Ask PB: Zero-Extension Stems and Air vs. Coil Suspension

 PB standard response: the shorter the better for stems, just make sure your bars are at least 800 mm.

 I had Vector expert bars on my BMX race bike in the late 80's. They had a quill stem but the bars were welded right to the quill giving 0mm reach. there was a slight angle to keep the bars rising vertical. They had about a six inch rise. They were definitely lighter than a bar-stem combo, but they also handled strangely. Much like if the front tire was skipping along the ground and never really digging into the turns. Like most trends and innovations in mountain biking, there comes a point of diminishing returns.


"http://bmxmuseum.com/forsale/9806"

 @ChampionP I hear you. A zero reach stem is a bad idea, no matter ow you look at it, especially for a BMX. The deal is, the tires on bicycles are not that heavy and the momentum they keep is not that high, causing a lot of bump translation to the handlebar. As you said, the feeling that the tire is actually not touching the ground sounds like a perfect explanation.
XC has longer stems for control because of, you know DH has shorter fr quicker turning and better response, but there is a limit.

 I've got one of the 10mm stems on my Foxy XR, and while it does look a bit odd when you are side on to the bike once you are on and riding it...
a) I doesn't look crap at all from that angle.
b) Makes the handling awesome with the 800 wide bars (once you are used to just how much leverage you have!).
c) Just ignore the haters as you whip off into the singletrack!

 at some point won't lots of people wish they had more reach adjustability than 0 to 30 mm?

that's part of the reason modern geometry is desirable -- with 80-40 mil stems you can actually fit the bike to your weird body. I somehow doubt that a few frame sizes can account for all the bio mechanical differences from person without being able to adjust reach and stack with stems and spacers. but since even this is an imperfect pseudo-science...I hope I'm wrong. I'm no sports scientist...just a bike rider.

with bikes like the summum...you have one shot at making the fit correct and buying the appropriate size...can't shorten the freaking top tube.

we can't all afford to make these sorts of mistakes---however a pro rider like Ragot gets a fit and a new frame if need be. doesn't have to worry about the grand or so they just wasted.

 Here's a better 0mm stem design.
Also sporting some super short chainstays!

i.imgur.com/okIJr2j.jpg

 This does depend a bit on where you are at in your riding style, but the general rule is that the stem is a bike handling device and not a bike fit device.

 Well... just from my own practical experience, a stem does have a huge effect on bike fit....and my handling changes from bike to bike, accommodating that particular stem, within reason of course.

 Also depends on the bike and the style of riding.

 Pinkbike standard stem comment: put 800mm bars and the shortest stem possible on whatever bike you got.

Even if it's an XC/Trail rig and you're not descending like a madman. Even if it's a trIAls bike (oh the comments on Lenosky's bike post!)

Even if the reach is too short because most bikes are too short.

Even if the person has narrow shoulders.


*sigh*


It's the equivalent of roadies saying slam that stem.

While there's a reason it's popular and there is value in it for many, the gross generalization needs to stop because there are many riders (or rider/bike combinations) where it's a bad idea. There is no one size/approach fits all when it comes to bike fit.

 Well, im going to try a 20mm first i reckon, seeing as how the RSP stem im currently on is 50...

 @dontcoast It's a common complaint because bikes are still coming off the showroom floor with 80mm stems & ~700mm bars. most riders will have a better experience with bars wider than that, & if you specc something wider, it can be trimmed later, but you can't make bars that are too short longer.

 I did make the disclaimer about riding style. Most XC guys feel comfortable locking their shoulders and elbows trying to consentrate on making perfect circles... so yeah, long stem narrow bars makes sense for that riding style, because they are actually turning the bars and not leaning. They "need" the stability of a longer stem.

I personally run an 805mm/40mm bar stem combo and a dropper on my XC hardtail single speed. Every corner I go into is with my seat dropped, leaning my bike, steering with my hips, ripping it as hard as I can. Seeing as PB is a more DH/Enduro specific site, they are typically spot on with recommending wider bars/shorter stem on bikes to open up the potential for this riding style.

