Author Topic: Sloppy chainrings and cranks  (Read 2532 times)

Sloppy chainrings and cranks
« on: November 14, 2016, 04:55:56 pm »
  TA chainrings are supposed to be made on a lathe and should be rounder than stamped ones.  However, all chainrings benefit from being fine-tuned on the spider to try and eliminate tight spots, since there is usually some slack between the ring and spider.  With a chain fitted and tightened to the point where it binds a little, get the binder bolts just loose enough to allow the ring to shift on the spider with some persuasion, turn the crank to a tight spot and tap the ring backwards towards the sprocket before re-checking the tight spot.  It's a bit hit or miss, and takes a feel for how hard to tap, but eventually you should have improved the roundness of the crank-ring combination and you can then tighten the binder bolts properly.

I wonder what cranks and chainrings has that slop?

On the cranks and rings I've used, there's no slop. You actually have to push the ring onto the spider or/and once you've starting to tighten the bolts, there's absolutely no slop.

I've used:
Campagnolo Super/Nuovo Record, the pre-1986 144mm BCD ones.

Re: Sloppy chainrings and cranks
« Reply #1 on: November 24, 2016, 02:26:38 pm »
OK I guess out of all the people who've read this thread, none of them have used this "trick" and /or they don't have sloppy cranks and rings!

I've always thought this trick only works on low grade cranks and rings.

LittleWheelsandBig

  • Whimsy Rider
Re: Sloppy chainrings and cranks
« Reply #2 on: November 24, 2016, 02:31:56 pm »
The last time I did it was over 15 years ago. It worked but the chainring was a pretty sloppy fit on the crank. Both were cheap. My Campag SR and Dura-Ace (pronounced "do you race?") track cranks and rings were very snug fits. I've not raced track for a long time, so that kit hasn't been used since then either.
Wheel meet again, don't know where, don't know when...

Re: Sloppy chainrings and cranks
« Reply #3 on: November 28, 2016, 01:27:13 pm »
I've done this in the past, we're not talking about a lot of slop, just a millimeter or two.

Re: Sloppy chainrings and cranks
« Reply #4 on: November 30, 2016, 01:57:22 am »
OK I guess out of all the people who've read this thread, none of them have used this "trick" and /or they don't have sloppy cranks and rings!

I've always thought this trick only works on low grade cranks and rings.

No slop on my Sugino75's.

Re: Sloppy chainrings and cranks
« Reply #5 on: November 30, 2016, 02:10:36 am »
I've done this in the past, we're not talking about a lot of slop, just a millimeter or two.

A mm or 2 of slop seems pretty major to me. I can just about accept that an OK chainring might be machined with the 'centre' offset 0.5mm, giving a mm's variation at the circumference, but if we're talking actual movement after mounting but before the bolts are fully tightened rather than snugged up, surely not?

Re: Sloppy chainrings and cranks
« Reply #6 on: November 30, 2016, 08:27:33 am »
I've done this in the past, we're not talking about a lot of slop, just a millimeter or two.

A mm or 2 of slop seems pretty major to me. I can just about accept that an OK chainring might be machined with the 'centre' offset 0.5mm, giving a mm's variation at the circumference, but if we're talking actual movement after mounting but before the bolts are fully tightened rather than snugged up, surely not?

I'm talking that little movement that I can't see it, perhaps I phrased it poorly. I've done the centre the chainring on the spider routine in the past and managed to move it again on a long hilly ride, sixty plus miles, and had to recentre it again for the next ride dispite well tightened chainring bolts, though that hasn't happened very often. I'm particular about chain maintenance though.

Re: Sloppy chainrings and cranks
« Reply #7 on: November 30, 2016, 08:51:27 am »
I suspect I might have been misreading things, or trying to impose too much precision ...

Jonah

  • Audax Club Hackney
Re: Sloppy chainrings and cranks
« Reply #8 on: December 10, 2016, 05:29:42 pm »
OK I guess out of all the people who've read this thread, none of them have used this "trick" and /or they don't have sloppy cranks and rings!

I've always thought this trick only works on low grade cranks and rings.

No slop on my Sugino75's.

+1
I replaced a worn Sugino chain ring earlier on this Year;  I went for one of those Aarn hipster ones for a change; it's shit.