Lance Roberts Posted November 10, 2015 Posted November 10, 2015 Hi everyone, I need some advice from all the knowledgeable Hubbers on an issue that I'm having with my 2015 Scott Scott 910. I've just upgraded my cassette, derailleur, shifter and chain to the new XT M8000. The cassette is a 42 - 11 and shifting works like a charm. My problem now is the chain line... I've left the old XT crank on the bike and it has a 32t Absolute Black Oval chainring on it. The line is fine on my 11t on the back, but when I get around the top three gears (32, 37 and 42) the chain is really bent. It's so bad that I can not back pedal while in 37 or 42, the chain jumps down to the middle of the cassette... What are my options now? Should I try a M8000 crank with the 53.4mm chainline? Or should I try to put spacers in between my oval chainring and the old crank to push it outward towards the 42t gear? I hope someone can give me some advise because I've got a race this weekend and still want to get some training in before it.
shaper Posted November 10, 2015 Posted November 10, 2015 Did you adjust your chain length for having a 42 at the back?
Lance Roberts Posted November 10, 2015 Author Posted November 10, 2015 Did you adjust your chain length for having a 42 at the back? I checked the chain length and the derailleur arm isn't over extending when I'm on the 42t, so I think it's ok. Will that affect the bending of the chain? I got the longest chain available, 116 links.
Mike Bike Posted November 10, 2015 Posted November 10, 2015 rather take a spacer out of the bb to move the chainring closer to the frame
ALLMTB Posted November 10, 2015 Posted November 10, 2015 Check if there is a spacer between the drive side BB cup and frame, you can remove that.Also put some spacers between the crank and chainring. Such as these:http://www.kalbo.co.za/productsCS.html
Lance Roberts Posted November 10, 2015 Author Posted November 10, 2015 Did you adjust your chain length for having a 42 at the back? Also, I previously had a 40t with 34t on the front, that was with a 116 link chain. So now I've gained 2 teeth on the rear with a 42t, but I dropped 2 teeth on the front with a 32t. So in my broken math it should be almost the same as previously...
ALLMTB Posted November 10, 2015 Posted November 10, 2015 rather take a spacer out of the bb to move the chainring closer to the frameBeat me to it!
Lance Roberts Posted November 10, 2015 Author Posted November 10, 2015 rather take a spacer out of the bb to move the chainring closer to the frame The bike has a pressfit BB and there are no spacers on the drive side.
JXV Posted November 10, 2015 Posted November 10, 2015 Also, I previously had a 40t with 34t on the front, that was with a 116 link chain. So now I've gained 2 teeth on the rear with a 42t, but I dropped 2 teeth on the front with a 32t. So in my broken math it should be almost the same as previously...Your chain must be able to wrap around the chain ring and the 42 plus 2 links (without the RD) when the suspension is at max travel. Your math is more or less correct, you should be able to use same chainlength with the new combo - if it was correct before.
JXV Posted November 10, 2015 Posted November 10, 2015 Check if there is a spacer between the drive side BB cup and frame, you can remove that.Also put some spacers between the crank and chainring. Such as these:http://www.kalbo.co.za/productsCS.htmlI used spacer washers between crank and chainring instead of removing the spacer ring under the BB so it would be easy to convert back to 2x10, just in case 1x10 didn't work out for me.
Falco Posted November 10, 2015 Posted November 10, 2015 The bike has a pressfit BB and there are no spacers on the drive side. I had this same problem on a 1x10 I did a while back. To get around the no spacer issue, I machined aluminium 3mm spacers to fit between the crankarm and the chainring, then used longer bolts. It looked fine and worked fine. It probably isn't something the manufacturers would approve of, but it worked 100%, I rode that bike for plenty k's without any issues.
Lance Roberts Posted November 10, 2015 Author Posted November 10, 2015 I used spacer washers between crank and chainring instead of removing the spacer ring under the BB so it would be easy to convert back to 2x10, just in case 1x10 didn't work out for me. Did you get the spacers from Kalbo? Or equivalent to those? Problem I'm seeing is that the 32t chainring does not sit flush with the crank, because it's smaller than the 34t the 32t sticks out a bit and I'm worried that the spacers wont fit over it... 32t 34t
Mike Bike Posted November 10, 2015 Posted November 10, 2015 The bike has a pressfit BB and there are no spacers on the drive side.is the chainring on the inside or outside of the spider?
Lance Roberts Posted November 10, 2015 Author Posted November 10, 2015 is the chainring on the inside or outside of the spider? Inside of the spider, it replaced the large chainring that came with the crank. It's a 2x crank.
Matchstix Posted November 10, 2015 Posted November 10, 2015 I would not remove the spacer on the bb unless you can make sure your crank still stays centred. If it is a 2x crank you need to use spacers on the inside of the crank arm, outside of the chainring. Try a get the chainring to beas close as possible tothe centre of the casette.
Mike Bike Posted November 10, 2015 Posted November 10, 2015 Inside of the spider, it replaced the large chainring that came with the crank. It's a 2x crank.and there is no spacer on the crank spindle between the spider and the bb? if so the only way out is to space the chainring
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