tires!!!!!

[BrentSC]

hey guys, i have a problem i am beside myself here as i look at every picture i can with 245/45 18 tires all around, and 245/40 18 tires all around. i just orderd some 18x9 cobra r's. what do u guys think i should get ,whats your oppinion about the difference on these two tire sizes???? thanks

brent

[David Neibert]

I would use 245-45-18 on front and 275-40-18 on back. They are the same diameter on front and back and they are also the same diameter as stock tires, so the speedo doesn't read goofy.

David

[BrentSC]

wouldnt a 255/40/18 be between the sizes 245/40/18 and 245/45/18 , there are not very many sc's with the 255 tires... maybe this says something about them......

[patragz22]

I got 255/45/18 all around with y2k cobras and makes the car look more aggressive, in the future though will go 275/40/18 in rear for look and traction

[BrentSC]

I got 255/45/18 all around with y2k cobras and makes the car look more aggressive, in the future though will go 275/40/18 in rear for look and traction

you wouldnt happin to have a picture of your car with those tires on it?? if you do could you possibly post them that would be awesome

[patragz22]

I'll try this weekend, just put new motor in car so it is filthy.

[cudaz101]

Anything taller or wider than a 245-45-18 (Assuming your 18X9's have a +36MM offset) will RUB in the rear...Lowered or not. So if the wheel has a higher offset than +36mm, which it probably does its gonna rub the rear fender lip.

Be sure to test fit the wheels on the front before you mount tires to ensure clearance. If the wheels are not hubcentric (Most Common) you are going to need hubcentric rings. Otherwise they will Vibrate and you will spend $$$ on balancing, etc. when the actual issue is cured with the rings.

255-40-18 would be a poor choice IMO...Like David N. mentioned a 245-45-18/275-40-18 would be a good staggered setup & all ya need to run them is to run an airbag set in the rear spring set or roll fender lips (Rear only). The 255-45-18 is not bad but a lil on the tall side being .50" taller than stock. They rub in the front and the rear as well. Nothing major that can't be worked around but all the same, they rub...

With all that said...I recomend the 245-45-18 because its a simple bolt on with no fussing around. Stock height and you can rotate your tires for max tire life.

Sorry for the length.:o


Brad

[BrentSC]

Anything taller or wider than a 245-45-18 (Assuming your 18X9's have a +36MM offset) will RUB in the rear...Lowered or not. So if the wheel has a higher offset than +36mm, which it probably does its gonna rub the rear fender lip.

Be sure to test fit the wheels on the front before you mount tires to ensure clearance. If the wheels are not hubcentric (Most Common) you are going to need hubcentric rings. Otherwise they will Vibrate and you will spend $$$ on balancing, etc. when the actual issue is cured with the rings.

255-40-18 would be a poor choice IMO...Like David N. mentioned a 245-45-18/275-40-18 would be a good staggered setup & all ya need to run them is to run an airbag set in the rear spring set or roll fender lips (Rear only). The 255-45-18 is not bad but a lil on the tall side being .50" taller than stock. They rub in the front and the rear as well. Nothing major that can't be worked around but all the same, they rub...

With all that said...I recomend the 245-45-18 because its a simple bolt on with no fussing around. Stock height and you can rotate your tires for max tire life.

Sorry for the length.:o


Brad

thanks for the helpfull response! ... my new rims are 30mm offset, pretty much made up my mind to run the 245/45 and the 275/40. do you think there is going to be any rub!!??? other than i have to roll my fender or get airbags because of the wider tire on the back???

[cudaz101]

thanks for the helpfull response! ... my new rims are 30mm offset, pretty much made up my mind to run the 245/45 and the 275/40. do you think there is going to be any rub!!??? other than i have to roll my fender or get airbags because of the wider tire on the back???

With a +30mm offset you won't be in trouble in the front at all with the 245-45-18. Regardless rears however will need either a fender lip roll or the lil Airbag helper kit (I prefer the bag kit). So short of that you should be good to go.

You must have done a Hub-Swap to 5-4.50 lugs?? Don't know of any 5-4.25 CobraR's with that offset being offered. Feel free to hit me up if you have any other questions or concerns.


Brad

[ricardoa1]

255 /40/18 on my fronts.

[BrentSC]

With a +30mm offset you won't be in trouble in the front at all with the 245-45-18. Regardless rears however will need either a fender lip roll or the lil Airbag helper kit (I prefer the bag kit). So short of that you should be good to go.

You must have done a Hub-Swap to 5-4.50 lugs?? Don't know of any 5-4.25 CobraR's with that offset being offered. Feel free to hit me up if you have any other questions or concerns.


