Will 987S 18" wheels work on my 1998 986 & ride quality

[perleman]

Hi all,

I'm in the UK and am considering investing in some 5-spoke 987 Boxster S 'II' alloys (the ones with the rectangular hole cut out where the spoke meets the wheel). I presently have 17" wheels. My question is 4-fold:

1a - Is it OK to fit these to my car - I know the very early Boxsters weren't designed for 18" and it could cause suspension parts to become damaged, how do I know mine won't be affected?

1 - Will these work properly without requiring new alignment, ECU changes, spedo recalibration etc, will the rolling radius be the same

2 - Will the handling improve / deteriorate

3 - By how much will the ride quality deteriorate - I have the M030 sports set-up & it's already quite a hard ride. I know this is subjective but it it a significant change, marginal, or somewhere in the middle?

Thanks.

[berty987]

It will be cheaper and easier to buy 18" replicas from design911 , this will ensure you keep the correct rolling radius and have the right offset on the wheel for your arches/ suspension. Sourcing tyres for 19" wheels is also a real headache so save yourself time and effort and get the replicas, they look identical and to be honest will give a better ride. You will find it hard to notice the difference in wheel size between them and the originals when on the car .

Porsche re designed the suspension and hubs to cope with hte larger wheels and wider track on the 987, so fitting the 19" wheels may effect both handling and the life of the suspesnion , so not really a good idea.

Edited February 18, 2008 by berty987

[perleman]

It will be cheaper and easier to buy 18" replicas from design911 , this will ensure you keep the correct rolling radius and have the right offset on the wheel for your arches/ suspension. Sourcing tyres for 19" wheels is also a real headache so save yourself time and effort and get the replicas, they look identical and to be honest will give a better ride. You will find it hard to notice the difference in wheel size between them and the originals when on the car .

Porsche re designed the suspension and hubs to cope with hte larger wheels and wider track on the 987, so fitting the 19" wheels may effect both handling and the life of the suspesnion , so not really a good idea.

Hi, it's the 18" Boxster S II alloys I'm interested in, does the same apply - don't want to damage my suspension

[Chris_in_NH]

Hi, it's the 18" Boxster S II alloys I'm interested in, does the same apply - don't want to damage my suspension

the 18" wheels will fit/work fine on your car. they will not damage the suspension unless you track the car hard. if you are just doing street driving, i would not worry about the suspension.

the ride will be a bit harsher than 17"s, but that is to be expected.

edit: i don't know if the 987 wheels will fit a 986. if they don't, replicas are the way to go.

Edited February 18, 2008 by Chris_in_NH

[KevinC]

The wheels should work fine but you don't want tires intended for a 987. Boxster tires have an outer diameter of about 25" (front and rear). The 987 rear tires have an OD of about 26.5" and the front tires are about 25.5". So don't buy a 987 tire/wheel package - buy the tires separately.

[perleman]

The wheels should work fine but you don't want tires intended for a 987. Boxster tires have an outer diameter of about 25" (front and rear). The 987 rear tires have an OD of about 26.5" and the front tires are about 25.5". So don't buy a 987 tire/wheel package - buy the tires separately.

OK that's the problem- the wheels are £700 with good tyres on, and they'll give me 250 P/X on mine (mine are mint). so for £450 I can get the wheels that I like best. But if the tyres need changing that's another £700, and then I might as well buy replicas with brand new tyres on.

Is there not a quick and easy way to recalibrate the speedo, or is that not the right way to go about things?

[pk2]

I replaced my 17” turbo twist’s with 18” turbo twist’s. I can’t really tell the difference in handling but I definitely can feel degradation in ride quality. The 17’s just seemed a really nice balance in handling and ride for every day driving. I don’t really recall ever being disappointed in the handling.

Hypothetically bigger wheels should allow for better handling but I’m not altogether sure in practice. I seem to recall some debate here or there a few yrs ago about the merits of upping wheel size to 18. Might do a search.

Regards, PK