Tirerack experiences?

[brad]

6.5s on the Pacific when I was shopping for one.

The tyres will fit fine. A bit balloony but they'll fill the guards a fraction more & take some of the error out of your speedo. Probably a good idea to double check indicated against actual speeds with a GPS to work out what your new margin for error is.

Nice tyres, lucky you.

[Diesel_vert]

Dylan8 is right. 99% of tyres will have the same recommended rim ranges but every now & then you'll get an odd-bod that is half an inch either way.
This is because some manufacturers cheat in how they make a tyre (usually a low demand size). eg (plucks sizes out of air): to make a low demand 245/40x17 they might use the case of a 235/40x17 case & build it in such a way that the dimensions just slip into the size range allowable for a 245/40x17. I've seen the same "size" tyre from different manufacturers vary in both width & diameter by a visually noticeable amount (up to 25mm) & that's disregarding the optical illusion you get when the shoulder blocks are rounded rather than squared off.

It was also obvious when fitting the tyre. Some brands the bead would self seal with a quick blast through the valve; others needed a lubed-up rubber spacer inserted to take up the gap or an air blast ring

Very rare but it did happen.

Fair enough. Practical experience 1, standards manual 0.

[gareth_oau]

I can't imagine that there would be too much variation within decent manfacturers's tolerance.


With all the fines for speeding etc then tyre manufacturers wouldnt want to be sued for creating a legal loophole where someone unwittingly sped because their tyre had a different measurement to specifications indicated

[Diesel_vert]

According to Yokohama, 'the overall diameter of a radial is determined by its belts, so the tyre's overall diameter should remain virtually unchanged'.

So although a tyre's width and aspect ratio changes with different wheel widths, it's diameter should remain relatively constant.

[gareth_oau]

new tyres include at least 10mm of tread depth, so the difference between a new and old tyre might be over 20mm in overall diameter

[Diesel_vert]

new tyres include at least 10mm of tread depth, so the difference between a new and old tyre might be over 20mm in overall diameter

Yes, the diameter would change as the tread depth decreases, but that would be the same for all tyres.

The tread depth for new tyres depends on the make and model, if Tire Rack is anything to go by.

[gareth_oau]

interesting to note that the accuracy of your speedo is dependent on new tyres. the more worn the tyre the slower you will be travelling relative to the speedo reading, although only by around 2-3kph

[yowie]

6.5s on the Pacific when I was shopping for one.

The tyres will fit fine. A bit balloony but they'll fill the guards a fraction more & take some of the error out of your speedo. Probably a good idea to double check indicated against actual speeds with a GPS to work out what your new margin for error is.

Nice tyres, lucky you.

Yep, 6.5 's. Should look first, open mouth much later.
Thanks for the advice, Brad. Still waiting on Tire Rack.

[brad]

I can't imagine that there would be too much variation within decent manfacturers's tolerance.


With all the fines for speeding etc then tyre manufacturers wouldnt want to be sued for creating a legal loophole where someone unwittingly sped because their tyre had a different measurement to specifications indicated

Difference isn't within the same mfr. It's between mfrs. Back in the day, Goodyear was one of the narrowest tyres & I know for a fact they used to upsize off the same casing (eg: a 155/78x13 was the same case as a 145/78x13).

I can't remember the exact brands but a Yokohama in the same size (on the sidewall) was a bigger diameter tyre than a Toyo.

[yowie]

Ordered from Tire Rack today. The surprise was the .96 slug from the Bank on transfer rate AUD to USD.
So we will see what we get.