Is it okay to change the tire size?

So I want to change the tires on my Porsche 911 SC, and the reccomended tyre size for the front wheels is 185/70R15. There is only one pair of tires on the market with 185 width that has a v speed rating that I can find, but it has a 65 profile. If i fit these onto my vehicle, will there be any problems?

The 185/65 would be about 18.5mm (.73") shorter than the factory tire.

So I want to change the tires on my Porsche 911 SC, and the reccomended tyre size for the front wheels is 185/70R15. There is only one pair of tires on the market with 185 width that has a v speed rating that I can find, but it has a 65 profile. If i fit these onto my vehicle, will there be any problems?

One of the problems of owning an older car is that tire sizing tends to move on - and that is the case here.

Yes, there is a problem. The load carrying capacity of a 185/70R15 is more than a 185/65R15 - and that is in the direction of more risk of tire failure (Think Ford Explorer!)

A 195/65R15 is a better choice. There are more V rated tires available and according to Discount tire, they fit under the fenders without rubbing.