joeruge

So, I've managed with this crankset on my older Cannondale for some years, cursing along the way.

I mean, how are you supposed to get to the inside part of this chainring bolt? There's got to be something more to work with than 'hope' that it doesn't move while you loosen or tighten it.

I got so sick of messing with it that I went to my pile of parts and found a Specialized triple to put on the other side.



Now, I have easy access to these chainring bolts, at least on the this one crank arm.

Surely, Sugino had something in mind when they produced their crankset. What am I missing?

Leisesturm

If the short arm of an Allen wrench can't get a straight shot at the inside head of the chainring bolts when they are rotated to the 'crotch' between the seat tube and the lateral tube then you have to pull the crank to work on it. A pain, yes, but ... builds character. I can't see that you actually solved any problem here. If you needed to get to that granny, for instance, you'd have to pull the crank. Maybe even to access the middle ring. Just the way it is.

joeruge

Thanks for the reply. Sometimes you want to take the chain rings off, to clean them (maybe once every few months, if you're riding a lot) or to replace them (rarely, maybe every few years).

But even taking the crank off the bottom bracket does not get you much. You still don't have access to the side of the chain ring bolt facing the crank arm. Maybe, just maybe there is enough space to slip one of those chain ring bolt spanners between the crank arm and the chain ring. Of course that would mean you'd have the have the chain ring bolt in backwards to start with; the 5mm hex side facing inward. I don't know. Seems kind of funky to me. Obviously, I managed to deal with it for a few years while we road that Cannondale regularly. But it sure was a pain every time I had to deal with any of those cranks.

Leisesturm

Ah ... I see the problem now ... hmmm. I'm not even sure putting the chainring bolt in backwards would help. I usually need an Allen wrench on both sides of the bolts, because both sides have hex fittings! On the T900 the inside facing heads are 4mm and the outers are 5mm. Beyond a mere pain. I'm certain Sugino must have some low profile hex wrenches for fitting those bolts if they designed a crank arm that way. My OCD would not allow me to solve the problem the way you did, with another brand of crank-arm on the drive side. Good on you for initiative.

joeruge

So this discussion made me think that maybe a chainring bolt spanner would fit in there and be able to hold the back end of the bolt. But no diceI Sugino had thoughtfully added some reinforcement to the crank arm just there, where you'd like to put the spanner.




Thanks, but putting the Specialized triple might have caused more trouble than it solved.

It's been a couple of years now, but the way I remember it, though the spacing between the chainrings is the same for both Specialized and Sugino/Shimano cranks, the shoulders on their respective crank arms and rings are a little different. You can't mix rings and arms and get good shifting.

If I recall correctly, since I was using Shimano rings on the Sugino arms, I had to use shims (thin washers) to make the space between the innner ring and middle ring and between the middle ring and the outer ring the same (though slightly different than the standard spacing). This made the shifting better though trimming is less than ideal.

Philly Tandem

On cranks with the bolt "hidden" behind the crankarm, I do indeed put the nut facing out and the bolt in from the backside. Usually a small chainring nut spanner will fit behind the crankarm, but it's rarely necessary. I have an ancient Dia-Compe tool that I can't believe I haven't lost in the 30+ years that I've owned it :-0 But Park makes a good one, too, of course: https://www.amazon.com/Park-Tool-CNW.../dp/B01EONOXWE

If you absolutely can't fit the proper tool in there, usually a thin, flat-bladed screwdriver on edge will allow you to hold the nut enough to break loose the chainring bolt.

LV2TNDM

I would not recommend removing chainrings to clean them. Why? It's complete overkill. Plus, they're easily cleaned on the bike with the caveat that you NOT catch your fingers (or any body parts) under the chain while rotating. Timing chains are dangerous! Don't lose a fingertip! Plus, removing rings means you may have to "re-center" them each time to reduce timing chain tension variations. "Set it and forget it" is my approach to this task. Additionally, as I've posted a million times before (arguing against the use of solvents and solvent bath/brush cleaners), chains quickly get dirty, so why get it pristine when it's dirty again after one or two rides? Yes, chains need and deserve excellent care. But that consists of wiping down, cleaning rings and cogs, lubricating with a drip bottle, and then wiping off all exterior lube. That's it.

As far as the hidden bolt is concerned, proper assembly should result in securing the ring properly and avoiding future loosening problems. Obviously, the bolt and nut are switched, so the 5mm bolt is facing inwards. But the KEY with chainring bolts is GREASE! The industry has refused to assemble chainrings properly with grease since day one. Lack of grease on ring bolts leads to them loosening up and falling out. It also contributes to corrosion and creaking issues. It's strange this was never addressed when the whole "pre-assembly" campaign hit the industry 20+ years ago. Oh well.

This hidden bolt needs ample thread grease when assembling. Usually, I grease the bolt and nut heads too. But in this case, the side that's hidden you may skip the grease on the slotted nut head to increase friction between it and the spider. Then, use a large flat-blade screwdriver and wedge it between the nut and the crank arm. This pressure should increase the friction on the nut so you can fully torque the 5mm nut on the other side without it slipping. I've done this before with success each time. Never have I had the nut slip before I reached proper torque.

If you DO have slippage, then consider ways to increase friction on the nut. Roughing the edges or "brinnelling" the surface may help. If that all failed, then I would try to modify the chainring slot tool so it will fit within the narrow confines between nut and crank arm.

In other words, there's a way to do this. This crank has been in production for a long time and chainring bolt assembly never became such an issue that it was recalled. It works, but with some extra care and creativity.

Good luck.

joeruge

Thank you all for your suggestions. The Park chainring nut spanner that was suggested does look to be a little narrower than the one I own.

As I had mentioned at the start, I have managed to deal with this design, often using the flat-screwdriver pressure idea to add that little bit of extra friction to the the nut, between the arm and the spider. And, I did start using grease or anti-seize compound when assembling most threaded parts.

And it's not that I take the rings off all that often (Ok, I'll admit it, I'm too lazy to do it more than once or twice a year). I was really just wondering if there was a technique that I had missed. Thanks again for the input.

DCwom

I have the park tool and Sugino cranks, the Park tool is NOT narrow enough. As for disassembly for cleaning, I did that once when I had a bottom bracket problem, that was enough. I recently found that after years of using a toothbrush trying to get into and around the teeth, just spraying Simply Green all over the chain rings, then hosing them down works just as well, if not better.

Joint Venture

Rivendell has some tips on how to handle the hidden chainring nut. Scroll down the page about halfway:

https://www.rivbike.com/collections/...8t-x-36t-x-26t


They also recommend/sell the Park CNW2 chainring nut tool, which is a double-ended tool, so one the two different ends may fit.

joeruge

Again, mostly idle curiosity... but all good tips! Just for fun, I'm thinking that I may make a dedicated tool to deal with this. Maybe a thin bladed screwdriver, bent over to a very short 'L' and filed or ground down to fit in the chain ring nut. Or take the Park, recommended by Rivendale and grind that down enough to fit in between the arm and the nut...

Thanks to all.