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Are We Giving The Correct Tire Size Advice?

mhenshaw

By mhenshaw
in Tires, Wheels & TPMS

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RyanbabZ71 Senior Enthusiast

RyanbabZ71

Posted
Posted

Going back to the gmt-800's I know people who had rubbing issues with 285's and I ran 2 sets with no issues whatsoever.

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stlavsa Senior Enthusiast

stlavsa

Posted
Posted

The definition of "fitting" to me is NO RUBBING AT ALL ANY SITUATION!. I tried the 305/55/20 with 2" level kit, with +30 offset (oem offset,very conservative) and it RUBBED.. I even trimmed up all the plastic i could, but refused to cut or bend metal on a brand new truck.

 

Yes the tires physically fit in the wheel wells, and I could drive the truck around, but it was a bad experience.. Parking lots were miserable.. Turning both left and right in drive, rubbed.. IN reverse FORGET ABOUT IT.. i would be doing like 4 point turns to get out of a parking spot.. as soon as that tire catches fender and it starts rubbing, its SOOO LOUD and obnoxious people turn their heads thinking that i smashed into another car or something..

 

 

SO my experience was 305/55/20 w+30 offset = unacceptable rubbing turning in drive, reverse, and even on slight turns if they are on an incline, or off cambler.. Or if you hit a bump while turning. It rubbed in all situations and didnt even need to be at full lock.

I ended up running the 305/55/20" tires with 7.5" of suspension lift and no one says they look small, they are just a BIG tire that doesnt work with less than 5" of lift.. People have had rubbing issues even with 2"+3" combos, still need to trim.. Same with 4" BDS suspension lift. Trimming needed..

 

 

Possible explanation: Some times different tire brands are sized differently, but labeled the same.. One companies 33x12.5 could be 33.5x13 and another companies tire may be 32.5x12 Its almost like some companies measure with the tread depth and some dont count the tread depth and measure from wear bars. And it is the width every bit as much as it is the height that contribute to rubbing.. thats why either a 285 will clear as a 33" tire or a 305 will clear as a 32" tire.

txab Senior Enthusiast

txab

Posted
Posted
if it rubs it doesnt fit. saying it fits when it rubs is like saying my pants fit even though i cant sit down.

:seeya:

Big Whiskey Senior Enthusiast

Big Whiskey

Posted
Posted

I see a lot of valid points here, but I think were doing the right thing by being a little conservative with our recommendations. I'm still going to tell people that 285's are about the limit, when they ask about the biggest tire that will fit a leveled GMT900...without rubbing. Then, when someone slaps the 285's on their rig...it still looks a ton better than the stockers...and they can take it off road without tearing off their mud flaps or ripping their inner fender out...and they can buy aftermarket rims later if they want to...all without touching a pair of cutters.

 

I would be hotter than a firecracker if someone told me 33x12.50's would fit, then had to find out the hard way they would only "fit" if I cut the heck out of my new truck. I would want to go put knots on that guys head for giving me bad advice...if I spent $1000 on tires that sounded like I was going to tear my fender off every time I backed out of the driveway.

 

A few years ago, I helped a buddy mount 38x12.50x16.5 Swampers on a '82 K20 with NO lift. Did they fit...yes...with liberal use of a sledge hammer and sawzall. Just because a larger tire will "fit" doesn't mean everyone will be happy with it.

Superperv23 Enthusiast

Superperv23

Posted
Posted
Off topic somewhat,... but why do tires rub more in reverse than forward :seeya:

 

My understanding of this has always been because the front squats down a bit in reverse, kind of like the rear does when you are are going forward.

rgv Enthusiast

rgv

Posted
Posted
For the members asking what fits without rubbing, you need to be willing to trim. Stuff doesn't just bolt right up. The questions you should be asking is what will not work at all.

 

Put me firmly in the 'if it rubs it doesn't fit' camp. But I am off pavement a fair bit, often with heavy stuff in the bed.

 

I have to ask, based on your above post, what is your definition of 'what will not work at all'?

mhenshaw Senior Enthusiast

mhenshaw

Posted
  • Author
Posted
The definition of "fitting" to me is NO RUBBING AT ALL ANY SITUATION!. I tried the 305/55/20 with 2" level kit, with +30 offset (oem offset,very conservative) and it RUBBED.. I even trimmed up all the plastic i could, but refused to cut or bend metal on a brand new truck.

 

Were these wheels 8.5" or 9" wide?

 

For the members asking what fits without rubbing, you need to be willing to trim. Stuff doesn't just bolt right up. The questions you should be asking is what will not work at all.

 

Put me firmly in the 'if it rubs it doesn't fit' camp. But I am off pavement a fair bit, often with heavy stuff in the bed.

 

I have to ask, based on your above post, what is your definition of 'what will not work at all'?

 

 

I completely understand thay some of you think that even a little rubbing is bad. I however feel a slight rub is not a big deal at all. As far as you ripping off your fenders, I would be more worried about a mechanic not tighening my lugs and my tire falling off than the fender being damaged from rubbing. As far as not wanting to trim, I would rather trim before I cut my sub-frame and installed a 6" lift.

