How long will a presta valve last in a schrader rim?

Well, I ordered three 29er tubes from UDC and realized they were presta. Where I live, all they have are 26" tubes and I didn’t want to spend more money than I have to, so I put the presta valve inner tube in my schrader rim. I put 2 layers of electric tape over the valve stem hole and poked the valve through it to try and make the edge of the hole softer. So, the question is… Do you think that will hold long enough to receive the correct tube in 2-3 weeks? I’m running 65 psi, but I think I’ll drop it to like 50 just to be safe.

You should be fine. Only need to worry is if the valve isn’t centered in the hole (being tweaked to the side), or if your riding involves lots of impact in that area, such as riding through lots of mud. Your tape idea sounds like a good one to protect your stem. I my experience, most Presta valves seem to be metal already…

It’s probably fine, just don’t put too much pressure on the valve stem when pumping it up. You can also get an adapter at your bike shop designed to let you use Presta tubes (which are better for hand pumps) in Schraeder rims.

Thanks. I won’t worry too much about it then. I was just concerned about getting stranded and having to walk home, or being late to school because of a flat.

Put a valve grommet http://www.unicycle.uk.com/valve-grommet-3.html

I use it on my 36 with a 29 tube schrader valve, little bit tight but fine as 29 tube valve is smaller than 36 original tube valve

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^^ get some, otherwise the edges of the hole will chafe your tube and you’ll be walking home…

I drill all of my rims out for schraders, can stand prestas due fragility and leaking.

On the contrary - I’ve never had any problem with presta, and the only wheels I have schrader on are the uni ones which came with them.

In answer to the OP, I’ve been running presta tubes in schrader drilled rims on the tandem for 10 years or so and never had a problem, despite sometimes pumping those tyres to 130psi.