I need tires, need some good options

Gabe

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The higher the offset the more inward the wheel will fit.
A 10"-wide wheel with 45-48 mm offset is an awesome fit on the rear. A 305 tire on there will tuck into the fender over bumps, no rubbing.
 

06 T-RED S/C GT

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I agree and understand where your coming from Gabe, however, Pentalab mentioned in a previous post that the spokes on his 18x10's with 45mm offset barely cleared his rear OEM calipers and spring retainers. Needless to say, I'm a bit confused as to whether he's referring to wheel offset or dish size depth/wheel spoke design for the clearance issues in which he brought up :shrug:
 

Pentalab

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I agree and understand where your coming from Gabe, however, Pentalab mentioned in a previous post that the spokes on his 18x10's with 45mm offset barely cleared his rear OEM calipers and spring retainers. Needless to say, I'm a bit confused as to whether he's referring to wheel offset or dish size depth/wheel spoke design for the clearance issues in which he brought up :shrug:

Let me clarify. The spring retainers are only on the FRONT oem calipers..and only when hawk HPS front pads used.
(spring retainers only come with hawk HPS FRONT pads, included in the hawk front HPS kit). Oem front ( and rear) pads don't come with retainer springs

I also used hawk HPS pads on the rears... and on the rears, the HPS rear pad kit doesn't come with any retainers.

Gabe is correct, for the rears, 45-48mm ET is good for a 10" rear.... as far as tire never getting close to top of fender, even with rear suspension fully loaded from hitting a speed bump... going quick.

My minor issue was the rear spokes barely cleared the oem rear calipers.... by 1/32". No big deal, as that 1/32" is a fixed gap. That's due to the spoke design on my 18x10 AM chrome bullitt wheels..and their 2.5" deep dish. The same 18 x 10 bullitt wheel, when used on the fronts, the spokes just grazed the spring retainers.. hence the use of the 3mm spacers on the fronts... which results in an effective front offset of 45-3 = 42 mm.

Roush used 45mm ET on both front + rear 18x10 wheels..and also their 20x10 wheels..... and both their 18" + 20" wheels would clear the front 14" diam big rotors with the 4 piston calipers. ( Roush used 275-40-18 tires on all 4 x corners. They used a 275-35-20, again, on all 4 x corners, if 20 x 10 rims used).

On a side note, I installed steeda front strut mounts, with adjustable camber. I have the camber tweaked for max, aprx 1.7 degs on each front. This helps tuck the tops of the front tires inside the wheel well a bit more. Additional camber done this way has no effect as far as inside of wheel / tire hitting the strut, since the entire strut also moves inboard. ( top of struts moves side to side in the slots on the adjustable camber portion of the strut mount ).

On any 19" diam front wheel, the radius is increased by 1/2" vs a 18" wheel. That extra 1/2" radius makes for a larger gap between edge of rim and strut..... or the bulgy portion of the tire..and strut. A 20" front wheel has an even bigger radius, with an even bigger gap. Enclosed angle between the vertical axis of the tire and strut always remains the same. The gap increases as you move further upwards.

With a 48mm offset on the fronts, if a 18 x 10"rim is used, and also a 285 tire, you will only end up with aprx .013" between tire bulge..and strut. A 3mm spacer will be required.

I measured the gap between bulgy part of tire and strut, using the shank end of a drill bit. ( round shanks, not triangular shanks). With last summers 275-40-18 front tires being used on 18 x 10 rims + 45 mm offset..and a 3mm spacer, the gap was 21/64" = .328" . When the bigger 285-40-18 tires, on the same 18 x 10 rims used this year, the gap decreased by 5mm, to just .131". IF I remove the 3mm spacer, the gap drops to just .013". But tire widths vary a bunch between tire makers. My 285s are actually 290.2 mm. My rear 305's are actually 312.75mm...when used on a 11" rim..and reduced to 302.75mm when used on their 19 x 10 rims.

When the tire maker lists the..'section width' ( for ONE specified 'measuring width' rim) they mean sidewall to sidewall. Take their 'measuring width' and multiply x 25.4 to obtain the actual mm width of the tire. Tread width is always less... and Nitto only lists measuring width... but never tread width. Michelin lists both.

The listed (and stamped on tire) width they list is generic... what it actually is, can vary by a bunch...and vary a bunch between different tire makers. Sorta like a .44 magnum is actually only .429" etc.
 
