If you put your tyre size in search, TyreLeader is the first hit on DuckDuckGo.

I have brought from them several times, no problems at all.

Thank you chaps. I didn't know these websites existed until now. Didn't think of e bay either. I just typed in caravan tyres and all the websites that did show couldn't offer the correct tyres. I shall be on the case tomorrow. Thanks and once the again the forum rides to the rescue.

Cheers Concrete

Whilst i wouldn't leave them on to gain vintage or possibly veteran status like our mate John F ....his tyres, not his good self who i am sure is a mere youngster of a chap :-)

i'd be thoroughly inspecting them for any signs of perishing or cracking and if no signs of either i too would be leaving them on for a year or two yet...do you cover them by the way to prevent sun damage, that would help.

They may not dissolve or crumble away but both UV light and ozone cause the rubber to deteriorate with time. You can block the UV but not the ozone. The rubber will harden with time such that cracks may become visible. The harder rubber will also affect the interaction with the road surface, reducing grip which may not be too critical for a van or a low powered car of the 70's but you really don't want to be driving around on old rubber.

I had 4 original Michelin Energy tyres on one of our cars that were factory fitted when new. At the 4 year MOT the tester commented that there were surface cracks on all 4 which were not an issue, in truth I had not spotted them.

When I swapped the wheels for the winter ones I contacted Michelin about the cracks and they suggested that I sent the tyres back to them via ATS who would remove them from the rims FOC and if when inspected they were deemed to be OK they would be returned and refitted FOC. I explained I had no need for new tyres and was told there was no condition to buy Michelins if they were faulty. Only condition was the date code on the tyre was no older than 6 years, ours were just over 4 years.

Tyres went away and after about 3 weeks got a letter saying the tyres were faulty and that a cheque for just over £190 (the value of the remaining tread) would be on its way.

Very happy with the result but unhappy that the MOT tester said they were fine.

On the Caterham which does low miles and is garages for 100% of the time it is not being used - sunlight not really an issue) I change the tyres at 10 years (probably 15,000 miles) even if they still have plenty of tread. At that age they are getting hard even if they are not cracked.