The rear tires on my Centurion are in need of being replaced within a few months. I've got 235 / 15 / 75 on all four wheels right now, I'm just wondering if this is the stock tyre size for this car? The 235, which is the width of the tyre, is that a measurement in centimetres? 23.5 centimetres...??? The 15, which is the inner diameter size of the tyre, rim size I guess you could say, is inches right. The 75, which would be the profile of the tyre side, is that centimetres again? Like 7.5 Centimetres.. This has always confused me, and since I'm not too familiar with inches I'm probably all wrong here... It doesn't seem right any way I look at it. Let's say I would go with a lower profile tyre, like a 65 / 60 instead, that would mean that my car would be lowered by 10/15 mm x 2 = 2 cm / 3 cm ? I saw this 72 Riv with lower profile tires and it sat really nicely, I'm not sure if he had lowered it or not, but maybe it was all in the tires.. My tires look a little balloony for my taste, and I'm considering getting the lower profile ones to get a flatter look on the car. Maybe go with a 255 / 15 / 60 instead of what is on there now. Is there a big price difference in the sizes of tires? To be honest, I've never ever purchased any. Any suggested brands that have the raised white letters? White stripe? I'm not after any type of performance tires, just somthing to drive around on; any suggestions would be most welcome.. The speedometer would show incorrectly if you change the diameter of the tyre, and also the gear ratio would be different, anyone who knows straight out how big of a difference this would be? Kimson
On my Riv i had P225/75R15. Which is stock metric equivalent. H78x15 is the standard. So i assume its the same on the Centurion. Goodluck.
P235/75R-15. P is passenger car tire. The 235 is the section width in mm.(measured from sidewall to sidewall with tire mounted on the standard rim, and inflated) 75 is the aspect ratio(the percentage of tire sidewall height to section width). In this case the sidewall height is 75% of 235 or 176.25 mm. R is radial tire, and 15 is rim diameter in inches. There are 25.4 mm in an inch. 15 inches is (15 X 25.4=381 mm). Each sidewall is 176.25. 176.25 x 2 =352.5 + 381=733.5, 733.5 divided by 25.4= 28.87" This tire is 28.87 inches tall. If you want to put different tires on the car, try to stay as close as possible to the original tire height. This will preserve your speedo accuracy, and effective gearing. As you can see, the height of the tire is directly related to the width of the tire, by the aspect ratio. If you go with a wider tire, with a lower aspect ratio (70 or 60 ), the tire height will be closer to what you are looking for. A P255/70R-15 will be 29.1" tall, that might be your best bet. Hope that helps.
I've been looking around a bit, and I managed to do a calculation on 255 60 15's instead of the 235 75 15's. The car would end up about an inch and a half lower. Well, I guess it all depends on how much the tyre sides flex as well, but that's kind of what the calculation got to. I'm not sure how wide the rim is, but I've heard 7 or 8 somewhere, so I presume 7. Which would also be ok for a 255 tyre according to a site. I've got a few samples of raised white letter tires from tirerack.com http://www.tirerack.com/tires/Compa...GT2RWL_=4&qty_56TR5STOWL_=4&qty_56VR5SCOR0_=4 Now I just have to wait for the rear ones to be totally out, should take about another few months. I don't want to waste them since I'm a little short on cash for the moment, so it will be in the future some time. The spedometer is already out of sync. I changed the rear axle, and now I can do 85 on a 65 road and I'm still being passed by other cars. They both looked the same, but I should have counted the teeth. Many thanks for the help Kimson
