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adamhell
07-06-2019, 04:20 PM
hello PL,
asking for some help or wisdom since i am having a new problem. i recently sold my crust evasion and replaced it with a crust bombora.

most all the parts were swapped onto the new frame successfully, except the shifting no longer works perfectly as it once did. it's set up 1x11, with sram rival 1 mated to a gx 11sp rear der. it's my understanding the cable pull is compatible between the road shifter and the mtn rear der, and this is evidenced by how this setup worked perfectly on the first bike.

what's happening now is the indexing is perfect for half the cassette (upper or lower depending on how much i tighten the barrel adjuster). the other 4-5 cogs are suuuuper jumpy. if i barrel adjust so it shifts into the 42t cog, then it won't shift into the 11t cog, and vice versa. somewhere in the mid range it gets all jumpy and screwed up (ie it only shifts well in ~half of the available cogs)

here is what i've tried so far:
- derailer hanger was inspected and brought into alignment at my local bike shop (though it wasn't super off since it's a brand new frame)
- housing and cable replaced (shimano teflon-coated cable for maximum slippery)
- several hours messing with the indexing, limit screws, and b-limit. (my local bike shop also had a go of it after they straightened the hanger - they were stumped)
- chain shortened to accommodate chainstay length difference
- multiple cable routing/position @ clamp. here is how it is currently routed:
https://nuxx.net/gallery/d/110004-2/IMG_8953.jpg

i am beginning to think there is something off about the shifter or derailer. perhaps the der cage is bent? there also might be some sand in the shifter mechanism?

has anyone had a similar problem where the obvious culprits (most notably derailer hanger) were not to blame? anyone have any other solutions to try?

thanks in advance!

Adam

yinzerniner
07-06-2019, 05:15 PM
most all the parts were swapped onto the new frame successfully, except the shifting no longer works perfectly as it once did. it's set up 1x11, with sram rival 1 mated to a gx 11sp rear der. it's my understanding the cable pull is compatible between the road shifter and the mtn rear der, and this is evidenced by how this setup worked perfectly on the first bike.

This isn't exactly true. Cable pull is compatible between road and mtb Exact Actuation, but I believe that all GX 11s and up RD's are actually X-Actuation which uses a different ratio.
The fact that it shifted perfectly on your previous setup might have been a lucky occurrence.

A pic of the outside of the derailleur would help with the diagnosis. Other than that, it could also be a chainline issue where the different frames have different positions between the RD and the chainring. I had this issue with a bike using Rival 1x when I changed out cranksets, and had to do some fiddling with spacers to get it just right.

jtbadge
07-06-2019, 08:33 PM
You need a 10 speed mountain derailleur if you’re going to use road shifters. “Should” work with 10 or 11 speed shifter/cassette.

Better, get a road (“CX1” or “1”) derailleur.

stien
07-06-2019, 08:38 PM
You need a 10 speed mountain derailleur if you’re going to use road shifters. “Should” work with 10 or 11 speed shifter/cassette.

Better, get a road (“CX1” or “1”) derailleur.

The internet seems to back this up.

adamhell
07-07-2019, 01:21 PM
ok thanks for the feedback!

looks like i was wrong about cable pull. the rear der is x-actuation. i'm going to use one of these honestly bizarre setups for the time being since i have the gx trigger shifter and the paul adapter in stock.
https://www.starbike.com/images/2018/paul-component-sram-shifter-mount-31.8mm-1-lowres.jpg

in the meantime can anyone tell me if the CX1 long cage rear derailer can wrap a 42t?

GOTHBROOKS
07-07-2019, 04:07 PM
my long cage apex1 rear clears a 42.

ltwtsculler91
07-07-2019, 04:42 PM
ok thanks for the feedback!

...

in the meantime can anyone tell me if the CX1 long cage rear derailer can wrap a 42t?


Long cage Apex1, Rival1, and Force1 RDs will wrap a 42t on the cassette.

The mid cage RD versions only go to 36t on the rear, so double check it's Long before purchase.