New Wheels and Tires - Problem (maybe)

[gary442]

Well, I went and did it,,,after much deliberation , I bought a set of 17x8.5 wheels ( aftermarket) and Pirelli P Zero tires for my 2002 525i with standard suspension....the car looks great ( old wheels were the slug looking 16") but the ride has become noticeably rougher...I expected more stiffness because of the shorter side wall but the roughness is more than I expected....is this normal ?

[granit_silber]

Well, I went and did it,,,after much deliberation , I bought a set of 17x8.5 wheels ( aftermarket) and Pirelli P Zero tires for my 2002 525i with standard suspension....the car looks great ( old wheels were the slug looking 16") but the ride has become noticeably rougher...I expected more stiffness because of the shorter side wall but the roughness is more than I expected....is this normal ?

yep

[pundit]

Well, I went and did it,,,after much deliberation , I bought a set of 17x8.5 wheels ( aftermarket) and Pirelli P Zero tires for my 2002 525i with standard suspension....the car looks great ( old wheels were the slug looking 16") but the ride has become noticeably rougher...I expected more stiffness because of the shorter side wall but the roughness is more than I expected....is this normal ?
If you want the factory ride, then you need the factory wheels and suspension components. ie 15" wheels, standard springs and shocks. As soon as you go up in wheel diameter, and lower in tyre profile, your comfort level will suffer. It's a trade off! Also heavy aftermarket wheels will increase the vehicles unsprung weight and also effect the ability of the suspension system to control the wheel motion over bumps. Heavy wheels will also reduce the acceleration and increase braking distances. Almost anything you do to a car as well designed as something like the E34 will be at the expense of either performance, comfort or economy. It seems the best possible design compromises were achieved by the designers! ;)

[Tiger]

It's the wheel weight increase that makes suspension feels rougher... Lightweights are the best but also cost the most... 2 pieces or 3 pieces wheels.

[pundit]

It's the wheel weight increase that makes suspension feels rougher... Lightweights are the best but also cost the most... 2 pieces or 3 pieces wheels.
I fitted a set of factory T-Stars to mine with 235/45/17"s.
After the 15" basketweaves the ride is not as plush but still reasonable.
The T-Stars are a lightweight forged wheel of about 20lbs I think, but are no lighter than the original basketweaves which are in fact a light wheel already.
So for relative lightness and comfort stick to the standard wheels!!
Almost any aftermarket wheels (unless they're very expensive & ultra lightweight) will weigh (often considerably more) than the standard basketweaves.

[SharkmanBMW]

P zero is also a stiff tire compared to some of the other options, but you will likely learn to enjoy the added grip and stability at high speeds and cornering.
Bumps will be your problem as aftermarket are soft and heavy - easy to bend and hard on suspension parts.