Brad



hey brad, i bought these rims off of customwheelsmarket, they said they had an extra set of new 30mm cobra r rims in the back. my bolt pattern is still 5x 4.25.. maybe he got the offset wrong???? im not sure ill have to check them out when they arrive hopefully in afew days!!!!!! .. and the 255/40 / 18 has a smaller sidewall than the 245/45/ 18 dosent it????

thanks, brent

[cudaz101]

hey brad, i bought these rims off of customwheelsmarket, they said they had an extra set of new 30mm cobra r rims in the back. my bolt pattern is still 5x 4.25.. maybe he got the offset wrong???? im not sure ill have to check them out when they arrive hopefully in afew days!!!!!! .. and the 255/40 / 18 has a smaller sidewall than the 245/45/ 18 dosent it????

thanks, brent

Yes it is a shorter tire by .60" so sidewall height is obviously impacted.

I would be dead surprised if the offset of those wheels was +30mm(Maybe they are)...I have recently read where folks have had to use spacers with CWM's Tbird replica wheels. I don't know if they changed suppliers or what but alot of folks recently report they need spacers for the fronts...To the tune of a 5/16" spcaer. Do your own search @ the tccoa, your own test fitting and draw your own conclusions...If spacers are no issue to you then no foul I guess...

Good Luck


Brad

[Miller1995]

I am running 255-45-18's at all four corner with +36 offset and have no rubbing issues at all.

-Miller

[cudaz101]

I am running 255-45-18's at all four corner with +36 offset and have no rubbing issues at all.

-Miller

Interesting....

So is your Tbird an SC or LX?? Is it lowered?? Fender lips Rolled??

Lastly...You might wanna take a CLOSER look at the front fender skirt at the rear portion of it. At full lock to lock turn it has always rubbed with the cars I have worked with...Its not a BIG deal BUT it is infact rub so it has to be mentioned.

Brad

[Miller1995]

Interesting....

So is your Tbird an SC or LX?? Is it lowered?? Fender lips Rolled??

Lastly...You might wanna take a CLOSER look at the front fender skirt at the rear portion of it. At full lock to lock turn it has always rubbed with the cars I have worked with...Its not a BIG deal BUT it is infact rub so it has to be mentioned.

Brad

Brad, its an LX with Vogtland 1.6" drop springs, also didn't rub with the 1.25" Tokicos, and the fenders are not rolled. I have seen no evidence of rubbing the last couple times I have been under there. The tires are BFG KDWS mounted on FR500 replicas at +36 by the way.

-Miller

[cudaz101]

Brad, its an LX with Vogtland 1.6" drop springs, also didn't rub with the 1.25" Tokicos, and the fenders are not rolled. I have seen no evidence of rubbing the last couple times I have been under there. The tires are BFG KDWS mounted on FR500 replicas at +36 by the way.

-Miller

I have not messed with an LX to the extent I have SC's...The LX may very well clear since it comes with 26.9" tires as STOCK gear even though they are MUCH narrower than the 255-45 is. The SC however uses a 26.6" tall tire and every SC I have messed with has the same issue with 255-45-18 tires being 27" tall regardless of lowering springs up to 2".

You don't run that wheel set any longer if I recall correct, right??


Brad

[Miller1995]

I have not messed with an LX to the extent I have SC's...The LX may very well clear since it comes with 26.9" tires as STOCK gear even though they are MUCH narrower than the 255-45 is. The SC however uses a 26.6" tall tire and every SC I have messed with has the same issue with 255-45-18 tires being 27" tall regardless of lowering springs up to 2".

You don't run that wheel set any longer if I recall correct, right??


Brad

I have been running this setup since mid-March and have around 8k on them. There isn't much different with the SC front suspension other than bushing durometer, stablizer bar thickness, and ARC but even that stuff shouldn't make much of a difference on what clears.

-Miller

[cudaz101]

I have been running this setup since mid-March and have around 8k on them. There isn't much different with the SC front suspension other than bushing durometer, stablizer bar thickness, and ARC but even that stuff shouldn't make much of a difference on what clears.

-Miller

So are you challenging what I am saying then?? I don't get it...??

Brad

[Miller1995]

So are you challenging what I am saying then?? I don't get it...??

Brad

No no, just saying I don't know why my car would be that much different from an SC.

-Miller

[cudaz101]

No no, just saying I don't know why my car would be that much different from an SC.

-Miller

I don't know what the differance would be. If you saw the exact rub issue I am talking about you would probably shrug your shoulders and say who cares because its not a problem type rub issue. It just rubs against the plastic fender insert. BUT I have to mention it because it IS rub and some folks are not OK with leaving out even the smallest detail.

Maybe someone running this size on an SC will chime in...Maybe not...heh


Brad