Comments on: The Math Behind A Wide Range 2×11 Drivetrain

By: Eric

Eric — Wed, 30 Mar 2022 15:05:39 +0000

Calculating gear inches off the ISO rim size gives a relative difference between different wheel diameters but you need to take into account actual tire diameter for an accurate comparison. A 700×25 road tire and a 29×3″ mountain bike tire both have an ISO size of 622 for the bead seat diameter. Same gear inches with your method but drastically different in reality. Measuring the OD of the tire or doing a roll out test to measure circumference would be a better method.

By: alex mikolevine

alex mikolevine — Fri, 17 Apr 2020 23:28:07 +0000

Thanks for reasoning this out! I just had my one and only bike stolen, after customizing the gears many years ago to this: 48-34-22 crank (XTR back then could just barely do this, nothing can do it now?) and 11-36 cassette. I wanted to go fast downhill with road tires and climb long difficult climbs in dirt. 714% worked just fine! These big cassettes now make a double instead of triple crank possible, as you showed– but is there any new bike made that comes close to this? It sounds like your customization involves a lot of tricks: spaces in the chain and the crank, reboring the holes in the rings?
Do you think it is easier to buy a 1x and turn it into a 2x, or start with a 2x and change rings and cassette?

By: Paweł Łabaj

Paweł Łabaj — Sat, 31 Aug 2019 18:05:48 +0000

In reply to dirtdad.

Thanks the sharing. I thought that you found ready crankset and I didn’t think about replacing a ring.

I think I’ll try to use SRAM GX 1000 2×11 GXP 36-24T and replace outer ring. This set has also 64/104 mounts, so it should work.

Thanks again!

By: dirtdad

dirtdad — Fri, 30 Aug 2019 21:58:44 +0000

In reply to Paweł Łabaj. I started with a Shimano XT 785 crankset. It has a "standard" 64/104 bcd bolt pattern. I changed rings to an FSA 42T and a generic 26T. You might have to grind the rings to make them fit, but only the area around the bolt holes. I also needed to use some chainring spacers to get the distance between the rings right.

By: Paweł Łabaj

Paweł Łabaj — Fri, 30 Aug 2019 20:49:10 +0000

I am thinking about the same set up. However I have one big problem – where to buy or how to build 40-24T crankset.

Could you share a list of your drivetrain components?

By: dirtdad

dirtdad — Fri, 28 Sep 2018 01:55:10 +0000

In reply to Carolyn Franzone.

Thanks, the bike in the pics is a Salsa Cutthroat, so you are good. I found 3 ways to get a wide 2×11: Shimano with adapter, Shimano with a hacked combo rear derailleur, and SRAM 2×11 road with a 10 speed mtb rear derailleur. All work with a 10/42 cassette. I plan on making a follow up blog with more details.

By: Carolyn Franzone

Carolyn Franzone — Fri, 28 Sep 2018 00:48:54 +0000

Your setup looks great! I am buying a Salsa Cutthroat and am trying to decide gearing… I’ll be riding Tour Divide in 2019, so I need the low gears. I also ride/race gravel in the midwest, so I want to keep the top end. Will your setup work on a Cutthroat Rival?