 Well...most of the top xc riders I've seen are very fluid and still lean a bike. They hit jumps, rock gardens and turns at speeds that many would be scared to ride on their 160mil trail bikes. They might lock their shoulders and elbows sometimes, but usually use their arms to absorb shock. A bar can be too wide, a stem too short, a combination thereof terrible or excellent for an intended purpose.

So I just try to stay away from predefining what I will do, because so many things change all the time. I mainly want to be comfortable cos I ride a fair bit. @Thustlewhumber 's 805/40mm combo might be perfect on another bike, but not my current trail bike and trails. Cheers!

 "If you keep up on maintenance"

This is something people often forget. Don't run your shit in to the ground and then complain it doesn't work people!

 It's just like buying a brand new car, not putting any gas in it and then complaining it doesn't want to go forward...... Some people, I tell you man!

 I just bought a brand new bike and put gas in it and it still wouldn't go faster on the uphills. Felt heavy too.

 @grgsmith: I think you put in the wrong type of fuel. Make sure you put in UNLEADED fuel and not Diesel.
That could be your problem.

 @GOGRANDE How often do you have to do oil changes and servicing? I have a Marzocchi 55 RC3 and barely ever have to change the oil, its very reliable. I've heard stuff about fox maintenance and their crazy intervals on the manual, but how often do you really have to service them?

 Also not addressed in the article: get the right spring for your weight. If the fork is "giving you hard times" there's a good chance it isn't set up right for you. A coil fork with a too light or too heavy spring is going to feel terrible. (Well, too light might feel great until that first drop...) The correct spring should feel amazing. It's also much cheaper to try a few different springs before shelling out $1000 on a new air sprung fork for the Evo.

 @Revanchist it really depends on what you ride and how much. I crush the parks all summer and ride aggressively. I try to aim to service every 6 months because I ride a lot. I think for a lot of people once a year before the riding season starts is enough.

 If they sucked you wouldn't see em on pro level DH and EWS bikes.

 Coils are underrated. They are so easy, buy the right spring kit adjust the preload and rebound rate and you're done! Air fork seem to be continuous fiddling with pressures and you never seem to get it just right.

 @jaame all forks and shocks need to be serviced at the same intervals.

 This is going to go against everything that PB'ers rave about - like buying the most high end $$$$ and latest tech etc etc. But low and midrange coil shocks (and we're talking real life mid-range, not PB midrange) are surprisingly maintenance free. You can get away with never servicing them, and they can still work pretty damn well. Sure they perform a bit better if you service them every 2nd ride, but even if you never service a low end coil, most usually stay quite ridable - maybe not butter, but soft serve ice cream. Try that with a rock shox monarch, and well...kiss fun goodbye.

 ^^ best insult

 Thanks fatenduro. I replaced a monarch plus rc3 with a DSP dueler at approx half the price. Monarch had to be serviced twice in the first three months, kept losing rebound damping and developed a click on compression. I sold it after a year and three services. The DSP has now done 3 years and two sets of bushings without a service, and still works close enough to like new for me to not notice. Also my marzocchi dj has had one service in five years, which did not make any discernible difference to performance. Air shocks are easier to set up for weight, but are not as sensitive. They are lighter, but in my experience at least they rarely work properly and need servicing too often. Service isn't a problem if your're a pro on the black box program but I'm not.

 @jaame.. Because it doesn't really matter if you're telling the truth.. The neg button is a one-shot pistol for keyboard cowboys, with no repercussions. So you're bound to get shot every now and then. I applaud you for getting negged. Loving the 'bunch of bananas' too, very descriptive.

 IMO.... Air shocks need servicing roughly every 12 seconds of riding....

