olek

Hi guys

As a part of my 'new' bike restoration (very neglected specimen), I am trying to take apart old Sugino Mighty Tour crankset. 4 out of 5 chainring bolts loosened OK, although they were tight and I needed to use longer 5mm 'wrench', shorter one was not providing enough torque.

Problem is that on the 5th one, nut is spinning. Of course, I have park tool to catch those damn slots in it, and I even managed to catch the end of it on another allen wrench that was slipped through another chanring bolts' hole - to stop it from moving, but of course, with enough torque applied, tools just bends and slips out with a happy - BOING - sound.

Right now that thing is soaking in PB Blaster while I think that maybe I should rethink taking it apart after all. I have managed to clean it OK still assembled (I prefer to clean cranks when they are apart, if I am in a uber-restoration mode).

Still, I am not being defeated that easy. Any hints on loosening that bolt/nut in a non-destructive fashion?

... Torch time???

fietsbob

VAR the French company made a heavy duty tool .. it was partially like a C clamp ,
so It didn't slip..
perhaps you can grind a heavy duty screwdriver blade
to resemble the Tool of sheet-metal that has proven not to be up to the job.
one with a square shank and you can clamp it in the bench vise
and have helper hold the crank, (off the bike obviously), over the tool,
while you press the whole thing down and turn the allen wrench ..

soaking the bolt in liquid wrench for a while of course..

FBinNY 

If the bolt ends below the depth of the slot in the nut section, you can remove the crank. stand a screwdriver up in a vise, and push down on the crank to keep the screwdriver in the slot while turning the screw out with a hex key.

OTOH, keep in mind that chainring bolts are pretty damn cheap, and not worth sacrificing tools for. If it persists in it's stubbornness, use a 5/16" drill to drill it through and both halves will come out their respective sides. Then pay the $2.00 and buy a new bolt.

olek

After trying to keep the park tool in place this morning with a clamp, and it still springing out of nut's slot, I am starting to think that FB's words about chainring bolt being cheap are very wise. I think I will let it be for right now, and will put a note to buy some chainrings bolts in the near future. Next time crank comes off, I will drill that bolt out.

At this point, idea of truvativ dual-hex chainring bolts is very appealing

Thanks, guys!

bradtx

olek, I just this past weekend pulled the chainrings from a Sugino mountain bike crankset with the idea of replacing the rusted chainring bolts. I have a Shimano chainring tool that worked, but between the rusted bolts and that one spider arm is under the crank arm it was a battle to remove the bolts. FWIW I ended up simply sanding the bolts and spray painting them with a couple of coats of black trim paint.

Brad

HillRider

Performance used to sell a modified screwdriver tool that is significantly stronger than the sheet metal chainring nut holders but I don't see it on their web site any more. It even had a hex shank so you could put an open end wrench on it for more leverage.

olek

Thank you for the hints, guys. I came back to it this evening (I am stubborn ). First, attempted to use punch-and-hammer technique, hoping that vibrations will get it loose. No luck. After that, resorted to drilling. After (a) using wrong (dull and cheap) drill bit, (b) using wrong size of the drill bit (too small) and (c) drilling from the wrong end I finally did what was suggested here: 5/16 sharp HSS bit, from the side of the hex bolt head. It drilled out bolt head in a jiffy, and crankset finally came apart. Hurray!

It was not it, yet. 'granny washers' corroded and welded themselves to steel nuts and would not come off granny ring. After some tapping with hammer, all but one came off. That last one took a bit of soaking in PB-blaster and some very serious tapping.

All steel nuts and bolts are soaking in oxalic acid solution now, aluminum washers in degreaser. Tomorrow I will reassemble everything together, using one bolt from the spare sugino crankset that I happened to have at hand.

Thank you for your help again!!!

dsbrantjr

olek: Do yourself a favor and buy yourself a new set of nuts, bolts and washers. Removing the corrosion will leave the hardware rough and pitted and you are asking for problems down the road when you try to get them apart again. You may not be able to torque them correctly when you try to put everything back together.

olek

Good idea. I wish this hardware was easier to come by. All 3 rings are secured by one set of bolts - that means they are LOOOONG. And uncommon, since nobody makes that style of cranksets for a long time.

FBinNY 

I think I have a few sets of these, new in the package. I'll check tomorrow and confirm.

olek

Thank you! For your reference - nut is about 16mm long...

Mr IGH

Same length as used on bash guards, Universal has 'em:
https://www.universalcycles.com/shopp...12&category=54

fietsbob

3 rings on one set of bolts? , note: cyclo-cross setups, with 2 guard flanges and one chainring ,

that has the longer bolt (+ a spacer ) still being used , there's still a market,

olek

Interesting... never realized that this is modern cyclo-cross setup!

OK, just to be annoying, I want them in silver - preferably Sugino

Those black bolts look about right size, but will look like an eye-sore on vintage Sugino Mighty Tour crank.

Mr IGH

Flashback to 1981...managing an LBS...retail sucks...I'm going to Engineering School.

Srraff

Good tip. 5/16 drill gets them out real quick.

Geepig

Shake, shake, rattle, rattle, spray, spray...

sweeks

Now that this un-dead is up and around... doesn't a little grease on the chainring bolts prevent this problem? I've been doing this for 20 years and have never had one of these fasteners either come loose on its own, or fail to come off at need.

EDIT: FWIW, I have replaced the stainless steel chainring bolts on my all-weather commuter bike with titanium bolts, also greased.