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06 T-RED S/C GT

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Let me clarify. The spring retainers are only on the FRONT oem calipers..and only when hawk HPS front pads used.
(spring retainers only come with hawk HPS FRONT pads, included in the hawk front HPS kit). Oem front ( and rear) pads don't come with retainer springs

I also used hawk HPS pads on the rears... and on the rears, the HPS rear pad kit doesn't come with any retainers.

Gabe is correct, for the rears, 45-48mm ET is good for a 10" rear.... as far as tire never getting close to top of fender, even with rear suspension fully loaded from hitting a speed bump... going quick.

My minor issue was the rear spokes barely cleared the oem rear calipers.... by 1/32". No big deal, as that 1/32" is a fixed gap. That's due to the spoke design on my 18x10 AM chrome bullitt wheels..and their 2.5" deep dish. The same 18 x 10 bullitt wheel, when used on the fronts, the spokes just grazed the spring retainers.. hence the use of the 3mm spacers on the fronts... which results in an effective front offset of 45-3 = 42 mm.

Roush used 45mm ET on both front + rear 18x10 wheels..and also their 20x10 wheels..... and both their 18" + 20" wheels would clear the front 14" diam big rotors with the 4 piston calipers. ( Roush used 275-40-18 tires on all 4 x corners. They used a 275-35-20, again, on all 4 x corners, if 20 x 10 rims used).

On a side note, I installed steeda front strut mounts, with adjustable camber. I have the camber tweaked for max, aprx 1.7 degs on each front. This helps tuck the tops of the front tires inside the wheel well a bit more. Additional camber done this way has no effect as far as inside of wheel / tire hitting the strut, since the entire strut also moves inboard. ( top of struts moves side to side in the slots on the adjustable camber portion of the strut mount ).

On any 19" diam front wheel, the radius is increased by 1/2" vs a 18" wheel. That extra 1/2" radius makes for a larger gap between edge of rim and strut..... or the bulgy portion of the tire..and strut. A 20" front wheel has an even bigger radius, with an even bigger gap. Enclosed angle between the vertical axis of the tire and strut always remains the same. The gap increases as you move further upwards.

With a 48mm offset on the fronts, if a 18 x 10"rim is used, and also a 285 tire, you will only end up with aprx .013" between tire bulge..and strut. A 3mm spacer will be required.

I measured the gap between bulgy part of tire and strut, using the shank end of a drill bit. ( round shanks, not triangular shanks). With last summers 275-40-18 front tires being used on 18 x 10 rims + 45 mm offset..and a 3mm spacer, the gap was 21/64" = .328" . When the bigger 285-40-18 tires, on the same 18 x 10 rims used this year, the gap decreased by 5mm, to just .131". IF I remove the 3mm spacer, the gap drops to just .013". But tire widths vary a bunch between tire makers. My 285s are actually 290.2 mm. My rear 305's are actually 312.75mm...when used on a 11" rim..and reduced to 302.75mm when used on their 19 x 10 rims.

When the tire maker lists the..'section width' ( for ONE specified 'measuring width' rim) they mean sidewall to sidewall. Take their 'measuring width' and multiply x 25.4 to obtain the actual mm width of the tire. Tread width is always less... and Nitto only lists measuring width... but never tread width. Michelin lists both.

The listed (and stamped on tire) width they list is generic... what it actually is, can vary by a bunch...and vary a bunch between different tire makers. Sorta like a .44 magnum is actually only .429" etc.
To be honest, I'm not familiar with the Hawk HPS front brake pads and never heard of them until you brought them to my attention. Therefore I assumed when you mentioned your 18x10" AMR wheels barely cleared the "OEM" calipers, that you were referring to having clearance issues from either the 45mm offset or wheel spoke design but wasn't really sure as to which it was. Anyhow, thanks for clarifying as now I fully understand it was the Hawk HPS brake pads/spring retainers causing the clearance issues rather than the 45mm wheel offset.
 

Pentalab

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My 18 x 10 rims are chrome bullitt rims... made by American muscle, not AMR.... moot point. Deep dish rims look good, but have drawbacks, like they won't clear the 14" front rotors on the front big brake kits ( 4/6 piston). They will, if you use a big spacer, which will then require 3" long front wheel studs... which is a pita. On to plan B. Since I have a CDC brand lower front chin spoiler, I also used their optional front brake cooling duct kit, which comes with flexible 2.5" orange silicone air hoses, corrugated on the outside..and smooth bore on the inside.. + comes with a pair of new front 14.5" diam dust shields, with the 2.4" tube welded to the inside of each dust shield. No more brake stink, when oem 12.4"front rotors + oem 2 piston calipers abused. Works superb for the last several years. The 14.5" dust shields work just fine with the oem 12.4" rotors.
 

