Mountain Bike Reviews Forum banner
1 - 4 of 4 Posts

·
Registered
Joined
·
2 Posts
Discussion Starter · #1 ·
I recently built a Kona King Kahuna with a Sram XX group. I am having serious trouble with the shifting from the small chainring to the big. It's very inconsistent. In other words, it shifts up perfectly 50% of the time and gets stuck and grinds between the two rings the other 50%. I've had a couple different mechanics at my lbs give it a go and no luck. We contacted Sram and they are sending a new chainring and front der. I'm wondering if anyone out there has experienced the same issue or if anyone has any ideas as to what may be the cause. I really want to ride my new bike! Thanks!
 

·
Registered
Joined
·
2,431 Posts
Did you get the XX as a whole gruppo, and if so did you specify to whom you bought it from what bike it was likely to go on.

Initially what strikes me is that the FD is not the one for the specific XX crank you have. Also the chain should never get stuck between rings, which points also to a fundamental incompatibility.

I had a similar occurrence - but I was trying to get a Dura-ace FD to shift on a 2-ring crankset. The derailleur wasn't really designed to shift out that far, so would shift sometimes and just miss getting up others.

Another point is the setup.....cables/outer etc. Is it all in good order with no poorly cut ends and using sram inner and outer.

Then there are the limits/cable tension - but this case sounds like no amount of adjustment will work.
 

·
Registered
Joined
·
172 Posts
I just went through the same thing. And when I say just went through it I mean I just got my bike running this morning.

My trouble was with an XO front derailleur. It shifted fine about 50% of the time. The other 50% of the time it would either grind without shifting or get thrown off to the outside altogether. My LBS contacted SRAM and they thought it was either the derailleur or the big ring. They sent me an XX replacement to try out. After that they were going to look at the rings.

According to the spec you want 1 to 3 mm of space between the cage and the teeth on the large ring. When set to spec the XX replacement behaved exactly the same way. Crappy shifting and grinding.

I raised the cage to 6mm above the ring and it is now shifting fine. When in the little ring there is 6mm of space between the cage and the teeth. When it's in the big ring there is 8mm of space between the cage and the ring. Just ran it for the first time today and had no issues at all.

Raise the derailleur and bit and see if it helps.
 
1 - 4 of 4 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top