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Discussion Starter · #1 ·
I may have posted this before and I think I'll start a new thread, but I have the Epic Carbon Comp 29er w/ the 2x10 drivetrain. I've never had X7 shifters before (it has a X-9 rear der), but I'm having lots of issues.

1) When riding downhill, in the larger chainring up front, I'm dropping the chain regularly. I work on bikes regularly and know what I'm doing, but this thing is problematic. I'm not dropping to the outside (limit screw is set properly)- It's dropping to the inside. So, on rocky, technical terrain, I'm in the bigger chainring, cruising down the hill and when I come to a switchback or semi-technical section where I slow and need to pedal through, the chain binds up and gets stuck (again, derailleur is still set in the higher chainring position, but chain has dropped to lower chainring or sometimes completely off on the inside). This is not only sucky for riding and I have to stop and put the chain back on, but it's gouging the carbon around the bottom bracket.

2) In the rear (I think this is more of an X7 issue, and not a 2x10 issue), I feel like there is no happy adjustment that works- if the cable is set to shift smoothly up, it has a delay or lag coming back down. Set it to come down better, and I have to "over-throw" the shifter to get it to shift up. Again, I know my stuff (was a shop mechanic for about 12 years and still work on bikes for folks regularly), but this thing just won't dial in. I talked to Specialized today and they said SOME of the Epics shipped with a derailleur hanger that had a little extra material on it (a fraction of a mm, he said), so I'll check that when I get home.

Anyone else having similar issues front or rear? I have a $4300 bike that has more shifting issues than any bike I've ever owned...
 

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I know my buddy had to modify his stock chain by removing either a link or two (i can't recall from his epic because of the same prob). After that, problem resolved. I think the stock chains vary in their # of links and should be considered problematic.
 

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Discussion Starter · #3 ·
Thanks- I checked and the chain could probably lose one link, but it'll be close to maxxing the rear derailleur if I stay in the big ring up front and go to the easiest in back- not really cross-gearing, but if that solves it, I'll give it a try.
 

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Check the hanger alignment if you haven't done so. Also check to see if the cage on the front is bent or too wide. And loose chainring bolts are a possibility.
Good luck and let us know what it is.
 

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What is on the back short, medium, or long...sounds like going long would help take up the slack...or maybe xo...might have a stronger spring...just an idea..also could look for any burrs on the chainring teeth....and remove...good luck...let us know what u find out..
 

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Not sure if you have resolved your issue? I've never had a smooth drivetrain or shifting experience on my 2011 Epic Comp Carbon 29er until now!!!

Oddly enough I was taking apart my drivetrain to clean it and actually figured out their was a bigger issue!!! Apparentally Specialized forgot a critical spacer in the assembly of the Bottom Bracket.

http://www.sram.com/_media/techdocs/95-6115-006-000 Rev C - MTB Cranksets.pdf

look at Pressfit GXP - the green diagram indicates a spacer 89.5 which was completely missing from my assembly!!! I couldnt belive it!!!!

THe bike literally shifts like a dream and the crank spins smoother than ever! I hope this helps
 

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Discussion Starter · #8 ·
Thanks gents. I tried removing the link with no difference- still drops. I did find a thread in the drivetrain forum where lots of folks ar having similar issues with the SRAM 2x10 drivetrains. One thread seems to Tink that itls poor tension in the rear derailleur spring, though I'm skeptical that this is the issue as my tension seems pretty good.

http://forums.mtbr.com/showthread.php?t=669708&highlight=drop

Fwiw, I did also notice that the front derailleur is set kinda high. Normally, I think of setting fd's about 2-3mm's above the largest chainring. The one on the epic is set about 8mm high, but there's apparently no way to adjust this- the way that the derailleur is mounted to the frame, there is no vertical adjustment. Never seen that before, but there it is.

@dpastore- thanks for that diagram and the tip. I'll take a peek at it this week and pull the bb apart- however, I'm not having shifting issues. It shifts fine and the bb rolls fine- it's just the chain dropping on every single descent that is driving me crazy and isn't acceptable for a bike that costs this much (or any bike over $500 for that matter).

Keep the ideas coming...
 

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Discussion Starter · #9 ·
I talked to SRAM yesterday and they said they've heard of some issues with the rear derailleur spring, but mine is tight and strong. They also said that there is no danger in the cross-chaining on a 2x10 and you should be able to ride in the big-big configuration. They ALSO said that Specialized asked for a special 38X24 configuration (typicallyl 39t is the smallest "big" ring on a 2x10) which forced them to essentially use a 3spd front crank with the top chainring removed instead of a 2x10 specific crank arm. I think this is the issue.
 

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alshead said:
I talked to SRAM yesterday and they said they've heard of some issues with the rear derailleur spring, but mine is tight and strong. They also said that there is no danger in the cross-chaining on a 2x10 and you should be able to ride in the big-big configuration. They ALSO said that Specialized asked for a special 38X24 configuration (typicallyl 39t is the smallest "big" ring on a 2x10) which forced them to essentially use a 3spd front crank with the top chainring removed instead of a 2x10 specific crank arm. I think this is the issue.
It's a bit rich the SRAM guys pinging Spec for this. The reason for the 24x38 rings is very simple - they offer very close to equivalent range (with a 36-tooth granny) when on a 29" that you get on a 26" with a 32 cassette. SRAM should have made XX or X-glide rings available in a 24x38 size, but they haven't. Hence all Spec 29" bikes get the same 24x38 Truvativ rings, and no X-Glide. If I want XX rings on my SW 29er, I need the 26x39 which drops me to the equivalent of a 28 rear granny (in 26" gearing) - which is too big for the climbing I do.

