tyres metal valves

[david lloyd]

Derek Uzzell - 2016-06-02 7:48 AM

 

As should be apparent from the following link, valve cores come in different shapes and sizes:

 

https://www.schraderinternational.com/Products/Product-Folder/NA-Valve-Cores?sc_lang=en-US-NA

 

Snap-in valves have a rubber base and are ‘snapped' into the wheel-rin normally via a levering tool. Clamp-in valves are clamped into the wheel-rim via a nut threaded on to the valve-stem.

 

It’s commonplace within the motorcaravanning community to refer to clamp-in valves simply as “metal valves” which leads to potential confusion as all tyre-valves have a metal stem (usually brass) on to which the valve-cap screws.

 

Historically, clamp-in valves have been used for applications where the tyre inflation-pressure is high (say over 60psi). However, as clamp-in valves are trickier and more labour-intensive to fit as original equipment or retrospectively, in recent years specialised snap-in valves have become available able to handle a very high inflation pressure.

 

Schrader’s 65753 valve

 

https://www.schraderinternational.com/catalog/FR/HTML/CATALOGUE%20PRODUITS%20APRES-VENTE%20-%20%C3%89DITION%20N%2018/files/assets/basic-html/page11.html

 

can handle up to 14bar (203psi) and would fit Ducato standard steel wheels, while Alligator’s CVV snap-in equivalent would also be suitable. But even when appropriate high-pressure snap-in valves designed for easy fitting are chosen things can go wrong

 

http://www.motorhomefun.co.uk/forum/threads/alligator-cvv-high-pressure-tire-valves-a-warning.105093/

 

Thanks again Derek for the clarification.

 

I think it has become obvious now that when talking to tyre fitting shops about 'metal valves' it is necessary to be absolutely clear that you are talking about 'clamp in' types and not the 'snap in' type which is what happened in my case. All the places I spoke to were, in fact, referring to snap in type metal valves whereas I was always thinking along the lines of clamp in tyoe valves which are fitted to my wheels.

 

The difference was immediately apparent when they showed me the valves they had obtained and, as you quite rightly point out, as competent tyre fitters they were able to remove the tyres and fit the new ones without causing any damage to the much more durable clamp in ones fitted.

 

Another valuable lesson learned.

 

David

[david lloyd]

Final update. The larger tyres (Continental Compact 100 225/70R15 C) were fitted and the original clamp in metal valves were good enough to leave in so these give a loading of 2240kg on the rear axle. A DriveRite air suspension kit was fitted to the rear axle yesterday by Armitage Trailers of Ferrybridge which did a very neat job with the two inflation valves and a gauge sited on the side of the drivers seat box. Continental Technical department have just confirmed the correct tyre pressures based on the known weights when laden - 3.5 bar (50.7 psi) on the front and 4.5 bar (65.2 psi) on the rear. Just waiting now for SvTech to do the paperwork then we should be legal and, more importantly, safe again.

 

Total costs for the weight upgrade - rear tyres £187 fitted, rear suspension £547 fitted and the fixed SvTech price is £312 inclusive of VAT. Total cost £1046 - but the two nearly new 215/70R15 VancoCamper tyres that came off the rear may offset that a bit if I can sell them.

 

So, all in all, a bit of an expensive mistake on my part but well worth the money to give us the payload we need in a van that meets all our needs.

 

David

[gmacz]

I had to have 2 new tyres revalved as the metal o'ring leaked after new tyres were fitted.

I just got normal ones fitted and kept the metal ones myself.

They tend to leak in winter a bit and seal better in summer.

They were 14 years old so they were a bit past their best. *-)