Rims: how worn is too worn?

bompington
bompington Posts: 7,674
edited May 2012 in Workshop
I've had Shimano R560s for a while now, and they've been great - stayed true through a lot of abuse, right up to a 50mph blowout on the front tyre.
The braking surfaces are definitely looking a bit concave now though:
Not a great pic but the edge of the chisel (first straightish thing I could set hands on) shows the wear quite clearly.

So, at what point are these rims going to give? What is the likely mechanism of failure, and in what circumstances - pothole or bunny hopping one, rough road, or what? I was a bit nervous the other day descending from Glenshee, which is not the smoothest road in the land, at >90kmh - is failure likely to be catastrophic or will I notice increasing flex, for example?

Of course I could just buy new ones, but I'm a terrible skinflint and I want to get the most out of them!

And of course, when I do replace them, I want something cheap (budget is £100 or so), smooth-rolling, aero (but unaffected by crosswinds), light, and rigid, I'm sure that's not too much to ask, so what should I get?

EDIT: changed the pic to one that, while technically worse, shows the wear better

Comments

  • keef66
    keef66 Posts: 13,123
    Do those rims not have a wear indicator? My RS10's have a little dimple in each braking track diametrically opposite the valve hole. I thought I'd worn them off the front until I gave the rims a good scrub at which point I found them again :D

    Actually, if you're happy with a low spoke count factory wheelset, the RS10's have been prety reliable and appear to meet your other requirements.

    Ugo will be along in a moment to pour scorn on them, and suggest a pair of handbuilts for twice the dosh.
  • smidsy
    smidsy Posts: 5,273
    edited May 2012
    Never mind the rim - that tyre is well shot!!!! ;-)

    The rim as pictures is displaying quite pronounced dishing. If it were me I would say its done its job, time for new.
    Yellow is the new Black.
  • jibberjim
    jibberjim Posts: 2,810
    They tend to go explosively (first the rim, then the tube through the rim) under hard braking not surprisingly. So it's not really the sort of thing you want to particularly risk. Look for rim wear indicators.
    Jibbering Sports Stuff: http://jibbering.com/sports/
  • whobiggs
    whobiggs Posts: 23
    8) That rim is looking quite close to the end. If you are lucky the edge of the rim will begin to peel away first, on the other hand I had one go on my commuter at 25mph (thankfull rear) with a sudden bang and clatter as the rim hit the deck. Brand new Schwalbe bitten through too. I have now bought a tool from Velo plus in Switzerland to check remaining thickness, alternatively you can bend an old spoke round until it is parallel then use a vernier or similar subtracting the width of the spokes. As for when is too thin mine went at 1.5mm which I thought was ok, it depends on the material. This was a Sun Rhino touring rim (very soft but thick) and only 70psi. Some rims don't have much more than that to begin with. I would normally expect it to be ok at 1mm. One other option is to inflate the tyre excessively (wear goggles)and see what happens, you may sacrifice an inner tube but better than a blow out on the road.
  • bompington
    bompington Posts: 7,674
    smidsy wrote:
    Never mind the rim - that tyre is well shot!!!! ;-)
    New one is waiting on me being bothered to fit it...

    As for the wear indicator, I've never noticed one before, but of course I haven't looked, and there's a definite possibility that it's worn away by now :shock:
  • fish156
    fish156 Posts: 496
    Technically speaking they're f**ked.

    Personally I'd replace them - the risk of rim failure (particularly at the 50mph you quote) isn't worth the £100 you're looking to spend to replace them.
  • bompington
    bompington Posts: 7,674
    OK, I get the point, it was the answer I expected but there's always this pathetic little "just maybe it'll be OK" thing isn't there?

    So what should I get to replace? RS10, 20, 30, what's the difference?
  • keef66
    keef66 Posts: 13,123
    I think most of the difference is in the price.
  • keef66
    keef66 Posts: 13,123
    Looking at the exploded diagrams on Shimano Techdocs, most of the components are interchangeable, so apart from slightly deeper section rims with the RS30's I'd say most of the increase in price is down to Marketing BS.
  • smidsy
    smidsy Posts: 5,273
    I have found the RS20's to be reaonable all rounder for the money and they can be had for under £130 a set these days.

