and can be found everywhere from derailleur pulleys wheels to suspension pivots. We asked Matt Floyd, igus' Bicycle Industry Specialist, to explain more about the role that bushings play, as well as the potential benefits they can offer.

Let's go over some terminology first. What exactly is a bushing?

A bushing is generally considered a friction reducing part that does not consist of any moving components. In other words, it relies on a sliding versus a rolling element. Much like a bearing, its role is to not only reduce friction but to reduce the amount of wear between the two mating materials.At igus, we often interchange bearings and bushings as the wear and friction results often can be superior to that of ball bearings, but igus® iglide® plastic bearings have the advantages of a bushing as a sliding element, making them maintenance-free.


What are the advantages of using a bushing versus a sealed cartridge bearing? Any disadvantages?

Here are some advantages based on years of testing results at the igus Test Laboratory:

• Weight – All igus iglide parts are plastics and offer a considerable weight reduction vs. sealed cartridge bearings (SCB).

• Vibration dampening – The polymers in iglide plastic bushings can absorb vibrations and help shock loads, increasing comfort as well as reducing fatigue and wear of other biking materials.

• Low and consistent coefficient of friction – The coefficient of friction over time will remain the same without the use of lubrication. iglide bushings work well with external grease and oils, however they do not require any external lubricants to maintain a consistent and low coefficient of friction. Sealed cartridge bearings often require lubrication over time in order to maintain the same coefficient of friction.

• Corrosion – Regardless of harsh conditions, iglide bushings will not corrode from the elements, UV light, or from exposure to chemicals typically found on streets and trails. Additionally, they will not rust, galvanize, or anyway oxidize.

• Resistant to contamination – iglide bushings can work well in dirty and contaminated environments without compromising the integrity of the bearing or need for a seal. Due to the bushing dry-lubricating function, dirt, sand and other particulate will have little impact on the bushings performance. With sealed cartridge bushings, the seals can be compromised leading to failures, increased friction or accelerated wear.

• No minimum travel and high acceleration – Ball bearings usually have a minimum travel distance in order for the balls to begin rotating inside of the bearing. If there is a high acceleration with a short pivot, the ball will fail to rotate and rely on the oil or grease to skid over the shaft or race. This can cause scoring or flattening of the balls leading to a higher coefficient of friction and higher wear. iglide® bushings are sliding elements and can handle very high levels of acceleration with no minimal travel required.


What type of mountain bike applications are bushings best suited for?

Bushings are a great design element for suspensions, brakes, drive trains, derailleurs and seat posts. igus bushings have been used in many mountain bike applications. We know how critical the feel and fit can be for riders and we take pride in our attention to detail in designing and testing tolerances for fit and performance are met for each application.




The term 'self-lubricating' is often used regarding bushings. How exactly is this accomplished?

Self-lubricating effects can be accomplished in a number of ways as this implies that the lubricant is released over time or at once. Some bushings offer a very thin preliminary layer of lubrication such as Teflon that makes contact onto a shaft and will lubricate until the layer is gone Other bushings have a lubricant sintered into their pores that require frictional heat from motion to release the lubricants.

All of our bearings contain three primary components; base polymers, which are responsible for the resistance to wear, reinforcing fibers and filaments, which make the bearings ideal for high forces and edge loads, and solid lubricants, which are blended into each material. By homogenously blending the components, there is no doubt that the part will create an optimal gliding surface for a plastic bearing. This also eliminates any need for external wet lubricants. The elimination of these wet lubricants makes iglide bearings completely free from maintenance requirements and also helps to keep the environment clean.


Many bushing are made of plastic, but there are different types of plastic. What are bushings intended for bicycle usage typically constructed from? Can you give us a brief description of the manufacturing process?

igus offers 6 (six) main materials for use in the bicycle industry, however each application is reviewed thoroughly before a material is specified. These materials are composed of different polymers, strengthening fibers, and sold lubricants. Each material will give different wear characteristics for different applications. This is dependent on the application motion, speed and mating materials.

All igus products are injection molded in Germany and held to tight tolerances. The process of injection molding is not new but to obtain the tight tolerances we do, takes years of application testing and patience. Typically in the biking industry we choose materials that have the lowest coefficient of friction and which can handle very high shock loads.

Previously, metal-backed bushings were commonly used in the eyelets of rear shocks, but recently full plastic bushings have become more prevalent. What caused this change?

From our understanding in working with those in the bicycle world, the primary reasons for change include weight, cost and most importantly empirical data, as well as an actual review of customer’s needs for achieving a better ride.

A PTFE bushing on the left, and an igus plastic bushing on the right.


In a weight comparison, an iglide plastic bushing weighs approximately 80% less than a PTFE-lined bushing. As an example, an iglide G300 plastic bushing weighs 0.0144 pounds per piece, while a PTFE-lined bushing weighs 0.0750 pounds per piece. Our engineers have worked very closely with those in the industry to find a bushing that would increase the life of the product, decrease weight, offer a lower coefficient of friction, save costs, and give the desired fit and feel. Field testing has shown that in these rear eyelet applications the wear of the bushing was decreased significantly allowing the riders to change out the bushing less frequently. Also there is a noticeable reduction in friction and increase in performance. Weight in the shocks was reduced as reviews from riders have indicated a better feel and ride.

Wear surface is another important factor, meaning the actual amount of wear surface that a homogenously blended bearing offers in comparison to a bearing with a thin lining. A PTFE-lined bushing is comprised of a metal shell and a very thin polymer coating (PTFE) applied to the inside. These types of bushings typically have a maximum wear surface of 0.06 millimeters (0.002 inches), but as the PTFE coating is stripped off during operation, the metal shell becomes exposed. This creates a metal-on-metal effect between the bushing and the shaft and can cause serious damage. This problem is common when high edge loads or oscillating movements are present.

During operation with plastic bushings, lubricants are transferred onto the shaft to help lower the coefficient of friction and wear, and unlike PTFE-lined bushings, plastic bushings eliminate the danger of metal-on-metal contact. This is huge benefit since the acceptable amount of wear can be determined by the type of application (unlike the PTFE-lined bushing, which will fail if the wear rate surpasses 0.06 millimeters).