06 T-RED S/C GT

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My 18 x 10 rims are chrome bullitt rims... made by American muscle, not AMR.... moot point. Deep dish rims look good, but have drawbacks, like they won't clear the 14" front rotors on the front big brake kits ( 4/6 piston). They will, if you use a big spacer, which will then require 3" long front wheel studs... which is a pita. On to plan B. Since I have a CDC brand lower front chin spoiler, I also used their optional front brake cooling duct kit, which comes with flexible 2.5" orange silicone air hoses, corrugated on the outside..and smooth bore on the inside.. + comes with a pair of new front 14.5" diam dust shields, with the 2.4" tube welded to the inside of each dust shield. No more brake stink, when oem 12.4"front rotors + oem 2 piston calipers abused. Works superb for the last several years. The 14.5" dust shields work just fine with the oem 12.4" rotors.
Actually, AMR wheels are also made by American Muscle, however, the chrome bullitts you have are branded as AM, rather than American Muscle's AMR brand. Anyhow it was just a typo error on my part. Therefore, moot point just as you previously brought up. At any rate, I'm glad the 3mm HR spacers resolved the clearance issues you were having without the need for having to upgrade to longer wheel studs.
 

nawagner

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It sounds like that fire stone is a big bang for the buck....cost effective. If it's good in rain /wet /dry, priced right, works good, it's a winner. Tread life is rated at 340. W speed rated (168 mph). With all the good reviews, this is probably an ideal replacement tire for the OP. Heck, it's probably a good replacement period.

Had a chance to drive the Firestone's in the rain this week and I was very impressed. I had to work pretty hard to break them loose. I am very happy with them so far.
 

06 T-RED S/C GT

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If only the Firestone Firehawk Indy 500's were available in 285/40/18? I'd buy these over the Continental ECS in a heartbeat, as you just can't beat the price for an ultra-high-performance summer tire with a UTQG rating of 340 AA IMHO.
 

Gabe

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If only the Firestone Firehawk Indy 500's were available in 285/40/18? I'd buy these over the Continental ECS in a heartbeat, as you just can't beat the price for an ultra-high-performance summer tire with a UTQG rating of 340 AA IMHO.

They're available in 275/40/18 and that size will fit perfectly on those 18x9.5's
 

06 T-RED S/C GT

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They're available in 275/40/18 and that size will fit perfectly on those 18x9.5's

That's very true, Gabe. However, 275/40/18's are approx 0.5" under Ford OEM diameter specs of 27" If that's nothing to be really concerned about? Let me know, and I'll go ahead and purchase the Firestone's over the Conti Extreme Contact Sport in 285/40/18 instead :shrug:

Also, keep in mind that I'm also running FI with 4:10 gear ratio as well.
 
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Gabe

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That's very true, Gabe. However, 275/40/18's are approx 0.5" under Ford OEM diameter specs of 27" If that's nothing to be really concerned about? Let me know, and I'll go ahead and purchase the Firestone's over the Conti Extreme Contact Sport in 285/40/18 instead :shrug:

Also, keep in mind that I'm also running FI with 4:10 gear ratio as well.

I've run 275/40/18's on my 18x9.5 GT500 wheels, looked and handled great.
A half inch overall tire height difference only means a 1/4" ride-height difference, something very hard to notice unless a measuring tape is involved.
 

06 T-RED S/C GT

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I've run 275/40/18's on my 18x9.5 GT500 wheels, looked and handled great.
A half inch overall tire height difference only means a 1/4" ride-height difference, something very hard to notice unless a measuring tape is involved.
Especially when a set of the Firestone's is $529.20 compared to a set of Conti Extreme Contact Sport at $1,071.00 for nearly the same quality? The Firehawk Indy 500's are by far the much better value without a doubt. Therefore it appears I'll be reconsidering my previous choice of the Conti Extreme Contact Sport in favor of the Firestone Firehawk Indy 500's instead :waytogo:
 

Gabe

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A couple of shots for you with the 275/40/18 Continental DWS's, to show how they fit and give you an idea of the overall ride height.
This was sitting on Steeda Sport Springs:


2013-05-31_clean1.JPG 2013-05-31_clean3.JPG
 

Norm Peterson

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Shorter than OE tires are a problem only if you're committed to getting X mph out of any particular gear and anything less is a deal-breaker (like it might be at autocross). I'm running 25.9" tall tires for my track time plus the street driving it takes to get there and back (plus a bit more if I get lazy). My normal street tires are only a little taller at 26.3". I plan on not ever go back to 27".


