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Chain sizing

ebarker9

Monkey
Oct 2, 2007
683
130
I have a 2017 Scott Gambler with en E13 LG1 chain guide and XTR/Zee 10 speed derailleur (Zee short cage grafted onto an XTR).

I wanted to try running without the lower chain guide roller because I was tired of trying to keep it running smoothly. To do this, I had to shorten the chain by a couple of links. On the smallest cog I still had to max out the B adjust to get tension on the chain. But in the largest cog, the derailleur is pretty much fully extended at full travel. I'm also getting a ton of chain slap noise (or the derailleur hitting the B adjust screw). I'd probably shorten by one more link, but concerned about damage in the unlikely event of bottoming out in the largest cog.

Suggestions?

PXL_20220917_194629816.jpg
 

buckoW

Turbo Monkey
Mar 1, 2007
3,375
3,789
Champery, Switzerland
That bike has a lot of rearward axle path/chain growth and is above what a short cage derailleur can handle. A medium cage Sram works the best or use the limit screw on the biggest cog so you can back off the b tension and shorten the chain.
 

buckoW

Turbo Monkey
Mar 1, 2007
3,375
3,789
Champery, Switzerland
Get rid of the two largest cogs and put a spacer in their place. Limit the dérailler and put the b tension back into a decent spot. Shimano deraileurs work better with less b tension from what I remember.
 

ebarker9

Monkey
Oct 2, 2007
683
130
Thanks for the response. I may just switch over to a GX DH setup, which I didn't realize was a medium cage, assuming I can find an xd driver for my hub. Does that lower roller help significantly with reducing chain slap? It definitely pedals a lot better without it but things are now certainly louder.
 

6thElement

Schrodinger's Immigrant
Jul 29, 2008
12,885
9,768
Thanks for the response. I may just switch over to a GX DH setup, which I didn't realize was a medium cage, assuming I can find an xd driver for my hub. Does that lower roller help significantly with reducing chain slap? It definitely pedals a lot better without it but things are now certainly louder.
I think the GX 7 speed cassette is normal HG driver. I've got it on my DH bike but bought it complete so haven't take it off. But as it's 11-25, versus the X01's 10-24 I'm pretty sure.
 

ebarker9

Monkey
Oct 2, 2007
683
130
I think the GX 7 speed cassette is normal HG driver. I've got it on my DH bike but bought it complete so haven't take it off. But as it's 11-25, versus the X01's 10-24 I'm pretty sure.
You're right, I just looked it up. Alright, well that's a pretty easy sell then.
 

Leafy

Monkey
Sep 13, 2019
312
219
How many teeth are on the largest cog? My gambler came with a full saint derailleur but has an 11-23 cassette (either saint, ultraga, or dura-ace based on how the rest of the bike is built), and it can bottom out the shock in the 23 cog.
 

buckoW

Turbo Monkey
Mar 1, 2007
3,375
3,789
Champery, Switzerland
How many teeth are on the largest cog? My gambler came with a full saint derailleur but has an 11-23 cassette (either saint, ultraga, or dura-ace based on how the rest of the bike is built), and it can bottom out the shock in the 23 cog.
Yes, it’s a lot to ask from a short cage dérailler. I would limit screw the 23t so you don’t have to be on the limit of what’s possible.
 

ebarker9

Monkey
Oct 2, 2007
683
130
I'll have to check but it's larger than 23. I just kept it out of the larger cogs riding today and I'm trying to source a GX dh drivetrain (rear derailleur seems to be hard to find in the US) longer term.