For example, igus' lifetime calculator uses a preset wear rate of 0.25 millimeters (0.01 inches), but the user can easily increase or decrease this number to meet the wear limit acceptable for the particular application.


www.igus.com
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134 Comments

  • + 46
 Great info..pinkbike needs more of these in helping to keep riders educated and conscious of the benefits that technology has allowed us to take for granted
  • + 6
 The coefficient of friction is not lower than sealed cartridge bearings, otherwise we would use bushings in hubs or bottom brackets.
  • + 22
 For the application, it is... bushings are used in shock eyelets and suspension pivots because they don't have to fully rotate ever. No suspension bike frame employs has a pivot that goes thru a 360 degree rotation. This fact always amuses me, nobody thinks twice over the fact that except for Action Tec and Cannondale forks, NO brand uses anything but bushings to deal with the loads of sliders passing over stanchion tubes, but you put it in a rear pivot and OH MY GOD THE SKY IS FALLING whining occurs.
  • + 2
 I'm just saying that the article is incorrect, bushings coefficient of friction is 10 times higher than bearings one. But I agree that for this application coefficient of friction is not very important. Bushings can fully rotate, like in the pedals.
  • + 1
 @Sylvain, a lot of hubs do contain at least one bushing, usually as a support between the freehub body and axle. It's very rare on more expensive hubs, but if you're using anything Joytech based (like Transition, Superstar, Spank, Azonic etc) or Shimano there are probably bushings in your hubs.
  • - 1
 Also as the article said... derailleur pulleys.. most always employ bushings...shimano especially....ceramic bushing pulley for decades now on the DuraAce, XTR, Ultegra and XT derailleurs. They rotate millions of times without failing and usually without ever cleaning, to the point the pulley teeth die first. All the aftermarket pulleys that were made in metals of some sort relied on heavier/cheaper to design cartridge bearings... which in my experience having used them for over a decade...wear out a lot sooner, are heavier, and the aluminium alloy pulley teeth in particular, do wear down just as badly as the plastic polymer ones shimano makes. I have one alloy pulley in particular that would likely be seized by airport security as a stabbing weapon the teeth having been sharpened to points by chain wear.
  • + 8
 As a direct quote from the article you obviously didn't read, this is why bearings aren't used: "No minimum travel and high acceleration – Ball bearings usually have a minimum travel distance in order for the balls to begin rotating inside of the bearing. If there is a high acceleration with a short pivot, the ball will fail to rotate and rely on the oil or grease to skid over the shaft or race. This can cause scoring or flattening of the balls leading to a higher coefficient of friction and higher wear. iglide® bushings are sliding elements and can handle very high levels of acceleration with no minimal travel required."

I.e.: bearings for high degrees of rotation - good, low degrees of rotation - bad
  • - 1
 No. for hubs there would be too much wear. he talked about for the distance traveled bushings are better for shock eyelets. where as in a hub the bb's are doing a full rotation so are working and not being flattened
  • + 1
 The only reason bushings are not used in places like hubs is because they could potentially melt. However you're never going to have the same level of energy input into your suspension pivots. The initial force needed to get a bushing moving is far less than that of a bearing. I don't understand why manufacturers of frames insist on bearings in these places. Another reason for bushings in suspension pivots is the fact they sperad out the forces much more evenly, for they have practically infinite contact points, whereas bearings only ever have as many contact points as they do ball bearings inside them!
  • + 2
 And of course they mention little to nothing about the cost of replacing bushings compared to bearings. Years of research and plastic parts should lead to cheaper parts... so we think. I had to replace my bushings last year for my suspension pivots... that set me back $50 on top of the 2 bearings I replaced for almost $120. Either I got hosed on a small piece of plastic or they're charging far too much for these bushings in general. Although this is great technology and have advantages over bearings in certain applications, I still think they are charging far too much for these little guys.
  • + 1
 Im not sure where you bought your bushings from. but Igus bushings tend to cost around a dollar each. Its not the bushing manufacturer's fault your LBS is overcharging you.
  • + 1
 The cost is both with the small batches they buy, or the shaft that they should be replacing. If your dealer is upcharging, then go elsewhere The Bushings themselves, if IGUS, can be bought from any IGUS supplier, and they aren't that pricy, compared to an SKF bearing for instance. It's the shaft that holds most of the cost for the assembly, so check out what they replaced. And Mars has it right. I've beat this dead horse here and before.
  • + 5
 The biggest single problem with bushings is their susceptibility to contamination - once there's dirt or water in there, they need to be serviced. Try riding some Straitline pedals for a few days in wet conditions and see what happens - they just seize up. Bushings also have wear issues that cause play to develop (the most commonly replaced pivoting component in most bikes is the DU bushing in the shock...), particularly when used in non-lubricated pivots such as suspension linkages (ask anyone that rode a Banshee before they went to bearings!). They work well as linear bearings (such as in forks) when they're immersed in a lubricant and don't have to deal with thrust (axial) loads, but in most situations I am not a fan at all. Having owned frames, pedals etc that use IGUS bushings in place of bearings, I've never once been even slightly impressed with their performance.
  • + 1
 A grease fitting helps remove water, and some bikes (Nicolai) use a simple seal system that helps keep them dirt free. I've never seen a ball bearing pivot last as long as my Nicolai's pivots did. And that's racing and Bromont sand.... We're talking 3+ years on the same bushings, with just cleaning them once a year. So, if done 'right' they are great. The problem is all those before that did it wrong.
  • + 3
 How come I have to replace bushings seemingly more often on shock eyes then? I get a little play after like 4 months of riding and have to replace. Granted, the replacement costs approximately a dollar.
  • - 1
 How often do you wash your bike / shock off (and if often, are you using a bucket and sponge or a pressure washer gun at the car wash) ?
  • + 1
 It gets hosed down once a week at low pressure. That said, mine have probably been the really cheap ones and it seems there have been leaps in tech. Thanks!
  • + 8
 I used to work for a UK distributor doing import/sale; well known Canadian owned / Taiwan made brand which used IGUS bushings on its short-link virtual pivot suspension frames ranging for 100mm to 200mm

to say we had problems an understatement: the last year I worked for this distib. we had a warranty return rate of +75% on the frames we sold to UK customers. loads of pissed off customers wanting refunds / replacements, spouting their anger all over the internet forums and many vowing never to touch the brand again or use our company for any future sales!

