Bicycle Mechanics - hook bead rim?

the soma new xpress tire i've got here says it will inflate to 150 psi on a "hook bead rim", 100 psi otherwise. my rims are mavic ma3s. i can't find anything on the net stating whether these are "hook bead rims" or not. any ideas?

thanks,
alex

Yes they are. "Hook bead rims" are also known as "clinchers".

Yes they are. "Hook bead rims" are also known as "clinchers".

WRONG!!!

A hook bead rim is a clincher, but one where there is a "hook" on the inside of the rim, enabling the tire to hold greater pressure than it would otherwise hold on a smooth rim. Hook type rims have been almost the only kind sold for the last 20 years, so it's rare to find the other type anymore.

For the record, yes, you have a hook-bead rim.

ok, thanks to ya both for the quick responses. i've put the new tires on my bike and will be experimenting with pressure over the next week.

thanks again for the quick responses!

-alex

Dave, my bad--I've never seen a clincher without a hook bead!

When you are as old as I am, you remember these old things.

I dont know if I'm as old as you but I've seen plenty. Not fun...

Originally posted by Dave Stohler
When you are as old as I am, you remember these old things.
And it depends on how you learned about them. I found out about them on a '92? Bridgestone I bought. I'd be riding along, and for no apparent reason, a tire would blow off the rim, creating a unrepairable 4" gash in the tube. The tires were only inflated to, like, 100psi. A friend pointed me to the Nashbarf catalog that, at the time, showed cross-sections of hook and non-hook bead clincher rims. Some tires just wouldn't play with the straight bead rims. FWIW, I'm still using one of those rims on my commuter (the Bridgestone), now running Avocet Cross IIs, usually inflated to ~80psi.

Normally, you have problems with folding tires (kevlar bead) on older non-hook rims. Wire beeds work fine on my older Weinemann clinchers.

my schwinn varsity had non-hook rims...

I think one of the keys to non-hook bead rims is to have a tire that is considerably wider than the rim. Most of those rime are realtively wide, say 23-25 mm or so. therefore you'd want a tire at least 28mm or more. Just make sure the tire is wider and of course dont use high pressure tires.

khackney is right, folding tires are a recipe for disaster.