wheels tires

rcoppol · Post by **rcoppol** » 01 Oct 2016, 15:51

I have had a Volvo S80 T6 since 2000. The first two had 17" wheels. The one I got in June is a 2011 with 18" wheels. Two of the tires (Pirelli) developed bulges on the sidewalls. One of the four new tires (Continental) developed a big bulge on the sidewall when it had less than 3K miles on it. Since I never had this problem with the 17" wheels, I want to put 17" wheels on this car, if this happens again. Would there be any problem to overcome if I replaced the 18" OEM wheels with 17" wheels ?

Thanks

Volvo S80 · Post by **Volvo S80** » 30 Oct 2016, 17:31

The problem with the bulges on sidewalls is because the bigger the wheel you have less rubber so it does not touch the fender. Less tire means less play on tire and when you go through potholes and touch curbs the wheel pushes the tire (also helped by the car weight and force of gravity) to it`s maximum and snap the steel belt inside the tire which is under air pressure and develops bulges (which are considered as not safe), so the higher the sidewall the probability for sidewall bulges is smaller and the ride is smother through potholes but the handling in sharp turns is not as great ( so it is your choice). You can put 17 inch wheels on it but they have to be tire 225/50 ZR17 94W, wheel 7jX17 ET 50, Pcd 5x108 or tire 245/45ZR17 95W, wheel 8jX17 ET55, Pcd 5X108.

Enjoy your S80

Post by **chrism** » 31 Oct 2016, 16:31

Are you running adequate air pressure in the tires?

Post by **oragex** » 31 Oct 2016, 16:46

As above, first make sure the tire pressure is at least 32psi, in particular during the cold season when some tire pressure decrease because of the outside temperature - incidentally potholes also form during the cold season when the temperature suddenly fluctuates . This makes the tire more difficult to "compress" when it hits a sharp-edged pot hole which are the reasons why the sidewall bulges form (which as noted means the tire must be discarded immediately).

17" tires have less tall sidewall, 18" even lesser. The lesser the sidewall, the more chances the tire will be crushed between the wheel and the pothole edge. 17" wheels are already known to be sensitive to this issue, 18" are definitely prone. There might be certain tire brands less prone to this, with more stiffer sidewall. Maybe - just maybe - some Michelins can help.

Legofan · Post by **Legofan** » 01 Nov 2016, 17:40

rcoppol wrote:I have had a Volvo S80 T6 since 2000. The first two had 17" wheels. The one I got in June is a 2011 with 18" wheels. Two of the tires (Pirelli) developed bulges on the sidewalls. One of the four new tires (Continental) developed a big bulge on the sidewall when it had less than 3K miles on it. Since I never had this problem with the 17" wheels, I want to put 17" wheels on this car, if this happens again. Would there be any problem to overcome if I replaced the 18" OEM wheels with 17" wheels ?

Thanks

Those bulges are from being pinched between the rim and pavement, generally potholes. They are no longer any good and need to be replaced. I wouldn't drive on them since the rubber has separated internally.