Piplodocus

Hello!

To cut a long story short, Shimano GRX doesn't have the same gear range on 1x as SRAM Force/Rival/Apex (11-42t vs 10-42t), so with Shimano you get 380% range vs SRAMs 420% range (regardless of what size front chain ring you put on it, that just shift the whole lot up or down).

I also hear though there's compatibility between SRAMs 11-speed and Shimanos 11-speed chains/cassettes/derailleurs (obvs not between levers and derailleurs or brakes, but that doesn't matter), and *supposedly* SRAM purposefully followed Shimano chain/cassette/spacing when making 11sp. But there's a lot of mixed/old info, additional info that means it probably isn't *always* the case, etc, etc, and nothing I found that directly and clearly compares the latest SRAM and Shimano that includes GRX. I've read a lot of pages that lead to no final conclusion! So the questions are...

• Can I happily use an 11-sp SRAM 10-42t cassette with an 11sp GRX groupset?
• Doesn't SRAM have different freehubs depending if it's road or MTB: the XD vs XDR? But is it true that SRAMs MTB and road cassettes fit either driver though, so either all or no SRAM cassettes are compatible with GRX, you just need whatever freehub (XD or XDR) that matches that particular wheels/frame, so isn't a worry. Or can you fit any SRAM cassette on any SRAM freehub, but they don't necessarily have the same gear spacing between MTB and road?
• Doesn't Shimano have some other smaller new freehub body too and does now do some cassettes with smaller 10-tooth cogs? Are they all incompatible with 11-speed GRX though, else don't have wide enough ranging cassettes (i.e. I might get 10 teeth, but not on the same cassette as a 42t). Basically if you can point me to any cassette that gives me 10-42t that works with GRX-810 11-speed would be dandy.

Any help much appreciated. And no, 2x isn't the alternative answer! ;-) (Neither unfortunately is a wider range 1x12 GRX that comes out the box with a bigger front chain ring!)

redlude97

gear spacing and compatibility between 11 speed groups is the same, mix and match. for 11 speed the only option is the sram xd driver to get a 10t cog or shimano microspline with the m9100(10-45) 11 speed cassette. sram xdr is 12 speed only i believe

Piplodocus

Cheers for the quick answer.

Hooray! My Fairy Godmother says I shall go to the ball!

My large gears spreadsheets and hours of daydreaming obviously weren't in vain then!

Piplodocus

BTW, Any reason I should go for that M9100 10-45t and a microspline over the SRAM? Or is the SRAM probably better as the XD is currently more ubiquitous than the newer microspline?

The wider 10-45 is wider range than the 10-42 so I'd also gain an extra 1.5 gear inches in the bottom end too! Not sure what point it could go too far though and start making the jumps between gears too big even, although it's not much more on the low end so not sure how noticeable it'd be. Will do some more head scratching either way though.

Piplodocus

(P.S. I think the M8100 equivalent version for >£100 less would be the more likely for now, but I only found that after googling the 9100!)

redlude97

I think m8100 only comes in 12 speed? Yea XD is way more common and cheaper. The m9100 cassette alone is $380. Things are a lot cheaper if you stick to 11-4X

loheiman

I went from a 11-42 and moved to a 10-42 and dropped my chainring from a 42T to 38T and am very happy with the decision. When running 1x, the more range the better. The SRAM XG-1150 10-42 cassette (which is quite a nice cassette at only 394g and made entirely of steel) can be had for ~$100 so it doesn't really cost that much more than a 11-42. You do have to get a XD freehub for your wheelset which may be an additional cost.

Piplodocus

Oh yes, you're correct, the 8100 is 12-speed.

I think the more sensibly priced and easier to find answer lies in the XD driver and SRAM cassette then. Thanks everyone for your input.