thebob Posted June 4, 2018 Share Hi allSo I’ve been struggling with some shifting issues on my BMC Trailfox TF02. Setup is as follows: e-thirteen 9-46 cassette, 30t chainring, new shifter cable, X01 11 speed chain and a new XX1 chain. I have confirmed that the hanger is straight and that the limit screws are correct and that the chain length is right. So the issue i have is that the shifting is perfect for 90% of my rides, but at some point the rear mech starts skipping like the cable tension is too tight making the chain want to jump up to the next sprocket. It can also be set off after a big bunny hop or taking a big drop off. Get the bike home, slack the cable off and it shifts ok on the stand, get it out on the street and have to add a couple turns of tension back to get it shifting up properly. So it seems like an intermittent issue that I cannot get my head around. Any suggestions as to what to try or look at would be most appreciated. Link to comment Share on other sites More sharing options...
PeterF Posted June 4, 2018 Share Does the gear cable have enough slack to allow for suspension travel? Link to comment Share on other sites More sharing options...
ALLMTB Posted June 4, 2018 Share Check that there is enough slack in the cable housing when the suspension gets a compressed. When there is no weight on the bike it might look like there is enough slack, but once the suspension gets compressed the cable and housing can pull tight causing odd shifting and cable tension issues. Usually a problem when cables and housings get installed on full suspension bikes where the cable routing goes underneath the bb. Let all the air out from the shock, compress the bike untill it bottoms out and check that the housing is not pulled tight against the bb or somewhere else on the frame. I hope this makes sense. Link to comment Share on other sites More sharing options...
thebob Posted June 4, 2018 Share Think you guys are on to something. Doesn’t look like there is much slack under the frame. Will dive into it tomorrow afternoon and see if that is the issue Link to comment Share on other sites More sharing options...
BMXER Posted June 4, 2018 Share For perfect shifting, I recommend Shimano ???? Link to comment Share on other sites More sharing options...
AlanD Posted June 4, 2018 Share For perfect shifting, I recommend Shimano Wash your mouth out... MTB-More and Undun 2 Link to comment Share on other sites More sharing options...
Simon123 Posted June 4, 2018 Share For perfect shifting, I recommend Shimano Even as an XO1 Eagle groupset owner, I'd agree! Link to comment Share on other sites More sharing options...
PeterF Posted June 5, 2018 Share Think you guys are on to something. Doesn’t look like there is much slack under the frame. Will dive into it tomorrow afternoon and see if that is the issueJust to be safe you should check your chain growth with the chain on the 46t cog and the suspension compressed. The easiest is to disconnect the shock to make it easier to move the rear triangle up and down. If there is not enough slack in the chain you could stuff up your rear derailleur. Quagga 1 Link to comment Share on other sites More sharing options...
thebob Posted June 5, 2018 Share Just to be safe you should check your chain growth with the chain on the 46t cog and the suspension compressed. The easiest is to disconnect the shock to make it easier to move the rear triangle up and down. If there is not enough slack in the chain you could stuff up your rear derailleur. Yup, that was one of the first things I changed. Original chain was too tight, the new one is perfect. For perfect shifting, I recommend Shimano I am tempted. Never had a issue on my Deore equipped Trek Edited June 5, 2018 by the_bob Link to comment Share on other sites More sharing options...
Dicky DQ Posted June 5, 2018 Share Yup, that was one of the first things I changed. Original chain was too tight, the new one is perfect. I am tempted. Never had a issue on my Deore equipped Trek but did they have a proper 1 x? Link to comment Share on other sites More sharing options...
David Marshall Posted June 5, 2018 Share Are you sure that the new chain is not slipping on a worn gear? This will happen on the most worn gear only. Quagga 1 Link to comment Share on other sites More sharing options...
Adrian Fogg Posted June 5, 2018 Share Try a Shimano chain. With the E-thirteen cassette i found the SRAM chain to wide and caused shifting/grinding issues. Link to comment Share on other sites More sharing options...
thebob Posted June 5, 2018 Share Are you sure that the new chain is not slipping on a worn gear? This will happen on the most worn gear only. Chain and cassette are both brand new. Had the same issue with the stock 10-42 cassette and chain. Try a Shimano chain. With the E-thirteen cassette i found the SRAM chain to wide and caused shifting/grinding issues. I'll keep that in mind if it isn't the cable routing Link to comment Share on other sites More sharing options...
Bigjim Posted June 5, 2018 Share +1 for some sort of lack of cable slack under suspension load, sounds like the cable is getting hung up somewhere. Also look at possibly damaged cable outer? I ran SRAM chains on my 9-46 E13 with no issues, so would tend to discount that. What RD are you running - long cage? Link to comment Share on other sites More sharing options...
thebob Posted June 5, 2018 Share It's a standard SRAM X01 Type 2.0 11 speed rear mech. as per link below: https://www.sram.com/sram/mountain/products/x01-x-horizon-rear-derailleur Link to comment Share on other sites More sharing options...
thebob Posted June 5, 2018 Share Success! Issue was caused by not enough cable slack under the BB. Loosened the cable holders, adjusted everything for a bit more slack with the bike bottomed out and everything is groovy. Did some big (for me) hops and everything is staying put and no funny business with the rear mech. So happy to get this right, been haunting me for some time now! Still want to get back on the Shimano train though Link to comment Share on other sites More sharing options...
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