Front Wheels on Mach

[Donr75]

I have some new 17x9 Rims, whats the largest size Tire I can put on Front?
275/40/17 OK?

[AirborneRanger]

I have some new 17x9 Rims, whats the largest size Tire I can put on Front?
275/40/17 OK?

on 9inch wide wheels, not having to do any grinding or anything I think you can even get a 295 on there. Most places will test fit for you, if you take your car somewhere. 275 is what I, along w/ other ppl who want the full handling effect are runing, but Im pretty sure you can even go wider. Enjoy :bna

[tach9]

I have some new 17x9 Rims, whats the largest size Tire I can put on Front?
275/40/17 OK?

On a 17 x 9 wheel..the widest you can go optimally is 255...the 275 will fit, but optimally the 275 requires a 9.5" wheel...295..no way....Danger Will Robiinson :D Also remember you have the 3% rule involved for the ABS..your wheel/tire combination must exist within 3% of the stock 245's in order for the ABS to function...

[Lonestar 7]

Tach Knows Best!

[2003_shaker]

On a 17 x 9 wheel..the widest you can go optimally is 255...the 275 will fit, but optimally the 275 requires a 9.5" wheel...295..no way....Danger Will Robiinson :D Also remember you have the 3% rule involved for the ABS..your wheel/tire combination must exist within 3% of the stock 245's in order for the ABS to function...

Tach, that's +- 3% of diameter, right?

Donr75, don't forget you're probably going to get clearance issues when you go beyond around 255. I've got 275's up front and they rub at the extremes of the steering. I've got a pair of new steering stops I've got to figure out how to install. . .

[red03shaker]

i want to get 18X9 rims, in the front id have to get 245? or 255 is arite? id have to get low pros for the abs to work well?

[tach9]

i want to get 18X9 rims, in the front id have to get 245? or 255 is arite? id have to get low pros for the abs to work well?

18 x 9..optimal fit tires are 255's...245's are too narrow for optimal fitment on that width (9)....ABS..you must stay in overall diameter within 3% of the 245-45-17 for the ABS to function properly...

Mach On :spinem:

[351c.i.d]

Tach on my 18x9's I have 275's and hardly any sidewall over the rim. You really think they are the wrong size? They almost look like they are on the ede of being not wide enough! The "look" like they fit almost perfect.
But what do I know?

[Ralph Greene]

Tach on my 18x9's I have 275's and hardly any sidewall over the rim. You really think they are the wrong size? They almost look like they are on the ede of being not wide enough! The "look" like they fit almost perfect.
But what do I know?

I'm running Michelin 255X40X18 on my 18X9 FR500's. The 9" wheel is exactly in the middle of their recommended wheel sizes for this tire. 265X40X18 would "look" better probably, but is a little large for speedometer accuracy (maybe...borderline anyway), but it's not the optimal size...like Tach9 says. A 265X35X18 might be optimal for handling, but diameter is a little short for my purposes (looks). Anyway wheel width has more to do with how wide a tire looks than most think. My 255's are 10" wide on the 18X9 wheel. 275's won't measure 275 MM wide on 9" wheel. They will on 9.5" wheel.

Wheel widths and how they look are deceiving on some wheels. Remember wheel widths are measured on the inside where the tire sits, not on outside of wheel rim. Most Ford wheels have a "lip" that sticks out about 1/4" on each side for their pound on weights etc, that make the wheel look wider (or make tire look narrower) than is actually the case.

Point is you can't go much by looks as to how a tire fits a wheel. IMHO a lot of folks are way over tiring our 275 RWHP cars with over wide and over heavy tires. These wide tires grab every road irregularity in the pavement in front, and wide is way down the list on things that affect traction for the rear.

You will notice Tack 9 stayed with stock size in front and his wheels are very light weight. He mostly went with wide rears for looks, and even he will probably admit, if not for looks, he probably would use a somewhat narrower rear tire for better balanced overall handling. But I agree...looks are a big part of our mod decisions and I would do same. MHO

[Koz-04Mach]

On my Cobra R wheels on my 95 Cobra I ran 285/40 in the rear and they fit perfect. The 255/40 up front seemed a bit to small for the 17x9. It may be specific to that tire however. Different brands seem to fit different.

/mourn my old Yoko A520 8( Best tires I have ever used.

[AirborneRanger]

On my Cobra R wheels on my 95 Cobra I ran 285/40 in the rear and they fit perfect. The 255/40 up front seemed a bit to small for the 17x9. It may be specific to that tire however. Different brands seem to fit different.

