Tyre compatibility

[Graham4]

Having read the latest "Star letter" I find it strange that there was no mention of contacting the caravan manufacturer ref the suggestion of fitting a tyre(s) that is not specific to the van in question. Going from a 175 to 185 could quite easily invalidate any warranty let alone infringe any insurance claim. Tyres (psi) can only be increased to the max load given for that tyre, and if this has already been taken into account then jumping up a grade just because it doesn't infringe the wheel arch isn't the answer. Unless you have the approval of - especially your insurance provider.
I have recently heard of a car insurance comp. refusing to permit someone from fitting snow tyres as it is an "unauthorised assessory".

regards
Graham

 

[JonnyG]

ummm can of worms this one and the "i herd" if snow tyres are winter tyres then the vast majority of companies will not invalidate or ask for more money alas some insurance companies employ idiots and dont seem to know the law or their own industry terms and conditions......but most now follow this practice indeed one or 2 will drop your premium if you fitt winter tyres between november and march.....

 

[otherclive]

Agree with JohnG tell your contact to refer their insurer to ABI who have stated a set of guidelines for winter tyres even when fitted to different size wheels but with the same rolling diameter. As for fitting different size tyres to your van I did it with mine when the payload was upgraded. I looked at the heavier Series 5 Senators which were on the same chassis and just confirmed with Bailey and got their agreement bit could only affect your warranty or insurance if it were established that the different tyres contributed to the event. Going from 175 to 185 is reasonable providing the OD doesn't change or only by a small amount and that the load index is equal or greater than the OEM tyres. My change kept the OD within 3-4mm and increased the LI. Speed index was higher than OEM tyre too so overall I think the insurer (car that is) shoul have reduced my premium as I had improved on the OEMs specification and improved my own state of mind re the vans tyres!

 

[Lutz]

It's not only the OD that needs to be taken into account, but also the width of the tyre. A wider tyre must have enough clearance to the wheelarch, not only when stationary, but also on full jounce.
Don't forget that a larger OD might also put the hitch height over the limit if it was already close to that limit with the standard tyre.
Winter tyres should be the same size, both OD and width, as the respective 'summer' tyre.

 

[JonnyG]

hi lutz
"the width"? not sure what you are getting at as so many cars come with a possibility of having 15 16 17 ect inch wheels and as they go up a wheel size its actually the width that gets bigger and nothing else,as the circumference is kept to as near as possible standard. for example 195 width by 60 ratio by 15 inch wheel will be swaped for say 205 width by say 50 ratio by 16 inch and then 225 width by 45 ratio by 17 inch wheel the width seems to be well catered for in modern cars its the circumference one must be carefull of

 

[otherclive]

For Volvos in UK the change from summer to winter tyres seems to go for smaller OD wheels, slightly narrower tyres but same OD for both summer and winter. This is with sets supplied by main dealers.