8david8

Been looking everywhere for answers, I bought some tubes online for my bike (700x25c) the presta valve is 40mm which wasnt included in the description. It was too short for my tires to pump air in them, I'm not that knowledgeable when it comes to these things since I just started out with bikes. So which presta valve size is the best one?the rims are 45mm deep (which by know tells me the valves needs to be longer)
(700x25) tube
(??mm) valve
45mm deep rims
will also appreciate some advice on good tubes to buy

Litespud

I would say 60mm would be ideal for 45mm rims

CliffordK

I personally would prefer not to use valve extenders unless you absolutely need them.

If your Presta valve just barely fits, then if you can get the nut on, it may stabilize the valve enough to pump up.

I would assume that a 45mm (clincher?) rim will be about 35mm on the inside, and you may be able to barely squeeze those 40mm valve stems in. Or do you have 48mm stems?

But, I'd get say 2cm longer or so, so go for either 60mm or 80mm.

Some of the cheapest tubes you can get are "Lifeline" tubes from Wiggle.

https://www.wiggle.com/lifeline-road-inner-tube/

Obviously depending a bit on tire size, etc.

But, buy 10 of them, and you get them for $2.12 each.

Toss in a couple of other items (chains, brakes, etc) to hit the $50 minimum for free shipping.

sch

You need at least 15mm longer stem than rim depth for the pump to reliably grab the presta valve stem. It helps to have the nut hold the stem

in place for these shorter stems but then you need a bit longer to account for the nut. Unthreaded stems should be longer as well due to their lesser frictional grab for the

pump to hold on to, but these are uncommon.

woodcraft

Just getting a few valve extensions is another approach,

then you're always set for roadside situations & don't have to worry about finding & buying just the right tube.