Ask Pinkbike: Mismatched Suspension Travel, and Quieting Chainslap

Jul 11, 2017
by Pinkbike Staff  
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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.



Why Design More Travel up Front?

Question: Mountain-man99 asks in the All Mountain, Enduro & Cross-Country forum: Does anyone have any ideas on why manufactures are making bikes with different travel front and rear - such as the Santa Cruz Hightower (135mm rear and 150 front) Or the Pivot Mach 5.5? There are more and more brands doing this. Why? What is the benefit?


bigquotesGood question. There are two main reasons for designing a bike with more fork travel than rear-wheel travel. The performance reason is that when you are smashing down the trail, the fork does the hard work for the lion's share of the time. It is the first part of the chassis to smack a bump, and the momentary deceleration the impact creates causes the rider's and bicycle's mass to un-weight the rear suspension, so the rear wheel clears the object with less difficulty. There is more to that equation, but the bottom line is that if you were to choose one or the other, a longer-stroke fork results in better suspension performance than adding more rear-wheel travel.

If you are talking 29ers, however, the reason is simpler to explain. Frame designers must limit the rear suspension travel in order to maintain a proper chainstay length and keep the larger-diameter wheel from contacting the seat tube at full compression. In order to make up for that deficiency, and for the same reasons mentioned in the first paragraph, bike designers often spec longer-stroke forks on 29ers.— RC


COYHAIQUE PATAGONIA CHILE - 19 January during the inaugural Aysen Rally Patagonia for Santa Cruz Bicycles launch of the Hightower. Photo by Gary Perkin
Santa Cruz Hightower. - Gary Perkin photo




SRAM vs Shimano Derailleur Clutches?

Question: Pinkbike user @BarnaK asked this question in the Bikes, Parts & Gear forum: I'm replacing my rear derailleur from XT Shadow M8000 to SRAM GX or GX Eagle. I don't mind the weight, I don't mind the material, I just care about the chainslap and noise control (aka clutch). The XT M8000 shadow disappointed me badly, (tried to harden /soften the clutch, played with chain length, taped the chainstay...) too noisy.

So, the question: Is the new version v3 clutch (which is on the newest Eagle's) that much better than the earlier v2.1? Is it worth it to upgrade the whole drivetrain to 1x12 and spend a fortune? I'm on 1x11 and it's just enough for me; I don't need more gears. And obviously I want to spend as little as possible.Anyone tried both?


bigquotesI'm not sure that you'll find the solution to your chainslap woes by switching to a SRAM derailleur – the amount of resistance provided by SRAM's clutch mechanism isn't drastically different than what's provided by a Shimano Shadow derailleur. If anything, there's less resistance than what you'd be able to achieve by tightening down the clutch on a Shimano derailleur.

That being said, if you have your heart set on switching to SRAM, don't forget that you'll need a new shifter too – Shimano shifters and SRAM derailleurs don't play nicely together due to the different cable pull ratios. If you're happy with your current gear ratio, I wouldn't rush out to buy an Eagle drivetrain, especially since you're looking to spend as little as possible.

I'd also recommend taking a closer look at your frame to try and figure out where the chainslap noise is coming from. You mentioned that you taped the chainsay, but you didn't say what you used. Some frame designs are inherently noisier than others, but applying a thicker rubber mastic tape to both sides of the chainstay, as well as to the underside of the seatstay may help quiet things down. — Mike Kazimer

Shimano M 8000 drivetrain review
The amount of clutch tension on a Shimano M8000 can be adjusted with a 2mm Allen key...
SRAM GX Review
...But the clutch on a SRAM derailleur isn't adjustable.



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

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174 Comments
  • 328 6
 I mismatch suspension cuz it's rad. 125 in the back and 160 up front. Small ass big tits.
  • 114 1
 the 'dolly parton'
  • 12 1
 Love this
  • 21 0
 "reverse mullet"
  • 39 0
 party in the front afterparty in the back
  • 17 0
 Kentucky waterfall!
  • 15 2
 what about the old school classic hardtail with 180 mm up front - that's double crown of course!!!
  • 12 1
 @Jaylynx: I believe it's a Kentucky mudflap
  • 7 0
 @panchocampbell:

