Quote:
Originally Posted by Othen
I think rims might be an issue Dave - I suspect one might need 4.5J for those (I think the aspect ratio was something like 80% on SR tyres).
Alan
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A general rule of thumb is the tyre should be no more than ~2" wider than the rim it's being fitted to Alan. This minimises the "balloon" effect where the tyre looks like a balloon on the rim.
Working that back, a 4.5J rim is ~115mm wide so a 165 is on the limits, better to go with a 5J or 5.5J for 165 tyres to maintain the sidewall in a straighter state.
You are correct, the aspect ratio (if memory serves) was something like 78% on standard tyres, whether they were SR, TR, HR or whatever speed rating. I believe 80% is used as a close approximation when working out rolling circumference.
Going too wide on the rim with a narrow tyre results in something now being seen as fashionable and is called "stretching" - this would be (in an extreme case) something like a 135/15 tyre on a 7J rim.
Something in the back of my mind says the original fitment on the 244 was 5J x 15 rims with 165SR15 tyres. I may be wrong on this but don't think so. I've no idea what the base model Skoda had or indeed if you could fit a "tall'n'skinny" tyre to the steel rims but it's generally accepted those sort of tyres are better in snow and ice.
All that said, with tyre technology having come a long way from when i first looked into winter tyres, it's entirely possible now that a wider tyre will still grip better than a narrow tyre if they're both winter compounds.