I've been a reading a ton lately trying to decide what to do and haven't done much more than confuse myself further, so I turn to the experts for help.

I've got BC coilovers waiting to be installed and wheels on order (20x9.5 +5, 20x10.5 +5) and I'm trying to decide on a tire size. I will be rolling the fenders and ride height won't be as low as some but I want to minimze fender gap as much as possible without being unable to drive to work (need a bit of clearance for a couple spots).

I'm all for tire stretch to help fit the wheels but not a fan of stretching for the sake of stretching, nothing against it just not a fan. I want to maintain as much of a contact patch with the road as I can so adding wider tires would make sense... But I would have to run more negative camber the wider they get to make them fit unless I pulled the hell out of the fenders which I don't really want to do.

So at what point does negative camber lessen the contact patch and make a wider tire less effective?

For example, I'm sure I can fit a 255/35 rear no problem with a rolled fender, but if I wanted 275 or wider, would I be running so much camber to make it fit that I'd end up with less rubber on the road? At some point there has to be a deminishing return right?

Btw, the reason this is messing me up is that I'm away from home so I'm trying to do this by visualizing it from a distance rather than just doing it, and the wheels haven't been delivered yet anyway, but I'd love to have tires ready and waiting when they arrive.

 

Naturally, you pull about 1 degree of camber for every inch you drop the car (give or take)

-2 you won't have lost very much.

285/30 rear and 245/35 would work nicely. Roll flat, adjust camber to -2 and you'll be good from there.

Every degree of camber ( can't recall right now as I am super deprived of sleep) is about 8mm difference in offset. So if you want to view that 8mm for every bit of camber you'll be losing say 16mm of contact patch making your 285/30 actually a 269/30. But in all honesty, you won't be losing that full amount. Tires are a malleable material that squishes when pressure is applied to them (and at about 1 tonne a corner, there is a fair amount of pressure on them) so you'll probably only lose about 10mm of total contact patch.

Oh, and I will go as far to say that 275/35 out back will look too fat and with 20s you don't need to worry about ground clearance, the wheels already give you enough lift to pull of 30 series tires.

 

Blain that's about right. I think its right around 5mm.

 

I actually had 5mm typed in there and changed it to 8mm for good measure lol

52nd hour sleep free.

I'm gonna sleep sooo fine tonight!

 

That's the kind of thing I hadn't seen before and pretty much exactly what I was looking for. Whether it's 5 or 8, either way good to put a number on it. Thanks for the info 4DGS and Marcus.

Now to start shopping around for tires

Oh, and damn dude, get some sleep!

 

I have at least another 4-5 hours in me haha. Back to a busy week tomorrow!