GT3 Track Wheels 18 or 19

[slodge]

Looking at some OZ wheels for my 6GT3 MK 2 which is used pretty much just on track so not fussed about ride on the road etc.

For info still consider myself a novice having started tracking this year and attended 9 days since Feb.

Wondering what are the pros and cons between 18 Alleggeritas and 19 Ultraleggeras? To be honest prefer the look of the larger wheels but that is of secondary importance if they spoil the learning process and provide a less progressive experience on track.

Any views appreciated!

Cheers

Slodge

[Harris_I]

Don't mess around with 19s. You will ruin the car.

[nxi20]

Harris_I said:

Don't mess around with 19s. You will ruin the car.

Really? Based on what evidence do you claim this? Please define "ruin".

I have run 19" OZ's with either MPSC or MPSS rubber for the last year (approx 14K miles) & I genuinely cannot say that the ride (or indeed any other aspect) is worse than when it was on 18" wheels. In fact, it has more grip because using 19's allows me to run slightly wider tyres front & rear. Despite the doomsayers predicting horrible consequences for the ABS & accuracy of the speedo among other things, there have been no adverse consequences & in fact the speedo is now more accurate than it was on the 18" wheels.

I still use 18" OZ wheels with slicks for track work on some trackdays, but it's mostly been the MPSC option...

Edited by nxi20 on Friday 21st June 11:27

[Harris_I]

nxi20 said:

Harris_I said:

Don't mess around with 19s. You will ruin the car.

Really? Based on what evidence do you claim this? Please define "ruin".

Assuming this is for a track car, then the car will thump heavily over kerbs and the dampers will struggle to keep up. That said, I don't know what weight the above mentioned 19s are, but I wouldn't spend thousands of pounds in the hope that I could do better than Porsche's own chassis engineers in finding a better balance between grip, traction, damping and braking. On the last point, most track day drivers don't get the best out of their brakes anyway so increasing the contact patch makes little difference.

We briefly experimented with 18s and 19s on 911 race cars, found little benefit in outright grip, and struggled to find the right size rubber on slicks. You may also find 19s require you to roll your wheel arches depending on your ride height.

The standard car can be well set up in stock form.

Edited by Harris_I on Friday 21st June 12:23

[nxi20]

Harris_I said:

Assuming this is for a track car, then the car will thump heavily over kerbs and the dampers will struggle to keep up. That said, I don't know what weight the above mentioned 19s are, but I wouldn't spend thousands of pounds in the hope that I could do better than Porsche's own chassis engineers in finding a better balance between grip, traction, damping and braking. On the last point, most track day drivers don't get the best out of their brakes anyway so increasing the contact patch makes little difference.
{...}
The standard car can be well set up in stock form.

Ah, OK; I never tried 19" on the standard car. Mine's been non-standard for so long now that I can't remember what it felt like TBH. I don't have any of the standard suspension or brakes left on mine; it's all rose jointed & has 2-way adjustable Moton's so the damping & geo is far better controlled than with the factory stuff. I had (perhaps wrongly) assumed that the OP was already some way down the modifications road...

The 19" OZ's the OP mentions are much lighter than the stock 18" rims. The rears are just under 12KG & the fronts are just over 10KG.

Arch rolling isn't required with 305/30 rears & 245/35 fronts. I run fairly low heights at 100mm F & 122mm R and only very occasionally get an arch liner rubbing.

If the OP wants to try a set of 19" fitted with MPSS on his car, he already knows how to contact me [Hi Simon!].

This picture illustrates the car with the suspension loaded up pretty well.

Edited by nxi20 on Friday 21st June 13:05

Edited by nxi20 on Friday 21st June 13:10

[slodge]

Thanks for the comments guys - useful points of view on both sides.

Hi Nick!!

Just got back from Spa - epic is the only word. Blew my mind. The addiction is only getting worse...

About to pop Ohlins and Black Series polybushes on then geo etc and thought I may as well do the wheels at the same time, hence the forum question.

Thanks for the kind offer of a wheel loan - I'll have a think over the weekend!

Cheers