Seems like SRAM have mis-interpreted the extent of the 29" wave. I note that they have released an X0 24x38 chainring set at Sea Otter, but still no X-Glide.
 

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Not sure if you fixed your rear cassette shifting but you want to check your "b" adjustment screw. There may be too much space between the der. pulley and the cassette.
 

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Discussion Starter · #12 ·
Thanks Scuuder3, but I don't have shifting issues, I have chain drop issues- and it's up front.
 

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alshead said:
Fwiw, I did also notice that the front derailleur is set kinda high. Normally, I think of setting fd's about 2-3mm's above the largest chainring. The one on the epic is set about 8mm high, but there's apparently no way to adjust this- the way that the derailleur is mounted to the frame, there is no vertical adjustment. Never seen that before, but there it is.

Keep the ideas coming...
I suggest that you adjust your FD to ensure that it's height, as you suggest, is a mm or so above the big ring. Best to do a complete setup from scratch on the FD.
 

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Discussion Starter · #14 ·
Thanks skiwi. It's a direct mount derailleur. No way to change height adjustment.
 

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Don’t know if this is helpful or not. The crank is basically a 3x10 with the large ring taken off. Try running a 3x10 front shifter. Maybe that would change how far the FD is moved and help keep the chain on. Don’t know just throwing the idea out…
 

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Discussion Starter · #17 ·
Spacers?

Skiwi- what spacers? On the FD?

Here's a pic of the FD showing the height above the bigger chainring. No way to adjust it down. SRAM says it's supposed to be for a 39t chainring, so that could be the issue, but Specialized spec'd it...
 

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alshead said:
Skiwi- what spacers? On the FD?
Correct - there may be 2 spacers in the mounting holes for the DMD FD. These are used to "offset" the FD in relation to the mounting holes. I know the Shimano FD's have them, not sure about the X.7. If they are there, make sure that these have the correct orientation - they can be turned around 180 degrees.

You should have between 1-3mm of vertical clearance between the FD and the large chain ring, and 1.5mm of lateral clearance between each side of the FD cage and the respective chainring when on the Low and High stop respectively.

You certainly look like you have a greater clearance than that. If you don't have spacers, it wouldn't be too hard to expand the current mounting holes in the FD to lower the FD mounting. You'll need to make up a couple of alloy "plugs" to cover the excess space you'd have created...
 

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alshead said:
Skiwi- what spacers? On the FD?
Just double checked the SRAM site - it deosn't look like you have any spacer, nor any room to make them.


Having another look at the clearance you have - it is way too much so that is the obvious reason you are skipping chains...I can't believe that this the correct fitting - are you sure that this is an X7 in a 39t chainring-specific size??? I'd swear that they have given you the X7 in a 42t chainring size. If they tell you you can't get X7 in chainring-specific sizes, they need to learn a thing or two.....

BTW, the SRAM FD's also come in S1, S2 & S3-specific fittings. I believe that you should be looking at the S3 fitting for this frame.

S1 - Easy to recognise, as it is the only one with a 42.7mm gap between the centres of the 2x mounting holes!

S2 - Has a smaller 22.1mm gap between the centres of the 2x mounting holes. These 2x holes are also offset by aprox 5mm, with the front one being set further out (i.e. closer to the derailleur cage). The front mounting hole is almost flush with the inner cage of the derailleur when fully retracted (i.e. as it comes out of the box)

S3 - Also has 22.1mm gap between the centres of the 2x mounting holes. However, these 2x holes are flat, not offset. The inner cage of the derailleur sits a fair way out from the mounting bracket (aprox 16.75mm measured from the inside of the mount bracket to the outside of the INNER cage) when fully retracted (i.e. as it comes out of the box)
 

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Discussion Starter · #20 ·
F Der Specs

SkiWi- you are a good man. I talked to Specialized again yesterday and the guy told me he hadn't heard anything about this issue- even though I had just called a week earlier about this issue. He also said that he was aware of the "few people" talking about it on MTBR, and then went on to say AGAIN that he hadn't heard anything about this issue (apparently, it's his job to monitor MTBR for Spec related stuff). I love Specialized stuff, and have always had really good luck with their CS, but this was just plain frustrating.

As for you questions about the FD- I pulled her apart and snapped some shots. I most definitely have the S3 model, and it's spec'd for a 39t chainring (the bike comes with a 38). There were some numbers on the lower cage, but they're nearly impossible to read- the stamp says "chainstay angle," but I can't read the numbers. The guy at Specialized said I could take it into my LBS and see if they can contact their Spec Warranty Rep and swap out the 38t chainring for a 39t. Maybe that will help, but I'm skeptical and wonder if it'll jack my shifting elsewhere...

I also don't know how folks post text along w/ images, so all images will be below:
1. Frame without der or spacer/ mount
2. Spacer/ Mount
3. FD
4. Backside- you can see the S3 and 39 stamps
5. The washers/ spacers on the drive side
 

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