Barrymagrec
pfm Member
Only Boeing and Airbus ones in the main. Avoid any of those and you'll probably be ok
Be O.K. on early Comets and DC10s then.
Only Boeing and Airbus ones in the main. Avoid any of those and you'll probably be ok
Be O.K. on early Comets and DC10s then.
But if you’re aware, and know not to exceed, say 27 indicated in a 30 limit, would you still be illegal? And how much discretion does an MOT tester have over an opinion that something is ‘inappropriate’?
A quick back of the envelope calculation suggests a 3% change in diameter would give you just slightly under a 10% change in the rolling circumference, which would potentially increase your car speedo error beyond the 'nominal' +10%/-0% that manufacturers are believed to be allowed*
Might be just a case that somebody's done the calc. and figured out that's the max change you can have before your speedo is legally unfit for purpose ?
*I haven't had my morning coffee yet, so that calc could be rubbish btw..
It's not going to be sufficiently far out to make a difference, service intervals are nominal anyway. If 10,000 miles becomes 9500 or 10500, no big deal.And since the odometer is part of the speedo, your mileage would also be off, affecting service intervals and such.
Excess width is the killer in my wet climate, aquaplaning can start at very ordinary speeds
My wife's SLK needs tyres and, having been impressed by the Michelin Cross Climates on my C-class, I'm also thinking about putting all-season tyres on that. The front (225/40R18 92Y XL) is no problem as there are plenty of all-seasons available in that size, including the Michelins. The rear seems to be a problem though - it's 245/35R18 92Y XL and there don't seem to be any all-seasons matching that size and speed rating. The closest (and which some sites list as a fitting for the car) is the Continental AllSeasonContact however it's a W speed rating in that fitting (and the front fitting), not Y. Given W speed rating is 168mph (compared to the 186mph of the Y) then that still seems like it should be ok (given the top-speed of the car isn't much over 150mph).
Any thoughts?
Is the Michelin Pilot All Season 4 available in your sizes?
Doesn't look like it. Looks like they tend to be for bigger and lower profile options.
My wife's SLK needs tyres and, having been impressed by the Michelin Cross Climates on my C-class, I'm also thinking about putting all-season tyres on that. The front (225/40R18 92Y XL) is no problem as there are plenty of all-seasons available in that size, including the Michelins. The rear seems to be a problem though - it's 245/35R18 92Y XL and there don't seem to be any all-seasons matching that size and speed rating. The closest (and which some sites list as a fitting for the car) is the Continental AllSeasonContact however it's a W speed rating in that fitting (and the front fitting), not Y. Given W speed rating is 168mph (compared to the 186mph of the Y) then that still seems like it should be ok (given the top-speed of the car isn't much over 150mph).
Any thoughts?
Even if the rear wheels are wider? I think that would look naff.TBH if you can fit the same size on the rears as the fronts, they are only 20mm diff width, I'd just do that.
PS on speed rating: of course winter/cross climate tyres aren't available in the higher bands - poor conditions are the definition of mitigation against needing such!
PS on speed rating: of course winter/cross climate tyres aren't available in the higher bands - poor conditions are the definition of mitigation against needing such!
sincerely
Captain Obvious.