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Supreme Being
Group: Forum Members
Last Login: 10/27/2008 10:34:12 PM
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With respect to a '99 M3:
I've got g-force 235/40R18 in the front and 255/35R18 in the back.
I'm going to change out my wheels and want to get the optimum width for them.
bfGoodrich says I can use between 8 and 9.5" in the front and 8.5 to 10 in the back.
When their table gives the tread width, they use wheels of 8.5 and 9.0 to make the measurement.
If a wider tire improves cornering, wouldn't the wheel closest to the tread width of 9.5 in front and 10.2 in the rear?
What goes into the optimum wheel width?
Tnx,
Bill
Bill
Arlington
e36, 38, 39
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Supreme Being
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Bill,
Generally speaking the wider the better when you're mounting street tires on wheels. R compounds tend to have stiffer sidewalls so you don't have to stretch the tire out as much. A 9.5" rim will not fit on the front of an E36 unless you run 3.5 degrees of camber. A 9" wheel will fit. This is assuming we're talking about a car with coil overs where you can put the wheel right up to the strut housing.On the rear (with fender rolling) a 9.5" wheel fits easily. I think a 10" wheel would fit on our car, but it has a little extra emphasis on "rolling".  This is a 255/40-17 tire mounted on these wheels and it is stretched. Keep in mind too that the tire on there, Yokohama, runs big. More like a 265. 
Brian
Brian Hanchey
vorshlag.com Check out ast-usa.com
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Supreme Being
Group: Forum Members
Last Login: Today @ 5:38:05 PM
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| Generally, I would say the optimum width match ups are: Rim = Tire
7.5 = 225
8 = 235
8.5 = 245
9 = 255 However I think you are overthinking it a bit, and coming from me thats sayin somthin.  What are you trying to accomplish and for what application? The most amount of contact patch? The best look? The best street performance vs comfort? Best track performance? If you are getting new rims and tires I suggest get 8.5" (+40 to +42mm offset) rims and 245/40R17 tires all around. They should fit without spacers and without rolling your fenders and it the most amount of tread you can get without mods.
Jeron
BMW / PCA / Apex HPDE Instructor
97 M3/4 Byzanz/Magma; 2001 330i Silver/Gray; 97 R1100RT; 91 F-150 5.8l
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Supreme Being
Group: Forum Members
Last Login: 10/27/2008 10:34:12 PM
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I think I'm going to stick with 18" g-force tires so 18" are what I need.
I've got a set of the stock M3 17" for a smoother ride at some point perhaps or when what i'm looking for now get shod with Hoosiers.
Over the long term, I'm looking at some track work so, for example, when I replaced the radiator, I put in a Fluidyne. I'll think hard about big brakes when the time comes (Jeron, you know the condx of the rotors). However, we're first and foremost street people.
On the other hand, other than having opened up the in and out of the engine, I don't plan to do any more there.
So, that's the background.
I've been told 8.5 is the widest I can get for the front of the '99 M3 because of the tie rods, but anything goes in the rear (so I need more information for the back).
I'm guessing 9.5 right now just because that's where Goodrich measured the tread width on the 255/35's I have on there now.
I've been surprised at the paucity of options.
I figured everyf maker out there would have already dialed in an optimum set of e36, M3 wheels, both staggered and not.
I've only found a couple of choices in the AC Schnitzer Type II or the BBS RG-R, but even TireRack doesn't have what I want in the BBS and say shipments have stopped from the factory.
Where are the forged replicas?
I'm looking for a tough, not fragile set of street wheels that can hit an occasional hole like those on some of the Dallas on ramps right now. Forged to get the weight down below 20.
I'd be happy with 18 - 8.5, 5-120 and 9.0 or 9.5 in the rear.
So, can I get a 9.5 wheel under the rear fenders? That is, has anyone done it without rim rolling? I've got some room with the set-up now and I think they're 8.5's.
Thanks everyone.
Bill
Arlington
e36, 38, 39
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Supreme Being
Group: Forum Members
Last Login: 10/27/2008 10:34:12 PM
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My mistake.
Goodrich measured the 255/35R18 with a tread width of 10.2 on a 9.0 wheel, not a 9.5.
So, without coilovers, I'm looking for 18" x 8.5 for the front and 9.0 for the rear.
Can I figure on not having to roll? Has anyone got 9's in this sort of circumstance?
Thanks again,
Bill
Arlington
e36, 38, 39
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Supreme Being
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| It's my understanding that within limits a stretched tire is better able to resist tread rollover and helps to keep the tread face flat on the road. If that's true then you might want to go to the widest recommended width, rather than the measured wheel width, assuming there are no other physical limitations.
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Supreme Being
Group: Forum Members
Last Login: Today @ 5:38:05 PM
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| Blow off the big brake idea. Until you get VERY serious on the track it is a waste. Instead get 1st) track pads and 2nd) a dedicated set of track rotors and 3rd) forced air cooling. It certainly isn't anything goes in the back. 255/40R17 will most likely require some rolling. Since you are going 18 and can use 255/35R18 them you are a bit better off and should be able to make them work without rolling. The front has a bit more room than the back. If you go one size all around, and you should, you will probably need a small spacer, 5mm, in the front to clear the oem spring stay. The tie rod will not come into play with oem struts. I would look for 8.5 and 9" widths. Like I said above don't go staggered. I have 18x9 +40 with 245/35R18 Kumho V710 on them if you want to test fit. Frank is right about the theory but like Brian said above, rollover is much less a issue with the low pro 35's and especially once you get R-comps.
Jeron
BMW / PCA / Apex HPDE Instructor
97 M3/4 Byzanz/Magma; 2001 330i Silver/Gray; 97 R1100RT; 91 F-150 5.8l
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Supreme Being
Group: Forum Members
Last Login: 10/22/2008 3:19:15 PM
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| There are some new, bigger choices coming for BMWs...  
We have a shipment of 40 qty of these 17x9 wheels inbound. Some LSC folks here have already gobbled up part of the first shipment (some even ordering multiple sets). 16.4 pounds, squeeze forged, made to fit a BMW hub and bolt circle (no hub-centric centering rings needed). These are D-Force Wheels' brand new LTW5 model. 
Available in silver, gunmetal gray and black with machined lip... $259/each. We're literally adding them to our website tonight and the cart tomorrow. We should have these in our hands by next week. More soon! 
Terry Fair - www.vorshlag.com & www.ast-usa.com
"Alpha" E36-LS1 (XPrepared/G Class "No Class") '97 M3 (STU/F Class), '91 318is (STS/C Class)
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Supreme Being
Group: Administrators
Last Login: 10/28/2008 9:56:31 AM
Posts: 260,
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| Is there a 17x8 fitment in the pipeline? My poor old E30 M3 won't take a 9" rim. I rub badly enough with the 235/40/17s I have now. Thos black rims are hot though.
________________________________________________________________________ Yes, I know my wheels are gold, but I DO have a car so check it. My name is Will and I like long walks in the rain...ahhhh my ankle!!! And I have a friend named Richie that abuses his powers.
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