valve Extenders?! Mavic Carbones

cameron1985cameron

I have just borrowed my brothers mavic carbones and i am to embarrased to ask him but i am struggling to get the pressure up when you put the valve extender on!!

Also do you remove the valve extender once you have pumped them up or do you leave the massive extender on? cos it is hard to screw the valve cover on!! any help would be great!!!

andrewgturnbull

cameron1985cameron wrote:

I have just borrowed my brothers mavic carbones and i am to embarrased to ask him but i am struggling to get the pressure up when you put the valve extender on!!

Also do you remove the valve extender once you have pumped them up or do you leave the massive extender on? cos it is hard to screw the valve cover on!! any help would be great!!!

Hi there.

What kind of valve extender is it, there are two main types:

If it's the kind that fits in the middle of the valve then you need an inner tube (or tub) with removable a valve cores. You then unscrew the top section of the valve (might need some thin nosed pliers), screw the extender in it's place, then screw the top section of the valve onto the top of the extender.

Alternatively if ir's the other type of extender you just screw it onto the top of the valve using the threads that the valve cover goes onto to. The crucial thing to remember here is that you need to open (unscrew) the valve first, and leave it open.

Don't bother replacing the valve cover - you don't need them for road riding.

Cheers, Andy

ps You could of course have asked you brother for help!

cameron1985cameron

Yeah i know i should have asked but i would never have heard the end of it.
They are for clinchers and you just screw the extender onto the valve which is what i did but when i attach the pumb cant get a lot of pressure into the tyre!
The attachent however has a different end to it it is not like a high pressure end it has a ribbed end.
So does that mean when you are racing you carry an extender on you a
s well as the CO2 or the pump in case you have a flat??

andrewgturnbull

cameron1985cameron wrote:

Yeah i know i should have asked but i would never have heard the end of it.
They are for clinchers and you just screw the extender onto the valve which is what i did but when i attach the pumb cant get a lot of pressure into the tyre!
The attachent however has a different end to it it is not like a high pressure end it has a ribbed end.
So does that mean when you are racing you carry an extender on you a
s well as the CO2 or the pump in case you have a flat??

Hi there.

If you can't get the pressure in, check that you've opened (unscrewed) the valve before you fit the extender. I guess you could leave the extender in place if you wanted to. I've always used the type that fits in the middle of a removable valve core - a much better system me thinks.

Cheers, Andy

LangerDan

The Mavic extenders are a machined brass sleeve that screw over the valve body. There are small o-rings supplied with the wheels (about 6mm diameter) that need to be put into the threaded end of the extender before screwing it over the valve body. This seals any gap when inflating the tubes. If you dont have them, you'll start leaking air as you pump. The Mavic extenders are supposed to be left on when you are finished inflating. I haven't used them but I believe that Planet-X do a carbon extender thats much lighter and probably doesnt rattle as much as the metal ones.

The type that Andy suggest are easier but sometimes you can end up with a spare tube without the removable core and then you're stuffed.

Oh and dont use the extender with 60 mm long valve stems. the combined assembly nearly reaches up to the bloody hub!

alan_sherman

Buy michelin latex tubes with the long valve - no need for the extender then as the valve is just long enough to get a pump on without them

I think you are missing the rubber o-ring that you put on the valve - so extender is leaking pressure.

farrell

I have the same issue with my zipps....

It's impossible to pump them up sometimes - I think the open valve get stuck as I cannot even deflate them sometimes.

I usually have to take off the extender ( with an hex key ) and re-attach it.



Are the long valves long enough for 45 - 60mm rims?

Ashley_R

Had the same problem with my Bontrager Aerios wheels, couldn't get the pressure up

I had a Topeak valve extender which had a faulty rubber seal, one pump in, 2 pumps equivalent out!

drewster_70

I'm using Vredestein tubes with 80mm valves, that should solve your problem!! I've been told that Bontrager also make tubes with 80mm valves, but not sure if this is 100% accurate.

I also find the Topeak valve extender is good...

andrewgturnbull

Ashley_R wrote:

Had the same problem with my Bontrager Aerios wheels, couldn't get the pressure up

I had a Topeak valve extender which had a faulty rubber seal, one pump in, 2 pumps equivalent out!

HI there.

The Bonty Aeolus should have come with a pair of valve extenders in the box - the good type!

Cheers, Andy

farrell

[homer simpson] 80mm valves...grrrrrrrrrr [/homer simpson]

I didn't know that!!........Cheers

Johno68

oh yes, 80 mm valves, that's what you need.

Got them on my cosmic carbones and it saves all the faffing with extenders.