/mourn my old Yoko A520 8( Best tires I have ever used.

Ive been riding around for the last 2 mo. on kumo 275/40/18s, and they dont hang over the side wall at all ( on a 9" wheel ). Im positive you can go larger, but thats kinda pointless, because once you start leaning over the sidewall you could be lookin at disaster on a sharp turn ie. breaking the bead. If I can squeeze a 315 on a 9 inch rim like I have on my rears, im sure he can handle even bigger than a 275. Just my .02 though :hehe:

[2003_shaker]

IMHO a lot of folks are way over tiring our 275 RWHP cars with over wide and over heavy tires. These wide tires grab every road irregularity in the pavement in front, and wide is way down the list on things that affect traction for the rear.

Your comments are focused on drag racing, right? Yeah, 275/35R18's are crap at the strip, even when factoring-out driver inexperience. Also true that with 275's, you feel more irregularities - but after that, I'm going to have to respectfully disagree with you, Ralph.

Wider tires of the same diameter as stock - when used properly - give you a larger contact patch. If you get everything else close to right, like profile, tread, compound, tread depth, diameter, temperature, and inflation, it's going to hold better in a corner than a narrower tire with the same spec's under the same conditions.

Not all bigger/wider setups are heavier - mine shaved six pounds over the stock wheel/tire combo. And I don't think the car is over-tired at all with 275's - not when it comes to corner-carving.

[Ralph Greene]

Your comments are focused on drag racing, right? Yeah, 275/35R18's are crap at the strip, even when factoring-out driver inexperience. Also true that with 275's, you feel more irregularities - but after that, I'm going to have to respectfully disagree with you, Ralph.

Wider tires of the same diameter as stock - when used properly - give you a larger contact patch. If you get everything else close to right, like profile, tread, compound, tread depth, diameter, temperature, and inflation, it's going to hold better in a corner than a narrower tire with the same spec's under the same conditions.

Not all bigger/wider setups are heavier - mine shaved six pounds over the stock wheel/tire combo. And I don't think the car is over-tired at all with 275's - not when it comes to corner-carving.

I said "a lot" are. And I understand your point, and it's well taken. Of course some understand importance of lightweight wheels, and I agree 275X35X18 tires of correct type would work great in the corners, especially if struts, shocks, sway bars. and air pressure were tuned for their use. But I still believe you might go faster, or as fast anyway, with 265's...either 35 or 40 series depending on how rough the surface is...depending on how big a part of the suspension tires become on a particular surface. I really think you might go faster with 17's, with their higher aspect ratio, on a lot of these old rough roadrace tracks. The 95 R came with 255X45X17 tires on it's hi quality fairly light and strong 17X9 Cobra R wheels, and the 2000 R came with 265X40X18 tires on it's very heavy 18X9.5" wheels. When the 95 R came out, 17th were more popular then, and that old rough suspension needed all the help it could get to keep the tires on the pavement.

But I'm not a road racer, so defer to you guys for info on that.

[2003_shaker]

I said "a lot" are. And I understand your point, and it's well taken. Of course some understand importance of lightweight wheels, and I agree 275X35X18 tires of correct type would work great in the corners, especially if struts, shocks, sway bars. and air pressure were tuned for their use. But I still believe you might go faster, or as fast anyway, with 265's...either 35 or 40 series depending on how rough the surface is...depending on how big a part of the suspension tires become on a particular surface. I really think you might go faster with 17's, with their higher aspect ratio, on a lot of these old rough roadrace tracks. The 95 R came with 255X45X17 tires on it's hi quality fairly light and strong 17X9 Cobra R wheels, and the 2000 R came with 265X40X18 tires on it's very heavy 18X9.5" wheels. When the 95 R came out, 17th were more popular then, and that old rough suspension needed all the help it could get to keep the tires on the pavement.

But I'm not a road racer, so defer to you guys for info on that.

With the Autobahn Country Club's new track, I should be fine. But I agree, Ralph, that at least as far as wheel size goes, the 17" might be grippier over average to rough surfaces given a lesser aspect ratio and the same width/diameter. You'd have to factor in the 'rate' of the wheel/tire vs. the surface quality to determine the best wheel size, just like you wouldn't want to run springs that are too stiff - a matter of compliance. My 18's are pretty good on the street but if I find they don't cut it at the track, I may go to 17's when I get around to buying D.O.T. race tires. . . I have noted well that tach9 has gone with 17's on his setup as have the "Mach 1 Racers". . .

:beer:, Ralph.