Kona Cowan with a Monster T?!?!
  • 2 0
 Ya know????
  • 2 0
 Nice, Mississippi Mudflaps!
  • 11 9
 Riding a hardtail most of the time, I don't see why anyone would run more travel in the back than in the front. Just use your legs and the rear end floats. Arms will always be weaker and you need them for a bit more subtle control too. That said, in DH/FR it used to be quite common to have more travel in the rear. The Santa Cruz V10 had 10" in the rear, the Specialized Demo 9 had 9". And both where typically used with 8" forks. Maybe because with big hucks you'd prefer to land the rear end first. Of course now that 24" is pretty much out (#24aintdead and all that) and 29" is attempting to get in there is no more room for that. But for riding where the front encounters the obstacle first, front suspension will always be the more important. Same goes for running a bigger front wheel. I'm telling you, once UCI drops the ban on using dissimilar sized wheels front and rear, other brands whose bikes are being used in competition are going all "innovative", look at the past and/or follow what Liteville has been doing for a while.

As for the full susser, yeah I'm running 160mm in the front and 140mm in the rear.
  • 3 16
flag finnmcmtb (Jul 12, 2017 at 0:38) (Below Threshold)
 @vinay: Are you thinking of 26" #26aintdead , because i don't think 24" was ever alive
  • 21 0
 @finnmcmtb: Y'ain't from round here are you, boy.
  • 1 0
 @RichPune Best comment ever!
  • 4 0
 @finnmcmtb: ummm... BigHit!!! I bet 90% of us on here remember them and would still take one on a few runs for fun. I loved my brother's.
  • 1 0
 @Warburrito: Banshee Scream too. The British called it Mythic back then. I've got a Specialized P1 (2006, I think) dirtjumper which also came with 24" in the rear and 26" in the front. It's fun, the rear end likes to fly all over the place.
  • 1 0
 @trialsracer: yep
  • 2 0
 Well said. I ride a 160-115 U-Turn Domain with a 115 rear. I love it. Lively, responsive, poppy, yet still forgiving with the longer travel front end. If I could keep this bike and get a second I'd bump up the travel of both....130-140 rear 160-170 front would be my ideal go-get-everything setup. I'd even complicate that further by going either 29-27.5 combo or 27.5-26 combo (smaller out back obviously)
  • 7 0
 @sjdeweese: Growing up in Kentucky myself, we simply referred to it as "haircut"
  • 1 3
 Why do they need to be women at all? Why can't it just be a bike?
  • 1 1
 145 at the back 180 up front, what you gonna do about it?
  • 1 0
 @WasatchEnduro:

you betcha!!
  • 1 0
 @Jaylynx: Huh ? Smile
  • 1 0
 127mm rear + 170mm front=broken frame after just 6 rides

Years ago I put a 170mm Lyrik coil on a Yeti ASR5 & rode it like it was built for a 170. It was actually designed for 120 to 140. It was delivered a quick death.
  • 2 0
 @Aust95: Sad to hear. They have frames designed specifically for longer forks, see. Better do that than get a long fork in a frame not designed for it. Alutech ICB2.0, DMR Bolt (Long), probably some Transition and Banshee stuff too.
  • 253 1
 Remember- a 150mm front 140mm rear travel bike is not actually mismatched

Rear travel is measured vertically. Front travel is measured in line with the head angle. So 150mm @ 67 degrees is actually
140mm of vertical travel.
  • 142 0
 Mind. Blown.
  • 33 0
 More people need to see this.
  • 18 0
 But on a 33 degree slope you can totally bottom out and use all 150mm of travel
  • 107 3
 67 degrees? what is this, 2015?
  • 7 1
 Let's not forget to take sag into account... with more rear travel you can have more sag yet the same useable travel as the front and get a better ride.... MX bikes have more in the rear than front...
  • 8 2
 @sk133872: Most 140/150mm trail bikes #notenduro are around 67 deg still - 5010, Stumpy, Int Spider , Orange 4, Switchblade, Remedy, sb5.
  • 84 0
 Hang on a second....this reads like an informed statement....theres no place for this kind of talk on PinkBike
  • 75 2
 Thanks for letting me know. I plan on purchasing an angle set to get my HA to 90 degrees so that I can use 100% of my vertical travel.
  • 3 0
 @greasecheese7: but on almost all bikes with a rearward axle path you will also get more travel out of the back
  • 2 1
 @kleinblake: Almost all bikes have a slightly rearward travel then change to forward travel somewhere in the middle.
  • 10 0
 @fartymarty: You don't have to pedal an MX bike...
  • 3 0
 wait, whats the equation for this?
  • 12 3
 Bro, more time riding, less time math.
  • 4 0
 Wow! Learned something new and useful today
  • 9 1
 My next frame is going to have a 90-degree head angle so I get the full travel?

