stuartph

Guys


Would a 285 30 18 tyre fit up front on a GT , the wheels to be used are 10" ET65 and the car has been lowered

dprantl

No way. You will need higher offset wheels and a bunch of negative camber to make them fit. Or you will need to modify your front fenders.

Dan
'91 928GT S/C 475hp/460lb.ft

Mrmerlin

you should test fit the rim on your car see how far it fits into the wheel well I tried fitting a 18 x 9 et 52 twist wheel on the front and the edge of the wheel was past the fender lip, then the next problem will be with the tire possibly hitting the inner portion of the fender well or the rear of the fender well when the wheels are turned

stuartph

The rim fits just fine but i was about to order the tyres but thought i best ask, maybe i should go with 265 35's

mark kibort

the only way you can fit that tire, is with an 8" backspacing 9.5" rim or 8.5" backspacing 10" rim. ask me how I know
mk

IcemanG17

MK
How do you know?????????????? It will also work on a 10" wide rim with 9" backspacing.....ask ME how I know.....

Or you can be insane like me, run around 100mm front ride height, with 305/35-18 front tires on the 10" wide 9" backspacing rims and RUB LIKE CRAZY at anything more that perfectly straight.

However...the 10" wide 65 offset translates too a 8.05 backspacing so its not too far away....the 285's would stick out a bit, but 265/35's should fit.....

dprantl

No, 10" 65mm is 7.56" backspacing. 8.05" backspacing on a 10" wheel would be 77.47mm offset. I have personally tried test-fitting a 10" ET65 wheel on the front with a 265/35-18 tire and it stuck out past the fender way too much for me. If my car was lowered enough with those wheels, they would rub the tops of the fenders without question.

10" wheel with 9" backspacing? You have a wheel that has a +101.6mm offset?

Dan
'91 928GT S/C 475hp/460lb.ft

IcemanG17

Dan
Yup 10" wide with 9" backspacing custom forged wheel from CCW....

However I used this calculator to determine the backspacing-offsets....your math comes out different....since I end up with my front wheels 10-9 at 88.9mm offset? I forgot exactly how the offset-backspacing math works..so I just use the calculator

http://www.autolounge.net/calculators/tirespacing.html

dprantl

Yeah, I wouldn't use that calculator anymore... backspacing + frontspacing must = total wheel width right?

backspacing = (width / 2) + offset
offset = backspacing - (width / 2)

Remember that: mm / 25.4 = inches

http://www.tirereview.com/?type=cc&id=179&53L3c73d=179

Dan
'91 928GT S/C 475hp/460lb.ft

Brett928S2

Hi

I don't think 265 will fit either...

On my 18 x 7.5...245 locked on the inner wing (S2)...235 "MAY" have fitted but they had none in stock for me to try....so I fitted 225/40/18s.....that way I could turn my wheels more than around 3 inches lol....

So I would TRY a 265 first......

All the best Brett

martin D

Stuart
I think DrNick ran 18x10 on the front of the orange beast for a while, I dont know the tyre size . PM him if he doesn't chime in.


P.S. I've just fitted 11 x 18 45et with 295/30/18 on the rear , I knew they shouldn't fit , but they do.... sort of.

MrGST

It's my understanding that when converting offset to backspace and vice versa, you have to remember that every wheel has two width measurements.

For offset, we use bead to bead nominal width, the stated size of a wheel, e.g. an 18 x 10 wheel will measure 10" from bead to bead.

For backspace, we measure rim lip to rim lip, which is the overall width of the wheel. In general, actual width is about .5" more than nominal.

stuartph

Martin

Yes i know nick ran them with 255's i just want more , i dont mind if they stick out a bit, looking at the car with just the rims on the front its not alot so 265's toyo r888 are on order

The 11"s fit with a baseball bat in the arch, i've got my car low and i dont get any contact on the rear at all.

drnick

stuart,the 255s fit but i did need to fold the inner arch edge on my S2 fenders. i would have gone to the 265s next. i like what kibbort has done with his fenders lately, good idea!