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-   -   Tire and Wheel size guides (https://www.seccs.org/forums/showthread.php?t=3542)

sperry 2005-08-26 02:11 PM

Tire and Wheel size guides
 
Here are some resources for calculating tire sizes and wheel offsets:

Edit: Here's a neat graphical wheel & tire calculator: http://www.wheelsmaster.com/rt_specs.jsp

Tire size calculator: http://www.miata.net/garage/tirecalc.html

Wheel offset clearance calculator: http://marksink.com/tire_wheel_offset/offset.html

Feel free to add links to other resources!

Kevin M 2005-08-26 02:20 PM

My favorite wheel/tire calculator

http://gs.tolan-hoechst.com/tirecalc.htm

M3n2c3 2005-08-26 09:12 PM

Helpful! :disco:

100_Percent_Juice 2007-04-11 09:25 AM

2 questions.
How wide is the stock 02-05 wrx 16" wheel?
What is the general rule as far as wheel width vs tire width?

This tire looks too narrow...
http://i3.photobucket.com/albums/y62/thumpyJ/021.jpg
This tire looks too wide...
http://i3.photobucket.com/albums/y62...04c0reykd4.jpg
This tire looks just right...
http://i3.photobucket.com/albums/y62...594resized.jpg

Kevin M 2007-04-11 09:36 AM

Actually the middle is about right.

WRX wheels are 16x6.5

Nick Koan 2007-04-11 09:39 AM

Stock WRX wheels for that MY range are 16x6.5. There are plenty of charts out there on width of wheel versus width of tire, but I think on 16x6.5 anywhere between 195 and 215 depending on sidewall height.

Here is a more indepth chart from Yokohama
http://www.yokohamatire.com/utrimwidth.asp

And I would also disagree about the middle picture being too much tire. I think both the second and third pic look just about right (with the third pic maybe on the small side).

sperry 2007-04-11 09:40 AM

2 Attachment(s)
IIRC, WRX wheels are 16"x6.5".

Your second picture is the only one w/o stretched tires.

Here's a set of 255 Azenis on an 8" wide wheel. That's a little too wide. 235 or 245 is right for 8" wide.

100_Percent_Juice 2007-04-11 10:47 AM

thanks for all the response.

I guess what I was getting at with the pictures is not which one is the correct size, but which look I like the most. Out of the first 3 pictures the one i like the best is the bottom. The look I would like to get(with aftermarket 18") is as wide as I can go while keeping somewhat of a rounded look to the tire. Not the square look like in the second pic or the super streched like in the first.

MPREZIV 2007-04-11 11:21 AM

The "rounded look" you speak of is bad for the tires, potentially. If you plan on driving *hard* on them, i.e. auto-x, then there's a good chance of F*ing up the tire's sidewall rolling them over...

cody 2007-04-11 12:43 PM

I like the rim protector effect though.

I run Toyo Proxes 4's on my stock WRX rims in 225 width. Apparently they're designed for "plus-fitment applications". They squirm a bit, but the handling and wear is superb.

Bob Danger 2007-04-11 04:44 PM

Quote:

Originally Posted by 100_Percent_Juice (Post 95188)
thanks for all the response.

I guess what I was getting at with the pictures is not which one is the correct size, but which look I like the most. Out of the first 3 pictures the one i like the best is the bottom. The look I would like to get(with aftermarket 18") is as wide as I can go while keeping somewhat of a rounded look to the tire. Not the square look like in the second pic or the super streched like in the first.

So you wanted to ask people which "look" you like most?

100_Percent_Juice 2007-04-11 05:25 PM

No basically I showed 3 different looks and said which one I want to go for. I have no experience with what a certain size tire would look on a certain size wheel so I was asking for advice on that.

Nick Koan 2007-04-11 05:31 PM

Looks aside, you'd probably want to go with a tire sized similarly to the second picture. Unless the way your tire appearance is more important than shortened lifespan due to uneven wear. If that's the case, then by all means do whatever floats your boat man.

MattR 2007-04-11 05:34 PM

I love the way my 18x8's look with a 245...

100_Percent_Juice 2007-04-11 05:42 PM

Quote:

Originally Posted by nKoan (Post 95202)
Looks aside, you'd probably want to go with a tire sized similarly to the second picture. Unless the way your tire appearance is more important than shortened lifespan due to uneven wear. If that's the case, then by all means do whatever floats your boat man.

