Quick question on Tire size fitment

6003 Views 15 Replies 5 Participants Last post by AHazzardToAll, May 7, 2009

Lo-C

Discussion Starter · Apr 1, 2009

I'm putting 20's on my Catera. Was wondering if I would have any problems with a tire size 245/40/20 goin on in the rear. The rim size is 20x8. Will I have problems with that tire size in the back? Will it fit that size rim? For the front I will be going with 225/35/20 tires.

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CateraMV6

· #2 · Apr 1, 2009

Lo-C said:
I'm putting 20's on my Catera. Was wondering if I would have any problems with a tire size 245/40/20 goin on in the rear. The rim size is 20x8. Will I have problems with that tire size in the back? Will it fit that size rim? For the front I will be going with 225/35/20 tires.

http://www.rims-n-tires.com/rt_specs.jsp

OEM Tire diameter is 25.7"

The 245/40/20 is a 27.7" and that wont fit my friend!

The 225/35/20 is 26.2" and that is also too much...

The below listed sizes will match the OEM diameter ona 20" rim.

235/30-20
245/30-20
255/30-20
275/25-20

:thumbsup:

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Lo-C

Discussion Starter · #3 · Apr 1, 2009

What kind of problems can I run into if I go slightly bigger than oem? I've heard of catera owners going with 225/35/20 tires with no problems. I just want to make sure it will fit./

CateraMV6

· #4 · Apr 2, 2009

It might rub somewhere depending on the offset. Also your speedo will be off by a mile or two if you go bigger... how much bigger can be calculated.

Lo-C

Discussion Starter · #5 · Apr 2, 2009

Thanks MV6.

CateraMV6

· #6 · Apr 2, 2009

Check this Comparison Tool input your OEM tire size then the new size it will calculate and tell you all the differences.

Later man... dont forget to post some pictures of those bad "S" 20s

gunther1000

· #7 · Apr 6, 2009

Would that be assuming that the oem tire size IS the max one should put on there car and give you a new OD that is very close to oem? I am inclined to thing that if you can safly lower the car with oem rims and tires then there is some room to go bigger on the OD over stock given all other points dont touch as well....

Just trying to get my mind around this one and no real plan to put 20's on but I may change springs at some point and wondered the same thing about tire heights.

CateraMV6

· #8 · Apr 8, 2009

Well if you can get under the car and find out how much distances you have around from the tire to any other point on th suspension.

The front will be limited by the spring perch on the strut... that will limit your largest OD... and then the width of the wheel will be limited by distance to the strut body and any other components that come close.

If you stick with something that is as close to the OEM size as possible you will have no problme.s

I am running 245 45/17s on my Winter tires...
Also 245 40/18s on my summers and no problems at all..

So if a 235 35/20 seems to work or is close to the OEM or maybe within 5% of the other dimensions then you will be in good hands.

If you go too big you will end up rubbing somewhere and that wont be pretty!

Good luck. Keep learning, its not hard.

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Lo-C

Discussion Starter · #9 · Apr 15, 2009

Rims and tires are mounted on the Catera now. Pics coming soon. My tire size is 225/35/20 all around. Only issue I've encountered is on bumps or tight turns one of the tires on the front, depending which side hits the bump or which side takes the weight of the turn, will rub something. Sounds like the top of the tires scrapes the wheel well. Anything I can do about this?

CateraMV6

· #10 · Apr 15, 2009

Not quite, maybe stiffer springs will help but will worsen the ride...

Lo-C

Discussion Starter · #11 · Apr 17, 2009

Couple pics I took with my phone. Not the greatest quality.

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2

CateraMV6

· #12 · Apr 17, 2009

I like it, the wheel choise is stunning, looks nice and without a doubt this is one sweet Pre-90 example...

Now whats up with that rubbing, is it your struts, or the fenders, the offset looks alright!

kamorgan

· #13 · May 6, 2009 (Edited)

It looks real nice. I was thinking about throwing some 20's on my 2001 but I was kind of skeptical about the ride comfort. I will probably just go 18's to keep the ride smooth.

kamorgan

· #14 · May 6, 2009

That looks real good. I was thinking about throwing some 20's on my 2001 this summer but I'm kind of skeptical about how it will ride. I will probably just do 18's to keep the ride comfort smooth.

AHazzardToAll

· #15 · May 7, 2009

I have some 20's just put on mine. just have the back ones on right now. I have to get t tire on one of the fronts then they'll be on too. They have 285/30/2o and rears do fine, i'll see how they do in cornering once i get the fronts on. the weight does hurt a little but they look really clean. Ride doesn't seem bad at all either.

AHazzardToAll

· #16 · May 7, 2009

oh, speed is off by 4% but i can calculate for it. when my speedo says 60 i'm doing like 62. my gps is my new speedometer. =]

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