Weinmann concave rims

Discussion in 'Cycling Equipment' started by kranz, Aug 20, 2004.

  1. kranz

    kranz New Member

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    I've been riding on old Weinmann "concave" rims with low flange normandy hubs for a while now. I quite like them, but don't really know much about them and am curious about the design of the rim. Was the concave design done for some special purpose or specialty? Comments from anyone familiar with these rims appreciated.

    thanks,

    kranz
     
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  2. mgagnonlv

    mgagnonlv New Member

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    It was a great design of the late 1970s and 1980s. The concave design added a lot of strength compared to the typical "convex" single-wall rim that was (and still is) available. Modern double-wall rims are stronger and tend to stay straighter.

    Compared to modern designs, there are a few drawbacks:

    - Still a single-wall rim. I never was able to straighten my rear wheel at closer than +- 4 mm, whereas my double-wall rims are straight within 1-2 mm. Not a problem with the "good old" centrepull brakes, but it wouldn't work as well with modern brakes.

    - No hooks. Some tires – especially foldable ones – need them, and almost all tires need them if you want to inflate at more than 70-80 psi. Remember that back in the late 1970s, a tire at 60-70 psi was called "high pressure", and that those who really wanted performance used tubulars.

    - Hard to keep clean. Minor problem, except if you want sparkling clean bikes and ride in rain, sand, gravel, snow...
     
  3. kranz

    kranz New Member

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    Thanks, Michel. Thats great info. Is it true, that hooks are a feature of modern rims? I've refurbished a couple of 70s vintage Raleighs. When replacing tires, I bought some Continentals. Continental prints a warning on the tire that they are only to be used with hooked rims. They even print this warning on their 27 1/4" tires. None of the steel or alloy rims that I have from that era have hooks. I tried discussing this with the guy at the bike shop. He told me all rims had hooks and I must be mistaken if I thought mine didn't have them. I didn't trust what he was telling me.

    So am I at risk if I inflate tires beyond 70-80 lbs on these rims without hooks?

    Is the Continental warning to be heeded only if their rated air pressure is used?

    thanks,

    kranz
     
  4. twerne

    twerne New Member

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    RE: Hooked rims
    I am just repeating what I read ... but believe the safety trick is ... hooked rim is required for non-wire (kevlar) bead clinchers. If non-hooked rim, then insist on non-folding wire bead clincher.
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  5. biker7

    biker7 New Member

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    Its going to be a compromise of sorts with beading and non-hooked rims. Trick is you can't run your tire pressures too high with the old non-hooked Weinmann rims...not over about 85 psi or so. Here is a set of Weinmann rims with Normandy hubs of mine from the early seventies I am getting ready to put on e-bay. I've cleaned the rims up a bit and polished the hubs...could stand to be trued a bit but rideable with fresh rim tape, tubes, repacked bearings and adjusted cones. For vintage 27" tires, I like the Conti Sport 1000's which look correct on those old rims as well. Tires shown in the pics only have a few rides on them.
    George
     
  6. boudreaux

    boudreaux New Member

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    I duno what you call modern. I've seen plenty of older 700c rims and all had a hooked bead. The stuff I've seen with no hooks was cheaper 27" stuff. If you have non hooked rims the warning is there for a reason. My non hooded stuff went to the landfill.
     
  7. boudreaux

    boudreaux New Member

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    That crap should be in a landfill or recycle bit,but I guess you are hoping for the ebay sucker mentality?
     
  8. biker7

    biker7 New Member

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    guys...there is no end to it. A shame.
    George
     
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