Tyres

[vauxhallbitz]

Hello all,

Time to buy tyres for the Portafold, what do people recommend for the 10" rim?

Fraser.

[Admin]

I've got 10" caravan and trailer tyres.

Not being a tyre expert I couldn't tell you what makes them different to car tyres but they do the job very well and I don't have any wandering.

The receipt shows '145/10 Camac T/L'

The T/L should stand for tubeless and in 2003 they cost me £20 each including fitting and balancing.

[txfsealord]

Hi all, I'm back! - the bloke who looks after my computer damaged its motherboard last Friday, trying to add memory.

It's been a long, weirdly quiet week.....

Tyres. If your van's loading, or overall weight, is on or near the 12cwt maximum specified for the towing-hitch, then it's also close-ish to the maximum load for the 4-ply tyres. As caravan tyres don't wear out very often, I think it's advisable to have 8-ply tyres like Matthew has, rather than the 4-ply car ones. That way, as well as better handling, there's a much larger reserve of loading capacity, so as the tyre's structure degrades there's less fear of casing failure. This degradation is a function of the tyre's advancing age (the molecules of the carcass lose their flexibility), there's only so much we can do to preserve them. It's a good idea to protect them from direct sunlight if your van's kept outside, & not to leave them standing in pools of oil or petrol - unlikely this, as these fluids aren't in caravans. The handling of the caravan is better on 8-plies, with less wallowing & wandering, again as observed by Matt.

In my case, it's quite easy to go over the 12cwt maximum weight as I've so much added gear with my van, & my wife likes to take enough food for our entire stay; hard on the old Morris, as well as the van.

8-plies, usually of Camac make these days, are quite a lot dearer than 4-plies. The 8-plies are marked 'Trailer' on their sidewalls, otherwise they look identical to the 4-plies. The section is 145x10 for both types. The 8-ply speed rating is lower, about 75mph I think. 4-plies are 85 or so; the small diameter means the wheels are going faster for any given speed than, say, 12" ones so the speed ratings are somewhat lowly.

As stated elsewhere on this site, these are both RADIAL types. Crossplies are measured differently. Their section is 5.20x10. It's illegal to use crossplies on your caravan if your car has radials on it, & almost all post-war cars use radials nowadays.

I hope this helps people's decision-making processes.

Steve Lord

[Admin]

Steve,

I've got a relevant question regarding the tyres. As 99% of us would now have radials on our vans and the original paperwork states to pump the (crossply) tyres up to 24psi...

what would you recommend we pump our radials up to?

[txfsealord]

An important point! Well raised by Matt. Radial tyres need more pressure than crossplies would on the same vehicle & loading.

If using 145x10 4-ply radial tyres, the pressure should be at least 30psi. The 4-plies can be run at up to 36psi; if you've lots of weight on board & the tyre looks under-inflated at 30 go to 36.

The 145x10 8-ply, having more casing plies which generate frictional heat, should be run at 40psi. I imagine my van's heavier than anyone else's & I've not found the need for any more pressure than this.

Always check the pressures cold, before running. A tyre correctly inflated to 30psi can easily gain a further 10psi on a long motorway trip on a hot day. Hot pressure readings are largely meaningless, unless they're lower than the correct cold reading......!

Steve

[Admin]

Well, after bringing my Portafold 'home' on Tuesday night I had a good 2 hour drive from mid Devon across to the East Dorset/Hampshire border to try out the new tyre pressures as recommended by Steve.

I took mine up from the 25psi I had been running them on, up to 40psi. There was a difference in the handling, it didn't seem to bounce so much but it still held the road well and didn't weave. When I did stop to check everything at a couple of intervals on route the tyre tread was quite warm. Not hot, but warmer than just warm. If that makes sense.

I also checked the pressures the minute I got home while they were still hot to check if they had increased at all and they'd gone up by 1 or 2 psi. But bare in mind that I was towing in the late evening and that mine weighs in at 450kg, well below the maximum of 600kg that the chassis is supposed to be able to handle. On another day with more on-board weight it might be different.

Now it's back I can get the hinges fixed ready for 'Wroughton'.