Need Help With My Tires

[justinkolman]

im new to this and i recently purchased 33x12.5x17 Mickey Thompson MTZ for my 2004 tacoma not knowing they would be too wide. i have a 3in suspension lift and i need help getting them on. I Was thinking about buying new wheels with 2.5 backspacing or getting some wheel spacers... i would rather get new wheels but im not 100 percent what size...17x? with a 6x5.5 bolt pattern. What is best for me to do?

[04 Rocko Taco]

Welcome to UY!

Most rim manufacturer's are going to recommend a certain wheel size for their tires that they are designed to be run on. a tire will almost always be wider than a wheel except in RARE cases. BFGoodrich (I have thier sizing chart handy) recommends an 8.5-11 inch wheel for thier 33x12.50 KM2 MT's. I run 10 inch wide wheels with my 12.50 TSL's on my '84, I would rather they be a hair skinnier, but they are okay. New wheels are expensive. I would go with wheel spacers first, and you don't need anywhere near as drastic as 2.5 inches of backspacing. In my opinion on a 2004 (I DD an '04 DoubleCab Tacoma) that would make your tires stick out like a frog.
I would think 3.5-4 inches of BS would be fine, but I am sure someone else will chime in on this. BS also depends on how wide the wheels are.

[justinkolman]

Ok thanks. Like I mentioned the tires I have are 12.5 wide. I was told that spacers wouldn't be a good idea so I was wanting to do new wheels. I like the pro comp 98 series monster mods but I was told they won't fit on my truck. I don't understand why though if they are the right size..17x9 6 on 5.5. That's what I need though so them not fitting makes no sense to me. I've had these wheels for 2 months now and they still are not on my truck, it's killing me. I'm willing in dropping the money if it's not too crazy. I just want these suckers on

[04 Rocko Taco]

I am unfamiliar with those wheels, so I don't know why they wouldn't fit on your truck either. The main causes of wheel fitment issues with our trucks are the brake calipers (which cause issue with 15" wheels, NOT 17" wheels) and backspacing can be an issue with the UCA's. If the wheel doesn't have enough backspace, or if the tire is too wide, then it may contact the Upper Control Arm at some point through the suspension cycle, or even all the time. Where/Who is your source for the info that these wheels will not fit?

[justinkolman]

Well I talked to a sales rep at 4wheelparts.com because I was going to order them and he just said the don't fit bit he didn't say why and he recomended a MIckey Thompson style rim made by Pro Comp. I don't understand why they wouldn't fit either. The problem I'm having mounting them now is like you said:!the tires (on my wheels) will rub the control arm and not even allow them to mount woch is why I was saying 2.5 backspace. But you and the sales rep both said 2.5 was way too much haha. He said maybe 4.25 is all I need

[04 Rocko Taco]

Just to make sure we are on the same page, you are measuring backspacing from the inside of the mounting surface (where the lugs stick through the wheel) to the inboard lip of the rim, right?
http://i198.photobucket.com/albums/aa48/afmomto2/WheelBackspacing.jpg

The smaller the number, the more the wheel will stick out.
A wheel with 0.0" of backspace will be entirely outside of the lug nuts, the center part of the wheel, would be dead even with the backside of the rim.
Say you have a 9" wide wheel, if it had 9" of backspacing, the mounting surface would be dead even with the front side of the wheel.

So a wheel with about 4" (or 4.25" - as recommended) would be almost dead center in a 9 inch wheel.


I would also try another source, call around to a local big name tire shop (discount tire, kauffman, or NTB or what have you) and ask about those wheels. Tell them what the guy at 4WP told you and ask if they can shed any light on the subject. Whoever is the most helpful might also be a consideration on where to order your wheels from.

[CJM]

Need 3.5 backspace most likely and even then they might be to wide.

How wide are your wheels themselves? If they arent 10 inches your gonna get whats called cupping b/c the tire is to fat for the wheel.

[04 Rocko Taco]

I have to disagree Marc.
I run my 33x12.50's on a 10 inch wheel, and I feel like for rock crawling the wheel is to wide for the tire. It doesn't put enough tension on the bead to keep it on at low pressure. On the street, of course this isn't as much of a concern. On my 2004 DD, my 10.5" tires are on 7" wheels.

[CJM]

I do agree Chris if your really wanting to air them down and crawl it may not work to well..

Still, its really squishing them on 8 inches or less wide rims no? Did you get the cupping effect when running street pressures?

[justinkolman]

My tires are 33x17x12.5 inches and I need to know what size wheels and how much backspacing to get for them to fit on my truck without rubbing the control arm

[04 Rocko Taco]

My tires are 33x17x12.5 inches and I need to know what size wheels and how much backspacing to get for them to fit on my truck without rubbing the control arm

Unfortunately Justin, its a tough question to answer online. Without seeing your tires exactly, its tough to say. Backspacing needed will once again depend on how wide the wheel is that you choose. You might look into what wheelers recommends, you can check them out at http://www.wheelersoffroad.com/ they have some good information about their wheels which may lead you in the right direction.

You need to do some basic figuring and measuring to get a good ballpark idea though. you have 12.5 inch tires, lets say you are looking at some 10 inch wide wheels... that means your tires are going to inflate to roughly 1.25" of tire outside of the rim lips at pressure, which means that you need to find out how far in from the mounting surface to the control arm is..... once you have that measurement, you need to adjust the backspacing until your rim width and that 1.25" of tire will fit into that space. Is that clear at all? or to jumbled?



I do agree Chris if your really wanting to air them down and crawl it may not work to well..
Still, its really squishing them on 8 inches or less wide rims no? Did you get the cupping effect when running street pressures?


I didn't notice any cupping effect, I mean there is definitely some curve to the sidewall, but you figure a 10 inch wide wheel (15 inch) with a 12.5" tire (33 inch) you are only talking the sidewall has to come out 1.25" in 9 inches of sidewall. Thats really not very much angle, or bulge at all.

[CJM]

I would take a stab to say your gonna need 1.25 wheel spacers or more to run those b/c you will rub your upper control arm.

[04 Rocko Taco]

I agree that is a very likely outcome Marc.

[justinkolman]

Ok...I called around and the outcome I got for getting new wheels was 17x9 6 on 5.5 with 4.5 BS. I am going to try that and worst case just sell my tires and get smaller ones lol. Thanks for all the input and all the help guys!

[brian2sun]

Ok...I called around and the outcome I got for getting new wheels was 17x9 6 on 5.5 with 4.5 BS. I am going to try that and worst case just sell my tires and get smaller ones lol. Thanks for all the input and all the help guys!


That backspacing isn't going to work without 1-1.25" wheel spacers in the front. 4.5" BS is about what the stock rims are (4.65"). You need about 3.5" BS'ing to run 12.5" wide tires.

FYI, Do yourself a big favor and don't ever ask advice from 4WheelParts again. Fred Durst and his "bros" at 4WP are idiots.

[CJM]

Brians right, aint gonna work no matter what without spacers. Need at least 3.5 inches backspace.