Ask Pinkbike: Wide Rims, Coaching and Skipping Chains

Mar 31, 2015
by Pinkbike Staff  
Ask Pinkbike Header

Here at Pinkbike we get inundated with all kinds of questions, ranging from the basic "Can I have stickers" to more in-depth, soul searching types of queries like if you should pop the question or what to name your first child. Ask Pinkbike is an occasional column where we'll be hand picking and answering questions that have been keeping readers up at night, although we'll likely steer clear of those last two and keep it more tech oriented.



Wide Rims Worth it?

Question: Pinkbike user sevensixtwo asked this question in the 29er forum: I have a question about rim width on 29ers: I'm wondering if an upgrade from a rim with a 19mm inner cross section to one with a 24mm width be extremely noticeable? I currently ride 19mm internal width Easton EA90XC wheels, and my tires are all 2.2 - 2.35'' wide. I usually use Schwalbe's Racing Ralphs for cross-country racing and Nobby Nics for fun. Thanks!

bigquotesThe short answer is that yes, it will be noticeable, but only if you take the time to experiment with the slightly lower tire pressures that a wider rim allows you to use. This is because of the extra support the wider rim provides, and you should be able to drop 3 - 6 PSI depending on how you ride and your local terrain. This will make your bike feel more forgiving, almost like you're running just slightly softer suspension, and you'll also have more traction. Start by dropping 2 - 3 PSI and continue until the tires begin to feel vague in the corners from casing roll, then go back until that feeling goes away. Also, watch for burping. - Mike Levy

Sea Otter

A wider rim provides more support for the tire, allowing you to run less air pressure for more traction. On the flip side, it adds volume to tires, so cross-country racers could use a skinnier, lighter tire without the usual drawbacks..






Chain Skips on the Smallest Cog

Question: Tfree asks in the All Mountain and Cross-Country Forum: So, I took my one-by-nine setup off of one frame and installed in on a Stumpjumper frame that I am looking to sell. I tuned the derailleur, and when it is in the smallest cog, the chain skips - even with hand pressure on the pedals. I never had this problem when it was on my other frame. It rides smoothly and shifts great in all other cogs but the smallest skips like crazy. Any help would be great!

bigquotesI assume that you know how to tune a rear mech, so I won't bother with the proper chain wrap speech. Normally, an 11 or a 12-tooth cog skips under load when either the sprocket teeth or the chain are worn beyond their service lives. The slight mismatch between the length of the chain and the width between sprocket teeth compounds until the chain jumps a tooth and then the process repeats. Unless you replace your chains often, both the chain and cassette tend to wear evenly, so skipping is rare unless a new chain is installed on a worn cassette.

I read in a following post that you used the same chain on the new bike, which should have produced the same skip free performance as before - unless you flipped your chain upside down, which would make it behave like a fresh chain and skip like mad. Try flipping it around. and if that doesn't work, the culprit may be that your Specialized's chain line is too far inboard and you may have to space the chainring or the crank axle outwards three or four millimeters to get the chain to run smoothly over the outboard cassette cogs. - RC


Tech Tuesday
The rear derailleur setup in this photo provides the maximum amount of chain wrap, so if the chain skips over the small cog under load, the culprit is probably a worn chain or cog. In rare cases, a bent hanger or a bad chain line can cause similar symptoms.




Skills Coaching

Question: Pinkbike user AlanP asked this question in the All Mountain, Enduro & Cross-Country Forum: Hi, can anybody recommend any skills courses at intermediate/advanced level? I'm looking to improve and gain confidence in jumps, drops, speed, flow. I'm happy with most black trails at trail centers, but less confident when things get a bit gnarly and I lack confidence to use speed in gravity enduro racing.


bigquotesWell, considering your location in Birmingham, current riding level, goals and the enduro racing aspect, there's a brace of local options: Choose from The Bike School or Neil Donoghue Coaching.

