Short Crank Help

[Mr.Gib]

Greetings all,

Mrs Gib is suffering an injury and we need to go short on the cranks. 155mm or 160mm. It looks like my only decent option is Rotor. However Rotor seems to be going though a product change. The new crank look great but is super expensive. Too complicate matters I need a 24 mm axle. Scanning Ebay seems to indicate that finding a Rotor 3d24 in 155 length is unlikely. An google search of 160 mm cranksets doesn't turn up much either.

An other suggestions?

[AZR3]

Quick google search brought up this
https://speedandcomfort.com/products/alloy-short-cranks

[Lelandjt]

Lightning is my favorite crank for unusual lengths. They'll even do different length arms. Also, very weight weenie.

Edit: I just saw the requirement for a 24mm spindle so maybe nevermind. I've never seen a frame that couldn't take a 30mm spindle.

[Mr.Gib]

Quick google search brought up this
https://speedandcomfort.com/products/alloy-short-cranks

Thanks - they definitely have short cranks. But 770 grams and when you add in the BB Infinite bottom bracket that is required in order to maintain the warranty, then it's not much cheaper then the new stuff from Rotor. Shame the big three all stop at 165mm.

[TobinHatesYou]

Shimano 105 R7000 comes in 160mm and obviously it’s 24mm too. Not the sexiest option of course. Not sure when Shimano will start offering Ultegra/D-A in 160mm.

[jeanjacques]

Rotor Vegast, only 20g heavier than Aldhu, 100€ cheaper. And there is a new 24mm axle.
Don't forget the BSA30 bb to run 30mm axle on bsa frame.

[TobinHatesYou]

Edit: I just saw the requirement for a 24mm spindle so maybe nevermind. I've never seen a frame that couldn't take a 30mm spindle.

Just about any modern carbon Trek. BB90 can’t even take a DUB 28.99mm spindle.

[Lelandjt]

Edit: I just saw the requirement for a 24mm spindle so maybe nevermind. I've never seen a frame that couldn't take a 30mm spindle.

Just about any modern carbon Trek. BB90 can’t even take a DUB 28.99mm spindle.

Wow, for Trek and Sram to not be compatible is pretty wild.

[TobinHatesYou]

Wow, for Trek and Sram to not be compatible is pretty wild.

GXP exists.

[kytyree]

Take a look on the slowtwitch forum. They've got some folks there pretty into the shorter crank-arms, you might find some options that we're not all that familiar with here.

[morganb]

The 24mm Rotor are available in 155mm but you need to go through a special distributor. My shop was able to order in that size through QARV Imports. They are cheaper than the 3D+/ALDHU also.

[LouisN]

Shimano 105 R7000 comes in 160mm and obviously it’s 24mm too. Not the sexiest option of course. Not sure when Shimano will start offering Ultegra/D-A in 160mm.

That's what I ordered for my tiny legged twin daughters for their TT bikes.
I'll put the original Ultegra 8000 chainrings that were on the bikes on the 105 crank.
I would have liked to go Rotor 3D+ but for the same reasons cited before decided 105 was fine (short crank arms 3D+ are pricey !! And pooor bearings on BB86 frames with 30 mm spindles option).

louis

[Lelandjt]

Wow, for Trek and Sram to not be compatible is pretty wild.

GXP exists.

Weird, the press release for DUB said it was replacing both BB30 and GXP. Maybe they backpedaled that just because of Trek.

[Mr.Gib]

Thanks to TobinHatesYou. The Shimano 105 is really the only sensible option. The few other such cranks, Rotor, Praxis, etc. are a combination of insanely expensive, 30mm spindle, or impossible to get. In some cases all three. As it is, the Shimano crank in that length needs to come out of Asia.

Not to turn this into a crank length phylosophy discussion, but I just finished watching a super high-end fit on my wife involving pressure mapping, power output throughout the pedal stroke, the whole deal. Watching the power curve smooth out and increase in her bad leg as the crank was dialed shorter was eye openning. Change was from 170 to 160mm. The improvement in pedal stroke was visible. Mrs. Gib is a highly trained athlete, so we're not talking about some hacker who was way off on her bike fit.

[TobinHatesYou]

Glad I could help. In a way I wish manufacturers would stop offering half sizes like 167.5mm and 172.5mm in favor of a broader range...