Bushings seem like a fantastic idea on paper (or CAD if you like) for pivots, but rely on having proper sealing from elements, and most importantly very critical of frame manufacturing tolerances,design of axle and torque settings.Once dirt gets involved its chaos...

if these tolerances are off by small margin (as they were on all the frames we imported) or sealing not adequate, then you get problems from Ride One with pivots that either bind or are laterally sloppy, and quickly degenerate wearing the bushing sockets and axles of each pivot location.

customers given replacement bushing kits, axle kits, replacement frame parts, some given new frames, and all kinds of "mods" were suggested (cutting bushings down and gluing into the pivot) all FOC which cost a small fortune as these parts were not cheap.

to keep it simple,let's just say the brand learned the hard way ($$$ and pissed off customers) that bushings do not work in the "real world" for suspension frame pivots, and moved their entire 2nd generation suspension frame line over to cartridge bearings. Very few brands have ever got the use of bushings for pivots correct (Turner?)

cartridge bearings, on paper, are not ideal for the limited rotation of suspension pivots, but are much more tolerant of alignment issues, cheap / easy to replace, can be relubricated at home and do not cause damage to expensive frame parts unless you leave it for... way too long
  • + 1
 Hahahahaha, poor SC. This is precisely why my shop dropped them back in...2003ish?
  • + 2
 @JonnyGonePlaid

if you mean Santa Cruz by "SC" its not that brand, although they have had their fare share of problems with VPP like Intense

the brand I was talking about is "born on the shore" in Vancouver, Canada
  • + 2
 I'll go ahead and spell it out since i'm not affiliated... Banshee
  • + 1
 @MarsTheGuy

I am not affiliated any more either..not for 2+ years, I work for a much bigger brand these day, red and "S"

but did not want to mention the older brand directly because of the power of search engines

its always better to give a brand breathing room when they have turned a difficult corner
  • + 1
 I stand corrected. That's right, VPP1 had bearings, not bushings.
  • + 1
 Judging by the bikes you ride and your comment there's not much left to the imagination.
  • + 2
 Have bushings on my Nicolai - work fine. Had bushings on many other bikes - worked fine for years. If they do not work fine, it means it is a crappie made bike. Not sure if bearings would have saved it. If you mean Banshee, problem was bad loading on links, not bushings. They just did it wrong.
  • + 2
 You can't use banshee as a testament on how to use bushings. Doing so just negates the entire argument: they did a well known botch job with them. Again, go ride a Nicolai or Turner with bushings then report back.
  • + 1
 @Hampsteadbandit. I know exactly who you're talking about, the worst bit is when they were running the protos (2006-7ish? I forget) for those frames and all and sundry (forums, trade show folks, press) told them how great the bike looked, but to use bearings instead. Some lessons just have to be learned the hard way I suppose.
  • + 1
 Also, I always laugh, out loud, when someone uses the term "On paper" to argue a point about something they have limited knowledge in. Hey guess what? ALL good ideas worth anything start off on paper. ALL things that work in the "real world" are penned on 'paper' long before they are tested. And then when they are being tested, there's more pen to paper. Everything well thought out starts as a design, and the more research, math, design work, etc, done initially, the better off the product usually ends up. Haters hating on paper... sheesh.

To further the bushing point, using the worlds worst example of utilizing bushings on a bike frame is akin to saying: "Hey, I had a 1995 ford explorer that broke, and now every ford ever made sucks", or "I've tried pad thai at the one star restaurant/brothel down the street and got herpes so therefore all Thai food is bad". You can't use the worst examples to negate the ones that do work.
  • + 1
 Let's pray the bushings, they will save us from ball bearing damnation!!!

In my country, this is called NTA (non traditional advertising).
  • + 1
 @hampsteadbandit
I agree brands should be forgiven for these past mistakes, but clearly some people didn't quite understand. Also i think it's fairest that people can find out this history and make from it what they will about the company, no point trying to cover it up.

Oh, and this big red 'S' you speak of... awesome company! Smile
  • - 1
 deeeight, do you get the difference between telescoping & rotating? For telescoping motion bushings are employed for a couple reasons, one is because to telescope with a mechanical bearing it is much more complex than to rotate. Take a look at a linear bearing. Look like an inexpensive device? Additionally those forks you spoke of, are lubricated, nowadays in a tub of oil so you actually have a bearing. Oil & grease molecules do the rolling instead. Further, balls don't spread loads out like bearings so on aluminum stanchions you have a problem. For the application, bushings are used to lower costs. The only other advantages are less weight & less space. This crap about friction & wear & blah blah is bogus kife biased by a manufacturer of bushings. On higher end bikes bearings are used, because they are better. A sealed bearing does not require more maintenance. Find a different example because stanchions don't qualify since they're linear & lubricated constantly, they're not a dry running bushing. No one pays attention to your statement because it doesn't qualify. Sorry.
  • + 2
 Right... i'm going to take lessons on bearings from someone who was in diapers when I was starting to service suspension forks... put simply, I know all there is to know about bearings and bushings in suspension forks and not all forks rely on oil baths over the bushings to keep them lubricated and maintain their durability, even today. Oil baths are on the way out with a number of brands, Magura in particular.
  • + 2
 @freeride-forever: At higher end bikes, like Turner, or Nicolai, bushings are used, because they are better. And you do not know what you are talking about.
[Reply]
  • + 29
 Im confused. was this meant to be an informative article or an advertisement? Because although it does provide some good information its sounding a lot like the later...
  • + 7
 The best part is the comparison picture with the dirty-cheezy-greezy-PTFE vs. their white-good smelling-best in the world bushing ! WAOW ! I want igus plastic for my condoms !
  • + 6
 These 'advertising' tech articles are difficult to accept as accurate as the manufacturers always say they are greatest thing while riders with experience using them often say otherwise. I usually end up doubting the whole article when there is no 3rd party testing. The 'how things work' aspect is always good.
  • - 1
 Except on a forum... people who post are always representing a MINOR percentage of the actual number of users of a product, who by and large don't care to post, or don't even know or care the website that hosts the forums exists. I constantly encounter mountain bikers who have never heard of pinkbike, even the sorts who spend much more money on their bikes than likely anyone here who posts regularly. The total pinkbike user database is a tenth of a percent of the bicycle world at best.
  • + 1
 This is an igus advertisement disguised as journalism. I'll take the weight penalty of metal over cheap, crappy, lightweight plastic whenever it is a high stress area. Plastic is cheaper and lighter so they are trying to justify using it on more parts of mountain bikes... meanwhile your bike becomes less reliable and has increased service intervals and more cost and pain in the ass in the long run.
  • + 5
 @Protour, I totally agree this article is an Igus advertisement. However having used Igus bushings extensively at my last job for a company that made suspension seating, they are FAR superior to the shit DU bushings that normally come in your shock eyelets, and the majority of bearings you will see in suspension pivots. They are in fact extremely reliable (usually lasted 2 years of daily use) and normally cost around a dollar. Bottom line for suspension pivots, properly engineered polymer bushings will last longer, be replaced cheaper, and save you weight. This is fact.

