Presta valve question

[alan_sh]

My first time with a Presta valve in my tyres. My wifes bike came with the valve 'head' tightened -mine were both loose. So, two questions:

1. Should they be tight? I guess so and the dealer just didn't bother when he blew them up
2. Blowing the tyres up. I have a pump that says it does presta and shraeder. Shareder works fine. With Presta, I change the top of the pump so I can screw the end on, but when I pump (with the valve loosened), it doesn't seem to be working. So, what's the secret?

Thanks for any advice

Alan

 

[steve_sordy]

1. Yes they should be tight; tight, not hero tight!
2. Is there a lever at the top of your pump? If so, move it 90 degrees. That will tighten a rubber clamp over the valve and ensure that all the air goes into the valve.

Unsolicited advice: If you look carefully, you should see a pair of opposing flats on the valve. That should allow you to loosen and remove the valve core. That will be handy for:
1. Replacing the core when it gets damaged or bunged up with sealant.
2. Inflating a tubeless tyre; the air goes in faster and pushes the tyre bead onto the rim faster.
3. Adding sealant.

When replacing the valve core, as above, tight but not hero tight.

 

[alan_sh]

The bit at the top of my pump is like an old bicycle pump - flexible hose. That seems the screw onto the end of the presta valve but when I pump, I can't seem to hear or feel air going into the tyre. I have loosened the valve.

I tried it on a spare inner tube and that seemed to work, so maybe the tyre is already up to pressure. I have no way of measuring it because my tyre gauge is for a Schraeder valve.

Alan

 

[steve_sordy]

If the pump and connection works properly, then the more you pump, the more air is going in. The fact that you can't tell the difference is maybe because you aren't pumping for long enough? MTB tyres have big volumes and old style bike pumps have small volumes.

So how do you normally decide whether your tyres are at the right pressures? I'm assuming that you use the tried and tested thumb. Whilst I have used my thumb, it was in the days of "if the tyre wasn't hard, it needed more air until it was!"

I find that MTB tyre performance can be affected by a small difference in pressure. On a new type of tyre or a new bike, I normally mess about with pressure until I'm happy, then measure it with a digital tyre pressure gauge, like the Topeak D2. Once I've found pressures that work for me, I use the D2 to replicate it rapidly and I check before every ride.

 

[alan_sh]

I've purchased some adapters so I can use my electric car pump (with gauge). They should be here tomorrow and I'll try then and report back.

I've got a decent gauge but only for schraeders.

Alan

 

[steve_sordy]

Smartgauge D2 Digital Gauge

Buy your Topeak Smartgauge D2 Digital Gauge - Hand Pumps from Wiggle. SAVE 20% - RRP £29.99 now only £23.99. Free worldwide delivery available.

www.wiggle.co.uk

 

[Mikerb]

You do not say if you are running tubeless or not. If tubeless then yes the valve nut needs to be tight enough to ensure it seals the valve seat inside the rim.
If you are running with tubes then the nut should not be done up tight...in fact not done up to the rim. The reason is twofold. If you tighten the nut and then inflate the tube the valve prevents the tube acquiring the correct shape within the rim. Secondly, if you get a puncture that causes rapid air loss the chances are the tube will rip where it joins the valve. Some do not bother with a nut at all but depending upon what type of pump you use ( ie most modern pumps push onto the valve rather than screw on) it can be useful to have the nut there unscrewed a few turns from the rim , just to help avoid pushing the valve into the rim when attaching the pump.
PS...sounds like you need to invest in a decent track pump!!

 

[Beekeeper]

I've purchased some adapters so I can use my electric car pump (with gauge). They should be here tomorrow and I'll try then and report back.

I've got a decent gauge but only for schraeders.

Alan

I bought one of these electric rechargeable inflators from Argos. One of my best purchases. You simply program in the pressure and press a button. Great for popping the rim back on too.
You will need a tiny Schrader to Presta adaptor but you can get them from amazon.

 

[alan_sh]

Thanks both for the informative answers. I'll loosen the locking nut when I go out. I am using tubes, not tubeless.

As for the Argos tool, I'll have a search for it. Could be good to keep in the car.

 

[Tubby G]

I bought one of these electric rechargeable inflators from Argos. One of my best purchases. You simply program in the pressure and press a button. Great for popping the rim back on too.
You will need a tiny Schrader to Presta adaptor but you can get them from amazon.

View attachment 38818 View attachment 38819
View attachment 38820

Spotted one of these in our local Lidl last night …

£35

Also can be used as a Power Bank and a torch. Handy for the boot of the car. Osram products tend to be decent quality too. Anyone got one, any good ?

 

[RustyMTB]

This is serious. It appears you have bought so many primo E bikes, you can no longer afford to despatch the butler to Fortnums for your comestibles.

 

[Tubby G]

This is serious. It appears you have bought so many primo E bikes, you can no longer afford to despatch the butler to Fortnums for your comestibles.

or maybe I can afford emtb’s because I shop at Lidl

 

[Marksou]

I got one of these Electric Air Pump A2