BFG Rival Question

Stock rear sizes for my E46 M3 are 255/40/18, The Rival doesn't have a comparable size -- but is available in 245/40/18. I am thinking about running a square set up (I have the rims in a square fitment) in that tire. What compromises am I making if I do so? The RS3 is available in my required size, but it is more expensive, and it appears the Rival is a better product.

Autox and HPDE uses. I have a TCKline coilover set up, and camber plates.

Thoughts?

You're looking at 10 mm less width on all four corners. There will also be a corresponding decrease in overall tire diameter, which will act like a numerically-higher final drive ratio.

^STock E46 M3 fitment is staggered. 225/255

OP, any reason not to step up to a larger size to go square with? Those fenders can easily handle 275/285s all the way around, right?

In reply to z31maniac:

Rivals don't have good sizing -- the next size up is 275s and my rims are 9 inches wide.

You should EASILY be able to fit 275s on a 9" rim. I've got 255s on an 8" rim.

In reply to ZOO:

I'm running 225/45/15 on a 9" wheel, and as stretched as the tires look I don't think you'd have to squeeze the 275s much to fit on a 9" wheel.

ZOO wrote: In reply to z31maniac: Rivals don't have good sizing -- the next size up is 275s and my rims are 9 inches wide.

Ahh OK, didn't realize wheels weren't in the picture (though should have based on your sizes).

I don't think 275s would be too bad on the 9s.

For what it's worth, the press introduction for the Rival used E46-chassis M3s.

David S. Wallens wrote: For what it's worth, the press introduction for the Rival used E46-chassis M3s.

Oooh -- do you know the sizes?

ZOO wrote: In reply to z31maniac: Rivals don't have good sizing -- the next size up is 275s and my rims are 9 inches wide.

And? I'm running a 255 on an 8" wheel. You've got 25.4mm of more wheel to run 20mm more tire.

I'd Run 245/40 front and 275/35 rear. Both are the same basic 25.6" diameter. Should work great.

nocones wrote:

ZOO wrote: In reply to z31maniac: Rivals don't have good sizing -- the next size up is 275s and my rims are 9 inches wide.

And? I'm running a 255 on an 8" wheel. You've got 25.4mm of more wheel to run 20mm more tire. I'd Run 245/40 front and 275/35 rear. Both are the same basic 25.6" diameter. Should work great.

Not really an "and" -- just looking at all the options available. I will be running a square set up for tire wear purposes. I will have to see if I can clear a 275 up front . . .

I'd say run the 275/35/18s all around. They'll be a little bit squeezed on 9" wide wheels but not much. A little squeeze is good for a performance wheel setup, especially with low-profile tires, makes it harder for the tire to de-bead.

keep in mind that street tires (at least from a ST perspective) don't like to be squeezed quite as much as R-Comps do ...

i just read the GRM review of these in the last issue. doesn't seem like they were impressed with the choice of other tires offered for comparison.

they didn't even comment on the falkens, are they that bad? lol.

GameboyRMH wrote: I'd say run the 275/35/18s all around. They'll be a little bit squeezed on 9" wide wheels but not much. A little squeeze is good for a performance wheel setup, especially with low-profile tires, makes it harder for the tire to de-bead.

Then why is running a 225/45 on 9" wheel the hot ticket in the Miata world?

In reply to z31maniac:

Well, that's what I have - because I followed everyone else's logic. Which was based on last year's tires. I think an 8" wheel would be fine for a 225/45/15, they're really stretched on my 9" wheels.

Yeah I'm planning to run that size on an 8" wheel. Not just because that's the widest I could possibly fit, but because I don't want the stretch (and easier de-beading that comes with it).

GameboyRMH wrote: Yeah I'm planning to run that size on an 8" wheel. Not just because that's the widest I could possibly fit, but because I don't want the stretch (and easier de-beading that comes with it).

Any documented incidences of this happening on Miatas running the common sticky tires or R-comps in 225/45/15 on a 9" wide wheel?

Tons of guys are tracking these setups and I haven't read anything about that being an issue.

z31maniac wrote:

GameboyRMH wrote: Yeah I'm planning to run that size on an 8" wheel. Not just because that's the widest I could possibly fit, but because I don't want the stretch (and easier de-beading that comes with it).

Any documented incidences of this happening on Miatas running the common sticky tires or R-comps in 225/45/15 on a 9" wide wheel? Tons of guys are tracking these setups and I haven't read anything about that being an issue.

Because it's not. Match section width to wheel width.

Yes you CAN stuff a 275 on a 9" wheel. I'm not convinced it'll be much faster than the 245 on the 9", nor will it feel as good.

Not that I know of, it would take a proper scientific study to prove that using 9" wide wheels instead of 8" wide wheels with 225/45/15 tires on a Miata will make de-beading easier...but in general, lower profile and less squeeze/more stretch lead to easier de-beading.

GameboyRMH wrote: Not that I know of, it would take a proper scientific study to prove that using 9" wide wheels instead of 8" wide wheels with 225/45/15 tires on a Miata will make de-beading easier...but in general, lower profile and less squeeze/more stretch lead to easier de-beading.

The long and short of it is: If we don't see Stancey McStancerton debeading his tires 2-3 times a week on the streets, then the 225/45-15 suggested to be run on a 9" wheel and proven to be faster by famed endurance racers 949Racing is probably going to be just fine.

A 225/45-15 on a 15x9 wheel doesn't LOOK perfectly square, but it's faster than the same tire on a 15x8 wheel.

In my personal experience, debeading is something that only happens when you slide the tire sideways across an edge or lip of something. If you're going straight or anywhere near it, i dont really think its possible.

Mustangs factory run 275/40/17 on a 9" wheel...

I don't see what all the fuss is about...

Apexcarver wrote: Mustangs factory run 275/40/17 on a 9" wheel... I don't see what all the fuss is about...

Ditto C4 Corvettes.