If we're talking about cheaply made, poorly toleranced bushings... well then you are spot on. The problem isn't with plastic as a material for bushings, its with people making shitty product. Which happens with anything you buy.
  • + 3
 Its more ad than info.

If were merely informational, then Igus wouldn't be mentioned every other word. Okay, not every other word, but 10 times plus a website at the end. Of course Matt Floyd is going to have positive things to say about bushings, he works for them.

Why not ask RC about this stuff? He's been around the block a couple times, I'm sure he knows a thing or two as well...
  • + 1
 2 years doesn't impress me, I want something that lasts 10!

Do you thing the polymer bushings last as long as the slightly heavier coated metal bushings that Specialized has used? I don't see how they could be.
  • + 2
 RC doesn't help anything really. have you read his MBA stuff? i'm not sure whats worse than a review on here or the mba crap (which i started reading in 199Cool

this is strictly an advertisement. Locations with heavier loads always have bearings (for some reason) locations with minimal movement and minimal wear use bushings for manufacturers to keep costs down. it all comes down to money unfortunately!
  • + 3
 @Protour: I have a Turner Burner from '03 that is still running it's stock bushings. I bought a replacement set from PUSH and they are still sitting in the bag because when I pulled the rear apart they bushings still look like new. Zerk fittings to put a little fresh grease in them from time to time (they usually don't even need it) and they do in fact last for 10yrs+.
  • + 2
 @talderson

working for the UK distributor, we had nothing but trouble with these bushings used in a very popular Canadian brand "born on the shore", it literally killed the brand in the UK Frown


to keep it simple, they switched to allegedly inferior sealed ball bearings to save their brand from the cost of ongoing warranty problems (replacing bushings / axles / frames!!) with plastic bushings and from loosing pissed off customers to other brands...

what works in an engineering shop or lab does not mean anything on the dirty trail we ride, especially when throwing the randomness of manufacturing QC (frame alignment and pivot tolerance) into the mix - this is why they went back to bearings that pretty much all other brands use for good reason!
  • + 1
 2 years of daily US coast guard abuse pretty robust. Especially when exposed to constant salt water spray, large impacts, and large Americans sitting in the seats... I haven't used the specialized bushings, but I know I go through standard fox DU bushings in about 6 months.
  • + 1
 @talderson

I think we are talking about different applications here?

suspension pivots and shock bushings?

many of the premature wear problems I have seen with the steel / PTFE bushings commonly used in shock eyelets are also related to the poor frame alignment I mentioned in relation to the suspension pivot problems we had with the old brands.
  • + 4
 @Hampsteadbandit

I was talking about both suspension pivots and shock bushings. I am a firm believer that properly executed bushings can outperform bearings for suspension pivots. and Igus bushings are certainly better than OEM PTFE/stainless eyelet bushings (which are garbage)

As you said, many issues with bushings come from poorly aligned pivots, and/or poorly toleranced bores/shafts. My guess is when Banshee redesigned their frame to accept bearings vs bushings; they also worked on the tolerancing and alignment of their pivots.

Many bikes have premature bushing wear, but there are equal numbers of bikes which run bushings without issue. My 2004 Kona stinky had no bushing play after 4 years of abuse. Both bushings and bearings should last years on a bike before needing replacement if properly designed and manufactured. Bearings work great, but bushings are able to accomplish the same job (in this case) with less weight, less cost, and last longer than most cheap ball bearings.
  • + 2
 @talderson

good points!

the reason most bike manufacturers still use radial ball bearings (rather than bushings which the engineering / math tells us should be superior) is that these manufacturers know from real world experience that their frame vendors cannot guarantee 100% tolerances and alignment

the wisdom therefore is that its better to use an inferior, packaged ball bearing for a frame that may hit 90% of the QC targets, than using the superior bushings on that same frame

where that -10% on QC will just cause rider heartache and repeated warranty costs for the brand. Also, riders are shy on maintaining their bikes, and a ball bearing unit can be disposed of quickly and a new unit pressed in, remedying the situation

when I designed this back in 2005 of course I used IGUS bushings because I manufactured the frame myself and had control over the tolerances:

ep1.pinkbike.org/p4pb9285931/p4pb9285931.jpg


but my manufacturer in Australia insisted on using ball bearings for the actual manufacturing run because he knew the truth about QC when manufacturing high volumes of units
[Reply]
  • + 19
 Very informative. I thought a bushing was when you go off trail and get entangled in a bush. Turns out I was wrong!
[Reply]
  • + 5
 man that 0.0606lb difference is going to make a world of difference on my 38lb DH bike, where do i get them! Interesting thread, but i will always stick to bearings over bushings, the Cycling industry needs to start implementing roller bearings into more frame and suspension designs IMO.
  • + 2
 i dont aggree.. i love bushings over bearings.. not in every case.!! but the legend mk1 ran on bushings all over.. they discarded it due to wear,, but there is a guy here who found a good lube that works well with the system.
also they are cheaper.. easier to replace and dont rust.. lock up etc.
i am seriously waiting on a BB what is running on bushings.. thats a weight reduction that can be noted in the history books ! Big Grin
  • + 1
 check at Affix, they make BB. I've tried weight is amazing even if you feel a bit of a friction sometimes...
  • + 0
 In a way we have that, ceramic bearings exist now.
  • - 1
 ceramic isnt any better.. still the same principle..
i am gonna check affix, tup
  • + 1
 yeah because what's better about lighter, more durable, and lower friction...
  • + 1
 Sidermang, I agree, roller bearings have huge of potential. Devinci used them for a while, but couldn't get the bugs out. Poor tolerance between the axle and the rollers meant that dirt would get in. My chilli pepper was like a wet noodle in the rear end, even after the bearings were replaced.
  • - 1
 @ deeeight : light.. lighter.. broken . and nothing is "durable" with trials and street.. the friction i dont give a crap about..
your missing my point.. a bearing is still a bearing ! same PRINCIPLE as i said..
steel outer race.. steel inner.. when seized .. the damage begins !

if you can run a bushing, then it would be a comepletely different system.. and due to that, the weight would be less.. not making ceramic ballz and saving a few f*ckable grams..
and they cant seize.. and will never wear on your precious frame or any other parts.. Smile
  • + 1
 cyberhawk. there is a reason they dont use bushings. amount of times rotated and impact/weight forces. you would smash apart more bushings than anything. bottom brakets are designed to wear out and be a weak point so you save your cranks and frame.
I would rather break a few bearings and replace a bearing ring than replace a frame or crankset.
  • + 1
 @cyberhawk

actually the problems a very popular Canadian brand had with IGUS bushings in their suspension frames nearly killed the brand, and all of their 2nd generation frames now use sealed ball bearings with reliable results

bushings are notorious for causing wear to the bushing socket (the machined surfaces in the frame pivots) or to the axle hardware if there are any manufacturing issues with frame alignment or pivot tolerances, and once the dirt ingresses.
  • + 2
 This guy knows what's up
  • + 1
 @makripper

unfortunately your comment is true

I loved this brand (and still do...the owners are awesome guys) and actually rode for them but mainly on their earlier faux-bar bikes which used sealed ball bearings and we never had any trouble with those!

working every day selling the brand and seeing customers come back weeks or months later with ruined frames caused by manufacturing issues combined with plastic bushings was really sad...

really glad they turned it around, they have never looked stronger Smile
  • + 1
 bushings are nice and all, but there is also the running surface wear that's into play as well. add a little dirt into the mix, and the bushing acts like sandpaper. you can change the axle and fix the play .... but what if the main pivot hole gets bigger? or the hole in the swing arm? rain and one weekend of riding and that's enough to trash a frame. no amount of new bushings is gonna solve that play, huh? try changing the front triangle to fix it ... been there, done that and it's not nice.

trashed bearings are no problem. you can ride them to death, because you can replace them entirely. plus one trip to your local bearing shop/ diy shop, and your bike is ready in a few hours. try ordering 5$ worth of bushings, combined with a 20$ transport fee and 2 days to 1 week of waiting .... 30$ worth of bearings sounds nicer, doesn't it? you know .... skf isn't the only bearing supplier. the bearings made in my country cost a third of a skf bearing and are just as good ...

use bushings where there aren't high angle movements (chainstay-seatstay pivots), and bearings in main pivots, rocker arm pivots ... or stop being such a weight weenie and use bearings throughout ....
  • + 1
 note the usage of lb for a value of a few grams. psychological ploy to make it seem bigger
  • + 0
 you guys are creating problems that arent even there yet.. dirt will cause problems for everything. thats why they invented seals.. i did not opt to use bushings in every frame..or part for that matter.. just a BB would be nice,..
  • + 1
 Wear on the mating surfaces is the real problem and why no matter what IGUS says their bushings don't work in suspension pivots. I worked for Rocky Mountain when they used IGUS bushings extensively in their bikes. They had major problems with binding causing the main pivots to come undone in use, lateral play and the bearings grinding away the surrounding aluminum and killing the frame. I threw my RMB Element Race frame into the recycle bin because of this as did many others. I have no issue naming RMB especially since they don't lean from past mistakes and are reintroducing IGUS bushings in their bikes again. Bushings in suspension pivots are a bad idea any where its wet and especially if its wet more often than not like it is for any bike company located in or around Vancouver BC.
  • + 1
 @davemud

that was the same experience we had with Mythic (Banshee UK) using the IGUS bushings. Sometimes, even from new (especially with alignment issues), the bushings started "flogging" out the bored socket in the swingarm, linkage or whatever was pivoting.

There was a lot of confusion about torque settings on the pivots, some too loose (causing sloppyness / rear waggle under power or turning the bike), some too tight (suspension binding), this made things even worse.

Eventually the socket (bore) became too large for the bushing to be a snug fit, and this accelerated wear even quicker. People tried gapfill compound, glue, cutting shims from bushings and gluing, etc. but once that damage was done, the frame parts were toast. Putting in a new bushing made no difference as the bored socket was the problem. (just like crank arms that continually work loose because the axle bore is flogged out)

Thankfully they realised this and moved to ball bearings for the new production.
  • + 1
 new production ?? the MK1 was never "in" production.. there were 50 made for racers and testing..

and as i said there is still some one here who stll rides the MK1 without problems..
  • + 1
 @cyberhawk

I am not talking about the Legend Mk1. The 50 frames of Mk1 were all pre-production prototype made for riders signed to the Banshee development deal.

in my posts, I am talking about Spitfire, Rune, etc. running bushings

the "new production" I am talking about are the 2nd generation frames using "KS Link" suspension and ball bearings Wink
  • + 1
 really ! they switched hahahahahahaha i was in the middle of that so to say.. i switched to a wildcard , when i heard the axles worn down and not the bushings lol
but that does give food for thought..
  • + 1
 the wildcard and scythe were pretty bombproof (we did have a few Scythe with broken stays due to a welding issue).