No Koanbone appearance isnt more important to me then tire life. tire life floats my boat:rolleyes:



Quote:

Originally Posted by MattR (Post 95204)
I love the way my 18x8.5s look with a 245...

Do you have any pics?

MattR 2007-04-11 05:43 PM

Quote:

Originally Posted by 100_Percent_Juice (Post 95206)

Do you have any pics?

They're on here somewhere, but I'd have to look for them...I'll check when I get home from work unless anyone else feels ambitious.

Nick Koan 2007-04-11 05:52 PM

Quote:

Originally Posted by 100_Percent_Juice (Post 95206)
No Koanbone appearance isnt more important to me then tire life. tire life floats my boat:rolleyes:

Hey, I'm not here to roll eyes at you or anyone. I'm just trying to help. From a tire life perspective, you probably want to get properly sized tires and not buy ones that will show up stretched or bulged on your wheels. Its just a small warning since you posted that you thought the third pic had the best fitment.

Forgotten 2007-04-11 05:53 PM

It all depends on what size rim you are looking at, as well as your current suspension set up. I personally would try and run a wider tire such as 255/40/17 on a 17x8.5 or a 245/40/18 on a 18x8.5. Both of these set ups depending on how much camber you run will probably require fender rolling. If you didn't want to worry about that go with a 225/45/17 or 235/4017 on a 17x8. You have to take into consideration how wide the tires you are buying run, as well as ride height and suspension stiffness.
It's really easy to recommend rim and tires and sizes etc if you give us what you want to use them for and set up, rather than post 3 pictures.

100_Percent_Juice 2007-04-11 05:59 PM

I appreciate your help. I honestly didnt think the third picture was that stretched. Pictures can be deceiving anyways and thats why I posted. So i could get help from those of you who are more experienced with wheels then I.

100_Percent_Juice 2007-04-11 06:05 PM

Quote:

Originally Posted by Forgotten (Post 95210)
It's really easy to recommend rim and tires and sizes etc if you give us what you want to use them for and set up, rather than post 3 pictures.

Ok
I want 18" wheels and they are going to be for my 04 wrx that will have Tein coilovers possibly superstreet. The suspension will be set at the highest level for the coilovers because 99% of my driving is on city streets and I dont like to scrape. weather or not I have to roll the fenders is not an issue with me. If there is anything else that will help determine my setup for wheels just ask.

100_Percent_Juice 2007-04-11 06:08 PM

http://i3.photobucket.com/albums/y62...titled78-1.jpg

I like this profile. Is this setup bad for tire life?

Nick Koan 2007-04-11 06:29 PM

Nice widebody.

Anyway, personally I think those tires could stand to go another size wider. But, with wheels and tires that wide, it might not have been an option.

wrxkidid 2007-04-11 09:04 PM

with a 18x9 could you run 265s?

MattR 2007-04-11 09:25 PM

1 Attachment(s)
Here...Rota 18x 8's with Falken ZE512 in 245-40-18.

100_Percent_Juice 2007-04-11 09:49 PM

Thanks Matt that gives me a better idea. So lets say I got a set of 18x7.5(because the wheels I want only come that big with 5x100) would I buy a 235/40/18 tire to get the same look you have?

Also are your tires taller then stock? It looks that way to me in the pic.

MattR 2007-04-11 09:58 PM

Yes they are taller, quite a bit taller. I originally bought these wheels with a set of 225's on them, and they looked way stretched. So on a 7.5 with 235's, that should look great

MattR 2007-04-11 09:59 PM

1 Attachment(s)
Here are the 8" wheels with 225's.

100_Percent_Juice 2007-04-12 07:44 AM

Is there a benefit to going bigger? I always thought it was best to stay stock size if everything else is stock?

cody 2007-04-12 10:21 AM

Going with a wider tire means more contact patch which improves stopping and latteral grip, but if you too wide for a given rim, the handeling get's mushy from the sidewall rolling over and grip can actually be worse. I agree with Matt. In most cases 235 on a 7.5" rim would be ideal (as long as it doesn't rub). Some 245 wide tires might offer more grip, but possibly at the cost of spongy handleing and you wouldn't like the way it looks.

sperry 2007-04-12 10:29 AM

Quote:

Originally Posted by 100_Percent_Juice (Post 95244)
Is there a benefit to going bigger? I always thought it was best to stay stock size if everything else is stock?

