Login required to started new threads

Login required to post replies

GRX Chainring Questions
Quote | Reply
Has anyone found a way to put a 50/34 or 52/36 chainring set on a GRX crankset?

I use the same bike for road and gravel, and need bigger gears than what stock GRX allows. My plan was to run a standard Ultegra crank, but had to switch to a Di2 GRX derailleur to give enough space for a 40c tire, and had to change the crank to match spacing.

Thanks!

I am a bad runner.
I met Javier Gomez once.
I don't speak in miles.
I have opinions.
Quote Reply
Re: GRX Chainring Questions [Megaman] [ In reply to ]
Quote | Reply
Remember, a bigger tire changes your gearing.

48x11 on a 40c tire is like a 52/11 on a 28C.
Quote Reply
Re: GRX Chainring Questions [NordicSkier] [ In reply to ]
Quote | Reply
NordicSkier wrote:
48x11 on a 40c tire is like a 52/11 on a 28C.
The diameter of a 700c wheel with 40mm tires isn't even 4% higher than with 28mm tires. 48-11 on the 40mm isn't even as high as 50-11 on the 28mm.
And if the OP is using the same bike for both purposes, it's possible that they're using skinnier tires for pure paved rides.
Quote Reply
Re: GRX Chainring Questions [HTupolev] [ In reply to ]
Quote | Reply
HTupolev wrote:
NordicSkier wrote:
48x11 on a 40c tire is like a 52/11 on a 28C.

The diameter of a 700c wheel with 40mm tires isn't even 4% higher than with 28mm tires. 48-11 on the 40mm isn't even as high as 50-11 on the 28mm.
And if the OP is using the same bike for both purposes, it's possible that they're using skinnier tires for pure paved rides.

I didn't do the exact calculations.

I'm building an all road bike right now with GRX 48/31, 11-32. Road will be 32c, Gravel 38-40C.
Unless you are road racing, I don't see a need for a road crankset.
Quote Reply
Re: GRX Chainring Questions [NordicSkier] [ In reply to ]
Quote | Reply
NordicSkier wrote:
HTupolev wrote:
NordicSkier wrote:
48x11 on a 40c tire is like a 52/11 on a 28C.

The diameter of a 700c wheel with 40mm tires isn't even 4% higher than with 28mm tires. 48-11 on the 40mm isn't even as high as 50-11 on the 28mm.
And if the OP is using the same bike for both purposes, it's possible that they're using skinnier tires for pure paved rides.

I didn't do the exact calculations.

I'm building an all road bike right now with GRX 48/31, 11-32. Road will be 32c, Gravel 38-40C.
Unless you are road racing, I don't see a need for a road crankset.

Correct about switching wheels. I will be running 28c for some riding. The reason for bigger gearing is we have insane wind and on a slight downhill, 250w at 120rpm in max gear is more common than I'd like.

I am a bad runner.
I met Javier Gomez once.
I don't speak in miles.
I have opinions.
Quote Reply