The Retrobiker's Dilemma.. When 'Patina' Becomes.....

[torqueless]

I know they say; "if it ain't broke, don't fix it", but I'm really conflicted about these Mavic module-E rims, 'cause I'm not sure if they're 'broke' or not. Well... you know... they haven't broke yet..

Velobase informs me that these rims should be 20mm wide, give or take a small fraction of a mm., and this pair of mine are just about 19mm now. I wore out a set of Modolo sinterised brake pads on these rims through the late '80s/early '90s, and someone has commented on Velobase that those pads are famously efficient rim-scourers, and rumoured to contain asbestos. I remember digging the remains of those Modolo pads out of the shoes, years ago, and replacing them with some Fibrax that needed a lot of carving with a sharp blade to fit in the shoes. I have long suspected that Fibrax contained asbestos too.. with a name like that... well, presumably there is some fibre in the composition, some kind of mineral fibre?

I did change these rims once, but the MA2s I replaced them with just seemed so 'soulless'... (I can't think of a better word) that I changed them back again. They are so nicely 'worn-in' that I can't help suspecting they are pretty close to being 'worn-out'. I am pretty sure I can flex the sidewalls a bit between thumb and forefinger.

What do you think?

 

[foz]

if it's a bike you ride often, then I'd change them. If it's more of a show bike now that gets taken out a couple of times a year for a gentle ride, then I'd leave them.

 

[firedfromthecircus]

Have you tried measuring the actual wall thickness?
A pair of inside calipers should do the job.

 

[eastsidebikes]

You could also use a normal set of calipers and a two bits of metal of known thickness (2.0mm spokes say) to put the edge you're measuring outside the edge of the rim. Sorry if that's unclear!

 

[torqueless]

After a bit of messin' about with a micrometer, the 'known thickness' of a 2.4mm Allen key, and a 1000th" to mm. conversion table, I estimate the thickness of the sidewalls to be 1.7mm to 1.8mm...

Doesn't sound too critical in itself.. but once you factor in 100psi of tyre pressure, might be a different story. Alternatively, these rims may maintain structural integrity for years yet, and I'm worrying about nothing.

I'm antagonistic to the whole idea of a 'show bike', but I may have to accept that these rims should be retired from active service. I cannot complain... 30 years of service for £20?... I just wish those manufacturers would stop changing the shape of everything, apparently out of pure caprice, despite all their techno-innovation jargon bullshit....Rant barely begun... :x :evil: ...............

 

[firedfromthecircus]

So according to Jobst you have about 1.2mm left to wear out.

Plenty life in them.

 

[TGR]

If Jobst is right, you will have another 60+years of life left in them - perhaps you might want to re-think your coffin design now.

 

[torqueless]

Thanks all.. FFTC and TGR your comments are reassuring, but the Jobst link makes me wonder if I am measuring accurately. I cannot think there is that much difference in cross-section between Module-E and MA2... If MA2 sidewalls are indeed 1.5mm when new, it does not seem credible that my Module-Es are 1.7mm after 30 years... :? I'll have to go and do a bit more research..

 

[TGR]

Perhaps you may be interested in a pair of Wolber Alpines which are in reasonable nick!!! BTW - they are tubs.

 

[torqueless]

TGR, my understanding is that Wolber Alpines are clincher rims, not tubs...is this some subtle joke I am not getting?

Anyway, try as I might, I cannot get my Module-E sidewalls to measure anything other than 1.7mm. to 1.8mm. Maybe someone can check my figures/method...

On my last attempt, I started by measuring the thickness of the butt of a spoke with a micrometer... 3 little graduations on the barrel of the micrometer is 0.075", plus 3 little graduations on the revolving 'turret' of the micrometer brings it to 0.078"

Placing the butt of the spoke against the inside face of the sidewall underneath the 'bead', I measure spoke plus sidewall... 6 little graduations on the barrel of the micrometer is 0.150", plus 2 little graduations on the revolving 'turret' of the micrometer brings it to 0.152"

Subtracting the 'spoke' thickness from the 'spoke plus sidewall' thickness should tell me the thickness of the sidewall, yes? 0.152 minus 0.078 equals 0.074, so the thickness of the sidewall is 0.074", which, according to the conversion table, is somewhere between 1.7mm and 1.8mm

Anyone still awake? Here are some pictures... Am I alone in finding the MA2 visually unappealing next to the Module E? Bear in mind that these rims have the same nominal width of 20mm. The 'boxiness' of the MA2 makes it look much wider, at least to my eyes.. Well, they both function as rims, but the MA2 is sometimes recommended as a 'sympathetic' rim for a 'period' bike. Looking at it next to a Module E makes you wonder though, doesn't it?