@u4usman4u
further to your sms earlier today:
175/70R13 is 0.00% which equals 575.2mm (stock)
195/50R15 is 0.14% which equals 576.0mm (wider with +2 rims)
185/60R14 is 0.42% which equals 577.6mm (wider with +1 rims)
175/65R14 is 1.37% which equals 583.1mm (wider with +1 rims)
as for brands, michelin energy XM1 is better than Goodyear GPS-2 for economy cars as they have less rolling resistance and therefore offer a slightly better fuel average. rest is up to you, but honestly i wouldn't be too worried about tyre brands but more about if they are REALLY fresh or not (many vendors tamper with the date stamps). personally i don't think it makes a difference as long as the tyres are good and fresh. old tyres are a death trap as they can crack and fail at any time due to the never ending vulcanizarion process from the factory.
do not that it;s not the size of the rim which makes a difference but the added rollign resistance and extra unsprung weight which will effect your fuel economy and performance. if you can get a set of really light 15's it's possible that the setup will be lighter than the stock setup and therefore will offer BETTER fuel economy and performance. Similarly if you fit cheap local/chinese rims your average and performance will deteriorate as well.
I laugh at people who fit heavy replica rims and claim to get better fuel economy and performance (something which is very common with the vitz owners).
I hope this clarifies everyones questions and offers a set of solutions for you all. Good luck and enjoy your rides.