    These sit neatly in the middle of the wheels you mentioned so must be a good compromise in your dilema ;-)
    Yellow is the new Black.
  • andy_wrx
    andy_wrx Posts: 3,396
    Does nobody on BR forum ever look at the BR workshop articles :lol:

    http://www.bikeradar.com/gear/article/w ... nts-20934/
    see points 1 & 2 for how to measure rim thickness
  • bompington
    bompington Posts: 7,674
    Had the tyre off so I thought I'd weigh the front wheel.

    805g on pretty accurate scales - including the magnet, and the skewer which seems to have seized up so I couldn't get it out :shock:

    Quoted weight is 771g for the wheel, and skewers seem to be well over 100g - so does mean my wheel is now less than 700g? Weight weenies' delight!

    I'm thinking of setting up a machine shop company to shave bits off and drill holes in all sorts of bike parts - wheels, cranks, frames, anything goes. It must be a sure fire winner...
  • term1te
    term1te Posts: 1,462
    The Open Pro rim on my wheel blew fairly spectacularly recently. Fortunately whilst I wasn't on the bike. I pumped the tyres up to 120psi on frosty morning before my commute. Got to work and left the bike in the sun. Came back in the evening and found the tyre flat and about 10 cm of the rim split away. I'm guessing the pressure increased too much with the temperature difference between the early morning cold air pumped in and the hot sun later in the day? Whilst it was about 10 years old, the rim didn't look to warn before it went, so I'll err on the safe side in the future.
  • bompington
    bompington Posts: 7,674
    Well, RS20s at £110 or so at Ribble so they should be here early next week.
    Just as well as my back wheel, which has been 100% true for thousands of miles, has suddenly decided to do a pringle imitation. Never attempted to true a wheel myself but I had a spoke key hiding somewhere, got it out and discovered that none of its three heads fitted, tried pliers but nothing doing, I think maybe the spokes were just seized up.

    Up to Glenshee for my last proper run before the Etape Cal, a strange thing - every now and then my bike seemed to spend 5 minutes or so wandering all over the road, which I guess might be related: but only for a while, then everything would be fine for a good deal longer, so it only happened perhaps half a dozen times in 5 hours.
    Relieved to make it up and down in one piece, now I can ditch the old wheels, I'll maybe hacksaw through a rim and try and get a decent pic to post here.
  • bompington
    bompington Posts: 7,674
    Curiosity got the better of me so I got the hacksaw out: pic is a bit naff but gives an impression of how thin they are - I don't have calipers but I'm fairly sure it's less than 1mm in places :shock:
  • mister p
    mister p Posts: 405
    keef66 wrote:
    Looking at the exploded diagrams on Shimano Techdocs, most of the components are interchangeable, so apart from slightly deeper section rims with the RS30's I'd say most of the increase in price is down to Marketing BS.

    RS10 = shallow rim with plain gauge spokes
    RS20 = same hub and rim as RS10 but with double butted aero spokes
    RS30 = same hub as RS10 but with 30mm aero rim and double butted aero spokes
  • bompington
    bompington Posts: 7,674
    As mentioned above, I had ordered RS20s from Ribble - unfortunately they failed to deliver.

    I had a few other bits and pieces from them which got delivered very promptly but no wheels, I left it a couple of days to see if they showed up separately but no show, so I phoned them - unusually for this day and age I spoke to a human, who apologised profusely for the error and promised they would be with me the next day.

    Still no show, so I phoned them again - "sorry, they're still sitting in the warehouse, no idea why".
    That's another online retailer on the blacklist, not a lot left who haven't stuffed up something by now :-(

    By this stage I was looking at doing the Etape Cal on the wheels pictured above (I hadn't hacksawed the rim at that point though!) but it was a case of LBS to the rescue - Richards in Perth, who didn't have anything affordable in stock but took the pair of aksiums off a bike that had just been built up for another customer (they did phone him first, so if you're reading this, thanks).