The Bike School offers courses at Cannock Chase and Sandwell Valley as well as as guided trips out to Snowdon in Wales. They use three different instructors including Adam Halling who has been exploring the Chase for years, who is also an Elite level enduro racer and fitness trainer, so don't bother trying to out-sprint him. They offer varying types of course but a specific "Jumps and Drops" course is available. A 3-hour course runs between 10am and 1pm for 35GBP with a maximum group size of 6, so you can get all the help you need directly from the coach.

If you want provenance, Neil Donoghue is an ex-World Cup downhill racer, now spending his time as a fully qualified coach who still races enduro at the highest level. Two time UK Gravity Enduro champion and all round nice guy. A little further afield, Neil is based in Shrewsbury and offers skills courses and guiding at Eastridge and Coed Llandegla (as well as some more exotic locations), and also offers a specific "Jumps and Drops course". A full days coaching starts from 110GBP, and includes a video analysis, food/drinks and a USB stick with all your pictures and videos from the day to take home. - Paul Aston

OLYMPUS DIGITAL CAMERA
He's called 'The Don' for a reason. World Cup riding speeds, coaching skills and the ability to transform your riding.



Have some unresolved tech questions? Jump in the Pinkbike Forum and we'll look to answer it for next time.


69 Comments

  • 215 7
 So I'm starting up a new bike company. It's gonna be called "Sixer Bikes". We're currently testing advanced new prototypes of bikes with 26 inch wheels. We've found that these wheels provide a snappier and more fun ride compared to industry standard 27.5 or 29 inch wheels, and we feel there is a market out there full of people who just wanna have fun (not only girls just wanna have fun), and will jump on this new technology as soon as we can make it available. We're in talks with tire and fork companies about bringing back some old designs we found from back in the day when apparently the 26 inch wheel was widely used. We hope to launch at Interbike 2015, if all goes well. Just try to hold out until then...fun is coming!
  • 20 3
 ...yall catch me in Crested Butte, Colorado rippin some summit top freeride--peace
  • 11 40
flag mnorris122 (Mar 31, 2015 at 18:27) (Below Threshold)
 Ok cool enjoy
  • 21 2
 @ ctxcolor I already have some 26's and they are the most fun I can have with my cloths on.
  • 2 0
 @ctxcolor I'm down for shredding down the summit of Castle peak or Teo with you
  • 2 0
 Hahaha haha you just made my night!
  • 16 0
 take my money
  • 9 0
 I just sold all my shit, I must buy one of these sixers as soon as posible.
  • 25 1
 They roll better than a 24" or a bmx and more agile than the regular 650b.
  • 10 48
flag PLMedia (Mar 31, 2015 at 22:15) (Below Threshold)
 this seems like a bad business idea. the only people that like 26 inch wheeled trail bikes are people that are still riding 2007 kona stinkys and wont buy a new bike anyways. who would want a bike that is way rougher in washboard or any small bump, has less traction and rolls slower than 650b or 29er. I don't know anyone who would spend money on a new bike just so they can still be slower than their friends, even if you can do a neater tweak air off a root or skid around a corner better.
  • 4 2
 But they don't accelerate anywhere near as well as a BMX or 24", nor are they anywhere near as light, strong or agile.
  • 4 1
 true lets make 20in mountain bikes
  • 2 13
flag Matt76 (Apr 1, 2015 at 13:42) (Below Threshold)
 26 is dead. Dead as a dodo, dead as a T-Rex, dead as Jimmy Hoffa, dead as Micheal Jackson so let's get over it and move one. Come on let's all look on the brightside....we have 27.5+ to look forward to.....yaaaaayyyy!!!!
  • 6 0
 @Matt76 But i don't want stupid fat wheels i want the good old 26
  • 2 0
 I was being sarcastic. I'm as fed up as anyone else with all these different wheel sizes.
  • 2 1
 It's funny because I was staunchly opposed to 29ers, until I rode one. 26 is good for dj and pump track, but for trail riding, I'll never ride a bike with 26" wheels again.
  • 3 0
 I've had a 29er trail bike and now got 650b one. Even though I really disliked the 29er it was so much faster than the 650b even though the 650b is a much better bike to ride in terms of putting a smile on my face. I'm proud to still own a good old 26er and that provides the biggest smiles. Smiles is what mountain biking is all about and for that I will never own a 29er again!
  • 1 0
 @ Matt76 Well said. The 26er will never die.
  • 1 0
 Sure 29 and 27,5 and what ever is faster and so on and for those people who wants that go ahead i don't mind but 26 will always make me happy the same way as @Matt76 says
  • 37 0
 I mean I learn new things about bike all the time, but "flipped your chain upside down, which would make it behave like a fresh chain" seems a little dubious to me... My diagnosis would be simply that the high limit screw needs to be backed out. As a mechanic I've learned never to assume that someone knows how to tune a derailleur.
  • 15 0
 Yeah that's an april fool's answer if there ever was one. Chain rollers....ROLL...and they're round... there is no "up side" ever.

