How to replace a PRESTA valve core on a mountain bike

[@johngretton8543]

I spray a bit of GT85 on similar spray lube on the valve core before putting the core back in, helps stop the sealant gumming up the core and keeps the brass nut from sticking.

[@travers_bikes]

I am lazy and don’t tend to do anything to the valve core and never had an issue. Saying that I never put the sealant in via the valve, always pop the tyre off.

[@daniellarson3068]

I've drilled my rims out to take Schraeder valves. Can you do that with Carbon fiber rims?

[@travers_bikes]

From a warranty point of view I would say no. That would also apply to an aluminium rim. I guess it would depend on the carbon rim, these tend to be more rounded than an aluminium version, so there would be less material in the area, so cause a possible weak spot.

[@daniellarson3068]

@@travers_bikes Well - I guess I won't worry about the rims I drilled thirty years ago. I like my Schraeder valves.

[@travers_bikes]

I guess you are still using tubes then, do what works for you

[@daniellarson3068]

@@travers_bikes Yes - Tubes, cantilever brakes, front derailleurs and steel. I'm one of those.

[@travers_bikes]

As long as you are out riding thats all that matters