rcourtis

i have two lovely sets of wheels i built myself in the late seventies. both with campagnolo NR hubs of course and butted spokes
one set is Weinmann Concave 700c, the other, 27" Weinman aluminum, conventional looking with reinforced but not separate ferrules.
i recently bought two sets of tires to replace the well oxidized originals: continental gatorskins.
one set of 27 1/4" for the 27 inch wheels and one set of 28 x 700c for the concave rims.
neither of the rims has a ridge to accomodate the wire bead on the new tires.
the gatorskins are rated to 120 lbs.
the original tires i used on the 27" were michelin with a 70 lb max and on the 700c Concaves, some other sort of japanese tire that i think would accomodate at least 80 lbs without problem.
i have not installed the tires yet and i am concerned whether the rims will hold the tires under the rated pressure.
the continental gatorskins have a printed warning: using only on rims with hooked rim.
should i be worried about the consequences?
can anyone help me here?

DiegoFrogs

If something happens to you, you certainly won't be able to forge ahead with a lawsuit against continental... I would probably run them at a slightly lower pressure. You'll also want to make sure that the braking surface of the rim is still pretty substantial. I've run some modern tires at about 100psi on my weinmann concaves with no problems.

mswantak

Same here; 100 psi on concaves with no trouble.

And while we're on the topic...

I've got two concaves I want to use on a bike I'm building. Trouble is, the front's a 700C and the back's a 27". Either size would be okay, but I'd like it better if they matched. If it comes to it, I'll just use 'em -- as if I'll notice the 4mm difference. But if anybody's got either a 27 front or a 700 rear, and wouldn't mind trading for the other size, give me a holler.

We now return to our regularly scheduled thread topic.

rcourtis

the braking surfaces will not be a problem. 100 pounds it is! at least to start.
what kind of tires do you have on your Concaves?

John E

I have the same problem. I have a beautiful wheelset I would like to use with the Capo, Weinmann smooth-walled rims and Normandy Luxe Competition hubs, but I am extremely concerned about modern high-pressure tires blowing off the rims. Using a reduced pressure can avoid blow-off, but it will also break down the sidewalls.

I traded emails on this subject with Sheldon Brown, who recommended that I look for tires rated at around 70 or 80 PSI, like what we rode in the "good old days," and I came up with these on the Harris Cyclery website: Continental Top Touring 2000, rec. pressure 70 PSI, max 80 PSI (BINGO!).

DiegoFrogs

I also have some 700c x 32 Conti city something-or-other's that suggest a maximum pressure of 80 psi... I've only got one on right now and it runs pretty nice. I think many 27x1-1/4" tires were rated for 90 psi maximum. I've got some Nashbar Prima II+'s in 27x1-1/4" made by cheng shin that I run at 100 psi and top them off when they drop to 85 or 90. I kinda like them, for seven or eight dollar commuter tires.

kranz

I have been riding on Weinmann 700c concave rims with Continental Ultra 3000 700x28 tires. I inflate them to 100psi and ride them pretty hard. A couple of thousand miles later I have experienced no problem.

I was freaked out by the warning on the Conti tire so started researching hooked rims for use on vintage bikes. Mavic module E was apparently the first rim to offer hooks and used ones and some NOS can still be found in both 700c and 27" sizes. I've also managed to source NOS 27" hooked rims from Rigida and Sun. So I use these to build new stuff.

DiegoFrogs

If you're looking for the "new but old" stuff, I think Sun makes quite a few cheap rims that look very authentic... the M13II comes immediately [inexpensively] to mind. There may be others, but the M13II is a bit of a chamfered box in section, and is REALLY cheap. It's pretty common in machine built wheels. I think it comes in a variety of sizes, too.

nick burns

I absolutely love the Module E rim! Very durable, fairly lightweight, and nice polished finish. I see 'em pop up on ebay nos pretty frequently.

rcourtis

having a 700C Concave on the front, and a 27" Concave on the rear will not be a bad move
these new Continental GatorSkin tires are available in both sizes.
if the hubs and tires match, that should be enough.

USAZorro

There was a fellow from Virginia on e-bay selling some Clement "Gentleman" tires - that would have been ideal for those - rated to 90 psi and a bit on the thin side. He was asking some rather low amount on his buy-it-now too. I'd go back and check to see if he still has them up, but I'm getting ready to de-frag the ol' hard drive, and this is my last open window... I think Nashbar sells some suitable tires too.