911addict

My car is a 3.3 and has standard fit 17" Cup1's. I'm interested in filling up those arches.

First scenario: I'm fitting H&R springs to lower the car by around 3cm. Apart from the ride, I'm hoping my current wheels will complement my arches better than they do now as there won't be such a gap? Should they be spaced out a little?

Second, as my tyres get worn, I will consider replacing with a new wheel/tyre combo. Would wider 17" wheels work and if so what mods (spacers) needed?

Finally, if I look at 18", which Porsche wheels will be an easy fit? And will I need to fit spacers?

Any other suggestions welcome.

PS: Would 18" 3.6 Speedline replicas be a straight swap with existing spacers?

maverick

Here is my 3.3 after H&R coil overs and HD Bilstiens with the stock 3.3 Turbo 17" rims. I am now running 18" Porsche sport design (Offsets are 52mm frt. and 65mm), as you see in the other pics. No spacers required. Wheels weigh 27 lbs. Frt. 29 lbs. rear.

JBH

Maverick:

I think your wheels are a little too far inside the fenders. Watch for rubbing of the oil lines in your right rear quarter panel. I am using a 6mm spacer to take my 65m offset wheels out just a wee bit further - breaking an oil line would be disastrous.

911addict

Maverick,
I must say the car looks good with the 17's. The gap under the arches has been closed to similar proportions to the euro 3.6 look. Of course the 18's look even better, but I think I may be happy (for a while at least) with the originals.

I guess that spacers could be added to bring the 17" wheels slightly out, more flush. Would this cause a problem with clearance though?

One thing I have seen is where the spokes are painted body colour eg. for mine black, but leaving the rims silver. These can look great so might consider this option.

maverick

Jeffrey,
I havent noticed any clearance issues at all, but for looks i might consider the spacer as an option. Curious where do you get spacers?

kimo964

You should be able to get spacers from any H&R supplier. I agree that the offset does look a little too close for comfort, especially in hard cornerings.

JBH

Maverick:

As Kimo said, clearence is not an issue except under hard cornering. It's just a personal preference, but I like the tires to be closer to flush with the quarter panel. Those wheels do look good

nathanUK '81 930 G50

Mark, don't add spacers to your front wheels and ruin the geometry

911addict

OK, but rear only, if appropriate.

By the way is it adviseable to consider say 17's on the front and 18's on the rear? Would that work, lookswise and handling wise?

nathanUK '81 930 G50

I can't work out any benefit from that.

One problem would be getting the speedo corrected as I take it you mean to increase the outside diameter of the rear tyres as well.

911addict

Nathan, re. speedo effect. Do people recalibrate if change to 18's?

maverick

I didnt change anything and my speedo is spot on as checked by a radar display on a road near the house.

38D

You can do the math...the delta is normally very small (2-3mph max at ~75 mph).

John McM

Circumference is Pi x Diameter. Say 5 inches for tire = 69 inch circumference for 17 inch rims and 72.2 for 18 inch = approximately 5% difference. So speedo should read 5% slower than actual with change to 18 inch wheels, which is pretty much what 38D wrote.

911addict

I've noticed that speedo compared to Satellite speedo is actually around 10% too fast, eg. if I'm travelling at 30mph the Porsche speedo shows 33mph. therefore by putting bigger wheels the car will be going slightly faster so the speedo will be nearer to true speed.

BTW the reason i suggested larger wheels at the back (18s) but leaving (matching) front wheels (17s) is to give the benefit of filling the rear arches for looks, but saving money by only changing the rears. Also I think the existing compliant steering feel and tracking would be retained.

I'm wondering if anyone has done this and how it looks? I would imagine the different wheel sizes wouldn't be that obvious to the eye, but that the look would be quite aggressive giving a lifted back and lower front (assuming springs set up the same).

Or would there be an imbalance or disadvantage? I don't know.

PS: I like my Cup1's but have seen some 18" Cup1's. Hence my questions.