Another 19" wheels thread; help needed picking tire sizes
05-29-2011, 01:15 PM
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Another 19" wheels thread; help needed picking tire sizes
Pulled this from one of the other threads on 19"s. Andrew's post is re: space between inner and outer fender walls. Mine are 19x8.5 (54mm offset) & 19x11 (62mm offset).
I still can't get the wheel fitment calculator to work (won't let me download it)! If I go with 285/30s on the rear, based on Andrew's calculation method (200mm from end of wheel hub to inside fender wall; 100mm to outside), it looks like they will rub the inside wall (142.5 + 62= 204.5mm). Perhaps a 5 mm spacer will help there?
For the outside, looks like I've got plenty of room given the offset (142.5 - 62 = 80.5mm; add 5mm spacer = 85.5mm).
Is the same info available for the fronts? Also, for the front tires, it looks like I should go with 235/35s?
Thanks!
My best guess is based on my GT of 103mm. Since your fender lip is not rolled (GT is from the factory) I'd say about 100mm.
The '87 doesn't have a full inner fender liner like the '91 GT's, but it should be around 200mm.
So that means you have about 300mm to fit a tire in. This is why a 295 tire just fits.
Now take the 295 and devide it by 2. This gives you 147.5. This is where the offset comes into play. If you have a 51mm offset wheel, add the 51 to 147.5 and this is how far the tire will stick "in" from the surface of the hub - 198.5mm in this case which is less than 200 so your tire would fit. Now subtract the 51mm from 147.5 to get 96.5. This is how far the tire will stick out from the hub. Since 96.5 is less than 100mm it should clear.
Again, when you get to a 295, you're really getting close to the limits of what will fit without modifications. Mine rubbed on the inboard side just a bit, so I added a 3mm spacer. This shifts everything outward. So going back to the example, 96.5 would then become 99.5. In this case, 0.5mm is not enough clearance to not rub. I think you need at least 2-3 mm.
Make sense?
The '87 doesn't have a full inner fender liner like the '91 GT's, but it should be around 200mm.
So that means you have about 300mm to fit a tire in. This is why a 295 tire just fits.
Now take the 295 and devide it by 2. This gives you 147.5. This is where the offset comes into play. If you have a 51mm offset wheel, add the 51 to 147.5 and this is how far the tire will stick "in" from the surface of the hub - 198.5mm in this case which is less than 200 so your tire would fit. Now subtract the 51mm from 147.5 to get 96.5. This is how far the tire will stick out from the hub. Since 96.5 is less than 100mm it should clear.
Again, when you get to a 295, you're really getting close to the limits of what will fit without modifications. Mine rubbed on the inboard side just a bit, so I added a 3mm spacer. This shifts everything outward. So going back to the example, 96.5 would then become 99.5. In this case, 0.5mm is not enough clearance to not rub. I think you need at least 2-3 mm.
Make sense?
For the outside, looks like I've got plenty of room given the offset (142.5 - 62 = 80.5mm; add 5mm spacer = 85.5mm).
Is the same info available for the fronts? Also, for the front tires, it looks like I should go with 235/35s?
Thanks!
