Shimano GRX

[David Tollefson]

Originally Posted by Mark McM

According to the BikeRumor article, the BCDs are 110mm/80mm. SRAM has a 120mm/80mm 4 arm crank that has a standard 39t/26t combination (and 74mm BCD fits chainrings down to 24t), so it is likely that a 28t or even a 26t chainring could be fit to the GRX crank. Perhaps an aftermarket chainring manufacturer will make smaller chainrings for this crank (are you listening TA and Stronglight?)

Yup, I've got a SRAM X5 crank waiting on the next build, 42/26.

[LGrider]

Happy to see this. If it had been around a year ago I'd have the 48x31 crank and 11-30 cassette instead of the standard Ultegra 50x34 and 11-32. The 11 tooth cog still wouldn't get much use even with a 48 tooth chainring. 12-29 would have been perfect.

[jfranci3]

Those RX810 shifters look like the RS500 / 105 5800 shifters, which looked horrible but felt good.


I like the looks of the GX cranks. I was looking at cheap SRAM PM options, realizing that it winds up being $200 more than Shimano. Shimano cranks are ugly and I would needed new rings. At least cranks look better.

[bigbill]

I like the crankset. The only thing I'd change about my gravel setup is to replace the 36 with a 34 on the crankset. 34/46 seems more useful. Otherwise, my R8000 derailleurs, 685 levers, and 785 calipers have been flawless on all kinds of surfaces including single track.

[John H.]

Need more cassettes.
Shimano needs to make Ultegra/XT level 11-36 and also XTR level 11-36 in 11 speed.

[jtbadge]

Originally Posted by John H.

Need more cassettes.
Shimano needs to make Ultegra/XT level 11-36 and also XTR level 11-36 in 11 speed.

SRAM 11 speed 11-36 works great with Shimano, as long as you don’t need it to fit a 10 speed freehub body.

[eddief]

just picked up a new Specialized Roubaix Di2 and had installed an Sram 11-36 cassette with a Praxis Zyante 48-32 crankset. Shifts perfectly. I was afraid the braze front derailleur tab would not allow the front d to mount low enough. It sits a bit more than 2mm above the outer ring, but still shifts perfectly.

Originally Posted by jtbadge

SRAM 11 speed 11-36 works great with Shimano, as long as you don’t need it to fit a 10 speed freehub body.

[John H.]

The SRAM cassette does work ok, but it is pretty porky.

Originally Posted by jtbadge

SRAM 11 speed 11-36 works great with Shimano, as long as you don’t need it to fit a 10 speed freehub body.

[marciero]

Am liking. Here we have a bona-fide road-ish subcompact group coming stock with 30t ring and can likely fit smaller. If I were building up a new gravel or camping bike I might consider this. I dont mind higher Q so much for these applications. Am currently stuck in 10sp land, so I am also encouraged by what this says for future availability of wide-gear 10sp cassettes. I dont find the group ugly, though I would not put that shadowy thing on my road or rando bikes.

[Gummee]

Originally Posted by marciero

Am liking. Here we have a bona-fide road-ish subcompact group coming stock with 30t ring and can likely fit smaller. If I were building up a new gravel or camping bike I might consider this. I dont mind higher Q so much for these applications. Am currently stuck in 10sp land, so I am also encouraged by what this says for future availability of wide-gear 10sp cassettes. I dont find the group ugly, though I would not put that shadowy thing on my road or rando bikes.

Most of the bikes these parts are aimed at have a 12x142 rear axle, Moving things out 2.5mm is just an adjustment for the wider rear.

M

[David Tollefson]

Originally Posted by Gummee

Most of the bikes these parts are aimed at have a 12x142 rear axle, Moving things out 2.5mm is just an adjustment for the wider rear.

M

The 142 axle does NOT move the cassette outboard relative to a 135 qr axle at all. That extra 7mm represents 3.5mm each side protruding into the dropout slot. The inside face (not the slot) span of the dropouts still remains at 135mm.

[scharny]

Originally Posted by jtbadge

SRAM 11 speed 11-36 works great with Shimano, as long as you don’t need it to fit a 10 speed freehub body.

I'm running one with an RX rear derailleur and a 46/30 FSA Energy Modular BB386EVO Adventure Crankset up front and it works well. R8000 rear derailleur was not so good.

[jdp211]

Originally Posted by Gummee

Most of the bikes these parts are aimed at have a 12x142 rear axle, Moving things out 2.5mm is just an adjustment for the wider rear.

M

Its also plainly stated that the 2.5mm adjustment is for wider tires and short chainstays

[dddd]

Originally Posted by jdp211

Its also plainly stated that the 2.5mm adjustment is for wider tires and short chainstays

Wider tires and shorter chainstays both compete for the same space as the chainrings, so in order to maintain frame structure there are limits to these constraints as well as chainring count and Q.
Some frames are curving/moving the chainstay below this interference zone in order to push what the space will allow.

A 2.5mm increase in chainline equals 5mm increase in symmetrical Q, which sort of reflects the increase from traditional 130mm Road to 135mm Disc/Gravel, yet road cranks have by now already been designed to accomodate 135mm in back. So the difference would seem to be only in part due to the fact that 100% of the Gravel bikes will have the larger rear axle spacing (no 130mm).

I suspect it is always going to be the case that the majority of gravel bikes end up having more space for tires than most owners will actually use, so if shopping for a gravel bike I might look for the one that can better use a crankset with current Road chainline dimension (since I never experience cross-chaining toward the small-small while riding, only toward the big-big).

[Mark McM]

Originally Posted by David Tollefson

The 142 axle does NOT move the cassette outboard relative to a 135 qr axle at all. That extra 7mm represents 3.5mm each side protruding into the dropout slot. The inside face (not the slot) span of the dropouts still remains at 135mm.

But the 135mm axle does move the cassette outboard by 2.5mm relative to a 130mm axle (standard road axle). Some other road cranks have also increased the chainline a bit to accommodate this (such as Campagnolo HO cranks). But as mentioned above, the chainline increase for GRX was more about chainstay clearance for wide tires/short chainstays, and being able to accommodate 1x chainlines was probably also a factor.