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Discussion Starter · #1 ·
I built a 2011 S-Works XL 29er recently and so far everything seemed great except my heel on the drive side occasionally hits the chain and seat stays. I moved my cleats in as far as possible on my shoes to help cure this but the problem still exists. After my ride today I noticed a rub mark on the frame and on the chain protector right at the end of my crank arms. Then after inspecting it further there is very little clearance between the arm and the chainstay (approx. 3/16"). The non-drive side is more like 1/4"+. I thought that maybe the bike shop didn't install the crankset properly so I took them (S-Works carbon 180mm) off and after talking with a buddy and reading the directions everything is correct. Has anyone else heard of this problem or know how to resolve it? I will definitely take it into the shop tomorrow and have them take a look as well.
 

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Sounds like the Q-Factor for you cranks is tight.

I've got the SRAM XX crank with the 156mm Q-Factor and it happens to my bike/frame too. 'Stock" Epics come with cranks with a Q-Factor of 164mm (fyi)
 

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Discussion Starter · #3 ·
Yeah they seem really tight. They are not the stock ones since I bought a frameset but they are the same ones that they use on the stock bike. I may need to check out the q-factor on the 2011 XTR's.
 

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It is 'close' on the S-works, my 2011 with 170mm cranks on a small frame has a 1/4"gap both sides. Is there a corresponding rub mark on the crank arms (or protective rubber boot) opposite the mark on the chainstay - if not then it shouldnt be the crank arm rubbing, if there is its the crank arm. If you measure the gap and there is 3/16 clearance, then the crank arm should not rub the chain stay unless the crank is moving laterally when you pedal. Check your shoes for marks - but wouldn't you have to have a massive toe down action to rub the heels of the shoe on the chainstay opposite the end of the crank arms. Leave the shoe in the pedal and rotate the crank to see.

FWIW unless the crank moves laterally it shouldn't be the crank arms rubbing. Look for corresponding marks on crank arms and shoes. The only other suggestion is check that the swing arm pivot points are tight and the swing arm is central, correctly assembled and does not move laterally.
 

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GTR2ebike said:
Try angling the cleat on your shoe.
I agree with GTR. It sounds to me more like a fit issue than a mechanical issue on the bike. Did you have a professional fit (one that you paid for) done on the bike? Are your heels rubbing the chainstays? What method did you use to position your cleats? The Q factor may be too narrow for you hip width and causing problems with your pedal stroke.

J.
 

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I had the same problem with my Carbon comp. Heel rubbed paint off of chainstay by pivot. Angled my cleats a bit and problem solved. Called the 800 Spec line and he also said it was low Q of new SRAM stuff.
 

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BiknBob said:
I had the same problem with my Carbon comp. Heel rubbed paint off of chainstay by pivot. Angled my cleats a bit and problem solved. Called the 800 Spec line and he also said it was low Q of new SRAM stuff.
Here lies the problem. If you angle your cleats to prevent your heels from contacting your chain stays, then you are asking your foot to do something that it natually does not want to do. The result is poor knee tracking wich causes long term wear on the joint and reduces power through the pedal stroke. Today's bikes are trying to get narrower and narrower "Q factor" and as a result are messing with a rider's pedal stroke. Unless you have a really narrow pelvic structure, then you should not have a narrow Q factor. For most of the riders I do fits on, I end up widening the cleat stance to help neutalize lateral knee movement. My advice to you and the OP is to get a professional fit done. If you ellect to get a fit done then do some research and find an expirienced fitter.

J.
 

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It sounds like a combination of long 180mm cranks moving your feet backwards and your foot position when pedalling causing the rub.

If the shoe rub against the frame isn't too bad then you could just put some clear protective plastic on the frame at those points and ignore it. :)

Alternatively, file the inside of your shoe's heel cup down so that it doesn't protrude as far inwards at the point where it touches the frame. It won't weaken the shoe and will make it less likely for your feet to rub.

To move your feet further apart you can put a few pedal washers between the pedal axle and crank to space out the pedals, or even use some pedal extenders like these ones :

http://www.highpath.net/highpath/cycles/pedals.html

I'd do that in preference to adjusting the cleat if possible. If your cleat position feels right when riding then that's what counts. Don't move the cleats to an unnatural position for clearance as it will just hurt your knees.
 

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Discussion Starter · #11 ·
The heel rub isn't really a major concern as it rarely happens. I am more concerned with the clearance between the crank arm and the chainstay. The crank arm is definitely hitting the chainstay and has a mark on the back of the crankarm to prove it. Worst case maybe I could file a little off of the corner of the arm but will see what the dealer says before doing so.
 

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The 2011 Specialized Epic 29er has a 142mm width rear axle which forces the chainstays to flare out wider than on a bike with a standard 135mm width rear axle.

That may be a reason why your long 180mm cranks are rubbing - the frame was probably designed around 175mm cranks which don't extend so far backwards.

