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NB 1995 C4 Cab, Upgrade from 17" Cups to 18" Twist

robertdover

Monza
Joined
6 Feb 2013
Messages
160
Hi guys,

Any knows problems with doing this? I know of the Steering bracket, ive checked the VIN and it seems mine needs it.

But is there any issue with using Hollows or Solid Twist alloys? I believe mine to be the solid version. Ive managed to source some that need a bit of TLC cheaply. The codes for mine are:

993.362.134.06 (Front)
993.362.140.04 (Rear)

I was planning to use the Cups with winter boots and the Twists for the summer, any thoughts?
 
Apart from the steering bracket, there are no 'issues' with your change.

You do have a solidspoke set there (with those part numbers) and I have to say it's only an upgrade on looks, as they are significantly heavier than the so-called Cup2, and so extra rotating weight will blunt steering, braking and accelerating.

Also the fatter tyres up front reduce the telepathic steering 'feel' quite noticeably.

Whatever you do, keep the Cup2s in the shed for when you change your mind. :thumb:
 
Hi,

I'm still running 16" on my C2 Cab and the car runs well. A few have said that 16" do not fill the arches too well but TBH I'm happy plus this is how the car came from the factory and I like to keep things pretty much original. However, some of the guys on here that have tried 18" say the ride is not too good.

I'm sure someone with a personal experience will be along shortly and put you right.

ATB :)
 
Time to join the ECU remap thread then, might be needing a few extra horses........and a bigger shed :pc:
 
I've got 18" twists on mine & it's just fine - make sure your suspension is sorted & all will be well.
I've also got a strut brace which can do no harm :thumb:
 
You'll increase grip, and track, cant be anything but a good thing on the front end, if there's any real limitations it'll be down to your road craft.
 
Nb 993 = cup 2's :worship:
 
Nb 993 = cup 2's

17's for go.........18's for show*

*pretty sure I've stolen someone's quote there but I do like it!
 
Any issues with wheel offset differences, or is this a bolt on and go job?

I know the wheel arch clearances aren't great anyway but I'm guessing with the lower profiles required to run 18"s it shouldn't be a problem or am I wrong?

Attached are the recommended profiles and Alloy offsets. Im sure the 18" fronts I have are 7.5J not 8J.
 

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The overall diameter of the tyre remains virtually the same whether 17 or 18 in. So yes, it's the profile height of the tyre that has to change to accommodate the bigger alloy.

For a narrow bodied car the following would apply:

Fronts 7.5 width 50 offset tyre size 225/40 18
Rears 10 in width 65 offset tyre size 265/35 18

There are variations on the theme such as 8in fronts which would normally be a 52 offset but uses the same size tyre.

Also you can get 9in rears which for a NB would have a 52 offset but still use the same size tyre.

Wide body cars use basically the same size wheels but the rears have a different offset to make the wheels fill the arches/ This offset can either be built in to the wheel hub during the manufacturing process or the addition of a spacer.
Hope this helps
 
My car had the same solidspokes you listed above on it when I bought it. The offsets are 'correct'. Bolt and go.

The 7.5J when wearing a 225/40 tyre is indistinguishable from the 8J in looks and feel.

I have another wheelset which has 8J fronts.

FYI the 7.5J front was allegedly introduced for the 986.1 and 996.1, then Porsche reverted to an 8J front for the 996.2.
 

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