 

What would not work to me is any tire and wheel setup that you couldn't turn your wheels all the way (ie. you lose your turning circle). If you can turn you wheel all the way but it rubs, then you can trim to fix it. I would never recommend someone to get 33.5x13.50, but I would recommend them to get 33x12.5. Like some of you have stated tires measure up differently and trucks probally sit differently. So some may rub with a 33x12.5 some won't. But even if the truck does rub it is still driveable from the shop and it can be fixed.

Matt_ Senior Enthusiast

Matt_

Posted
Posted

I think the answer is obvious here....

 

YOU don't think rubbing is an issue, but the majority of this site does. So when someone posts a question and asks "what fits", we tell them. You're more than welcome to respond with a larger tire size.... just make sure you tell them its going to rub.

 

You ARE the exact reason I got screwed and had to cut metal on my brand new truck. When I confronted the person I confided in he said "oh yeah it does rub but I don't think its a big deal". He failed to mentioned that when he PMed me back initially with "oh Yeah they fit fine man".

 

Edit: :thumbs: if you can't tell, I'm still pissed about that. I did not enjoy cutting the fenders on my Denali. Although it looked perfectly fine when I was done (because I had experience with it on my silverado) it was a decision I made to not trim any metal on that truck. A little bit of plastic is one thing.... but not metal.

Doug_Scott Senior Enthusiast

Doug_Scott

Posted
Posted

To the OP, why not just offer your opinion when the question comes up, and let others offer theirs? It is simply an opinion, not a statement of fact. What works for you may not even be close for someone else, even with the exact same setup.

 

For example, I have a friend that has a 2008 Sierra Ext Cab 2wd, with the 4.8 engine, his truck with the stock wheels, running the original General Ameritracs 245-70-17 tire rubs when the wheels are turned to the left and backing up down the driveway onto the street. Has done this since the day he picked the truck up new. I have a 2010 Sierra Ext Cab 2wd and have the larger 265-70-17 tires on it, running the same wheel he has, no rubbing at any time, even though the tire is about an inch taller. There are tolerances is specs for the building of the truck, and that is what makes his rub. The rub does not bother him at all, it just polishes up the inner fender where it hits.

stlavsa Senior Enthusiast

stlavsa

Posted
Posted
I think the answer is obvious here....

 

YOU don't think rubbing is an issue, but the majority of this site does. So when someone posts a question and asks "what fits", we tell them. You're more than welcome to respond with a larger tire size.... just make sure you tell them its going to rub.

 

You ARE the exact reason I got screwed and had to cut metal on my brand new truck. When I confronted the person I confided in he said "oh yeah it does rub but I don't think its a big deal". He failed to mentioned that when he PMed me back initially with "oh Yeah they fit fine man".

 

Edit: :thumbs: if you can't tell, I'm still pissed about that. I did not enjoy cutting the fenders on my Denali. Although it looked perfectly fine when I was done (because I had experience with it on my silverado) it was a decision I made to not trim any metal on that truck. A little bit of plastic is one thing.... but not metal.

 

 

I was pissed too... I had my first setup with 305/55/20s and 2" level back when these trucks were still fairly new and then the general concensus was.. "yah they will fit"... They rubbed like a bitch and i was PISSED.. It wasnt close, it coulda been 8.5" wheels, 9" wheels, 7" wheels, 10" wheels non of them were gonna clear the wide, tall, tire with 20/32nds of tread depth. Who wants to spend $35,000.00+ dollars on a brand new truck, running like a dream, then the very next day you install the level kit and 33s and you cant even drive it normally it rubs loudly and scares everyone in the parking lot?? Turned your brand new 35k truck into a piece of shit.

 

You might think that some trucks sit differently and thats why some fit and some dont, but it still boils down to needing 5" of lift to properly clear them, so its not like one guys 2" level kit is gonna work and anothers doesnt"...

 

As far as Im concerned theres no reason to recommend the 305/55/20 tire size to the guys with the level kits when there is the 305/50/20. it WILL clear with just the level kit, and there are a few a/t tires available in that size, and they look much better than the taller skinner 285 width option.

blackout07 Senior Enthusiast

blackout07

Posted
Posted
Blackout07 you know a lot about trucks and I respect everything you say but did you try on +31 offest? These trucks don't like the offset or wide tires. But the wide tires have room to turn in the fenders. There is a lot more room in the inside corner by the engine, than the outside fender edge.

 

 

I didn't try the factory wheels, but we are talking about of difference of 13 mm. That's not a big difference. At least not in terms of changing from "these don't fit at all, to they rub a small amount." Like Steve mentioned, these trucks do have some variance in stance, but not enough to allow a leveling kit to magically allow any one person to mount a 33x12.50 with no rubbing. Also keep in mind that that 13 mm difference was even more negligible when I added the 3" body lift. I never trimmed anything, but the cold hard fact is that those tires rubbed even with 5" of lift.

Stevens03 Senior Enthusiast

Stevens03

Posted
Posted

Are we still arguing about this?!?!? If it rubs, it doesn't fit... if someone considers rubbing "ok"... then i suppose a circle will fit in a square hole :thumbs: I'm gonna have to change my entire approach when people ask for advice on whether things "work" or not.

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