[TP_Mantis]

Hi All,

I bought a larger chain ring for my fat bike (and chain) and what seemed like a simple project got more complicated.

I have Sram X7 - Low Direct Mount FD. there is no backing plate so it screws directly to the frame. The holes are circle and not oval - so no room for any height adjustment. How do i adjust the height? Are there backing plates i can get (where, quick google fu was a failure)? Do i need to buy a new FD? if so, how do i know what kind?

thanks!
Mantis

 

[TP_Mantis]

Bump - any thoughts would help

 

[aerius]

Unfortunately you're out of luck. SRAM makes a couple (possibly more) versions of the low direct mount derailleurs for different chainring sizes, if you change the chainring size you need to get the matching front derailleur. I can't say I'm a fan of this system.

 

[TP_Mantis]

Thanks aerius.
Can't say I am a fan either - but time to make do and Macgyver things where needed.

How can i find out the chain size on my current derailleur? and more important - how do i buy the right new one?

 

[Red Rock]

Front derailleurs are rated by chainring size. Your old derailleur was sized for the old chainring. The new front derailleur will have to be rated for the size of your new chainring. For X7 (2x10) it's either 36t or 38t max. If you chainring is bigger than that, X9 comes in 39t and 42t max.
Hope that helps.

 

[TP_Mantis]

Thanks so much - helps a ton!