1

I've got an old MTB hardtail GT Avalanche 1.0. Now it has SRAM X7 (3x10) crankset (but used in 1x10 setup with a nw chainring). This bike is my commuting and "road" bike.

With 36t chainring on the front I can't seem to ride as fast as I hopefully could with a larger one. So the question is: is it possible to install a road (or road-ish - like GRX mentioned in the title) double crankset and a derailleur on this bike? I want to leave flat handlebars in place in order not to make the geometry too strange.

Or, can I somehow use a double derailleur with a 3x crankset? Since I never use granny gear on this bike and don't like 3x mechs.

  • GRX is quite specific and different from other ones. Needs a different chainstay clearance and so on. What exact shifters do you have now? It should be possible to find larger cranks and keep your current shifters and front derrailleur. It would be strange to make a bastard between SRAM and Shimano. – Vladimir F Feb 28 at 11:51
  • I do not really get your last paragraph. What would you achieve? Just don't shift to the smallest chainring, don't bodge it with a different FD. – Vladimir F Feb 28 at 11:53
  • Now I have no fd and no shifter - I've removed them to make the bike more simple. To my mind 2x fd is more simple and threfore more reliable thing than a 3x one (I've got a double on my other bike and never had a problem with fd there). But... I might be wrong – k102 Feb 28 at 12:23
  • 1
    Yes, the 3x system is quite archaic and is not used on modern bikes. In that case you may use anything if it will place the chainrings at the right place (distance from the frame) so that the chainline is not skewed and if it has the same number of speeds (for chain compatibility). Because your frame is MTB, I would rather be looking at cranksets, FDs and shifters used for MTBs and hybrids. Don't forget that road bikes have different bottom bracket widths. Not sure about GRX, it might work too, it is made for wider tyres than road groupsets. – Vladimir F Feb 28 at 12:42
  • When you say "I can't seem to ride as fast as I hopefully could with a larger one", what exactly are you hoping to achieve? A 36-11 combination offers a cruising speed of 25mph, and 30+mph is possible for short periods. – Andy P Feb 28 at 12:58
2

The GRX is theoretically possible. Or at least better than road ones, bucause it s specifically designed for larger tyres so it gives more clearance for wider chainstays. It moves the chainline by 5 mm outward in comparison to road cranks.

Also, the 46-30T chainrings on FC-RX600-10 give a bit more clearance than compact road chainrings.

Still, your MTB frame's chainstay could be too wide. You will have to measure it or try it somewhere.

As for the flat bars, the Tiagra flat bar shifters SL-4700 should be compatible according to the compatibility chart.

| improve this answer | |
1

You're not gonna make that work. This issue is that all modern double cranks are 9 speed and above which will not pair well with a 7 speed rear and chain.

If you had a 9 speed rear I suggest somthing like a sub-compact or compact road crank from FSA and Shimano Sora derailleur and flat-bar trigger shifters (The Claris, Sora and Tiagra lines all include flat bar trigger shifters).

This assuming you have chainstay clearance for larger double rings of course.

I'd also hesitate to spend money on new components and then combine them with a old SRAM X3 setup. What I'd do in your situation is upgrade the rear drivetrain to an 11 speed 1x setup with a wider range cassette and get a bigger narrow-wide chainring. That will give you a higher high ratio while preserving the low ratios, stay simple and give you a shifting performance upgrade.

| improve this answer | |
  • 1
    hm... I guess you've messed the name (x7) of the crankset with the number of speeds, but I've explicitly mentioned that it's 10. maybe I should edit it somehow? – k102 Feb 28 at 15:40
  • 1
    My Claris s 8 speed, not 9 speed. I am not aware of any newer version, my is very recent. Not that it is imortant, because OP has a 1x10 drivetrain. – Vladimir F Feb 28 at 15:46
  • 1
    @VladimirF for some reason I thought the OP had a 7 speed rear (this is what I get for answering quesions too early in the morning) – Argenti Apparatus Feb 28 at 16:45

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.