AdelaaR

I have acquired a disc wheel for my TT bike last weekend and I also got one of those 90 degree valve adapters to be able to pump it up.
The valve adapter has a small rubber piece that is supposed to fit presta valves ... but it's hard to fit with the lock nut of the valve in it's way. The lock nut scratches the rubber while passing it through which can't be good.
I have then completely removed the small lock nut and it now perfectly fits and works flawlessly.
I have then removed the lock nut from my front wheel and my pump also fits much better and the rubber isn't damaged by the lock nut anymore.

Is this a good idea to ride around without lock nuts?
Is this common practice that I didn't know about or am I being weird here?
I pump my tubulars to about 10 bar so I think there's enough counter pressure on the valve to not start losing air by itself ... but that's just a guess.

UberGeek

I lost a locknut for one of my prestas, rode with no issues. I'm pretty sure the only reason for it is so you don't lose the valve's positioning when the tire is flat.

LowCel 

I haven't used that nut for around ten years. Makes flat repairs about three seconds faster.

2manybikes

There is no need to use the locknuts. One can buy presta valve tubes with no threads on the valve. I think ithe nuts are just to keep the valve from going too far into the wheel when starting with an empty tube. Not important.

AdelaaR

Okay ... I seem to have not explained sufficiently what I meant by "lock nut".
I meant the nut on top of the valve. The one which you have to unscrew to be able to pump your tube up.
I did not mean the lock nut at the bottom of the valve ... which obviously isn't needed.
It is this lock nut that gets in the way of pump rubbers.
The Vittoria Corsa Evo CX tubulars I'm using don't have thread on the sides and so using the valve lock nuts isn't even nan option ... definately not inside a disc wheel.

UberGeek

That one you need. I think. Sorta. It helps to keep the valve closed (Which, on it's own, will stay closed, given a high enough tire pressure).

I'd get a different pump. Lot's of pumps have presta/schrader attachments.

AdelaaR

Getting another pump is not an option in disc wheels since you can not reach the valve with any pump and need a special 90 degree adapter to be able to pump it.

svtmike

Once the rubber is past the "lock nut" it'll be sealing against the threads anyway, so you're probably worrying about something that isn't really a problem. The right angle adapter isn't going to be removed all that often, I hope!

mmmdonuts

I think you are being weird about the possible damage that nut could cause. Unscrew it just enough to open but not so much that it interferes with the adapter.

UberGeek

Then a different adapter, if the valve nut on the presta is causing issues. You shouldn't have to break a standard piece in order to make something work. You should find the right part for the job.

eja_ bottecchia

You may be weird....but only you can decide that.

Regarding the locknut, technically it is not necessary because air pressure will keep the inner tube inflated.

But you need the locknut to keep dirt out of the inside of the valve stem. Dirty inside the valve stem will eventually make the inner tube leak.

BTW, I don't quite understand how the rubber in your pump chuck was being damaged by the locknut. The outside diameter of the locknut is smaller than the outside diameter of the valve itself, so if anything is going to ruin the rubber in the chuck it will be the thread at the top of the valve stem, where the valve cap is screwed on.

Cheers!

LowCel 

You do not need the valve cover nut. Just close the valve and ride. I leave it on the tube when in my pocket to keep it from puncturing the tube but once it is installed I trash it.

In ten years I have never had any issues from not using it. Neither has anyone that I ride with.

Bob Dopolina 

Guy, he's talking about using a 'pipe' which is pretty much the only thing you can use on a disc wheel.

Go ahead and toss the locknut. It's actually there to keep the tube from creeping around inside the rim and eventually causing the rim to slice the valve. If you ride with proper inflation it's not much of an issue on road bikes.

Enjoy the disc:

Whoosh, whoosh, whoosh, clack,clack,clack, whoosh, whoosh, whoosh...

AdelaaR

A "pipe" is what it looks like, yes.
The tube will not move inside the rim since they're tubulars and they're glued on.
I don't even have valve lock rings.
What I'm talking about here is the valve air lock nut being removed.

Bob Dopolina 

Yes, I understood what you meant.

Toss it.

FYI: I called it a 'pipe' because that's how they are refered to but in the French: Pronounced pee-pay'.

zigmeister

The washer keeps the valve from being pushed down into the wheel while filling, especially when flat and steady in the hole. Another theory is to help so the tube doesn't slip/turn inside the tire when flat possibly...who knows.

Sure, you can remove it...not a huge deal. You don't use nuts on a tubular wheel, because there is no threading and you often run extenders...so it is certainly possible as others said.

You definitely don't want to turn the nut tight either and pull the tube/valve up through the hole, it will cut/ruin the tube likely.

Nerull

Is it really that hard to grasp he isn't talking about that nut?

He wants to remove this:

That doesn't have anything to do with the tube moving around.

Bob Dopolina 

I just re-read his post and you're right!

I just couldn't imagine wanting to remove it.

OP. That has to stay.

wkg

I don't think it should cause any major problems. While air pressure will keep the valve closed you will still probably lose pressure a little bit faster than if the valve was locked down. If you're pumping your tires before every ride you probably shouldn't have any problems.

That being said, if I was riding clinchers I would replace the tube as soon as possible. It sounds like you're on tubulars though so I would just try it out for awhile and see what happens.

Bob Dopolina 

^^^The valve won't stay closed without that locknut. It will open and close repeatedly over bumps releasing minute amounts of air each time. The result will be a significant loss of pressure over the course of a typical TT.

You need it to be there and to be closed.

svtmike

I run Zipp 404's with valve extenders on one of my bikes. I leave the valves open and have the extenders on the end of the valve with teflon tape for sealing. I have ridden centuries without any pressure loss. I think the pressure in the inner tube is sufficient to keep the valve closed against the forces from bumps in the road.

AdelaaR

The French word "pipe" is pronounced as English speakers would say "pip" but with a slight muffled almost nonsounding "euh" vowel at the end.

AdelaaR

I just tried it out and it doesn't pose any problems at 10 bar (145 psi).
The tubes are still perfect after about 15 miles.
Good thing I'll never have to unscrew those little nuts before inflating anymore
The tubes I use are very high tech with a latex inner layer ... they have superbly low rolling resistance but they lose their pressure quite fast ... this means I have to pump them up before every ride regardless of valve nuts.

LowCel 

When I ran tubulars I had to leave that valve open since I was running valve extenders. Wouldn't that pretty much be the same thing?

zigmeister

ROFL....thought he was talking about the nut around the valve stem...haha.

What you said ^^^