matthias39682

Hi all!

I recently bought a second hand 'vintage' racing bicycle (Nishiki) and I wanted to change its tires.
After some searching I found out that the rims I have are 1982 Araya model 18 (hookless) rims, size 700c. (you can check them out here: ARAYA Rim Catalog Archive 1982_01-02)

My guess would be that these rims are clincher rims, however I was very surprised to see that the rims as they are now have tubular tires glued onto them. Is it a thing to glue tubular tires onto these older hookless rims or can I just as well use modern day clincher tires? The discovery of the tubular tires made me a little uncertain.

Thanks!

cny-bikeman

No, it is not a "thing" to glue sew-ups (tubular tires) to clincher rims. Doing so would be extremely unsafe. Either someone was stupid, you don't have clincher rims, or you are mistaking a clincher that has become stuck to the rim for a sewup. The latter is quite possible as I don't recall Nishiki having a sew-up equipped model in the 80's. As can be seen from the pic in your link a sew-up rim is very easy to distinguish, as it has a curved surface for the tire to mount on. Sew-ups of course have no visible tube.

dabac

Why would it be extremely unsafe?


I've used tubulars on hookless clincher rims for several hundreds of miles w/o any "new" dangers becoming apparent.
Main reasons I stopped was:
1) that bike overall didn't turn out as fun to use as I'd hoped for
2) with the tire sitting deeper in the rim as when compared to on a tubular rim, the risk of getting pinch flats increases. And - possibly due to the sharper edge of the rim - even a short roll-out before getting off the bike is enough to shred the tire beyond repair.


I might have been able to overcome 2) by going to a wider tire. But then the bike had already been proven "not fun", so my interest pretty much faded.


But a flat is a flat is a flat.
It's a known risk unavoidable when dealing with any tire containing an air bladder.
I don't consider the increased likelihood enough to call the use of tubulars on clinchers "extremely unsafe".
But certainly impractical for regular use.

dabac

It's entirely possible to use modern clincher tires on hookless rims.
Just don't expect to be able to get to the listed maximum pressure before the tire blows off the rim.
And wear eye, hand and ear protection if the urge to experiment with maximum functional pressure becomes irresistible.



And pause after partial inflation, examine the tire/rim overlap closely to see that the tire is as well centered in the rim as possible before continuing to inflate.

matthias39682

Thanks for your answer!

Well I guess in my case someone before me has done a stupid thing since I double checked all my info before posting.
So you are saying I should change to clinchers immediately? Can I just use normal modern clinchers on my hookles rim (1982 Araya model 18) or do I have to look out for some special tires?

Thanks!

HillRider

You can use current clincher tires on those rims but, as dabac recommended, you will not be able to use full pressure and you should experiment with the maximum pressure before the tire starts to "crawl" off the rim. A friend had an older Raleigh with Weinmann hookless rims and modern tires would not stay on over about 85 psi. I'd try to find tight fitting tires to give you the best security.

fietsbob

Don't pump the tires up so Hard, use rims only in a bike that takes wider , thus lower pressure tires ,
and reject any tire that is too easy to Mount.

cny-bikeman

Dabac may be right that it's not outright unsafe, but I would not consider sewups on clincher rims to be advisable. As he noted they sit lower than clinchers would, which not only makes the (pricey) clinchers more vulnerable to damage, but will also compromise higher speed turning stability. You will face some fun getting every bit of the adhesive off the rims.

As for high pressure use, there were plenty of 85-90lb tires available in the early 80's, and not very many hook bead rims. I would say that at 80-90 lbs of pressure, which is plenty for most riders and 28mm or larger width tires, you should be OK with proper mounting technique.

JohnDThompson 

While not ideal, neither is it egregiously unsafe. In fact the Super Champion "Mixte" rim was designed to accommodate both clinchers and tubulars. It never really caught on, though…

3alarmer 

.
...as stated by the others here, I usually deal with hookless rims by selecting a tyre that has tighter bead, and is thus more difficult to mount, and is wider, thus requiring lower pressure. +1 on the wearing of hearing protection when you do your first inflation. When you manage to blow one off the rim due to too high a pressure it makes quite the sound. Kinda like a gun going off right next to your ear.

Schwalbe Marathons are sort of famous for tight beads. There are other tyres out there, too. go with 28-32 mm width if it will fit in the frame without interference.

matthias39682

Thanks everybody for all the provided information! You've been of great help!

Mauriceloridans

One more tip. . . Use wire bead clinchers, never "folding" or kevlar bead on hookless rims.