But the clue to the skipping was actually in the question...

"I tuned the derailleur, and when it is in the smallest cog, the chain skips - even with hand pressure on the pedals. I never had this problem when it was on my other frame"

The derailleur clearly was not tuned PROPERLY.
  • 5 0
 Yeah, that's what I was thinking too. Could've been a tweaked hanger on the new frame causing some odd behavior as well.
  • 14 0
 Actually there is some merit to this, not with the whole chain but with the quick link. Some, such as wipperman, are not symmetrical and can be fitted the wrong way up, this acts fine on most of the cassette until you get to the tighter cogs when the angle is increased and it causes skipping, it happened to me and had me stumped for ages until my LBS helped me out.
  • 5 0
 Interesting, MarkyB. I've never dealt with wippermans before. Thank you for the enlightenment!
  • 3 0
 A more important issue with master/quick links is making sure they're snapped properly together. SRAM/KMC links need to be pulled tight (a good way to do it is to hold the rear brake on while applying a load to the crank arm) to avoid skipping issues in the stand.
  • 3 0
 Right there with you guys. My bet is this guy knows how to set limit screws, but not b-tension.
  • 4 2
 So, the net never fails to astound me.

Sorry to puncture anyone's veil of infallability, I can however speak from personal experience of having an old chain skip on the smallest cog of a new rear cassette. Wipperman chain, new SRAM 9 speed cassette. The chain had been running on another frame on another rear wheel with an identical SRAM cassette. I didn't have a new chain at hand, so used the old one. And 9th gear slipped under load. Constantly.

I retuned the derailleur (properly deeight!!) numerous times that day but could not eliminate the problem until I suspected the problem lay in the "old chain, new cassette" perennial problem, so replaced the chain.

You might be interested to know that the derailleur needed no retuning after replacing the chain for it to run perfectly.

Must have been magic then.
  • 7 0
 Its also worth noting that some shimano chains are directional. The outside facing plates are optimized to engage with chain ring ramps. and the inside facing plates are designed to optimize shifting in the rear. From experience, a shimano chain that is backwards, can cause shifting issues.
  • 3 0
 My buddy had the same issue. It was because he was using a lockring for a 14t small cog on a cassette with an 11t small cog. Simple fix.
  • 4 0
 @deeeight Actually, there IS "up side" on DynaSys chains.

It shouldn't really affect chain wear, at least to my knowledge, though.
  • 3 0
 question was about a 1x9 speed drivetrain though... dyna-sys chains are strictly for the shimano 10 speed off-road groups.
  • 3 0
 Flipping your chain over regularly does increase the life of the chain. Shimano worked this out decades ago and I saw it reported in a magazine but I've never seen it since. Dynasys doesn't have upside down, it has outboard inboard.
  • 1 0
 I can see how flipping a chain might even out the wear on the plates.
  • 2 0
 That's because the plates don't wear
  • 3 0
 Flipping the chain has more to do with the side of the bushings the the teeth of the cogs are making contact with. Whist pedaling the teeth will only ever provide force to the bushing in front of it, which will eventually wear down the metal underneath the roller in that spot. The idea with flipping it is you are know getting the teeth to apply force to what was originally the trailing bushings.