The only problem I had with my 1st production team wildcard was the non-driveside bearing "socket" in the swingarm had not been machined 100% round (it was slightly oval). When bearing pressed into swingarm, it was felt rough / binded, removed same bearing, it was 100% smooth.

bike kept causing clicking noises when pedalling or pumping suspension.

took months to work out what was going on, we tried changing cranks/pedals/chainring bolts/wheels/forks. etc.

the solution was to take an old bearing and fit/remove about 20 times using force until the socket was round enough to accept a new bearing without causing binding. didn't have any problems after that...
  • + 0
 thats strange.. its impossible to cnc an oval bearing reces.. i found out during service that the lower pivot axle bore is ... how to say this.. knurled ? prob. to get grip on the axle,,
i ended up with the wildcard after some legend problems.. must say banshee itself is pretty good with warranty.. the after sale shops aint.. esp freeborn..
  • + 1
 @cyberhawk

you are right - the swingarm yoke is a forged piece which is then finished using CNC processing, which includes the bearing bore, when this piece is made initially, the bore is 100% in-tolerance.

however, the issue was that when the yoke was welded to the chainstays, they think too much heat was applied, or mis-direction of weld bead, causing the yoke to warp resulting the ovalisation of the bearing socket

if I remember, for production they started pre-heating this yoke/chainstay piece before welding, so that it would not act as a "heat sink" when the weld torch was applied, it was a rather large lump of metal after all Wink



I'd agree with your comments about poor after-sales backup from FB, in their defence they were getting so many poor QC frames sent from TW and very poor / long-winded backup, that they were doing the best they could to support customers, with very poor support from the manufacturer, they were having to strip down new frames to source parts for warranty claims, and then left with half-complete frames they could not sell Frown
  • + 1
 well they chucked my legend .. loose in a box.. and send it away.. the box looked worse than a rape victim.. and then i still had to open it for the "surprise"
  • + 2
 cyberhawk where do you get the idea its impossible to cnc machine oval bearing races. Creating bores on a mill or even races on a lathe out of round is very easy to do. That's why most blue prints include a spec for roundness. On a mill the fixturing can be loose or worn, the cutting tool dull or bent. You may think all bores done with an equivalent size cutter but that is not the case on larger bores they can be interpolated. This means the cutter doesn't simply drill a hole. When interpolating a bore the cut is done in a circular motion. On a lathe when cutting a race you can distort by over heating it, using too much pressure, dull tool, wrong tool. The main pivot bores on RMBs were ovalized by heat as with Banshee. RMB had to add a post weld machine process to fix the bore in production. Banshee likely did the same.
  • + 1
 yeah sure its possible.. but that would be one MAYOR fuk up.. wouldnt it.. ?
but you totally missed the point.. and assumptions are.............
it was a one time error on mine.. the bore wasnt ovalised.. the bearing was pressed in faulty..
  • + 1
 cyberhawk. its not a major fuck up for something to get made out of round or out of spec. All the manufacturing processes have to be constantly monitored by the machine operators and QC staff to ensure the output remains in spec. You're right about assumptions so maybe reconsider posting yours in reference to things you don't seem to have much direct experience with.
  • + 1
 getting cocky are we ? ?
[Reply]
  • + 4
 Ibis went for bearings after testing Norglide angular bushings in the eccentric links, mostly due to contamination issues. I have a lot of experience with the IGUS-bushings as shock bushings and they are susceptible to develop play, mostly due to contamination by dust and sand. Also, I am not conviced by this type of bushings when the movement is largely back and forth like a shock linkage (with small angular movements) as they develop play pretty quickly. With low speed, low impact rotational movements they probably work a lot better. Just my two cents.

I have a lot more faith in the zerk-type lubed bushings used by Turner and others.
  • + 4
 I agree 100%. The plastic will flex and deform due to the high amount of pressure exerted on a small surface area and just as you said create play. Ceramic is a possibility with the proper coatings but so far needle bearings seem to be the best way achieve long lasting consistent rotation.
  • + 3
 Simenf- you hit the nail on the head. The resistance of a material/construction to a certain direction of the force acting on it is crucial. I hope that people comparing bushings in frames to those in forks are not experimenting with building their own houses from wood.

Ask Bike mechanics and Keith from Banshee whether the decision to move from bushings to bearings was a move by marketing or customer service department.
  • + 1
 @WAKIdesigns

could not have said it better myself

it was a tough lesson for Banshee because "on paper" the bushings were ideal, but as a bike mechanic (technician) will always tell an engineer, what works on paper does not mean much in the real world

Keith was smart enough to understand this lession, and the brand has definitely benefitted from the K.S. Link and ball bearing redesign
[Reply]
  • + 3
 I ride a 2009 Devinci Wilson. First year ( 2008 ) of the former platform used bushings rather than bearings mainly for weight benefits. Unfortunately the bushing technology employed did not withstand the rigours of mountain biking and would develop intolerable play in less than a year of normal usage.

Devinci had to return to bearings in subsequent years. I would be curious to see igus specific technology for the same application.

Btw, the beast way to significantly increase bearing life is to never wash your bike with pressured water Smile
  • + 3
 You are correct. I have experience with those frames, and the bushings along with the design they employed were in poor taste. Not all 'plastics' are equal. Them along with banshee and RM helped pave the way for bad feelings towards bushings. Nicolai does it right though, and having experience with their pivot set ups, I've yet to see swingarms that stay as smooth and solid as long as they do. Needle bearings or IGUS bushings are great, when done right.
  • + 1
 The other way to increase bearing and cable life is to never use any kind of soap, detergent or bike wash to clean your bike. It goes without saying but I will any way not to ever spray or mist degreaser of any type on it either. They all strip lubricant and increase wear and tear in a shorter period of time.

