I have a 26" inseam and have been riding on 165mm (FSA gossamer cranks on a compact double BB30) through the hills, giving me nasty knee pain. I'm looking to go to shorter 155mm cranks, but having a very hard time finding reasonably priced options, and FSA doesn't make them that size. My solution is to have 175 mm cranks shortened for me.

Does anyone know where I can find FSA crank arms only used or new?

That way I can have just the crank arm shortened and not have to replace anything else or mess with the BB.

What if your bike is just too big?

How did you arrive at 155mm?

Why are you certain that the crank arm length is the issue and not something else?

EDIT: and, here. Not so difficult, non?

Cut arm.
Drill new hole.
Tap it.
Attach pedal.

Drills and Taps? Are you nuts?
I'm pretty sure the correct procedure involves a hack saw, duct tape and super glue.

I thought it involved an miniaturized rail gun, two lab rats, a stack of Keith Urban CDs, and bag of *****s.

But seriously OP, what size is your bike, are you sure your positioning is correct, and exactly where in your knees are you feeling pain, and under what circumstances?

I'm keen on getting shorter cranks, just want to know if there is a website other than ebay where people sell used crank arms so I can swap mine out easily.

If you're wondering how I came to this conclusion:
I'm on a 44 compact, have gone through fitting algorithms, and done all the adjustments one could cheaply do, including raising the seat, changing clip position and seat fore/aft. I'm an engineer and have done a good deal of research on this. The literature states what is of course intuitive, that crank arm, just like everything else on a bicycle, should be scaled for size of the rider. In this case it's femur length. I know many (normal sized) cyclists don't mess with shorter cranks, but for the extreme ends of the hieght spectrum, the research is clear.

https://www.scopus.com/redirect/linki...cb9490a24a9c18

https://www.scopus.com/redirect/linki...4bea19651139fe


https://www.scopus.com/redirect/linki...5d4ec8a00c2e9f


https://www.scopus.com/redirect/linki...b5b0f5e5eb9999


https://www.scopus.com/redirect/linki...1ff4f998b02547


BUT anyway, back to the first question. FSA gossamer crank only, or recommendations for shorter road cranks, think I could find it somewhere online fairly cheaply?

Thank you.
-r

How about stacking your shoes 1cm?

I suspect crank length is not the issue.

How long have you been riding?
Do you have an estimate of your power/weight?
What cadence do you climb at?

Haha nicely done.

Question to op, are you 4 ft tall?

I honestly though the smallest cranks available were 170 which incidentally are what's on my good lady's steed

gear selection when riding? as mentioned by someone else, what cadence?

No. TA cranks have always been available in lengths from 150mm to 185mm, and some specialty places (e.g. recumbent outfitters, Leonard Zinn) offer even longer or shorter arms.

Not a very economical option, but these are supposed to be adjustable
https://www.powercranks.com/Productdescription.html

If you have an FSA Gossamer BB30, you need to change out the whole crankset, not just the arms - the arm and spider are integrated on the right side.

I've never heard of cranks that short.

https://bikesmithdesign.com/Short_Cranks/index.html
And use a BB30 BB adapter as you may not find any short BB30 cranks

Yep, exactly what I did for one of my juniors; his workmanship is excellent and fast. I had him shorten a set of Tiagra 175s and used BB30 adapters; the cranks have been perfect.

@JT Right, FSA doesn't make shorter cranks. Your link to bikesmithdesign is exactly where I ended up too. That's why I was asking about FSA cranks only. I'd like to send him a set of 175mm arms that he can shorten to 155mm. Seems so simple but it looks like it'll have to be the whole set or nothing.

@ John, thanks, I've seen the TA and Zinn cranks, but was hoping to do it a bit cheaper than that.

Yes, you're right, not so difficult. I see those on ebay, mostly for bmx bikes. I just don't know enough about which one of those will work for a road application with my compact double and what BB I'll need to get to mate with it. Right now my BB30 doesn't seem compatible with much, and I'm not clear on what the advantages/disadvantages are of the square taper or other designs.

I had a set of these Phil Wood crank shorteners on the back of my tandem when my kids were little, but I sold them years ago. Not sure if they're still made.

I picked up these 155mm TA arms on eBay last week for $30. Keep your eyes peeled.

** Miche makes a 155 Young. Available from Wiggles: **

https://www.wiggle.co.uk/miche-young-chainset/

Potenital options! Thanks guys.

^^^ The brand is Miche. The model is Young. I assume it's meant for kids and juniors.