Sorted!
  • 9 0
 @Aydenebb: For Karve's example, sin(67*) x 150mm = 138.07mm.

Sin(degrees) = opposite / hypotenuse. The hypotenuse is 150mm, and the head angle is 67 degrees. What you're looking for is the opposite side of the triangle. I'm imagining the triangle with the right angle facing away from the bike.
So, sin(67*) = Y / 150. To get Y by itself, multiply everything by 150.

Therefore, sin(head angle, in degrees) x fork travel = vertical travel.
  • 2 3
 @Karve: that's so oldskool :v mine is a 2013 fuel ex, originally 68º HA, did some tune ups to make it 65º, way better! 130 rear 150 front, best thing ever
  • 6 1
 @fartymarty: ur mum has more in the rear than the front
  • 10 0
 @Aydenebb: I believe, he has used the AAS formula:
We know that the fork length plus its height (when mounted to the bike) is making a right triangle, so the angles are:
C = 67 degrees, B = 90 degrees and A = 33 degrees
Sides: b = 150mm (fork travel), a & c are unknown, but we are interested in c (which correspond to the height/vertical travel of the fork).
So we solve for C with the sin rule:
c/sinC = b/sinB =
c = (b*sinC)/sinB
c = (150 * sin67)/sin90
c = (150 * ~0.92)/1
c = ~138.08
The fork has ~138.08 mm of vertical travel if you are on a flat ground with a slope of 0 degrees.
  • 3 1
 @kleinblake: Most bikes don't have a rearward axle path. Most bikes typically have the axle rotate around a point in line with the upper bit of the chain. This means that when sagged, the axle is more or less in the most rearward position already. It moves forwards whether you load or unload the bike. This is even more the case if a bike has been designed for bigger wheels, as you need more bb drop for those (hence the axle is already higher with respect to the bb). There are exceptions of course, when you run an idler pulley like the current Commencal DH bike does. Same goes for the Trek Session 10 which, no matter what mathematicians try to tell you, is not like the Session 9.9. And of course with single pivot designs with the bearing around the bb, the axle moves forwards exclusively. This goes for the DMR Bolt (Long) and for the Starling Little Beady Eye. Not necessarily for the DMR Sled and the current Specialized Demo though, as these have a linkage in between.
  • 7 2
 @georgevorobyov: damn. Impressive. I suppose this is what I would be like if I'd spent more time reading the maths book instead of drawing bikes on it.
  • 2 0
 @georgevorobyov: Now consider a 15 degrees slope(so downhill) and recalculate the travel front and rear.... would be about the same, isn't it
  • 1 0
 @dubod22: Just turn your fork the other way round?
  • 13 20
flag WAKIdesigns (Jul 12, 2017 at 2:32) (Below Threshold)
 hey, how about this: buy a bike. Ride it. Borrow two forks: a bigger one and a smaller one. Try your bike with both. Go with what feels better. But if you have performed such experiment and you still ask people which is right: kill yourself
  • 1 0
 @bridgermurray: might make the steering a bit twitchy though!
  • 5 2
 @WAKIdesigns: Yes, how dare people ask questions.
  • 6 11
flag WAKIdesigns (Jul 12, 2017 at 2:49) (Below Threshold)
 @u-otter-b-sry: that was not a crtique of a person asking the question... rather explanation of the best way of Finding the answer. My other solution: buy pieces of magic metal and glue them to the frame with magic glue
  • 1 0
 @uskas: correct (143mm I think). I'm not sure how do they calculate the rear travel, though.
  • 2 3
 @WAKIdesigns: quality comment.
  • 1 1
 @vinay:
  • 2 0
 It blinded me with science.
  • 70 0
 The front of my hardtail definitely does most of the work. Still pretty quick though.
  • 131 0
 I prefer my 160mm bike with a rigid fork. All of the chatter with none of the pedaling efficiency!
  • 8 0
 140mm F 0mm R - Hell Yeah!!!
  • 2 0
 @src248: it's a good bike to practice manuals on
  • 2 0
 @src248: new standard from all manufacturers
  • 2 0
 @src248: Now there's an idea for business! I take two!
  • 19 0
 Using a Shimano shark fin chainstay protector with my 7 speed triple while riding in 'big big' on the dh I don't hear any chainslap..just the sound of my teeth splintering, though the 5mm cushy travel on my tioga farmer johns is helping.
  • 6 0
 I am not being silly, I think you are still gonna send it
  • 1 0
 shimano shark fin protectors....classic vintage. Saw a brand new in package on eBay awhile for $25!! Collectors I guess.
  • 18 0
 Covers chainstay in all types of sound deadening material, uses Chris King hub...
  • 13 1
 I really like ultra quiet bikes..so along with a zee derailleur i put a good amount of soft velcro (the hairy side) on upper, lower and vertical chainstays, and on all sides of chainguide..
The result ?? Ssshhhhhhhh...
  • 5 0
 i gotta a 101 dumby question; would going from a medium cage to short cage reduce noise / chainslap?
  • 7 0
 @rocky-mtn-gman: yes, shortening your chain, or shortening up your derailleur cage would help.... but, you can only go so far depending on your gearing and chain growth.
  • 1 0
 @cmcrawfo: got it, thanks man.
  • 2 0
 Velcro works awesome
  • 4 0
 You copied that old Sam Hill trick just like I did. It works a treat. Furry bikes are quite bikes. Maybe I will do the DT next.
  • 4 0
 But bikes noises are kewl
  • 4 0
 I don't know if the short cage would help. May hurt if it allows the lower chain to be closer to chainstay. Taking out a link or two from your chain would definitely help. Gear selection on the down can help as well, ie have it in an easier gear in back to reduce chain slap.
  • 2 1
 @andnyleswillriot: My bike is noisy as crickets. The chainstay protector (merely a piece of transparent tape) is worn so the chain hits the steel chainstay tube. My 9s X9 derailleur (shortest cage) doesn't have a clutch. The right crank (2004 Shimano LX) creaks loads. I've taken it off many times, cleaned and lubed but it always returns. I carry a 10mm allen key to tighten it if it gets too loose. The left crank is newer (2009 or so) though and still reasonably fine. The brakes and hubs are silent though. Seems like mostly other mountainbikers can't stand it. Glad to know my bike is kewl Smile .
  • 1 0
 @vinay: Yeah mate. Ride your bike til its dead.
  • 1 0
 Male and female velcro sandwiched works a charm for me, really cushions the chain.
  • 13 0
 Well, if lovin my V-10 is wrong, I don't want to right.
  • 8 0
 On the travel bias thing, I'll add....

