WTF is this rim ?

[PpPete]

Very unusual old Weinmann rim.
the "top" surface is concave as you can see here:

which is interesting cosmetically (if I could be arsed to clean it up) if nothing else....


but the cross section is weird:

It has no lip to hold the bead of a clincher, but it looks too deep for a tub.

Does anyone know what it is and what it's for?
More to the point is it worth anything?

 

[MadoneRider1991]

that looks like its a clincher setup,

i can see what you mean though about there being no lip :s,

weirddddd

 

[Chris James]

I believe (some) older rims didn't have hooked rims. I wouldn't pump the tyres up to high pressures though!

 

[Steve Austin]

airless tyres. Ie solid tyres non-pneumatic tyres.

If you use a clincher tyre it will blow off the rim!!

 

[MadoneRider1991]

airless tyres. Ie solid tyres non-pneumatic tyres.

If you use a clincher tyre it will blow off the rim!!

i know its an odd rim isnt it

 

[Steve Austin]

odd, and very old

 

[Chris James]

airless tyres. Ie solid tyres non-pneumatic tyres.

If you use a clincher tyre it will blow off the rim!!

e.g.
from Chris Juden of CTC

'I'm afraid that this "edge splits" problem, of tyres chafing through and exploding where they rub against the edge of the rim, is common with tandems nowadays – or any heavily laden bicycle. It was unknown 15 years ago and seems to have arisen since rims were given hooked edges to retain folding or very high pressure tyres. '

http://www.ctc.org.uk/DesktopDefault.aspx?TabID=3520

It appears rims were not always hooked for clinchers for fatter, lower pressure, tyres

 

[hubgearfreak]

hooked rims appeared in the late 70's, according to sheldon below.
i've got a pair on an old bike, and they're no bother, but they're not pumped up very hard either.

sheldon;http://sheldonbrown.com/harris/tires/630.html
Note on tire/rim compatibility:

Traditional 630 mm (27 inch) rims were straight side design, but in the late '70s they evolved to a "hook edge" design which would permit the use of higher pressures.

These days, many 630 mm (27 inch) tires are marked "For hook edge rims only" (some companies use the term "crochet type" instead of "hook edge"...this is the result of poor translation.)

The fact is that modern 630 mm (27 inch) tires will work on older straight-side rims, but they won't handle as much pressure as they are capable of with hook edge rims.

Generally, the "rule of thumb" for traditional 630 mm (27 inch) tires is that they should be inflated to 70-75 psi. This shouldn't be a problem with any tire, despite whatever disclaimer the manufacturer puts on the sidewall. However, if you're restricted to this pressure range, you probably shouldn't be running tires narrower than 1 1/8, or preferably 1 1/4, unless you're a very lightweight rider.

 

[mattsccm]

Got several rims with no hook. Hadn't even regarded them as unusual. Just older. Concave rims were not that unusual either in days gone by.

 

[swee'pea99]

My front has a concave rim. Don't know who made it (and can't remember what the inner looks like, tho' I do maintain it at 100psi, +/-, so I guess it probably has a lip) - came off an old Carlton Criterium - no idea of the age..perhaps '70s? It's a nice wheel - strong, true & light.

 

[PpPete]

And there was me hoping it was some very valuable rarity !!

Oh well - we shall see what it fetches on fleabay.

 

[swee'pea99]

Dare I ask why you're selling it?