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Old 04-02-12, 05:10 PM   #1
KB12
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Replacing a Sugino AT crank

Hello everyone,

I just built up a 1982 Trek 614 as a touring bike and while riding today noticed that 2 of the tabs in which the chainwheels bolt onto the crank are bent. This causes the chainwheels to move in and out as you pedal. I might be able to straighten them out, haven't tried yet. But if I can't, does anyone know what a good replacement would be? The original is a Sugino AT. I don't know anything about cranks and want to make sure I get the right size. Does it even matter as long as it is square taper?

Thanks for your help!
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Old 04-02-12, 06:30 PM   #2
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Fix or replace

I just picked up one of these bikes for myself, with the same crank. I think that'd be a good touring set-up with the granny gear.

First, you could try straightening things out a la Sheldon Brown's instructions. I think the ones for the spider might be the most appropriate, but you might be able to straighten out the tabs with a wrench. When I saw this, I thought the clothes pin idea was a good one - but have never done this myself.

http://sheldonbrown.com/straighten-chw.html

If you had to replace it, you might want to ask on the touring forum. I'd say a triple road crank, offhand - but some tourers still want a smaller granny gear than those have. I do think Sugino still makes a square taper crank good for touring. Any Japanese or American triple, square taper, crank should be the correct, JIS, standard (but you should check for that when you buy)

However, if you have to get new (or, new used), I wouldn't let the type of bottom bracket (e.g., square taper), etc. phase you if you can't get a square taper. Those trek BBs are standard and will take various cartridges and outboard bearings of all but the newest, raciest, $5000 carbon fiber bike bottom brackets. At worst, you'd have to get a new cartridge for the BB and those aren't expensive...at least not compared to cranks. Just make sure to match up the length (you can measure) center to center for crank arm length (e.g., 165mm 170mm, 175mm) - although, this doesn't seem to be a critical measurement from what I've read. 1 cm difference has never struck me as that large a difference compared to differences in human beings in height, leg length, etc.
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Old 04-03-12, 08:58 AM   #3
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If you end up replacing it you'll probably have to change out your spindle/bottom bracket since newer low-profile cranks use shorter spindles; I have a similar 80s touring triple and it requires a 127mm spindle. That being said you can probably raid your LBS/local co-op for a shorter spindle or go with a cartridge BB like a Shimano UN-55.

But try and fix the crank first, that's a nice one.
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Old 04-03-12, 09:15 AM   #4
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If you end up replacing it you'll probably have to change out your spindle/bottom bracket since newer low-profile cranks use shorter spindles; I have a similar 80s touring triple and it requires a 127mm spindle. That being said you can probably raid your LBS/local co-op for a shorter spindle or go with a cartridge BB like a Shimano UN-55.

But try and fix the crank first, that's a nice one.
I agree. Unless you put the exact model of crank back on the bike it is a good bet the spindle lenght will be different. Not all square tapers are the same and they range from 102 symetrical to 123+ asymetrical.

The shimano cartridge BBs are nice but just make sure it is correct for your chosen crankset.

Look at this! Even has the Sugino SingleKey releases still in it. http://www.ebay.com/itm/sugino-at-cr...item256f154530

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Old 04-04-12, 05:51 PM   #5
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Thanks to everyone who has responded. I was able to straighten it a little but its still off a bit. A little chain wheel wiggle shouldn't be a problem if its not affecting anything else, right?
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Old 04-05-12, 08:08 AM   #6
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Shouldn't be a problem... but it might get irritating having to trim the front derailleur more often to get rid of the rattling. Me, I don't worry about anything less than 1 mm on older chainwheels.
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Old 04-05-12, 08:24 AM   #7
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Originally Posted by Bianchigirll View Post
I agree. Unless you put the exact model of crank back on the bike it is a good bet the spindle lenght will be different. Not all square tapers are the same and they range from 102 symetrical to 123+ asymetrical.

The shimano cartridge BBs are nice but just make sure it is correct for your chosen crankset.

Look at this! Even has the Sugino SingleKey releases still in it. http://www.ebay.com/itm/sugino-at-cr...item256f154530

Not trying to hijack this thread, but have a question regarding that release key.
I have a similar Sugino crank, a mighty aero with 144 BCD and those Sugino SingleKey releases, I had no idea about those releases and have been using a pair of needle nose pliers in the open position to unscrew them, now upon a google search I see there is actually a small tabbed washer that you insert when removing with an allen key...does anyone know where one might find a couple of those?
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Old 04-05-12, 09:49 AM   #8
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Those are Sugino Autex self-extracting bolts. The tabbed washer is only used when installed the Autex core into the crank arm - once it's in you use the 6mm allen wrench to install/remove the cranks and the core stays in place. So unless you're removing the core you don't really need the washer (it'd be nice to have, though.)

I recently tried the Autex system on my Fuji and could not really get enough torque with the 6mm wrench; ended up removing them and using standard 8mm crank arm bolts.
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