Check http://www.eglider.org/catalog/subcat11.htm for one possibility.

njp

Chris OCallaghan wrote:
I was disappointed by Desser Tire of Memphis Tennessee last week when
they sent me three 5.00-5 tubes with a valve unsuitable for my wheel
(interferes with landing gear strut). They assured me this was the
only available valve and would work for my sailplane. I've removed
them from my list of suppliers.

I am currently seeking a source for 5.00-5 short valve and double bend
valve tubes common to glider applications. My preference is for the
Michelin Airstop TR-67A with short 90-degree bend valve. My preference
would be for an intelligent supplier with dedicated to customer
service. Price is secondary. If you have a suggestion, please share.

Thanks.

OC