In a couple of recent posts I asked about the importance of crank arm length. Specifically to riders who have longer inseams. I gather from the responses and the information available on the web that yes in fact there is some indication that length does matter - (sorry couldn't resist and it's Friday)

So my question is - if there is an advantage and need, why are crank arms with lengths over 175mm so difficult to find. I would think that like most other parts on a bike that there would be a full range of sizes available. And not just in the DA line.

Is this really a huge deal or are we talking .5% difference... And have the bike manufacturers looked at the delta and the cost to re-tool for the longer lengths and found it not to be worth the investment.

At 6'3" and a 36" inseam - It would indicate I should be looking at 185 to 190mm cranks - but you'd almost have to have them custom made - and I know there are alot of tall riders out there - and we all can't be doing this - so I can only assume that most tall riders are using the 175mm without issue.

Thoughts?

DA and Record come in 180. TA's come in 185. Longer in custom made as you have noted. One of the problems is with frame design and manufacturing. Companies are already cutting back to 5 stock frame sizes. To design a frame properly for 190 mm or longer cranks, the BB must be raised accordingly. This would mean setting up the jigs one more time for just a few frames. Many frames already have the same BB drop and seat angle throughout the size range to save costs. Also, you will run into tire/toe overlap with long cranks - not an issue and high speed, but it freaks some newbies out and can cause a low speed crash if you are not aware of it.

There are just not enough tall riders who want to use longer than 180/185's to justify the expense.

Who is TA... I am interested in 185 mm cranks.

175 is impossible for me to ride... just too short (I am 6'6"), I use DA 180 mm and they are really nice...

https://www.peterwhitecycles.com/carmina.asp (factory made 185mm, but you got to back to square taper)

Specialities TA are a well respected French manufacturer. Their cranks and chainrings are of the highest quality.
https://www.specialites-ta.com/produits/crank_gb.htm
US distrubutor is
https://www.peterwhitecycles.com/alize.asp

must be an echo....

You just have to wonder in this case if running a small frame is really worth it. Maybe it's better to run a larger frame with longer downtube/top tube and put up with the longer wheelbase than to try risking it with smaller frame and long stem.

Wouldn't the ride get a little rough as the pedal hit the ground at the bottom of each down stroke?

And you thought that ticking sound coming from the BB was anoying.



Wish there was a shop where you could borrow parts to try so that you knew it was worth the money.
Just hate going out and buying $400 worth of new parts only to find that they really don't help much.

Until I can find some used 185 cheap - I think I'll muddle along with the 175 that I have... or until that big loto check shows up - then I'll be looking at the all custom...

Thanks -

I think people are really just starting to realize that we need a much wider array of cranklengths (not just longer ones for us taller folks, but shorter ones for shorter folks).

Lennard Zinn sells custom length cranks over 200mm (By his formula I should be at 200 or 210) and also as part of full custom bikes with appropriately higher BBs.

Once the word gets out more, demand will increase and we'll start to see more variety.

https://www.velonews.com/tech/report/...es/5257.0.html
https://www.nettally.com/palmk/crankset.html