1) The front tire needs to track straight for good control and confidence. The rear wheel can get loose, while still having the rider feel in control. More front travel bias, and the fact your legs are aiding in rear suspension performance, makes more front travel help keep TRUE balanced performance.

2) On any hardtail mountain bike, I think it's generally accepted that a 100mm fork is a benefit, in rough terrain. Thats a 100mm front travel advantage! That same bias might feel nice even with rear suspension.
  • 2 0
 I have a banshee spitfire with 140/160 travel split. I would say that the bike feels like it is more pedal efficient on the way up but has the muscles on the front on the way down compared to 140 or 160 all round bikes.
  • 1 0
 @mattvanders:
Same bike, 170mm coil up front.
Good times.
  • 8 0
 "If you are talking 29ers, however, the reason is simpler to explain. Frame designers must limit the rear suspension travel in order to maintain a proper chainstay length and keep the larger-diameter wheel from contacting the seat tube at full compression. In order to make up for that deficiency, and for the same reasons mentioned in the first paragraph, bike designers often spec longer-stroke forks on 29ers."

There are two well known exceptions to this statement. The Evil Wreckoning has 160/161 frt/rr travel and the Specialized 29er Enduro with 160/165 frt/rr travel.
  • 10 0
 I love these posts. always enjoy solid input from folks in the industry.
  • 58 6
 I gave your mother some solid input last night (sean connery voice)
  • 7 2
 @greasecheese7: Get off of pinkbike and back to your game of Jeopardy
  • 2 1
 @greasecheese7: LOL. The internet has been won today by you.
  • 2 0
 @greasecheese7: So has the whole industry
  • 1 0
 @greasecheese7: i luv this website u all rock!
  • 8 0
 I have a rubber chain on my bike its very quiet but leaves black marks on the swing arm
  • 5 0
 @mikekazimer How has this not been brought up??!? Shimano rear derailuers have 2 holes for the cage spring to catch in, stock they are shipped with low spring tension (different than clutch tension) you can take the cage off of the body and clock the spring with a higher preload and it should drastically reduce chain slap. There is a significant trade off with shift lever feel but in my opinion it is entirely worth it
  • 1 1
 Also SRAM derailleurs can be altered in chain tension. Just remove the little plastic cap and use a Hex key / Allen key to tension up the screw that is there.. it will drasticly change the chain tension and I never drop a chain anymore without a chain guide...
  • 1 0
 Got a video of this?
  • 1 0
 Thanks Leviz! This was new info for me at least, and might be just what I need... Another thing I've noticed regarding chainslap, is that chain actually has quite big effect on how much there is slap. Back in 10x days, SRAM chains were bending noticeably more than Shimano ones when you twist the chain sideways. The increased sideways play shows as bigger chain slap. So I don't know how much has changed now with 11x and 12x chains, but I'd guess would be nice to do some head to head comparison between different chain manufacturers...
  • 1 0
 @BenPea: No.. just remove the cap ... with a little knife... the 2.1 and 3.0 ones are harder to do it... but below in the reactions you can read how to do it.. behind that is the screw...
  • 1 0
 @Trailstunter: Sorry man, I meant for Shimano. I'm struggling to see how an XT can be pulled apart to preload the spring (I'm talking 9-speed 1st gen shadow though...)
  • 1 0
 @Trailstunter: exactly what I was going to say... just pry off the plastic cap with a knife and tighten the allen key.
  • 3 0
