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View Full Version : Quick tyre size question


Adam
16-08-10, 08:12 PM
Astra currently has 205/55/16's or something like that.
I assume thats the size that GM picked to go on the 16s that it came fitted with.

Theres no issues with me just fitting some 195/45/16s?

Apart from probably a harsher ride?
MK999
16-08-10, 08:14 PM
And your speedo will be out, google tyre car bible for more info than you'll ever remember and a size calculator
George g
16-08-10, 09:16 PM
Speedo won't be that out. Vauxhall won't calibrate each speedo to each of the different size wheels. It will be a happy medium. If the astra comes with 15" alloys I would be tempted to say it is fine.

Other than that it would be fine to fit those tyres.
MK999
16-08-10, 09:24 PM
Speedo won't be that out. Vauxhall won't calibrate each speedo to each of the different size wheels. It will be a happy medium. If the astra comes with 15" alloys I would be tempted to say it is fine.

Other than that it would be fine to fit those tyres.

No they calibrate it to the standard tyre size... so deviating from that, puts it out. The standard tyre size, which is listed above, which is for 16 inch wheels, so it comes with 16" alloys, not 15's
mayhem
16-08-10, 09:25 PM
http://www.miata.net/garage/tirecalcold.html
djshaggeh
16-08-10, 09:58 PM
It will be fine adam.
Adam
16-08-10, 10:11 PM
Im hardly going to bother about a 1.2mph speedo difference or something like that lol

Think i'll drop the profile size down then :)
MK999
16-08-10, 10:16 PM
Im hardly going to bother about a 1.2mph speedo difference or something like that lol

Think i'll drop the profile size down then :)

Just be aware of what it is, is the best way really, gear ratios will also be shorter so you'll use more fuel on motorways probably etc... theres no real major issues to stop you though
mowgli
16-08-10, 10:17 PM
you'll get more difference in mph between new & worn treads anyway