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Measuring Wheel rim thickness
Posted: 24 May 2022, 2:08pm
by Richard of York
A couple of years ago I had a rear rim split and tear a section from the wheel with associated tyre damage. A friend had similar recently descending Otley Chevin. Both on roads. No injuries fortunately. How do folks here measure rim wear assuming no indicator on rim. Accepted wisdom seems to be replace at 1-1.5mm.
Would a micrometer do it. One like this from Screwfix for example.
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 2:16pm
by simonineaston
I know the answer to this Q 'cos you wouldn't be asking about micrometers if the answer was Yes they do, but Are you saying that your rims do not have wear tracks? (some of mine do and some of mine don't !)
I have often wondered about the same and have pondered that maybe the very cheapest micrometer would do - after all, it's not as if they have to be super-duper accurate, just consistant... Once calibrated against a reference, you'd know what to look for.
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 2:32pm
by Richard of York
simonineaston wrote: ↑24 May 2022, 2:16pm
I know the answer to this Q 'cos you wouldn't be asking about micrometers if the answer was Yes they do, but Are you saying that your rims do not have wear tracks? (some of mine do and some of mine don't !)
I have often wondered about the same and have pondered that maybe the very cheapest micrometer would do - after all, it's not as if they have to be super-duper accurate, just consistant... Once calibrated against a reference, you'd know what to look for.
Like you, I have some wheels with indicator marks, others not. I just wonder if the micrometer foot would fit in against a rim. I had thought I might be able to use a Vernier caliper if I sandwiched rim between too small blocks of known width, or 2 ball bearings of known diameter. But the micrometer seems easier if it fits. Perhaps I shouldn't be so tight and just buy it and try it.
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 2:36pm
by simonineaston
I'm sure a second-hand-but-perfectly-decent, old-school micrometer off of fleabay could be adapted, 'specially if only for a single task. Couple of pieces of filed-up scrap ally, super-glued in place.
- picture of second-hand micrometer, at 3 quid
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 2:37pm
by simonineaston
I think I'll give it a go!
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 2:41pm
by geomannie
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 2:42pm
by simonineaston
Nice! Perfect for the job, by the looks of it
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 3:04pm
by axel_knutt
Anything with flat faced jaws like a micrometer will overestimate the thickness because the brake surfaces are usually worn concave, so you need something with small, and preferably rounded, tips to the jaws. You also need something small enough diameter to fit into the recess inside.
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 3:07pm
by Nearholmer
You can even make your own Iwanson Gauge fairly simply, and if you make the outer legs quite long, maybe ten times the jaw length, it’s easy to mark them up quite accurately. I made a pair when I was a trainee 45+ years ago, and have carefully kept them in a safe places through multiple house moves ….. and now I need them for the first time in decades, I can’t blasted well find them!
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 5:10pm
by geomannie
simonineaston wrote: ↑24 May 2022, 2:42pm
Nice! Perfect for the job, by the looks of it
I would just add, make sure you measure thickness at mutiple points. It will likely vary.
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 6:08pm
by bgnukem
Iwanson gauge is cheap and far easier than faffing about with Vernier calipers and bits of spoke.
Expect to be shocked and appalled by how thin some modern rim sidewalls are. I had a couple of Mavics that were close to 1mm thick when new.......
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 6:13pm
by geomannie
bgnukem wrote: ↑24 May 2022, 6:08pm
Iwanson gauge is cheap and far easier than faffing about with Vernier calipers and bits of spoke.
Expect to be shocked and appalled by how thin some modern rim sidewalls are. I had a couple of Mavics that were close to 1mm thick when new.......
+1
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 6:20pm
by 531colin
003 by
531colin, on Flickr
Just take a file to a vernier gauge
Re: Measuring Wheel rim thickness
Posted: 24 May 2022, 6:24pm
by simonineaston
I can see what you've done there...
Re: Measuring Wheel rim thickness
Posted: 25 May 2022, 10:09am
by Mick F
I got one of those from a cheap tool-shop in Plymouth. Only a couple of quid.