1989 C4 Tire Question, Can You Help?
09-19-2009, 05:39 PM
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1989 C4 Tire Question, Can You Help?
It's time to replace my stock width tires which are worn from DE events and I've been told that wider tires can be used, but a relocation of the brake cooler lines in the front passenger side wheel well is necessary.
Does anyone know/have experience in fitting wider tires on a 1989 C4, and if so can you make a recommendation/walk me through what work is involved and the tire width specs?
Thanks
Does anyone know/have experience in fitting wider tires on a 1989 C4, and if so can you make a recommendation/walk me through what work is involved and the tire width specs?
Thanks
09-19-2009, 06:59 PM
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Brake cooler lines? There are two oil cooler lines, and they could be a point to rub on in the right rear, but on the right front, they are hidden behind the fender and inner fender skirts and are not a problem. Depending on the tire width and wheel offset, some folks have had rubbing issues on the inner fender liner orskirt, while others like me have not.
If you went to 265s on the rear, you almost certainly will rub the oil cooler lines in the right rear wheel well if they have not been worked over (flattened a little). Later cars were built with 'flattened lines' in order to provide clearance on wider tires. Mine were already flattened but I don't know if it was factory or done by the dealer when the PO installed 17" 255s.
I am currently running 17" Yokohama AD 07s with 225/45-17 in front with a 5mm spacer and 255/40-17 in the rear with no spacer. The wheels are Mille Miglia Cup II knock offs with a front width of 7 1/2" and an offset of ET 52. The rears are 9" wide and the offset is ET 47. Since I was not experiencing any bump steer at the RS plus 5mm ride height, I opted for the 5mm spacer in the front as it was easier to get tire clearance that way instead installing the 10mm steering arm spacers.
I also run a set of factory Porsche Cup IIs with SO3s with 55mm offests with no problem.
As anothe rpoint of reference, the PO had 205s in the front with no spacer and that worked fine. When I went to the 225s in the front I started rubbing the aft section of the inner fender well liner, thus the spacers. Check your wheel offsets and remember that not all tires that are the same size are the same width, so ymmv. Have fun
If you went to 265s on the rear, you almost certainly will rub the oil cooler lines in the right rear wheel well if they have not been worked over (flattened a little). Later cars were built with 'flattened lines' in order to provide clearance on wider tires. Mine were already flattened but I don't know if it was factory or done by the dealer when the PO installed 17" 255s.
I am currently running 17" Yokohama AD 07s with 225/45-17 in front with a 5mm spacer and 255/40-17 in the rear with no spacer. The wheels are Mille Miglia Cup II knock offs with a front width of 7 1/2" and an offset of ET 52. The rears are 9" wide and the offset is ET 47. Since I was not experiencing any bump steer at the RS plus 5mm ride height, I opted for the 5mm spacer in the front as it was easier to get tire clearance that way instead installing the 10mm steering arm spacers.
I also run a set of factory Porsche Cup IIs with SO3s with 55mm offests with no problem.
As anothe rpoint of reference, the PO had 205s in the front with no spacer and that worked fine. When I went to the 225s in the front I started rubbing the aft section of the inner fender well liner, thus the spacers. Check your wheel offsets and remember that not all tires that are the same size are the same width, so ymmv. Have fun
