Shimano 29" tube
 

I need a 29" 2.25" tube for a Shimano bike it has half inch thick rim centers. The regular shrader valve isn't long enough. Anyone know of the correct one. Or where to find valve extension's I'd prefer the correct tube with longer valve stem. 29" 2.25". Thanks let me know Walmart I might try box digging

Presta valves come in various lengths.

Thanks I found the extended 60mm for deep rims at Walmart standard is 35mm. Thanks

Shimano doesn't make bikes they make components for bikes and sometimes put their name on some questionable stuff. Typically bike with deep wheels are designed for aerodynamics and will typically come mostly in 700c or 650c sizes and will usually be drilled for presta valves. Deep rims with that use schrader valves and are designed to be used on bikes that look like mountain bikes should just be avoided. They tend to be very heavy and very hard to find tubes for and of a very low quality. Granted a shorter spokes can make a stronger wheel, heavy poorly made rims with low quality materials make for a weak wheel.

You're right it says Shimano equipped. It's a ground force genesis 29". Probably is from the 90s.