Largest Tires on 17x 9 rims

[emon]

Can I fit a 285 60 17 on a 17 x 9 cobra wheels? My suspensions are all stock.

 

[mikeresin]

i wouldnt go any larger then 275

 

[emon]

Why not? Do you have a 275? Isn't there room for 10mm?

 

[tbomb]

yea they will fit. i used to have them on my truck when i had cobra r's, and another member named willie chu has them too on his cobra r's. if you want pics, click the link in my sig and click on "stage 2" at the bottom. i should mention that youll need some 1" spacers though.

 

[emon]

Hi TBomb,

I never knew how to find the picture on the signature. I clicked on VIEW MY PHOTO GALLERY but there's no pictures or STAGE 2.

What am I missing?

PS. What is the right size size (or offset) so that a spacer is not used?

Thanks in advance.

 

[tbomb]

go here: http://dangagga.no-ip.org:8080/tbomb/stage2/

or another guy with the exact same setup is here: www.willychu.com

cobra r's only come in one offset, so youre pretty much screwed. you WILL need a 1" spacer, which is why i got rid of mine, heh.

now i have a set of enkei rt6's (they have a 0 offset, and theyre 17x8) and the same tires from when i had the cobra r's.

 

[mikeresin]

i still wouldnt go with larger then a 275.....
i never had em on my X but i do have cobra r's on my stang.
and 255 is as much as i want.
more then 255=less traction.....
unless you go with ET's or DR's

 

[tbomb]

Originally posted by mikeresin
i still wouldnt go with larger then a 275.....
i never had em on my X but i do have cobra r's on my stang.
and 255 is as much as i want.
more then 255=less traction.....
unless you go with ET's or DR's

uh, no.

 

[HowLeTT]

gotta agree with tbomb here... how would a larger contact patch not give more traction with the same tire compound?

Granted, an ET street/drag or drag radial will help things out, but even on a regular radial you're still getting more surface area on the street that will put the power from the drivetrain into action.

 

[emon]

C'mon guys let's stick to the subject here... So TBomb got a picture of your Zero Offset? Is that the right offset to fit the 275 55 17?

I guess what I am looking for is the largest tire that is a perfect fit on stock height. 17 or 18 inch tall, 8 or 9 inch wide. Offset? Back space?

I really need help here guys. Thanks in advance.

 

[mikeresin]

uh, yes.

wider tire = less pressure per square inch on ground.

i imagine that most of you guys dont make enough power to have traction problems though.........

 

[tbomb]

Originally posted by mikeresin
uh, yes.

wider tire = less pressure per square inch on ground.

i imagine that most of you guys dont make enough power to have traction problems though.........

this is gonna be one of those neverending arguments.

for one thing, how can you argue the point of "wider tire = less pressure per square inch on ground", when youre talking about a vehicle that weighs 4500 lbs? heh.

on one hand, youre correct about that theory (which is why race cars have wings to produce more downforce on the driving wheels.) but on the other hand, a wider tire = more surface area (just like on a race car, you always see slicks.)

i believe that the governing theory is the "more surface area is better for traction", though, youre also correct when you say that none of us are making enough power to worry about losing traction. (to sum up my analogy, sometimes youll see a race car without a wing on it, but youll never see one without wide tires.)

there are other ways to fix loss of traction (such as wings or traction bars), but wide tires is always #1 on that list.

(you can also argue that wider tires can produce more rolling resistance and generate more heat, but those factors are negligible.)

 

[tbomb]

Originally posted by emon
C'mon guys let's stick to the subject here... So TBomb got a picture of your Zero Offset? Is that the right offset to fit the 275 55 17?

I guess what I am looking for is the largest tire that is a perfect fit on stock height. 17 or 18 inch tall, 8 or 9 inch wide. Offset? Back space?

I really need help here guys. Thanks in advance.

http://dangagga.no-ip.org:8080/tbomb/stage3/

to fit a 275 55 r17, you dont need a 0mm offset. guys are running cobra r's with that size tire and no problems.

