325/660/18 On Rear

[Jeff80]

Anyone tried to jam this onto the rear on a proper wheel? I'm considering doing some experimenting if no one has tried it.

jeff

[sly1types]

thats a lot of tire, i would try a 325/645/18 first.

I think it could fit though if you have your car high, there are some guys running 325/30/19s

[Jeff80]

I've got them on now. About .5 inch shorter that stock wheel/tire combo but about 2 inches wider. They are pinched on my 11" wheel so I'll not be able to make the most of them but I'll eventually get them on a set of 18x12. I'll stuff one on the front too just to see what all it smashes and post up some pics.

jeff

[Jeff80]

320/660/18 on front with my standard street camber setting of around 2 degrees and an effective offset of +14. Dialed all the way in to 4 degrees this doesn't poke as much and sort of fits... sort of. I can drive on the streets with no issue but it looks like Charleton Heston's chariot. If I moved over the the GT4 uprights and arms (or aftermarket arms)I think it would be no issue at all to run this up front.





... and on the rear with all the rear camber that stock components will give. Effective offset is standard +44 but I have room to go to a +34 me thinks. Gonna stick a spacer on there to try later.





The tires are pinched on an 11 inch wheel. A 12 or 12.5 would be much better but I wanted to experiment. I'll dig up some 12's and try those. I'd rather mess with maximizing mechanical grip before trying to figure what aero actually works in the rear of these cars. We have a definitive solution for the front, but since I dont like giant wings I'd have to dig up a flat floor and diffuser design that's tried and true. I'm sure it's out there.

jeff

[sly1types]

wow! those look meaty, let us know how they perform and if there is any lap time to be gained.

[Alexander13.]

Following to see how you go with the rear and a 325/660/18. I have pulled my arches 10mm to fit a bigger offset wheel but the want to go fast with a meaty tyre has got the best of me

[JustAnothaM4]

Originally Posted by Jeff80

320/660/18 on front with my standard street camber setting of around 2 degrees and an effective offset of +14. Dialed all the way in to 4 degrees this doesn't poke as much and sort of fits... sort of. I can drive on the streets with no issue but it looks like Charleton Heston's chariot. If I moved over the the GT4 uprights and arms (or aftermarket arms)I think it would be no issue at all to run this up front.





... and on the rear with all the rear camber that stock components will give. Effective offset is standard +44 but I have room to go to a +34 me thinks. Gonna stick a spacer on there to try later.





The tires are pinched on an 11 inch wheel. A 12 or 12.5 would be much better but I wanted to experiment. I'll dig up some 12's and try those. I'd rather mess with maximizing mechanical grip before trying to figure what aero actually works in the rear of these cars. We have a definitive solution for the front, but since I dont like giant wings I'd have to dig up a flat floor and diffuser design that's tried and true. I'm sure it's out there.

jeff

How are you dealing with the fender liners with that huge wide/tall tire up front? Also, did you test a 10mm spacer on the rear?

[Jeff80]

Originally Posted by JustAnothaM4

How are you dealing with the fender liners with that huge wide/tall tire up front? Also, did you test a 10mm spacer on the rear?

I haven't gotten to load the suspension up on the track yet so street testing at an abandon warehouse complex is all I've done along with jacking up the combo into the fenders to see what they hit. So far there are no issues with clearance. I will get to test at the track next Friday September 2nd. I will have spacers with me incase there are issues.

jeff

[fanatic1]

look like they fit fine, but did rub the fuel vent line.

Didn't find this out until much later.

325/660 DH

[Jeff80]

Weekend report from the 320's (Pirelli DH 320/660/18) on the rear. First session out they rubbed very slightly on the inside fender wells when deflecting in corners. They are fine on the 11 inch wheel but would be better on a 12 or 12.5. These are much wider that the 305. More than the numbers indicate. I tossed a 5mm spacer on there and the issue was solved.

Car was great the rest of the day. More grip from mid corner to exit so I was on the throttle more aggressively but not necessarily sooner. All in all they are are better than the 305 at this HP level (BM3 stage 2 OTS - I hate stages) as along as you don't want to rotate front to back.

Biggest mistake of the weekend was that I drove an NA chassis miata race car with GM 3.6 LFX. Slicks on 15x11 wheels, penskes, light aero, very low weight and properly set up. Huge mistake. The MCS coilovers I have waiting to go on my F80 are now going up for sale and the progress of this car to a track focused car will cease. Outside driving a GT3RS and a 996 cup car, it was the most fun I've ever had in any car in my 22 years of driving and racing. When I got home from the track Monday after three days of track fun I started the process rolling and what may end up being a clone.


jeff

[fanatic1]

Originally Posted by Jeff80

Weekend report from the 320's (Pirelli DH 320/660/18) on the rear. First session out they rubbed very slightly on the inside fender wells when deflecting in corners. They are fine on the 11 inch wheel but would be better on a 12 or 12.5. These are much wider that the 305. More than the numbers indicate. I tossed a 5mm spacer on there and the issue was solved.

Car was great the rest of the day. More grip from mid corner to exit so I was on the throttle more aggressively but not necessarily sooner. All in all they are are better than the 305 at this HP level (BM3 stage 2 OTS - I hate stages) as along as you don't want to rotate front to back.

Biggest mistake of the weekend was that I drove an NA chassis miata race car with GM 3.6 LFX. Slicks on 15x11 wheels, penskes, light aero, very low weight and properly set up. Huge mistake. The MCS coilovers I have waiting to go on my F80 are now going up for sale and the progress of this car to a track focused car will cease. Outside driving a GT3RS and a 996 cup car, it was the most fun I've ever had in any car in my 22 years of driving and racing. When I got home from the track Monday after three days of track fun I started the process rolling and what may end up being a clone.


jeff

And the W2W pull? Resistance is futile 🤣 (so I'm told)

[Jeff80]

Originally Posted by fanatic1

And the W2W pull? Resistance is futile 🤣 (so I'm told)

That's exactly right. I'm clearly the next Fernando Alonso

jeff

[Jeff80]

I lied. I put my 2WR's on my F80 and bought an E36 racecar

[Jeff80]

Now with the 2WR on my F80, I am now at an effective offset of +9 in the front with 18x11 and 305/645 Pirelli DH. Camber is at -3.9.

jeff