Brett928S2

Hi All

Finally decided on size for front tyres....took a long time to decide
as there was the "narrow tyres" for less resistance versus the "wider
tyres" to keep rolling radius the same front and rear...at 83.752
(rear radius)...

The deciding factors were these...

1, If a couple of inches of extra rubber stop or seriously impede my
200 plus attempts, then I need more hp....lol

2, If all goes s**tfaced on my attempt, and I have a serious stopping
problem (even with my chute) then I think I might like that extra
couple of inches to assist my ABS on the front....lol

So final decision is...

Fronts 245/45/18
Rears 275/40/18

I know you will now all tell me reasons I didn't think of lol, but go
ahead

All the best Brett

PORSCHE 928 S2 AUTO V8 4.7 LTR 1986 IRIS METALLIC BLUE WITH X-PIPES ,RMB ,PROMAX CHIPS, KICKDOWN SWITCH, K&N, WIZARDS OF NOS - NITROUS KIT 1000 HP.
PCGB UK 928 FORUM MODERATOR - Email managingdirector@pchealthcare.co.uk

H2

Brett,

You're wise to think about the extra rubber from a cautionary prophalactic viewpoint....you certainly do not want to be screwed at 200+ mph!

Good luck.

H2

IcemanG17

Brett
I think those are the same sizes Tim runs on the Beast......it was good enough for 208mph for him!!

Brett928S2

Hi

Well I only need 212 (for my record) so maybe its a lucky size

Hopefully......lol...

All the best Brett

Mongo

If you want a street tire try Pirelli Corsas. The 996 GT2 owners on Rennlist have used these tires and they stick well. If you want R-compound, slicks, or drag radials, I don't think I can help you there.

marton

Just put a couple of the 928 emergency spares on the front.
They are narrow enough to limit the wind & frictional resistance & they will not be on the ground long enough to overheat. Of course stopping might not be so easy.
Look here for typical dragster front tire sizes
http://www.swracecars.com/shopdispla...d=64&cat=Tires

For the rear you need very wide tires so they can absorb & transmit the energy without the surface melting & losing traction like you experienced.
Have you thought about 345/35ZR18?

Cheers Marton

dprantl

I wouldn't use spares in the front. They are rated for like 60mph max. When I had my spare on recently, going anything over 75mph would cause a serious vibration.

Dan
'91 928GT S/C

marton

trick is to keep them off the ground as much as possible. You just need to touch down from time to time to input steering corrections.

marton

Brett928S2

Hi

If I used 2 spacesavers, I would turn mine into a bulldozer, I would be scraping up the tarmac with my front spoiler lol

All the best Brett

F451

LOL!

Btw: my 20 yr old spare and air compressor recently saved me!

And Go Brett!

Brett928S2

Hi All

Went to get front tyres fitted this morning...

Didnt fit

the 245/45/18 had too large a profile and on my S2 they were grinding on the lower rear arch on the slightest turn of the wheel..

So had 225/45/18s fitted and all ok...

All the best Brett

F451

Hmmm. I have Toyo Proxes RA1's 245/45 ZR18 that fit fine on the front of my '88 S4.

Maybe there is a difference in the size of tires vs tyres. Heh heh...

Brett928S2

Hi

I used the wheel calculator from Rennlist (the Excel one) and that said they would fit with a 7.25 mm extrusion from
the arch....and I put in my offset (50)

But they didnt

Maybe it was the tire make but I cannot see it making that much difference, I only had to turn the steering wheel around an inch and they were grinding badly

All the best Brett

F451

Perhaps it is the offset. I can't remember mine off hand.

And I've heard of variations between the size of different mfr's tires, but I don't imagine it would be that much.

In any case, you've got some new rubber on there that fit's correctly, and that's the important thing.

ew928

Ride height?
Higher the front end, the more the bigger tires will 'grind' on the inside rear front fenderwell.
Might not rub as badly if the front gets settled.