Bigger tends to mean more traction, which means better braking, higher lateral G's, better acceleration (if you were traction limited to begin with). But it also means, more tramlining, more noise, worse mileage, and worse acceleration (if they're heavier and you weren't traction limited to begin with).

Really, the process to pick wheels/tires for performance is to do this, and I'll include my own answers for my TT car:

Q: What width tires will meet my performance goals?
A: As wide as friggen possible that will fit under the car w/o a widebody kit

Q: What type of tire will meet my performance goals?
A: R-Compound DOT legal race tire

Q: What diameter tire do I need?
A: As small as possible while clearing StopTech Brakes, i.e. 17"

Q: What tire meets the above criteria?
A: Michelin Pilot Sport Cup, 255/40/17

Q: What size wheel is ideal for the selected tire?
A: 17"x9"

Q: What offset is necessary for the ideal wheel to fit?
A: +43 to +48

Q: What wheel fits the above criteria and matches the PCD of the car?
A: 5zigen FN01RC, 17"x9" +43 5x114.3

Granted, I've done a lot of other work to open up my possibilities, like converting to the '05 STi hubs, rolling my fenders, cutting fender liners, going to coilovers, etc. Most people can't start out looking for 255's... 245 is usually pushing it... but the process is the same.

For you, you're probably looking more along the lines of this:

Q: What width tires will meet my performance goals?
A: Something that will increase handling performance w/o drastic fuel economy or comfort sacrifices, probably a 225 or 235.

Q: What type of tire will meet my performance goals?
A: High-Performance All Seasons

Q: What diameter tire do I need?
A: 18" for decent bling factor w/o clearance issues

Q: What tire meets the above criteria?
A: Falken Ziex 512, 225/40/18 or 235/40/18 (both are very close to OEM overall size, 225's are a little short, 235's are a little tall, but both are fine)

Q: What size wheel is ideal for the selected tire?
A: 18"x7.5" for 225's, 18"x8" for 235's

Q: What offset is necessary for the ideal wheel to fit?
A: +48 to +53 for 7.5" wide, +45 to +50 for 8" wide

Q: What wheel fits the above criteria and matches the PCD of the car?
A: I'd go with any 18"x8" +48, or 18"x7.5" +48 in 5x100, the lighter the better

cody 2007-04-12 10:39 AM

Scott's post FTW.

Oh yah, on my most recent trip to Sonoma County last weekend, I had the RT-615's in 225 width (which is actually as wide as most 235 width tires) on and my gas milage was 25mpg instead of the 27-28 I'm used to seeing with my 225 width Proxes 4's. :eek:

100_Percent_Juice 2007-04-12 03:04 PM

Thanks for taking the time out for that post scott, it really helped.


Quote:

Originally Posted by cody (Post 95265)
Going with a wider tire means more contact patch which improves stopping and latteral grip, but if you too wide for a given rim, the handeling get's mushy from the sidewall rolling over and grip can actually be worse. I agree with Matt. In most cases 235 on a 7.5" rim would be ideal (as long as it doesn't rub). Some 245 wide tires might offer more grip, but possibly at the cost of spongy handleing and you wouldn't like the way it looks.

When I asked earlier "Is there a benefit to going bigger?" I wasnt really refering to width as I was to Height. I asked that after matt said his wheels/tires were taller then stock. I just know that from when I had my truck(which I know is way more of a size difference then we are talking about here) and put bigger tires on it, the noise went up, gas mileage went down, and braking ability went down. Does Scotts below statement about wider also apply to taller tires?

Quote:

Originally Posted by sperry (Post 95267)
Bigger tends to mean more traction, which means better braking, higher lateral G's, better acceleration (if you were traction limited to begin with). But it also means, more tramlining, more noise, worse mileage, and worse acceleration (if they're heavier and you weren't traction limited to begin with).


sperry 2007-04-12 03:54 PM

Taller tires change the effective final gear ratio between the engine and the road. Bigger tires will mean more rotating mass which effects you as described on your truck ('cept for the noise perhaps). It will also make your speedo read low.

Shorter tires will help your acceleration, and your fuel mileage because the freeway rpms will be higher. Also your speedo will read high.