The best way to clean a bike is to dry clean it with a wisk and then wipe it with a misted cloth on the heavier soiled areas. A bike only needs to be functionally clean unless of course your more concerned about how it looks on your Porsche at Starbucks than how it works on the trail. Big Grin
[Reply]
  • + 6
 Been testing plastic bushings and they're good, not much friction, last pretty long, but I still prefer needle bearings Smile
  • + 3
 yeah, feels way smoother. quite a surprise how my XC bike feels 'more active' after using needle bearings.
  • + 2
 I installed the RWC needle bearing shock kit on my Santa Cruz Tallboy C a while back. I can say the bike tracks much better over everything and actually feels stiffer. I don't buy into the plastic bushing hype. I had a 2001 Klein Adept Comp that used ceramic bushings and it was pretty lackluster on the back end. Rode a 2013 Intense Spyder Comp 29r with the new plastic bushings and my TB still felt more active and this was after lowering the shock pressure on the Intense.
  • + 2
 Yup, RWC needle bearings totally win. I'm shocked this isn't more broadly adopted for all high rotating pivots on a shock. It is the single best upgrade you can make to your rear suspension. I've had them on two bikes now. Unbelievable difference! Sorry bushings, I just don't buy it.
  • + 2
 The thing about test bikes is they never have a normal life span. They get used for whatever period until the next generation is ready and then either discarded or passed along. If the tester is a pro rider they may get more miles in a concentrated period than normal consumer bikes but they also are under the care of a factory tech during the test period.
[Reply]
  • + 3
 On my Banshee Spitfire V1 these bushings were not long lasting and I got wear issues on the frame... Not a fan of them for pivots exposed to dirt. Worse than ball bearings there. Eventually they are better for shock eyes than teflon coated metal...
[Reply]
  • + 3
 The best thing about bushings is that they are simple. This is the reason they can be small, light and maintainance free. Bushings have also a larger area to which any force is aplied that's why if there is a pivot that should hold a large force, the bushing is better than bearing, like in pistons mounting in car engines. However if bushings were really better in reducing friction than bearings, we would all be moving on sleighs rather than wheels.
[Reply]
  • + 2
 Big impact with no rotation, ie suspension pivots, bushing are better. They spread the load/impact and will last longer. Bearings will feel great for about ten minutes or till you hit something fast and hard. Why do you think there are so many bearings in a rear hub. The Teflon bushes in my rear triangle are still mint after 3 years of hard abuse but the scb a buggered every 6 months. The only exception is the fox du bushings on the shocks absolute rubbish. Get heavy duty plastic /steel pin kit million times better. If it spins scb if not bush that's my rule
[Reply]
  • + 4
 It would be great if the article was split in two:
1. what bushings are, where are they used etc
2. who we are and why our ®® bushings are the best in the world
[Reply]
  • + 2
 I was really confused why my Karpiel Disco Volante didn't have bearings and just gaping holes through the pivots, but then I found out about a month ago that they were bushings...my frame was built around 2001. Finding new replacements is hard though. Not many places that do the exact measurement I need. - Even on Igus..
[Reply]
  • + 2
 Can I fit iglide® plastic bushings to my Intense 951 FRO and Commencal Meta SX or have I missed the point? It's very wet and muddy over here and I have to replace the bearings quite a bit on both bikes. Wouldn't mind trying it out and seeing if they can last a season.
  • + 1
 Kron, you would probably have to custom make spacers to fit. And I mean FIT. The best material would be stainless steel, and they would have to be highly polished.
  • + 2
 Cheers foghorn! 'custom make' sounds like it could be a lot of effort and expense just to see if something eventually pays off, it it was a fit and forget part then I'd be dead keen, I'll keep greasing and replacing the bearings.
[Reply]
  • + 2
 I've used Igus stuff before when I worked at a CNC shop, building CNC routers. we used their plastic cable track and bushings else where in the machiens we built. I can say Igus knows their stuff.
[Reply]
  • + 1
 I am Matt Floyd, the "Bicycle Industry Specialist" for igus, Inc. I know I am late to respond to the article and comments. The discussion has been very valuable to me, both the good and bad comments help me to better understand the issues and perception within the industry with our technology. My purpose here is to offer additional information or answers to some of the points and questions brought up.

Also I would like to offer free samples for those interested to try us out. Please let me know of there is a product you would like to try out or an application you would like parts for . I will be happy to give technical support on the application to ensure we match you up with the correct materials and sizes. I would like to do this off the forum and you can communicate with me via email or phone from the link below (I'm the guy covering HI & AK) or you can send me a msg via pinkbike and I will respond at my earliest conveniences.

www.igus.com/default.asp?PAGE=61&STAT=US&FILT=5#601

Once again, thanks for the participation.

Igus Cycle industry Link
www.igus.com/wpck/default.aspx?Pagename=bicycle_design
[Reply]
  • + 1
 I'm an aircraft mechanic. I deal with bearings & bushings all of the time. Roller bearings are for high pressure & rpm applications. Bushings are for high or low pressure & small or slow rotational travel applications. Bushings must be cleaned & lubed often because of the lack of protection from foreign debris. Sealed roller bearings are the opposite. A worn or seized bushing will tear stuff up, like a pivot boss. A worn roller bearing tends to wear itself & the bolt or pin that is riding through it rather than the boss or mounting structure.

I don't see how plastic can be better than metal.

