changing compact crank gearing
#1
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changing compact crank gearing
I have a 2016 Domane 11 speed, Di2 shifting I am starting to use as a gravel bike. I am thinking I may be better running lower gearing than Ultegra 50-34 that came on it, do I have any options in this direction?
I expect one answer will be I have to change the entire crankset. Be nice if I didn't though.
Thanks!
I expect one answer will be I have to change the entire crankset. Be nice if I didn't though.
Thanks!
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Whats that largest cog in the back?
If there is a 34T in front then I at least want a 34T in back so I can go to 1:1. Even at one to one I usually can't maintain it for very long so I end up going to my Size 12-30". Over the past year I have been very happy with a 46/30 Square Taper Compact Crank from bikinGreen.
https://www.ebay.com/itm/124754009124
If there is a 34T in front then I at least want a 34T in back so I can go to 1:1. Even at one to one I usually can't maintain it for very long so I end up going to my Size 12-30". Over the past year I have been very happy with a 46/30 Square Taper Compact Crank from bikinGreen.
https://www.ebay.com/itm/124754009124
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#3
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You have to change the crankset. The cheapest option is a grx-610 with 46/30 chain rings. The next is a grx-810 with 48/31 chain rings. Both will need spacing washers if you don't want a +2.5mm chainline.
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if you have 11-28 cassette (?) - 11-30 or 11-32 cassette will provide a lower gear
might need a longer cage RD if the bike is equipped with short cage RD - and/or additional chain length (?) to prevent damage if you shift into 'big/big'
.
might need a longer cage RD if the bike is equipped with short cage RD - and/or additional chain length (?) to prevent damage if you shift into 'big/big'
.
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For 11 I would say a GRX 11 crank, 30/46 rings, you'll need a bottom bracket, about $170 all told. If you can source the crank.
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Pardon my ignorance; how does adding spacers to a crankset decrease the chain line? Or am I misunderstanding you?
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#7
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I recently bought a 46/30 chainring set for my 110mm BCD crankset (turning one of my bikes into something that will help this fat, old guy up hills). Look up "bikinGreen" and see if they have something that would work for you. I haven't put a lot of miles on them, but they look like a decent product.
John
PS I got mine on Amazon.
John
PS I got mine on Amazon.
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I am not so sure. I understand that Shimano gravel cranks have a chain line which is further out from the centerline of the bike than its road cranks.
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#11
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"I am thinking I may be better running lower gearing than Ultegra 50-34 that came on it"
Sometimes we over think things! Try it first. Unless you have some pretty challanging hills with soft gravel to climb, the 33 gear inches even a 28T rear cog gives you covers a lot of situations. If you have a 32T or higher rear cog, thats even better.
I think one gear lower (-10%) on firm gravel would require about the same effort as the low gear you use now on good paved roads. If you have that you"ll probably be fine with what you have.
Sometimes we over think things! Try it first. Unless you have some pretty challanging hills with soft gravel to climb, the 33 gear inches even a 28T rear cog gives you covers a lot of situations. If you have a 32T or higher rear cog, thats even better.
I think one gear lower (-10%) on firm gravel would require about the same effort as the low gear you use now on good paved roads. If you have that you"ll probably be fine with what you have.
Last edited by xroadcharlie; 06-08-22 at 08:06 PM.
#12
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The OP makes it sound like they have tried it.
I think one gear lower (-10%) on firm gravel would require about the same effort as the low gear you use now on good paved roads. If you have that you"ll probably be fine with what you have.
Out in the Seattle area, I'm nearly always comfortable on a 34-28 on the paved roads. My gravel bike has a 24-32, and I make substantial use of that gear.
#13
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The cranks use normal 24mm spindle shimano compatible BBs. I use wheels manufacturing thread together with angular contact bearings.
I use these cranks with sram axs 12 drivetrain.
Last edited by DaveSSS; 06-09-22 at 07:15 AM.
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the whole compatibility thing seems somewhat complicated, especially when you review the Shimano guidelines, especially when it comes to Di2 setup.
The chainline may vary quite a bit going from 'road' to 'gravel' components, depending on the frame, the mix of Drivetrain components, and the FD compatibility for Di2.
I would expect the newer 'gravel' designed components would be designed for a 142+ rear width, not road or cx width - which affects chainline, especially for 2x.
Simplest might be to do a cassette range adaptation and get a Di2 RD which can handle the broader gear range. Then, though more costly, getting the chainrings which might fit the Ultegra cranks, 48 or 46 x 32 (30?) - don't really have a handle on what the lowest inside ring could be on Di2 compatible cranks.
...sounds/looks a bit complicated - not knowing how finicky Di2 can be...
Ride On
Yuri
The chainline may vary quite a bit going from 'road' to 'gravel' components, depending on the frame, the mix of Drivetrain components, and the FD compatibility for Di2.
I would expect the newer 'gravel' designed components would be designed for a 142+ rear width, not road or cx width - which affects chainline, especially for 2x.
Simplest might be to do a cassette range adaptation and get a Di2 RD which can handle the broader gear range. Then, though more costly, getting the chainrings which might fit the Ultegra cranks, 48 or 46 x 32 (30?) - don't really have a handle on what the lowest inside ring could be on Di2 compatible cranks.
...sounds/looks a bit complicated - not knowing how finicky Di2 can be...
Ride On
Yuri
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the whole compatibility thing seems somewhat complicated, especially when you review the Shimano guidelines, especially when it comes to Di2 setup.
The chainline may vary quite a bit going from 'road' to 'gravel' components, depending on the frame, the mix of Drivetrain components, and the FD compatibility for Di2.
I would expect the newer 'gravel' designed components would be designed for a 142+ rear width, not road or cx width - which affects chainline, especially for 2x.
Simplest might be to do a cassette range adaptation and get a Di2 RD which can handle the broader gear range. Then, though more costly, getting the chainrings which might fit the Ultegra cranks, 48 or 46 x 32 (30?) - don't really have a handle on what the lowest inside ring could be on Di2 compatible cranks.
...sounds/looks a bit complicated - not knowing how finicky Di2 can be...
Ride On
Yuri
The chainline may vary quite a bit going from 'road' to 'gravel' components, depending on the frame, the mix of Drivetrain components, and the FD compatibility for Di2.
I would expect the newer 'gravel' designed components would be designed for a 142+ rear width, not road or cx width - which affects chainline, especially for 2x.
Simplest might be to do a cassette range adaptation and get a Di2 RD which can handle the broader gear range. Then, though more costly, getting the chainrings which might fit the Ultegra cranks, 48 or 46 x 32 (30?) - don't really have a handle on what the lowest inside ring could be on Di2 compatible cranks.
...sounds/looks a bit complicated - not knowing how finicky Di2 can be...
Ride On
Yuri
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If yours is like the new Domanes get a long cage rear derailleur and you can go up to a 34T in the rear. May be a 36T.