Having run SRAM for a good while I've recently given Shimano a go. Reasonably happy but would like to change crank arms from the current 175mm to some 170mm...
Questions is, if I am running a 11-46 cassette on a boost rear hub (Frame is an Ibis Ripmo) which of the many Shimano Chainline options works best? 53.4mm? Or will any of them work but some better than others?
On non boost the optimum chain line for me has been 49mm for 1x front and currently 11-46 rear. I've had chainrings that have been 51mm on non boost that haven't worked when back-pedalling on Shimano 40T and 42T cassettes.
I later discovered that Shimano doesn't actually claim their 40T or 42T cassettes were 1x certified but their 46T one is. So the tooth profile is different on the smaller ones causing more chain drops (for me it was only a quarter revolution). When I learned that I switched to SunRace and haven't had any problems since (I didn't actually buy a Shimano 46T cassette to find out - so annoyed with them, I was). I can back-pedal the SunRace 46T when I'm stuck in some muddy bog and it's fine now! No complaints.
On Boost they claim 53mm should be optimum.
Shimano's new 2019/2020 XTR Boost crankset is 52mm chain line though which I think might be the sweet spot.
RaceFace and Hope cranksets can have different offset chainrings which is very helpful. Their cranks will work on both Boost and non Boost.
Most SRAM and Shimano ones are specific to each width.
Hope it helps.
How do you find your Ripmo? I have a demo on one at the weekend 🙂