I know im not explaining myself properly Razz
  • 2 0
 What about the classic "cable on the wrong side of the clamp screw", at least with the older derailleurs?
  • 1 0
 The cable on the wrong side of the screw alters the geometry of the mechanism (its the same principle at work with cantilever brakes and straddle cables/yokes). The angle the derailleur cable pulls at is in effect, itself a lever. When Dura Ace rear derailleurs went from 8 speed to 9 speed cassettes, they adopted a 2-position anchor bolt so as to be backwards compatible to older 8 speed DuraAce shifters while at the same time bringing the cable geometry into the same standard as every other shimano indexed shifter/derailleur worked with (previously the 7/8 speed D.A. index shifters only matched the same rear D.A. derailleurs).

As to evening out bushing wear on chain pins... that was all fine and dandy decades ago when chains all used bushings between the pins and rollers, but shimano and everyone else have long since abandoned that form of chain construction for multi-speed chains. Eliminating seperate bushings saved weight, simplified construction (thus cheaper to produce/sell) and improved strength. They wear faster though but with wide cassettes ranges and weird chainlines, the lateral strength ends up being more important.
  • 3 1
 Best answer to the derailleur question is to get rid of the piece of shit.
  • 4 0
 Yep, gearboxes are the way to go. Wish I could afford one.
  • 21 1
 Together with Sixer Bikes, we'll be introducing tight single track trails across the country and worldwide to go along with 26er bikes. Trails with switchbacks and corners too narrow to fit your grandmother's cruiser.
  • 16 0
 No no no. Rocks, roots, and steep. That's what we need
  • 11 0
 MortifiedPenguin, You're Hired! Chief trail designer and CEO. Steeps so steep that steam rolling the rocks and roots will result in kissing some tree.
  • 4 1
 But big wheels ride proper double-track far better than sixers ever will. Can't you just straighten out the trails in your local woods a bit? Or a lot? Or ban riders over 6ft tall that can't fit L and XL sized bikes plus big wheels around tight tree-lined woodsy nonsense.
  • 11 0
 Professional coaching and instruction has been the single best bike-related purchase I've ever made--far better than any new bike/gear/etc.
  • 3 0
 Yeah man I saw you out on the trails the other day and you're killing it!
  • 1 2
 ^^^hysterical!
  • 2 1
 Did I miss the joke??
  • 9 0
 Are wide rims worth it??... guess it depends how many dollar bills are hangin' out of one's posterior. Seriously though, cycling like most hobbies can cost as much or as little as you would like it to. If you aren't to proud to rock 5 year old 26" wheels, your wallet is gonna be a lot heavier (which might slow you down).
  • 4 0
 Lets keep things civil. *too
  • 5 2
 The most expensive gear, biggest wheels and bermdest trail can always make up for ... skill.
  • 3 2
 Want to know, 29er reviews don't talk about them being hard to turn like when they first came out. is this just because people are getting used to the way they ride, 29ers are getting better geo now, or a combo of both. Thinking of going from a 2012 Blur XC to a Camber Evo. Want a word in from my fellow keyboard huckers.
  • 1 0
 I'd say a combo of both. Demo one with modern geo if you can. I like the stability and rollover of my 29er but will likely be going back to smaller wheels with my next bike to get back some trail "feel" and lose some of the additional wheel flex that larger wheels have in the gnar (because I'm so gnar). Ever considered a SC 5010 for your Blur replacement? A good compromise between climbing/descending with modernized geo compared to your 2012 Blur.
  • 4 0
 Love what Neil Donahue is doing with gmbn on YouTube!
  • 4 0
 I believe I'm sensing some early April Fools material here...
  • 4 0
 Is that a bike horn in the last picture?
  • 4 1
 Question: What's new for this year's April Fools' Day?
  • 2 1
 Wide rims, coaching and skipping chains?
  • 2 2
 Exactly why I love my AM hardtail
  • 1 0
 Thanks man!
  • 1 1
 29ers are cool AAAAAAAA april fools
  • 1 3
 Um..... Why is Bear Grylls teaching a MTB class?
  • 4 0
 That's Don
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