 @Trailstunter: This is what I do with every SRAM derailluer because the clutch will eventually loosen up. I use a dental tool to remove the top cap, then a #8 hex to tighten the clutch. Beware that the newer clutches have a pin driven into them to prevent you from doing this (to honor the shimano patent) but you can easily remove the pin. Just hammer it out with a die or a small eyeglasses screwdriver, so that its sticking out from the casing a bit, then pull it out with some pliers.
  • 1 0
 @rudeboybl: ^ this indeed...
  • 1 0
 @levizbrown So much clever monkey here, but few gave proper advice. This one, adjusting the spring tension made a big difference. Just done it 10 min ago, a bit fiddley, but worth it!!
  • 1 0
 @rudeboybl: I'll still keep the XT shadow now as I added more spring tension (levizbrown's advice) to test it, but I will also mount in a few weeks the GX 2.1 and will do the pin removal, add bit more tension from the beginning and try to keep the adjuster tight with locktite. Thanks for the advice.
  • 9 1
 Yeah no silly wheel size arguments to be had here
  • 10 2
 let's just start one because we can... Razz
  • 10 0
 24" is wicked sick 20" is lame
  • 3 0
 Minnar is in the lead on 14''' rims,.
  • 4 1
 I think the longer travel is pure geometry, and has nothing to do with the front taking the brunt of the hits. Proof is that most flats occur on the rear. Unless you are in 'attack' position, the rear wheel has much more of the weight. Plus, I think it is much easier to unweight the front than the rear.
  • 2 0
 I will say that I agree with Mike. I have the 2.1 XO1 on my Process 167 and it's hard to minimize the Chain Slap. I've shortened the chain, I've put some thick wrap on my chain stay, and I've even tried to grease up my chain with thicker lube. I'm still getting almost the same amount of chain slap. However, I will say that my friend just bought a Carbon Bronson with the Eagle XO1 and there's VERY little chain slap... if at all any. I'm not sure if this is because of the Frame Geometry or it may be because of the thick rubber chain stay protector he has that came with the bike.
  • 4 0
 My Bronson CC Eagle also has insanely minimal chain slap, so little that now all I can focus on is the slapping of the cables in the internal routing (at least I'm pretty sure that's what it is), SO ANNOYING. Not sure why the frame plugs aren't keeping the cables tensioned inside, haven't looked into a solution very hard.
  • 1 0
 @jcrrr13: Damm son! That's so annoying. Do the cables run through the frame with the housing or is it just straight cable going into the frame?
  • 3 0
 Chainslap used to be much better when you could ajdust sram clutches. Now that you can't, you're stuck with factory settings and I've found that their lifespan has been ridiculously low.
  • 1 0
 it's def the eagle, had xx1 on my insurgent last season and it was so slappy, eagle damn near eliminated it this season.
  • 6 0
 @jcrrr13: put a couple of zip ties with long tails around the cables and feed them inside the frame
  • 1 0
 @jcrrr13: I thought that SC bikes had molded-in cable routing that would eliminate any slap within the tubes...Someone correct me if I'm wrong.
  • 3 0
 @jcrrr13: Also possibly try putting moto foam down the down tube, I did that on my SB6 and the internal cable slap has ceased. Now I focus on chain slap noises.....
  • 2 2
 @PLC07: X9 Type2 - best rear mech Sram has ever made
  • 2 1
 Anyone with insight on the change in BB height/repercussions if one were to swap out a 130mm fork to 150mm (keeping the 130mm the same in rear)? Obviously the head tube angle will change, too, but thats kinda the point for me....
  • 5 0
 I've used this calculator before: bikegeo.muha.cc