If only the drive side crankarm is rubbing on the frame then you could remove the chainstay protector. This will give more space between the chainstay and crankarm on the drive side. :)

If both crank arms are rubbing then you might be able to file the inside of the crank arm down a little, otherwise it will mean a different chainset with a wider Q Factor.:(
 

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Discussion Starter · #13 ·
I am far too familiar with q-factor since I own a snow bike as well with a 170mm rear hub and 100mm BB. I realized heels hitting the frame is from the narrow q-factor and the 142 hub. The chain stay protector has already been rubbed down in the area where it is touching and a small rub on the carbon as well so removing it wouldn't do anything at this point. The 5mm difference in crank arm length may make a little difference but not by much from looking at it. Seems like the crank should be at least centered in the frame. Funny because I just checked out my 2010 S-Works SS and the drive side has a huge amount of clearance and the non-drive side is far less.
 

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Do you think that it may have some of the wrong bearing spacers fitted, or that some of the spacers may be the wrong width? According to the 2011 S-Works chainset instructions there are two different sets of spacers depending upon whether it's to be used with a PF30 73 x 46mm BB shell or OSBB 84.5 x 42mm BB shell. (2011 S-Works Epic is PF30 73 x 46mm BB shell).

Part no. 4 (Bearing Seal Spacer) is 2.5mm for OSBB 84.5 x 42mm and 4mm for PF30 73 x 46mm.

http://service.specialized.com/coll...assets/pdf/Crankset---Carbon-MTB-Crankset.pdf

If the chainset is aftermarket then it might have come with both sets of spacers. Some of the bottom bracket parts could have been confused during assembly by the bike shop perhaps? That might explain why the crank is rubbing and not centred in the frame.
 

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Discussion Starter · #17 ·
WR304 said:
Do you think that it may have some of the wrong bearing spacers fitted, or that some of the spacers may be the wrong width? According to the 2011 S-Works chainset instructions there are two different sets of spacers depending upon whether it's to be used with a PF30 73 x 46mm BB shell or OSBB 84.5 x 42mm BB shell. (2011 S-Works Epic is PF30 73 x 46mm BB shell).

Part no. 4 (Bearing Seal Spacer) is 2.5mm for OSBB 84.5 x 42mm and 4mm for PF30 73 x 46mm.

http://service.specialized.com/coll...assets/pdf/Crankset---Carbon-MTB-Crankset.pdf

If the chainset is aftermarket then it might have come with both sets of spacers. Some of the bottom bracket parts could have been confused during assembly by the bike shop perhaps? That might explain why the crank is rubbing and not centred in the frame.
That was the first thing I checked. I had my fingers crossed that they accidentally installed a 2.5mm spacer on there by mistake but when we pulled it apart everything was done correctly. The bike is at the shop now and they are going to pull the rear end off and make sure everything was installed and torqued correctly from the factory. Then they are going to contact Specialized and see what the deal is. I will keep you guys posted on what they find. Chances are with my luck I will be the first to have a problem like this. I'm really good at finding these issues for some reason. My guess is that a little filing and a thick pedal washer will be the fix. Just a bit bummed that a $5000 frame/crankset combo needs to be rigged a bit to work properly.
 

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I have a Sram 2200 crank 1x10 off of an evo right now and I can see/feel the frame flex even with everything torqued down. Try putting your left foot on the pedal while standing on the side of the bike, hold the brake, press down on the arm, and watch the gap between the right arm and chainstay. The arm never contacts the stay with the Sram crank but I can see and feel movement.

I initially installed a 175mm Lightning crank with xx spider and when I had a good chain line the q-factor was too narrow. While climbing or sprinting the arm and chainstay would rub. I put a spindle spacer on the Lightnings and then the chain line was out too far to adjust the xx derailleur without shimming it out. Anyone want a basically new Lighting xx crank for cheap?

I too will have to wait for an S-works 175. Until then the 1x10 will have to do.
 

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lancelot said:
That was the first thing I checked. I had my fingers crossed that they accidentally installed a 2.5mm spacer on there by mistake but when we pulled it apart everything was done correctly. The bike is at the shop now and they are going to pull the rear end off and make sure everything was installed and torqued correctly from the factory. Then they are going to contact Specialized and see what the deal is. I will keep you guys posted on what they find. Chances are with my luck I will be the first to have a problem like this. I'm really good at finding these issues for some reason. My guess is that a little filing and a thick pedal washer will be the fix. Just a bit bummed that a $5000 frame/crankset combo needs to be rigged a bit to work properly.
If you have 1/4"+ clearance for the non drive side crank arm then you could use the bottom bracket spacers to move the chainset 1.5mm outwards on the drive side.

Use a Specialized 2.5mm spacer on the non drive side and then use a Specialized 4mm spacer plus an additional 1.5mm spacer alongside it on the drive side. This gives the same overall bottom bracket width but will move the crank arms across 1.5mm increasing drive side clearance between the crank arm and chainstay.:)

http://www.cyclesurgery.com/wheels-...s/bikes-components-bikewear/fcp-product/10838

Hopefully the bike shop will get it sorted out but that is one option to consider with your bottom bracket which may work.:)
 
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