This article is obviously an infommercial
[Reply]
  • + 1
 Self lubricating bushings are cheaper for manufacturing, last longer, stronger, lighter, etc. Dont know why more companies arent using them in components like pedals and hubs. The bmx industry already started and having great success in keeping weight and prices down with bushings over bearings that wear out fast. I own some Straitline Amp pedals with the tigus bushings instead of bearings. Those are the best a.m. pedals I ever had and can see why even high end companies are switching to bushings. Small bearings wear out too fast. Specially in the rear hub. Companies pack 6 puny bearings in there, all it takes is one to fail and your creaking with every crank. Bmx hubs all using needle bearings or polymer bushings. First Mtb company to do this will own the market, I looking at you King or Mavic. Need a mtb hub with polymer bushing and straight pull spokes.
[Reply]
  • + 4
 no bushing company is going to give you an unbiased picture of the benefits and disadvantages of bushings vs bearings.
[Reply]
  • + 4
 I'm confused by the advert versus comments, Shall I buy igus® or just ride..
[Reply]
  • + 5
 Great article, but how does this information help me get laid?
[Reply]
  • + 1
 I'm using Igus bushings in shock eyelet more than 6 months without a problem. DU bushings usually lasted about 2-3 weeks on my bike.
I use this one, it's industrial grade (so no bike bullshit)
GSI-0809-08 iglidur® G, type S is the right one to order (0.90€/pc.)
[Reply]
  • + 4
 Bearings > Bushings. Always.
  • + 0
 Because "Ball bearings usually have a minimum travel distance in order for the balls to begin rotating inside of the bearing", The choice is obviously Bushing > Bearings. Metal skidding against metal doesn't sound too good does it?
  • + 2
 metal skidding against plastic doesn't really tickle my pickle either. I suppose its just a rider preference that we have to try out for ourselves
  • + 3
 Technically, both are 'bearings'. The right answer is bearings = bushings. Just depends on the application. Sometimes a bushing is better, sometimes a bearing is better. It's up to the engineer/designer to make the correct decision and sometimes it's done right, most of the time it's a simple cop out by copying what others do. What is a problem though, is the continued use of ball roller bearings in pivots. Ball bearings are designed to spin 360 deg, not rotate 15 deg with high frequency. You will not see bearings used this way in any other industry that expects any sort of respectable service life out of it's product (I'm in aerospace and defense, for instance) but bike designers feed this to the masses and here we are replacing bearings every winter. It's been my gripe for a long time now as the explanations for their use are erroneous in most cases.
  • + 3
 Exactly... somehow actual real world data goes out the window when bicyclists get involved... and what is REAL and known in airplanes...someplace the tolerances and need for durability is much greater... need to be retaught to bicyclists as if they are five year olds, over and over. Some bicycle companies put the money into R&D with their pivots (Rocky Mountain went from bushings, to bearings, and then back to bushings again) and others just copy everyone else. And yes a kit of the rocky bearings is expensive, more so than using generic cartridge bearings would be, but if you try ordering a full bearing/pivot rebuild kit from say Santa Cruz, for one of their bikes, they ain't exactly cheap either (the propack kit for the tallboy is $151).
  • + 3
 Atrokz, you can get the most out of your bearings by removing them after a few months, and rotate them 90 degrees. This spreads the wear on the races. Oh and yes you will see bearings used "this way in other industry". It's all about not undersizing the bearing which happens way too often.
  • + 1
 Since my latest bike relies on them, I have been running SKF bearings which helps, and I do know that 'trick' and that's good information for people to have. Doesn't help though, that they are just simply not right for the application. The only industries who use ball bearings for the types of loads they are subjected to, are doing it wrong (there are cases like the SB66 pivot, Ibis' new design pivot, etc, that are applications where it makes sense though). There are literally dozens of bearing designs that better serve a swing arm pivot, but this is the absolute cheapest way to do it, as you don't need to worry about tolerances like you do with bushings, nor do you need to worry about axle shafts as if you're running needles on a hardened shaft, or radial bushings to take the axial or moment loads, etc. I played around with angular contact ('tapered') needle bearings (think: a car's wheel bearing x2) for my last design, and the cost was $150+ per bearing.... So, it all boils down to cost, not what's 'right'. Now that IGUS is paying attention to this industry, we should see more options coming though. Check out Nicolai's that roll on bushings. You'd be supprised how much better a bike feels when done the way they do it. Needle bearings, Bushings, and ball bearings all used where needed depending on the application. After THREE seasons of use and only a greasing once a year on the needles, they rolled like day one with zero binding. I sold it and the guy is still rocking it from what I see.
[Reply]
  • + 1
 I go through 1 set of $150 bushings a year on my Rocky Mountain and have to order them from Canada. But they are made in Germany, that's practically next door. So where can I order some bushings in Germany?
  • + 1
 in any roller bearing store where you can find bearings for cars and motorbikes Wink the bearings usually are standard
  • + 3
 I'm not looking for bearings, I'm looking for the IGIS bushings in my Rocky Mountain Element frame. The ones that are discussed in this piece from Pinkbike.
  • + 1
 In the Igus webshop
  • + 1
 Those RM bearings are custom made for them so you're not going to find them elsewhere.
[Reply]
  • + 1
 The only thing I want to know is which iglide material they recommend for DU bushings. The article referes to G300, but playing on their website, it seems maybe the J material might be better?
[Reply]
  • + 3
 what about needle bearings instead of bushings in the eyelets of a shock is that ok for downhill?
  • + 2
 Look up the retrofit kits made by Real World Cycles. www.enduroforkseals.com/id275.html
[Reply]
  • + 2
 interesting article. would love to try out some plastic bushings! what they said about metal bushings I completely agree with and have seen it first hand
  • + 1
 Agreed. I want to try one exactly as shown in the photo - the shock eyelet bushing. They are one of the first things to wear on every bike I've ever owned.*

Test this on Pinkbike Product Picks and tell me how to buy some.

*Except the hardtails Smile
  • + 1
 Fox shocks now come standard with low friction plastic bushings...but you can purchase a retrofit set from www.mojostore.co.uk/acatalog/Fox_Rear_Shock_Bushing_Kits.html .
I replaced them on my DW link bike and the improvement was night and day.

That said my Turner frame has igus bushings too Smile
  • + 1
 man, yeah i just have not forked out the money for them. mainly because i would rather just buy a new bike now. However for my dh bike is another story. Can you run the fox bushings on a rockshox vivid air?
  • + 1
 How does the "new type (low friction plastic bushings) of Fox shock mounting hardware" work?
[Reply]
  • + 1
 Fuck bushings!! I have had to buy 3 sets a year for 46 pounds. Bearings I could get from my local hardware store
[Reply]
  • + 1
 I'm all over the idea of bushings. Rear-suspension maintenance is one of the main reasons I went back to a hardtail.
[Reply]
  • + 2
 ufff stone dropped from my heart they are manufactured in GermanyWink
[Reply]
  • + 1
 I love the V brakes on that bike. Works well with pulling suspension Big Grin
[Reply]
  • + 1
 The lesson is: use an appropriate bearing for an appropriate application.
[Reply]
  • + 1
 Nice article but looks like a comercial ad
[Reply]

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