 Feel free to disagree, but according to Craig at Avalanche DHR, tons of pros run air fork bodies with coils swapped in, because they want the coil feel, but their sponsors want to show off their high end air forks that their customers buy. and apparently fork makers like air forks so much because that means they don't have to stock hundreds or thousands of 3 or 4 different weight coils for each fork that they make, in each distribution center in every country they service all around the world. that's millions of dollars of parts lying around when an air fork doesn't require any of that. so, according to Craig, it's purely a matter of economics, not performance

 Sounds about right. Isn't it always about economics? (Read: the bottom line)
On another note, you've just outed Craig as the cycling industries Edward Snowden.

 heh- he's pretty open about his feelings about how the industry operates, but he also wouldn't have a job if these fork manufacturers weren't so terrible at theirs

 ... and then you get your new coil fork/shock and the stock spring is too stiff so you buy the slightly softer one and you bottom out all the time so you're stuck between a rock and a hard place, leaving you unsatisfied with the bike. Air is really cool for that, especially when you need to adjust it on the fly.

 That's what the preload is for. To be fair I have only have RockShox springs but with these a medium spring with the preload wound right off, is about the same as a soft spring wound down 2/3 on the preload.

 Pro riders have mechanics and an unlimited supply of parts. So yeah if it only had to last one race run or a weekend then yes run air for the weight saving but in the real world you want coils. Way more reliable, take way more abuse, service less often and work better.

 Like I said, air works very well fresh off a service. Five hours later... Not so well.

 I think it's ridiculous to generalize so much over coil/air. Maybe if you run a coil marzo fork its going to feel great forever with 0 maintenance but my rockshox coil forks only feel fresh for like... one run and the seals inevitably start barfing oil after barely a few days riding. Meanwhile, my F36 fork has a pretty consistent feeling and can be ridden quite a while before it shows signs its ready for maintenance. I'm not sure I could say the same about the 32s though.

 I put a Talas 5 cartridge in my 2011 van rc2 and I it feels great. With all the negative spring advancements air is feeling pretty good!!!

 Cost is about $260... but I bet he needs a rebuild

 This is usually not advised as the coil spring wears the inside of the leg and provides a sub standard surface for the air seal to slide against. Air to coil is fine, but the other way isn't recommended.

 However the new Talas 5 is a separate drop in cartridge and does not seal against the inner part of the stanch tube. Also, do not forget to remove your hydro bottom out in the damper side or you will not be able to achieve full travel. Now if you wanted a float then you cannot do that because it seals against the inside of the stanch tube.

 What about the Marzocchi air assist on 2006 dirt jams and so on. The same is on the Manitou Circus Expert, not an air cartridge, but air cap to put some psi in the leg to help out with damping. I'd try and just put one of the suckers if it would fit the thread. Just my too sents

 Good Answers.. Lame Comments...

 Lame good.... comment answers.

 Good lame answer comments.

 The first two were good but it looks like you are just fishing for props 2020.

 Cracking answer, I now know more than i did at start of today...

Good comments too.... mainly

 Good point, don't know if it actually works but its not a bad idea

 It definitely works, since the steerer doesn't care where the bar is mounted, only where your hands are applying the force. The physics would be identical, but it's possible some people just wouldn't like the feel of the back-swept bar fit-wise.

@wobbem but what if you need your hands BEHIND the bars, like on this speed demon???? goo.gl/ezCGdo

For real though, there are limits to the benefits of short stems. I think if you're mounting the bars on top of your steerer with these hideous high-rise stems you're probably about at the limit. Do people care so much about getting the "feel" of a 10mm stem, but somehow don't care about the feel of raising your bars upwards by an inch??

 I use a 9* back sweep flat bar on a 35mm stem, its ends come up about 10mm in front of centre of steerer.

 The only reason that would take a ton of effort is because your 10 ft stem and bars would have a ton of mass and a huge moment of inertia. Since there's effectively no difference in mass or moment between a 40mm stem with backsweep vs a 10mm stem without, the rider would feel no difference. For leverage and steering speed, what matters is the vector from the hand to the steerer.

