Electronic Shifting, 12 Speed, Chain Sizing and Varying Cassette and Chainring Sizes

harringtonp

Bought a new 1x Giant Revolt gravel last November, came with a SRAM Rival XPLR eTap AXS 12 speed rear derailleur, 10-44 speed cassette and 40 chainring. The chain that came with it had 116 links and shifting was perfect as you would expect with a new bike.

I'm in the process of converting it to a "race" setup using a different wheelset with a 10-30 12 speed cassette and 46 chainring. Sized a new chain according to the large-large + 4 links principle (yes its 4 rather than 2 for this derailleur) and this comes out 106+4 = 110 links

Put the chain on and found I couldn't shift into the 5 larger sprockets. Before cutting to 110 links, I did try it with 116 links and while I could reach more of the larger sprockets I couldn't reach the largest ones. So the shorter chain reduced the range. Manually pushing the derailleur forward (to release the pressure) and shifting did allow change and once on larger sprockets the chain stayed there and ran smoothly.

I then went at the B adjustment screw and after about 10 full anticlockwise rotations, I found I could shift into all 12 sprockets. The thing is while shifting is smooth going up the sprockets to lower gears, when coming down to higher gears sprockets are skipped. I can get any sprocket I want though by going up again. This is all done on a bike stand BTW, behaviour may be slightly different on the road.

As you'll see at:

https://support.sram.com/hc/en-us/articles/6014226075035-Are-SRAM-XPLR-eTap-AXS-parts-compatible-with-other-SRAM-components-

while they state that 10-44 and 10-36 cassettes are supported, there is no mention of other sizes though they do clearly sort of work

There seems to be very little info out there on these type of issues, would anyone have experience of these type of conversions or have found links to good articles which discuss these vagaries ?

koutoubia

I would connect the groupset with the app and make the very minor adjustments thru there.

I had the same with my force but was using a 12sp Campagnolo chain and cassette. Dialled it in with the app and it's spot on.