It's helpful, but doesn't really tell the whole story. My bike geo changes as soon as I sit on it, so I'm not sure what real benefit static numbers provide.
  • 2 1
 I've never heard anyone complain about the change in BB height when upping travel, I'd think with it being much closer to the rear it wouldn't make a drastic difference but that's just a guess
  • 6 0
 Seat angle will get slacker too which might be a problem if your bike already has a slackish STA. A degree or so slacker STA is much more noticeable to me than a few mm higher BB.
  • 4 0
 Super low BBs are overrated but as has been said you'll slacken the seat angle by ~1° (Same as the HA) with +20mm forkage which could be more of an issue. BBs don't need to be low to corner well, but they do provide low speed/ low rider input cornering stability - if we learn to corner more dynamically we can enjoy the benefits of a BB that isn't slammed on the floor the whole time. The BB height will in part dictate how 'planted' vs 'lively' the bike feels so it's all a balance as usual with geo but lots of very experienced riders over fork their bikes and don't seem too worried about keeping the BB that low.
  • 4 3
 @RichardCunningham - 29er can have as much travel as they want and still keep the geometry. First Specialized Enduro 29: 150mm rear travel, 430mm chainstays. It used to be the problem when seat angles were at 71-72. Santa Cruz suspension layout makes it a bit harder to make shorter chainstay but why would you want anything shorter than 440 on a bike that outpaces DH bikes from 2010 Wink
  • 3 0
 Nope, something has to give. Both of those bikes have compromised seat tube geometry, and the Enduro's BB height is pretty tall.
  • 3 0
 Yes and maybe. To answer the question, I used general terms. True, if you can make a DH 29er, you can have equal travel on a trailbike, but take a look at the profiles of long-travel 29er trail bikes and you can see the compromises. Doglegged or dramatically offset seat tubes... etc. The reasons for using a longer fork are still valid, regardless of whether some frame designs circumvent the issues. Both strategies require compromise.
  • 2 2
 @RichardCunningham: what doesn't require and create compromise Smile short chainstays create hell of a lot of compromise in handling. But they do make current freight trains handle well on climbs by a person who does not have balance skills in their trail vocabulary
  • 1 0
 On a random note, some rear suspension designs feel like they have more travel than they do (because of their progressiveness) and a fork with slightly longer travel (that is more linear) may feel more balanced with that type of setup. It obviously also comes down to rider preference and what travel forks the bike is designed to work with if you don't want to lose your warranty.
  • 1 0
 Gotta say ever since mtb suspension has been invented - yes i have been riding that long and am that old - ive always run more travel on the front than the rear and cant really see why it seems to have people scratching their heads. I also tend to run the forks slightly stiffer than the rear as well.
  • 1 0
 I have 135mm back and 160 front. Bike shop was supposed to put a 150 mm fork but accidentally put a 160. Can't complain. But I really only have about 110 mm of rear travel since I can't bottom my damn rear shock! Need a coil shock with a lock out but there isn't any of those for 190 x 51...
  • 4 3
 chainslap? well you are riding such a big cassette like eagle, that means your chain has to be longer, then its making more noise obviously on lower gears. reason for me to stay with 34/36t on rear as max
  • 6 12
flag Boldfish (Jul 11, 2017 at 14:14) (Below Threshold)
 No. Chain stays the same relative length in all gears. That's what derailleurs are for.
  • 10 1
 @Boldfish LOLWAT? Eagle will require a longer chain, period! Therefore there will more more chain for the derailleur to manage.
  • 2 1
 I do a 30T front with 36 rear...have to walk the odd stuff but the gear jumps, chain length and derailleur fiddling aren't for me with the 40+ gang.
  • 1 0
 No i'm on 34/42, and with the shortest chain I can get away with. I'm mid-pack for my age/weight but I do monster truck
  • 1 0
 @simeon10: 42 could be the reason, tax for big cassette, moto foam?
  • 4 1
 What is a proper chainstay length? I have 460mm on my 29HT and it's great.