Norm
 

Pentalab

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Gabe, what rear wheel diam / width/ ET + tire sizes are your using right now with that much hp ?
 

Gabe

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Gabe, what rear wheel diam / width/ ET + tire sizes are your using right now with that much hp ?

I'm on 2010 GT500 convertible 18x9.5 wheels front and rear (45mm offset).
Rear tires are Nitto 555R 305/40/18. A little bulging going on, so the patch is probably closer to about 285, which is making me think my next set of rear tires will be 285/40/18 and maybe go to a Nitto NT05R or a Mickey Thompson DR like the ET Street SS
(just for info, front tires are Continental DW's in 285/40/18 size and the car is now sitting on BMR GT500 "Performance" front springs, BMR GT SP012 rear springs, and Koni 05-10 struts/shocks)

40971863651_722b7d4396_o.jpg


40971863461_76b4e4f9da_o.jpg
 

06 T-RED S/C GT

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I've run 275/40/18's on my 18x9.5 GT500 wheels, looked and handled great.
A half inch overall tire height difference only means a 1/4" ride-height difference, something very hard to notice unless a measuring tape is involved.

A couple of shots for you with the 275/40/18 Continental DWS's, to show how they fit and give you an idea of the overall ride height.
This was sitting on Steeda Sport Springs:


View attachment 67337 View attachment 67338

I'm on 2010 GT500 convertible 18x9.5 wheels front and rear (45mm offset).
Rear tires are Nitto 555R 305/40/18. A little bulging going on, so the patch is probably closer to about 285, which is making me think my next set of rear tires will be 285/40/18 and maybe go to a Nitto NT05R or a Mickey Thompson DR like the ET Street SS
(just for info, front tires are Continental DW's in 285/40/18 size and the car is now sitting on BMR GT500 "Performance" front springs, BMR GT SP012 rear springs, and Koni 05-10 struts/shocks)

40971863651_722b7d4396_o.jpg


40971863461_76b4e4f9da_o.jpg
Gabe, what I don't quite understand is this. If the 275/40/18's looked and handled so great for you, then what was your purpose for making the switch to 285/40/18? I also recall from the other site forum that you went from 275/40/18 then made the switch to 285/40/18 both front and rear and then went to 305/40/18 for just the rears. Anyhow, unless I somehow misinterpreted? I really don't get why you would make the switch from 275/40/18 to 285/40/18, if the 275/40/18's looked and handled so well for you :shrug:
 

Gabe

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Gabe, what I don't quite understand is this. If the 275/40/18's looked and handled so great for you, then what was your purpose for making the switch to 285/40/18? I also recall from the other site forum that you went from 275/40/18 then made the switch to 285/40/18 both front and rear and then went to 305/40/18 for just the rears. Anyhow, unless I somehow misinterpreted? I really don't get why you would make the switch from 275/40/18 to 285/40/18, if the 275/40/18's looked and handled so well for you :shrug:

Sometimes I do something just cuz I can :)

Lol, really though, I wanted a wider tire, the little extra height didn't bother me since it was bringing the car back within the factory range anyway.

The order of things for me was: 275/40/18 all around. Blower install. Rear tires bald. 305/40/18 drag radials install. 285/40/18 Goodyear F1's off the wife's stock rear wheels installed on front after she got new rear tires (dr's). Then just kept 285/40/18's on the front.
 

06 T-RED S/C GT

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Sometimes I do something just cuz I can :)

Lol, really though, I wanted a wider tire, the little extra height didn't bother me since it was bringing the car back within the factory range anyway.

The order of things for me was: 275/40/18 all around. Blower install. Rear tires bald. 305/40/18 drag radials install. 285/40/18 Goodyear F1's off the wife's stock rear wheels installed on front after she got new rear tires (dr's). Then just kept 285/40/18's on the front.
Wasn't trying to come off as a wiseass or anything, Gabe. Just wanted to make certain that going with 0.5" shorter sidewall below factory specs isn't anything to be really concerned about despite running a Saleen blower and 4:10 gear ratio. Anyhow just wanted to double check with you once again before going ahead with purchasing the Firehawk Indy 500's in 275/40/18? :)
 

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