 However much backsweep there is on the bars, the handling would be affected at where its anchored (ie: stem), wouldnt it?

 Eh, that's a tradeoff that people already make (compare techy climbing on say an SB5 and a XC-trail 29er full squish bike ). On the all mountain super bikes there is much more tendency for the front to lift and it's harder to track straight on very steep climbs.

These ultra short stems just take it on step farther (so yes you are right).

 coils are so awesome that you don't need to do anything.

 I have a feeling it's done with the compression damping cartridge, but I'm far from savvy about suspension. Maybe someone will elaborate or possibly shoot me down for talking rubbish.

 Actually.. I prefer eoin-j's reply.

 Higher end coils usually allow you to add high speed compression (bottom out protection) without compromising small bump sensitivity.

 There is such a thing as a rising rate or progressive coil. That alone can provide a softer more responsive feel in the early stages of travel while requiring more energy as you get deeper in. There are pluses and minuses of course. Check this out if interested.

automotivethinker.com/suspension/linear-vs-progressive-rate-springs

@justincs : It's really "the damper" or shock absorber (there inside the spring) that's going to provide low or high speed compression adjustment as well as rebound and ramp up or bottom out (if so equipped). The spring is a static (non-adjustable other than preload) part of a coil setup that is affected by fine tuning the damper.

 I understand that, but the higher end dampening cartridges give you the ability to tune the fork such that it can remain quite plush without bottoming out, not exactly the same as rising rate, but I think better overall for higher speed/ rougher trails! The fact that most coil applications are linear and newer air systems are trying to achieve a more linear feel suggests that a more linear spring rate has a greater advantages for most riders!(maybe that's why I haven't seen any variable rate coils available for bikes) I can understand if you require more front end pop for jumptracks, or slopestyle, air forks will give a bit more pop, but a good coil fork using maybe one spring weight higher should be able to achieve the same outcome. just my two cents!

 I'd disagree with you there justin, most people seem to be looking for less linearity in their air forks, reducing volume to get them more progressive. As for using the damping, you can do that on an air fork, but I'd rather use as little damping as I can get away with...

 @justincs : I suspect the reason many (producers) prefer a linear rate on the spring is because it's more difficult to get a damper to work well at all points in the curve for a progressive spring. So why bother when you can use the damper or absorber portion of the unit to tune ramp up and compression.

That said, I agree completely about the offerings of higher end cartridges. I too prefer to set up (or try at lest) my stuff to be soft in it's initial travel then ramp up. I like a rather dramatic ramp up I supposed.

 Fer shizzle! It's actually Cesar Rojo that did the bulk of the work there.

www.mbr.co.uk/how-to-2/tech-advice/mondrakers-forward-geometry-explained-323495

I like that the article points out that you can't just slap a short stem on a bike and call it good. Guys like Mark Wier went up a frame size then reduce the stem length (www.pinkbike.com/news/Mark-Weir-Bike-Check-2012.html). And that's the forward geo stuff in a nutshell. Increase the length of the front triangle then reduce the reach via the stem.

 In other words: pushing the wheel forward without using crazy headangle like 60°. Well who knows, may be we get 60° on trail bikes 5 years down the road... Some DH bikes already have this value I think.

 I think the slackest out there right now is the Scott Gambler. It comes with adjust-ability and is capable of being set at 61 degrees so pretty damn close to 60 there eh? :-)

But there has got to be a limit to how far out you can push the front wheel in front of you before traction (especially in fast sweepers) becomes an issues. You have to have weight on the tires for them to work after all. ;-)

I do remember Rob Warner during a World Cup broadcast stating that Brook MacDonald actually put a 50mm stem on his Mondraker to help get better traction out of the front end. I don't know if that helped or not.

 @BDKR

Thats exactly my thinking.....

My frame is an L, and tried a M, it just didnt feel right...

 @BDKR: I think the Gambler can also be adjusted +-2 degrees, which would mean down to 59!
I think Fairclough rides with 60.