  • 11 0
 CS length debate in 3...2...1...
  • 2 0
 that's a propper CS length, then
  • 3 0
 I ve got a 420mm cs length and it's also great
  • 4 0
 Anyone want to hear about my chainstay length? I've got chainstay lengths too. Anyone?
  • 7 0
 Speaking as an engineer, it's often considered advantageous to have a CS length thats at least a bit greater than your rear wheel radius. Whatever you consider to be a proper wheel radius is the topic of another debate
  • 1 0
 @vinay: oooh, mine is 451mm
  • 1 0
 @graeme187: 451 is respecable but I've got 470mm on my other bike. It's a whopper.
  • 4 2
 @ROOTminus1:
I haven't heard of a bike with shorter chainstays than the radius of the rear wheel
  • 3 0
 Try mastic tape (scotch 222Cool with the soft side of velcro on top of the mastic to the chain/seatstays. Worked for me.
  • 3 0
 Still got slap with clutch xt/One up cage, now use solid bionicon C-guide; sorted
  • 1 0
 My Shimano rear mechs clutch is basically a glorified jubilee clip/hose clamp, tighten this little fella up and it stops the little axle going through it from rotating so easily.
  • 1 0
 No need to care about mm, geometry is the key! Shimano use to have more tension rather than sram, also typically adjustable and more quite! Anyway frame design plays crutial role...
  • 1 0
 I believe in the case of the Mach 5.5, it was designed as a 150/140 bike but in real world testing they found it performed better with a 160mm fork, so that is what they spec all their builds with.
  • 10 7
 I ride with headphones. Makes all bike noises completely disappear.
  • 1 0
 +1
  • 9 9
 SRAM tension adjustment is just under the plastic cap.
Pop it off with a knife, then use an 8mm Allen key in the torx t55 to tighten.
Should only need 1/4 to half a turn.
  • 10 0
 That's no longer the case with version 2.1 and 3.0. There's a non-removable pin that prevents any adjustment on version 2.1, and version 3.0 is a different configuration entirely.
  • 2 0
 Only the first version
  • 2 2
 I did that, and then after 6 months the carbon swing arm snapped in half while bombing down a fire road. I think the increased tension stressed it too much.
  • 8 0
 @mikekazimer: I stand corrected. I'm obviously way behind on my drivetrain!
  • 5 1
 How is the 2.1 pin non-removable? It's not like it's welded in or something. Started getting chain slap after a week of riding since new, removed the pin and tightened the clutch and it was ok for a week or so of bikepark riding. Had to adjust it couple of times since until the adjustment cap bottomed out and clutch started binding on return.
  • 7 0
 @mikekazimer: I hate to disappoint you but the pin is removable. Just a little wiggle with an 8mm Allen key and the pin will start to dislodge itself. SRAM had to put this pin in as shimano were not happy about sram having an adjustable clutch and got legal teams involved. I remove it on all my 2.1 versions. I only know of this as a high up tech guy at sram Germany told me.
  • 16 0
 @void, @Wheelersmtbholidays, ok, non-removable might not be entirely correct - how about "removable with some patience and little more effort than before"?
  • 3 0
 @mikekazimer: can't catch a break lol. Great advice on tightening the M8000! Turned mine last week a little and it's silent now
  • 1 0
 @mikekazimer: keep tightening up that clutch till your plush suspension is not plush anymore!
  • 1 0
 @MX298: So.... if I'm running a chain device, I can turn my clutch off for better suspension performance?
  • 1 0
 @graeme187: try it! I sure love how you (almost) never drop a chain but when I first installed a clutch derailleur I noticed it right away.
  • 1 0
 Mastic tape with the soft side of velcro on top. No more chainslap that you can here.
  • 2 0
 it's getting pretty nerdy up in here
  • 1 1
 I aim for my bike to make zero noise. What's the first thing you think when you hear a noisy bike? "Something's broken" or, "Shitty componentry", at least I do.
  • 1 0
 or that you're no longer focused on riding the trail, you're out of the moment and thinking about your equipment instead.
  • 1 0
 Business up front, party at the back! Or is that my hairstyle?
  • 1 0
 I have 150 in the front, 0 in the rear. That's how I roll.
  • 1 1
 So much noise in this post, can't hear chain slap!
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