backspacing

Ski-Dooman · February 28, 2003

What are you all running for back spacing on 16x8 after market wheels? can I run 3.5" on a nonlifted 2500ld ? Or is less than 4 gonna rub?

Any help is appreciated.

ski-doo ???

Chris97K1500 · February 28, 2003

Not sure about your specific situation, but the less the backspacing, the less likely you are to rub things like the ball joints and suspension components. Too little backspacing will make your tires stick further out from the hub, which will increase the likelihood of rubbing either the front fender, or the inside rear of the wheel well. I'd say 3.5" would not rub any of the suspension components, since stock is somewhere around 5", if not more. Sorry I can't be of more help. Chris

Professor · February 28, 2003

Mine are 4 1/4 and I wish they were 4 5/8. I have 305s but I'm thinking anout mounting a set of 285s when these are finished. I think you would be making a mistake with the 3 1/2 wheels.

My Truck

Ski-Dooman · February 28, 2003

I am looking at the mt classicII with 285's, these have 4" back spacing. I dont see a real problem just checking to see what you all were using and where the problems start.

thanks

Big Boy · February 28, 2003

for the good of your hubs and lugs you want to stay as close the the factory (5 I think) as possible taking into consideration what you may or may not want to do to the truck later. For instance if you ever plan on getting a lift you may need to change the back spacing. Rancho's 4" lift requires no more than 4.5 backspace

Good luck. let us know what you decide and post some pics.

varmint2506 · February 28, 2003

I agree with you professor on the 3.5" backset.

I would go for the most backset as you can or get as close to stock as you can. Stock GM wheels have 5.5" backset. I believe my 16x8 AR's are 5" or 5.5".

The further the wheel sets out the more problems you will have with rubbing and bearing wear.

jmeredith · March 2, 2003

I dont' know about the 5.5 backspacing on stock rims. Unless the non-HD wheels are different.

My 03 2500HD stock wheels were 4.75" backspacing. I replaced them with Weld SS II's which have 4-5/8" backspacing. For 285/75's, 4-5/8 is perfect. There is no possible way I could put either a 5.5 or a 3.5 on my truck. 5.5 would rub all the suspension parts. I'd have to remove the bumper and trim the fender behind the wheel with a 3.5 in order to turn the wheels. As it was with the 4-5/8's, I had to do trimming on both the inside and outside at full lock--air dam and the fenderwheel both in front and behind the wheel. I have not cranked my t-bars. If I had, I could have avoided trimming the plastic fenderwell.

If you go 285/75, get a rim with 4.5 or 4-5/8. No more, no less.

All this stated of course assuming the non-HD 2500 is the same as the HD.

-jm

jmeredith · March 2, 2003

Skidooman, if you want, I'll take a few digital pics of the clearance at full steering lock and you can decide for youself if you think the 4" rims with 285/75's will clear. They would stick farther out 5/8's of an inch.

Ski-Dooman · March 2, 2003

I would be greatfull if you did that jmeredith.

Thank you

jmeredith · March 3, 2003

alright, here you go. all pics are of the front drivers-side tire. tire width is the fit problem, not the height which is why backspacing is so important.

the first three pics are with the wheel turned slightly to the left, about 15 degrees. note the straight cut on the air dam. I think you'd be okay on the front clearance with a 4" backspace.

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit01.jpg

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit02.jpg

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit03.jpg

pics 4 and 5 note the cutout portion of the plastic fenderwell liner. you can avoid trimming the liner if you crank your t-bars but I chose to trim. pic number four is nearly full turn left, pic five is full turn right. you can see where the tire makes contact with the liner even though I've removed a good portion of it.

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit04.jpg

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit05.jpg

6, 7, and 8 are behind the wheel. note here the tight clearance with the plastic fender flare. this is where I'd be concerned with backspacing. these clearances are freaking tight. pic 6 is full crank right. pic 7 and 8 are slight turn left, about 25 degrees. also note the cutout portion of the fenderwell liner again. in pic 7 and 8 note how close the tire comes to the metal portion of the fender. the fenderwell liner used to be attached with a plastic fastener on the outside of the fender. I removed the fastener and tucked the liner in behind the metal lip there. I had major rubbing on the fastener.

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit06.jpg

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit07.jpg

http://home.attbi.com/~jasonsmeredith/tirefit/tirefit08.jpg

i still do have rubbing on the fenderwell liner when the suspension compresses but not much. I will be cranking my tbars someday to alleviate this but for now the extra little lift and minor rub on compression aren't worth the realignment hassle and cost.

when you do buy tires (285/75) you will need to trim the air dam (or take it off) BEFORE you go have them installed or you wont be able to turn the wheels more than about 15 degrees. I used a dremel tool which worked very well.

best of luck to you. it's worth it. it's just a little bit of plastic.

-jm

Ski-Dooman · March 4, 2003

Thanks jmeredith, that helps a ton. I think 4" bs is not gonna work unless I go 265's. MT does have the II with a 5 1/8" backspace but I think the might change the look of the wheel for the worse.

Big Boy · March 4, 2003

GREAT PICS Thanks. now I KNOW I need to crank the Tbars.

How bout a full on pic of the truck?

THX

jmeredith · March 4, 2003

there's a link in my sig for a picture. picture was taken at one week old.

I now have a leer 100xq canopy on it.

-jm

Ski-Dooman · March 5, 2003

Well I talked to a guy from Desert Rat and he says mt redesignd the classic II and the 4" b.s. is the new wheel for my truck. What I will do is order the wheels only then buy my tires local and have them test a 285. If that works thats what I get otherwise its 265 for me. When I finally get all this together I will post if 285 works or not(on a 4" bs wheel, I know they work on 4.5" bs wheels).