kida5887

I'm trying to convert my hollowtech bb/crankset (Deore M590) to a velo orange triple with a square taper on my 2016 Salsa Marrakesh. I'm having some trouble finding the right information about spindle length for the new square tapered bb. I emailed Salsa and they recommended the 124mm based upon Velo Orange's "recommendation," but it's too narrow, causing my front derailleur to be unable to shift into the lowest cog and to push way out beyond the largest cog and even hit the crank arms while pedaling. I tried shimming the tapers with some bits of beer can, but it's still too narrow.

Any thoughts on the best way to calculate the appropriate spindle length before I buy a new one? Should I just measure the Hollowtech spindle? I've noticed that the crank arms on the Hollowtech have a few degrees of outward flare, but the VO crank arms are at or near 90 degrees. This doesn't create a noticeable difference in feel, so I'm really only concerned about clearance and making the front derailleur line up with the chainrings. The most common BB spindle length after 124 is 127/127.5, but I'm not sure if that will be enough. I saw that Phil's hubs have some longer spindles, but I obviously don't want to go too long either.

tFUnK

Did you replace the front derailleur with a FD made for triples?

kida5887

The FD is made for a triple. The original crankset is a triple Shimano M590 hollowtech.

Jeff Neese

You always start with getting the chainline correct, which I think should be 45mm on that bike. Then adjust the front derailleur appropriately. It sounds like you're approaching it backwards, trying to make the new crankset match up to where your derailleur is currently adjusted.

It's unclear where you are in the process. Did you already install the square taper BB and new crankset? If so, you can measure how far off your chainline is and that will tell you whether you need a different size BB and by how much. Once you get the chainline correct, the rest is gravy. Read up:

All About Bicycle Chainline

mprince

Did you adjust the limit screws on the front derailleur? That will adjust it's "swing", but as others have mentioned it sounds like your chainline has moved far inward. A few measurements from center of seat tube to the center ring should show how much inward it has moved, that will tell you how much more spindle length you need.

And the beer can shims were a bad idea, sounds like a good way to damage the tapers on the new crank.

70sSanO

What I would do is put the chain on the middle ring and see what cog gets the chain perpendicular to the cassette/crank. It should be about in the center of the cassette. If it is more inward than center you can move the crank out by the amount it is inward from center.

While still in the middle chainring, shift to the lowest cog. Loosen the FD cable, and turn the low limit screw out. Check the gap between the inner cage plate and the chain. Now place the chain on the inner chainring. The chain will probably be against the inner cage plate.

What you are trying to do is determine how much more outboard the crank needs to go to give you a better chainline and be able to shift in the the inner chainring and have cage clearance in the lowest cog.

If the chainline is good, you’ll need to swap out your FD with one that will give more inboard movement. Sometimes this is not an easy task with mtb shifters.

John

squirtdad

you may have to adjust the front derailler height and twist especially if your new crankset has larger rings


https://www.parktool.com/blog/repair...eur-adjustment

himespau 

You asked Salsa, but did you ask Velo Orange? BB spindle lengths are crankset-specific, not frame-specific (assuming the BB is correct for that BB shell).

Darth Lefty 

^^^ what he said, but more so. It's a road crank. You need 5mm more spindle length to get it out to MTB-triple chain line to match your MTB-standard crank and derailleur and frame.

It might also not be compatible with indexing, if you are doing indexing. Some old style replica cranks have their rings spaced much closer together than a standard MTB triple. If you have the barcons with ratchets it's going to be ok, if you have the flat bar version with a trigger shifter you may have trouble. That would also require you to bring in the limit screws.

That just covers the chain line. You might need some luck with the crank clearance too. The touring bike came with a MTB crank for a reason, you need the width to have clearance within the chain stays for big tires and their fenders.

kida5887

Cool, thanks everyone. I think I've got what I need after measuring the chain line. I'm using friction shifters, so I shouldn't have any issues with indexing. I just need a spindle that sits out a little further.