In general, I'd try to match the stock size in outside diameter, just for speedo accuracy alone. Or lean towards the short side.

Joeyy 2007-04-12 04:02 PM

1 Attachment(s)
235/40/17 picture for you on a 7.5 wheel.

Kevin M 2007-04-12 04:12 PM

235/40R17s on 17x8.5

100_Percent_Juice 2007-04-12 04:54 PM

Thanks for all the pics^ those look nice.

ryan4601 2007-04-16 05:10 PM

scott or matt can probably chime in with experience on this one. Im looking to get some summer only rubber for my car. im looking at 245/40/18 on a 18x8 rim +48mm offset. will i have rubbing issues with this? my car isnt lowered all that much, and it dosnt seem like im really close to rubbing with the 235/40/18 all seasons im on now. thanks for the help.
ryan

by the way im deciding between:
Bridgestone potenza RE050A PP (tread life will be an issue)
Falken Azenis RT 615
Never tried the Falkens before but it seems everyone on here has, i have the RE050APP's on my s2000 and they pretty much rock on that car. decisions decisions.

cody 2007-04-16 06:16 PM

The 615's are an amazing bang for the buck but they tramline like a mofo. I don't know, maybe all wide sticky tires will do the same thing. They run wide too so getting them in the same size as the all seasons you're running would be like getting them in 245 width.

Kevin M 2007-04-16 08:51 PM

245/40R18 is awfully tall for a WRX. I'd stick to 235/40s personally.

k-dogg39 2007-04-17 09:47 AM

What about 225/45/17 Azenis on a 17 X 7.5 +48 on a wagon? Would there be too much rub?

Kevin M 2007-04-17 09:55 AM

Shouldn't rub much, if at all.

k-dogg39 2007-04-17 10:17 AM

Quote:

Originally Posted by BAN SUVS (Post 95672)
Shouldn't rub much, if at all.

Didn't think so really, but wanted to get some opinions. The only other suspenstion mods I have are STI Pink wagon springs. Thanks!

Dean 2007-04-17 10:37 AM

Quote:

Originally Posted by k-dogg39 (Post 95674)
Didn't think so really, but wanted to get some opinions. The only other suspenstion mods I have are STI Pink wagon springs. Thanks!

Those may well cause a bit of rub with the 615s in the rear.

Pull the rubber strip off and maybe a little roll of the lip.

Cody???

I think he has/had rub with 225s, lowering springs, and 48 offset.

Kevin M 2007-04-17 10:49 AM

Cody's 615s didn't rub this weekend. He pulled the rubber strip off but there's no roll to his fenders.

Anything that doesn't rub stock won't rub with different springs on the car.

Dean 2007-04-17 10:52 AM

Cody had rub. Not sure what he has done to alleviate it. I defer to him.

cody 2007-04-17 11:39 AM

Running exactly what K-Dogg is asking about (225/45/17 Azenis on a 17 X 7.5 +48 on a wagon), I did have rub, even with -2.2* of camber and the rubber strip removed. Now I have only -2* of camber in the rear and they don't rub at all. The only difference is that replacing the Eibach's with Crucial Racing Springs has raised the rear a touch and they have higher spring rates.

If bugeye and peanut eye wagons have the same clearance in the rear, I think K-Dogg will be fine since we basically have the same rear springs, but he might need to get a similar alignment to mine. If anything, I think peanut eyes may be able to fit slightly wider tires.

http://www.crucialracing.com/products/springs.php

Quote:

These are the same high performance spring rates as the highly-lauded and thoroughly-tested JDM STi "Pinks," but the Crucial springs have better materials quality, smoother progressive rates (plus are progressive both front and rear, while the JDM Pinks are only progressive on the rear, and linear front), offer slightly more drop up front for a nicer, more even stance (JDM Pinks are 1.0" both front and rear on WRX, 10mm front/rear on STi)...

Kevin M 2007-04-17 01:28 PM

wtf m8? You told me this weekend you didn't rub at all. :lol:

cody 2007-04-17 01:51 PM

I told you that I didn't have rub at all since installing the new springs...

Dean 2007-04-17 02:04 PM

Toldja! :P That is why I lightly rolled Sue's while I had the tool.

k-dogg39 2007-04-17 03:28 PM

Thanks guys! I might be able to get these for pretty cheap, so wanted to check if it would be worth it.


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