    The moral of this story? I guess it's something like: do your research and buy your new wheels well before you need to. Rocket science eh?
  • WindyRob
    WindyRob Posts: 32
    The moral of this story? I guess it's something like: do your research and buy your new wheels well before you need to. Rocket science eh?

    Or support your LBS in the first place.
    Wot, get up early and ride to work?!.... Are you mad?
  • Monty Dog
    Monty Dog Posts: 20,614
    An indicator of a very worn rim is 'pulsing' whilst braking - feels like the wheel is out of true, but spinning the wheel shows it isn't but the rim sidewall starts to take on a distinctly wavey shape. You'll often find some circumferential cracks in places. A rim blowing out when riding is pretty scary as it usually means a sudden and painful stop.
    Make mine an Italian, with Campagnolo on the side..
  • unixnerd
    unixnerd Posts: 2,864
    He's right about the pulsing whilst braking, that was the first symptom on my very old Mavic rim failing. Then it started to bulge outwards, then it detached along a 12" section the wheel and the tyre came off!

    I was 15 miles from home on my mtb in the middle of nowhere and it was about +2C at the time. As the rim was dead anyway I put the tyre over my shoulder and cycled home on the bare rim! Surprisingly good off road but on tarmac the noise was truly deafening. Everyone stopped to look and see where the noise was coming from, but it was quicker than walking.....
    http://www.strathspey.co.uk - Quality Binoculars at a Sensible Price.
    Specialized Roubaix SL3 Expert 2012, Cannondale CAAD5,
    Marin Mount Vision (1997), Edinburgh Country tourer, 3 cats!
  • ugo.santalucia
    ugo.santalucia Posts: 28,301
    bompington wrote:
    Had the tyre off so I thought I'd weigh the front wheel.

    805g on pretty accurate scales - including the magnet, and the skewer which seems to have seized up so I couldn't get it out :shock:

    Quoted weight is 771g for the wheel, and skewers seem to be well over 100g - so does mean my wheel is now less than 700g? Weight weenies' delight!

    I'm thinking of setting up a machine shop company to shave bits off and drill holes in all sorts of bike parts - wheels, cranks, frames, anything goes. It must be a sure fire winner...


    There is already... there's a guy on e-bay that sells all sorts of drilled components.... Campagnolo was heavily into drilling conponents back in the 80s... I have drilled brake levers on my 1980s, fluted cranks and setpost, chainrings with holes... I've got them all man! 8)
    left the forum March 2023
  • bompington
    bompington Posts: 7,674
    WindyRob wrote:
    The moral of this story? I guess it's something like: do your research and buy your new wheels well before you need to. Rocket science eh?

    Or support your LBS in the first place.
    Well yes, but I paid £80 (that's about 56%) more than I could have got them for online. I am certainly getting a bit more inclined to support my LBS, and I have to give credit to Richards for their helpfulness, which is winning them my custom, such as it is. But it's a business, not a football team, and I see no reason to support them beyond my own interests - in the same way as they have no moral obligation, for example, to give me a discount for any other reason than to increase their sales.
  • andrew_s
    andrew_s Posts: 2,511
    whobiggs wrote:
    I have now bought a tool from Velo plus in Switzerland to check remaining thickness.
    Alternative source

    I've found that my rims that have started to fail (as revealed by pulsing braking and subsequent detection of the first cracks), have failed at about 0.7mm (Mavic Open Pro, T217).
    If you notice the problem away from home, let half the air out and ride directly back, avoiding using the brakes on the affected wheel
  • russyh
    russyh Posts: 1,375
    I bought some apparently lightly used rs10 wheels off this forum (6 months old I think I was told) when they arrived I thought the rim was fairly dished, but fitted them anyway and sent the seller an email. On spinning the wheel after inflating the tyre you coul see the rim was out of shape and when you applied the brake the rim bent off. Anyway my local bike guru told me they were dangerous and I was lucky not to blow a rim at 40 mph. He suggested they had done some long hard miles! So I bought a brand new set, I have learnt my lesson and the thought of a high speed blow out for the sake of a hundred quid or so is mental! Buyer had responded to my first email but not offering a refund or anything, for me it's not the money but a rim blowing on a fast decent could be really dangerous!