 

[mikeresin]

nuh-uh....

you cant count race cars becuase those arnt regular tires......

in order to get better traction from a wide tire you need a very soft compound tire.

ive noticed it on my car and 2 of my friends cars.....

i went from a 225 to a 255 and lost traction.
but thats also becuase i went from a 60 side wall to a 40

one friend went from a 245 to a 275 and lossed traction with samesidewall hight

another friend went from a 255 to a 315 and lost traction.

i only know what ive seen.

when you start to go larger then a 255 you loose traction unless you have a soft compound tire or wrinkle walls.....


but yes this is going to be a never mind argument.

 

[DocVijay]

My wheels are 17x8 and I have 275/55's on them. You could probably go a bit wider on a 17x9 wheel. How much more? I don't know. Maybe up to a 295 or so. But I'm just guessing. I do know that an 8" wide rim will fit a 275, so your's should be able to handle more tire.

 

[tbomb]

Originally posted by mikeresin
nuh-uh....

you cant count race cars becuase those arnt regular tires......

in order to get better traction from a wide tire you need a very soft compound tire.

ive noticed it on my car and 2 of my friends cars.....

i went from a 225 to a 255 and lost traction.
but thats also becuase i went from a 60 side wall to a 40

one friend went from a 245 to a 275 and lossed traction with samesidewall hight

another friend went from a 255 to a 315 and lost traction.

i only know what ive seen.

when you start to go larger then a 255 you loose traction unless you have a soft compound tire or wrinkle walls.....


but yes this is going to be a never mind argument.

well, theres a lot of engineering and physics in this, but the mustang world is different than the explorer world. i know i didnt pick my tires for traction

 

[emon]

Guys guys guys... let's leave traction issue on another email. Let's concentrate on the problem at hand... please.

Okay, I need specifics here...
17 x 9 ... what is the proper offset so that I do not need the aforemention 1" spacer?

Once I have the offset, what is the largest biggest tire I could fit inside the wheel well?

Please help me end this issue... thanks.

 

[tbomb]

ok, heres the deal: good luck finding a 17x9 wheel thats not a cobra r (almost all 17" wheels are 7" wide or 8" wide, though, on occassion, youll find a 17x8.5".) also note that cobra r's only come in one offset, i believe its 24mm, which is perfect for a mustang - the vehicle those rims were designed for.

now, just a lil math will do the trick here. since you would have needed a 1" spacer, just move the offset in 1", right? right. so, since offset is in mm, just convert inches to mm and youre golden...1" = 25.4mm, but youll have to round, and it doesnt have to be exact. you can get away with only moving in the offset 22mm - 26mm or so, it all depends on manufacturing tolerances (remember, all animals are created equal, but some are more equal than others.)

so heres what you do now. forget about tires for the time being, and find some wheels that you like. unless youre going to lift your truck and put really big tires on there, tires cannot be the keystone around which you pick rims. you must pick rims first, then you can pick the largest tires that will fit on said rims (if thats you want - the largest ones that will fit.) start looking around for rims that have a very small offset. something close to 0mm, but it doesnt have to be 0mm - you can get away with something close. trust me, i know a lot about wheels and tires and fitment, and i learned it all the hard way and it cost me a lot of money, heh. pick your rims first, and dont say to yourself, "i must have 285's on there"; just look/ask around for rims with an aggressive offset, and just pick ones that look cool, then worry about tires. we'll cross the "tire bridge" when we come to it.

good luck.

 

[DocVijay]

One thing to keep in mind. A 17x8 wheel with 275/55 tires will fit perfectly with minimal rubbing on the front sway bar. Also, teh diameter is within 0.1" of the factory, so no problems with speedo, etc...

 

[tbomb]

Originally posted by DocVijay
Also, teh diameter is within 0.1" of the factory, so no problems with speedo, etc...

not necessarily. it depends on what tires he has stock on his truck. mine had the 255 70 r16's, so my speedo is on the money (well, its off by like 0.4 mph at 65 mph.) another thing to keep in mind is that those speedos arent that accurate anyway. how many times have you been pulled over and the cop says he clocked you at one speed, and you know for a fact you were going faster or slower than what the cop said? so, if the speedo is gonna be off by a hair, its not the end of the world; its really what size tires he has from the factory that will determine if the world is going to end