Pukeskywalker

I'm building a touring bike that I'm going to be using for commuting as well. I'm worried the crankset I want does not exist...

Here are my weird requirements

- triple
- approx. 52t outer chain ring
- 180mm crank arms

I was all set to buy an XT crankset. Then I saw that the outer chain ring is 44t, which is too small for my commute... There are stretches of my commute where I am riding 53t x 12t and need it.

As far as I can tell, there are no MTB triples out there with outer chain rings bigger than 44t. I would be okay with buying a decent MTB triple and replacing the outer chain ring with a bigger one... ::edit.. doesn't look feasible::

My other choice is a road crankset, but I can't find any road triples that have ~52t chain rings and 180mm arms.

antokelly

you can get shimano triple with 52 outer chain ring or campag as far as i know .you could then change the rings to TA rings if you wish.

positron

Look for a vintage MTB crankset with 50.4 BCD and use any TA rings you want.

The sugino supermaxy came in lengths of 165-185 and the 50.4 rings canme anywhere from 22 or so all the way up to ~62.

https://www.flickr.com/photos/24722971@N05/5291272913/

I found a supermaxy set in 185 at a bike coop for ~25 bucks.

fietsbob

given 11 t cassettes the current rage .. 44 is plenty big
velo Orange has 46/30 doubles

ask Lennard Zinn, his bike building company has 180 and longer crank arms available..

Settle for 175 and Campag race triples set up nicely with a 52 42, and sub the 30 for a 26T.
.. OR 50 40, 24..

NoReg

Does this do it?

https://www.davincitandems.com/comp.html#cranks

https://www.whiteind.com/cranks/mountaincranks.html

xyzzy834

The Shimano Deore FC-M590 triple is available in 26-36-48 rings. If you can switch to a cassette with an 11-tooth gear, 48/11 will get you very close to 52/12. The longest Deore crank arms are 175mm, not 180 like you want either, although if you can detect a 2.5mm crank radius difference, you're far more sensitive than most cyclists.

If you plan to index shift the MTB crank, you know you need to use a road front derailleur and account for the wider default chainline, right?

Pukeskywalker

I've decided to go with the 180mm XTs and deal with the loss of speed. Down the road might replace the 44t chainring with a 48t.

I appreciate all the suggestions. There are 180mm triples out there with bigger chainrings, but they're all in the ~$400+ range..

I was also crunching the numbers on a weird alternative set up.... getting a 180mm road double, setting it up with 50/34... then getting one of the newer 36t rear cogs. You can get gear inches around 25.7, and the 180mm crank will make it feel even lower. Not quite the 22/24 gear inches sheldon says most mtbs have, but it's something.

Interesting! I did not know that. I'm going to be doing bar-end shifters on this one... might get a road derailleur anyways then...

xyzzy834

When you set up the MTB crank, move at least one of the spacers they give you from the drive side to the non-drive side. Hopefully, the XT spacers are 2.5mm each like the Deore spacers. If they are, normally 2 spacers will be specified for the drive side and one for the non-drive side. Moving one to the non-drive side will give you a 47.5mm chainline. You'll need it because I don't know of any road front derailleur that can reach the big ring at the 50mm chainline the MTB crank would be normally set up to be.

Edit: I say all of this on the assumption that you had planned to index shift the front with road STI shifters. If, in fact, you were planning to index shift it with MTB shifters, you'd need the MTB front derailleur.