Crank Arms/Rings/BB

Phantomrider · Feb 8, 2023

I recently acquired a new to me 2017 S40 that is very nicely equipped with E-Tap, Sram Force 39/53 rings and 175mm arms. For several years now I have ridden a v20 and an ICE VTX with 150mm cranks and 36/52 Q-Rings(110bcd) paired with PG1170 11-32 cassette, E-tap, the Cranksets are Sram Apex modified by Mark Stonich and have served me very well. I had some reluctance riding the 175’s and now after 150 or so miles I’m finding the cranks are just to long for me. So I’m having difficulty locating a short crank set that would accommodate the GPX BB and the 130BCD chain rings. The only alternative that I have discovered is to either purchase another set from Mark or install a square taper BB with a 155mm set of Origin8 cranks. I’ve been told the square taper BB is not a good idea and won’t hold up to the torque over time, I have no experience with them so truly have no clue. I have a quote from Mark for a new set and obviously the price has gone up since my last purchase. By the way, that Force crank and rings are just gorgeous on the bike.

So with all this said, I’m curious if anyone has a different solution they have either used or contemplated that I could entertain. Moving the crankset from one of the exiting machines isn’t an option as I will be riding all 3 depending on the day, weather, mood, etc. I am not opposed to going with a 1X drivetrain but need to remain 11 speed because the E-tap system is 11 speed and won’t support a cassette greater than 36 tooth.

appreciate any insight you may have.

Mathew Fy · Feb 8, 2023

I have used the Cobb crankset with success. It looks like the SRAM has quit the GXP format, but replacement bottom brackets and compatible cranks are still available, though limited in supply.

ALLOY GXP SHORT CRANKSET- CLEARANCE SALE!

Our Alloy Short Cranks are a John Cobb engineered product designed to improve speed and comfort on the bike for all athletes. These hot forged alloy cranks have a GXP style axle (22/24mm) that are easy to install and work well with all road frame bottom bracket standards. They are available in...

speedandcomfort.com

If you’re willing to get new a bottom bracket (I consider it a part that wears out), then the 24 mm format’s a good choice. I switched when going to the Rotor cranks system.

Here’s some discussion, I know many have had their crank arms shortened.

Power Meter Recommendations- might need new Crankset

I started investigating power meters for my 2019 v20. I thought a single sided crank-based system might be a good start. I went out and did some ID on my crank arms and they are SRAM APEX - GXP but they have been shortened. I assume I need a new crankset with a compatible single sided power...

forum.cruzbike.com

cpml123 · Feb 8, 2023

Here you go. It's 110bcd though. I have both Cobb and BBK cranks for my S40 and V20. Can't tell the difference.

BBK Road crank arms 155mm | eBay

Find many great new & used options and get the best deals for BBK Road crank arms 155mm at the best online prices at eBay! Free shipping for many products!

www.ebay.com

I think there are Cobb short cranks being sold in other sites.

Decher Kritzmire · Feb 8, 2023

I can't help with the Sram question but as an alternative I use a daVinci crank with 150 arm length and a White Industries square taper BB. Both are very nice quality and the BB is rock solid. They also come in 160 but not 155. daVinci makes one crank with multiple spiders to match your needs. My gearing is lower than your goal using the 110/74 triple spider but set up with no outer ring, a 44t middle and a 27t rotorQ inner.

chicorider · Feb 9, 2023

All of the above options are solid suggestions, to which I will add the Praxis Zayante carbon crank, which is moderately priced, goes down to 155mm, and is available either with or without rings. It also looks like it uses a standard three-bolt spider mount, meaning that you should be able to fit a 130bcd spider. You would need a newer 30mm bb, due to the larger diameter spindle.

https://praxiscycles.com/product/zayante-carbon/

Aerozine is another worth looking at, with a range of shorter cranks in aluminum and carbon. One thing I like I like about these is that many of them have a flip-chip at the pedal end that gives you 5mm of adjustment. Flip the chip one way for 150mm; flip it the other way for 155mm, for example. I have used a 160/165mm from them, and it worked well. Aerozine also sells sets with or without rings, and offers different spiders for a range of ring options. Like the Praxis, these also require a 30mm bb.