[Blue Angel]

Pics:

[Unspec]

Yea based on the pictures, I am unsure how he is not rubbing unless he only drives on the world's flattest pavement. That tire is straight up poking from the front wheel well, and KW's progressive springs aren't really all that stiff on initial compression. Maybe he swapped out for some crazy stiff springs?

I'm also not sure what the benefit of such massive front tires is, can anyone enlighten me why you'd need anything more than 255 on the fronts of our cars?

[BimmerHausPerformance]

Originally Posted by Unspec

Yea based on the pictures, I am unsure how he is not rubbing unless he only drives on the world's flattest pavement. That tire is straight up poking from the front wheel well, and KW's progressive springs aren't really all that stiff on initial compression. Maybe he swapped out for some crazy stiff springs?

I'm also not sure what the benefit of such massive front tires is, can anyone enlighten me why you'd need anything more than 255 on the fronts of our cars?

He is xdrive so he wanted the contact. Ps2, meth, hpfp, etc etc…

In talking with fitment industries 275 is about the limit before you have adverse effects on diveability on the fronts. I have no problems with mine, with the reduction in sprung weight the car feels more nimble.

[Blue Angel]

Originally Posted by Unspec

I'm also not sure what the benefit of such massive front tires is, can anyone enlighten me why you'd need anything more than 255 on the fronts of our cars?

More tire = more grip (as long as it's managed properly by the suspension). Time and time again you'll see people going with a square setup to maximize handling on the track.

I have a C5 ZO6 Corvette, and though I've never had it on a racetrack I have spent more than a healthy amount of time in Corvette forums. It's not uncommon to see square 295's on these cars set up for the track, and these things barely break 3100 lbs without the driver. I run a square 18x10.5 wheel on mine (stock rear wheel on front as well) with 285/35 and 305/35 r-comp setup, a carefully chosen alignment, and on a familiar on-ramp with a great surface I've never gotten the nerve to get it into any kind of slip angle - it's just absolutely STUCK. With the terrible stock seats it's all my leg and elbow can do to keep me off the door panel... I need a driver's seat upgrade for sure.

The car came with 17x9.5 fronts with 265/40's and 295/35 rear GoodYear Supercars. The magazines could break 1G on skidpads. The car could also break free in 3rd gear, part of what made the car such a wild ride. With the wider sticky Nittos the car instantly felt like it could use 100 more hp, it's that tame, and the cornering grip is epic.

My F10X on Indy 500's doesn't have that same level of grip, but it's darn good for what it is. Lowered + camber arms up front, 275/35-20's all around, and equal camber front and back (~-1.3 degrees) it's very neutral with a tail that wants to play on lift-throttle. This is only subjective based on some cold wet on-ramp action, I haven't had a chance to push it in good conditions yet.

Originally Posted by BrowBMW

...275 is about the limit before you have adverse effects on diveability on the fronts.

The 285/35 on the front of my Z will follow grooves on bad roads sometimes, but it's not a deal breaker, you just get used to it on a car like that. So far the 275/35 on the front of my F10 feels completely natural.

Any hard-core readers of (the no longer published) Sport Compact Car magazine might remember an article called "The Dave Point", in which he laid claim to naming the point that represented where the steering axis intersected with the road surface. The distance between the Dave Point and the effective center of the tire's contact patch determines how much torque steer you have to deal with in the steering wheel. Holy crap, a little Google and voila: the article published under MotorTrend!

https://www.motortrend.com/news/9909scc-technobabble/

Dave Coleman was responsible for a lot of my early automotive education - glad to see his work lives on! Anyway, the SCRUB RADIUS is the distance between the Dave Point and the contact patch center; add a spacer, change your offset, add wider wheels, change tire pressure... do any of those things and you alter the scrub radius, which changes the steering feel of the car.

Fortunately for me, changing wheels/tires/offsets seems to have been adequately offset by adding camber, and probably has a lot to do with BMW designing a good suspension to begin with. Even my et22 245/45 winter tire setup doesn't feel odd compared to the stock et33 245/35, in fact it feels pretty darn good.

Originally Posted by BrowBMW

...with the reduction in sprung weight the car feels more nimble.

My 19x9 408M are 25 lbs and my 20x9.5 FC04 are only 23 lbs, both a big step down (UP? ) from the 36 lb 20" 434M wheels that came on this car. I do believe the lighter wheel weight is something that can be felt more often than just when removing them.

Bigger/stickier square tires, lighter wheels, increased camber, firmer springs and less body roll all add up to a car that turns in remarkably well, MUCH better than it ever did stock. Before it was like you were asking it a favor to take a turn at speed, now the front end just bites, grips and goes. The front end even feels great with winter tires. It's so balanced I'm thinking it may need more front sway bar to keep the rear in line - it doesn't take much to get it to step out. If it doesn't prove a hazard in slippery winter conditions I might just leave it as-is.

Granted, I never pushed the car on the fully modified suspension with the stock 245/275 runflat Dunlops so I can't say for sure how much of the improvement the square tire setup is responsible for. Even if I had, those runcrap dunflops and boat-anchor 434Ms would likely never do the car justice anyway. BMW made the M5 a pretty good handler with a 265/295 setup so square tires are certainly not a requirement, and getting a high hp RWD car to accelerate out of corners can be easier with more rear tire.

Sorry for the long-windedness. When I get on a proper keyboard there seems to be little reason to hold back.

[Blue Angel]

And a couple pics of my 275/35-20 square setup, 20x9.5 et30 front and et33 rear:

[BimmerHausPerformance]

Perfect fitment

[Blue Angel]

Originally Posted by BrowBMW

Perfect fitment

Thanks!

Keep in mind my reduced rear camber. With stock rear camber et30 would get you pretty much where I'm at. My wheels are all et45 and I run 15mm front and 12mm rear spacers, planned that way so I could dial it in.

Also don't forget that my front will rub with too much steering angle entering a steep entrance or raised curb. It's not hard to avoid, but I still feel I have to put it out there (and the winter setup rubs a little easier than the summers).

[stefan_bratu@yahoo.com]

IS RIGHT

Originally Posted by Blue Angel

My winter front fitment is 408m 19x9 et32. I run a 10mm spacer for an et22, and I use a 245. I will admit they rub.

Full disclosure: my tires are 1" larger diameter than stock, so for a given vertical fender gap I will be 1/2" less lowered. BUT, I have -0.5 degree camber arms installed which pulls the top of the tire inboard by about 5mm which more than offsets the 1/2" difference in camber curve of the suspension being higher.

So according to the internet:

275 et22: no rubbing
245 et22: rubs

Sounds about right!

[ApexWheels]

Originally Posted by Unspec

Any chance the VS-5RS in 5x120 20" will be on the road map soon? I looked at the sizing table and it looks like it's not a projected option yet.

Yes, it will be. We finalized the initial 5x120 20" fitments and offsets with engineering the other day and they are going to begin designing them soon. I'm not certain about the front wheel options for the F10 chassis yet though as the offering is going to be quite limited, at least initially. It's still early days for these wheels and I expect to have more information about the range of options later this year. I'll keep you posted.

-Tom

[ApexWheels]

Originally Posted by BrowBMW

You are right, I just spoke to him and he is 275's on 18's with only a 22 offset. He does not rub. He is on kv3's.

So he is on 18x9.5 ET22? I'm quite surprised that works with the taller tires.

[BimmerHausPerformance]

Originally Posted by ApexRaceParts

So he is on 18x9.5 ET22? I'm quite surprised that works with the taller tires.

Yes sir, if you hit him up on insta he'll reply. Good guy.

[Blue Angel]

Originally Posted by ApexRaceParts

So he is on 18x9.5 ET22? I'm quite surprised that works with the taller tires.

275/40-18 is a 26.7" tall tire, about the same as the stock 275/35-19 these cars came with on the rear which is what BrowBMW is using on the front.

I have the taller tire, 275/35-20 (27.6") et30 and 245/45-19 (27.7") et22, on the front.