Checking the fit of oversized tires.

[kcjaz]

So I’m starting to think of my next set of tires and want to bump up a size to 285/75R17 from 285/70R17. I have a ~2” lift BP-51 suspension.

In general, what I think people do is simply mount the tires and see where the rub by driving around or just turn the steering wheel from side to side. But generally, that won’t test each corner at full articulation.

Is there some other way to check the “extremes” without finding “full flex” terrain to drive over? I was thinking about putting the truck on my buddys lift and removing the springs so I can see what happens at full articulation. Or maybe I can jack up one corner by the frame and the opposite by the axle and achieve the same thing. Has anyone done something like that? I’ve see pics of people lifting one corner with a fork lift (not an option for me).

I know that the 285/75R17s shouldn’t be too hard to fit with my set up and the “slap them on, drive around, and adjust” method is probably adequate and easiest. Just curious how other approach this.

 

[montegofd3s]

What is the rim offset?

 

[kcjaz]

What is the rim offset?

25

 

[nwfl4runner]

The correct way: pull coil over up front, pull coil in rear, loosen suspension bolts, disconnect outer tie rods, and start jacking. Up front it’s full bump and lock to lock. In the rear it’s axle at full bump, and axle at full articulation (one side full bump, other side full droop). If you want to be sure, run aftermarket bump stops with published maximum compressed height, remove the bump stop entirely and use the compressed measurement. I say that as I know max compression of my Timbren stops, but dont know OEM deflection.

No other way to know. Edit: other than self clearance…

 

[montegofd3s]

They will fit with no problem, but I am not sure how specific you are trying to get or what you are trying to test with other methods. For peace of mind I can show you via the calculator how they would work compared to your current setup and a setup that is common for others.

Comparing them to your current tires, the inner and outer sidewall doesn't change because the width is still the same, but the top of the tire will be 0.55" closer to the inner fender.

Your new 285/75 would be nearly identical to running Rock Warriors with a 1" spacers, a fairly common setup for people here. Your tire would only be 0.02" closer to the inner suspension and frame (which is essentially no difference).

You would clear just fine with 285/75/17 at that offset.

 

[1Maverick]

They will fit with no problem, but I am not sure how specific you are trying to get or what you are trying to test with other methods. For peace of mind I can show you via the calculator how they would work compared to your current setup and a setup that is common for others.

Comparing them to your current tires, the inner and outer sidewall doesn't change because the width is still the same, but the top of the tire will be 0.55" closer to the inner fender.
View attachment 3080159

Your new 285/75 would be nearly identical to running Rock Warriors with a 1" spacers, a fairly common setup for people here. Your tire would only be 0.02" closer to the inner suspension and frame (which is essentially no difference).

View attachment 3080160

You would clear just fine with 285/75/17 at that offset.

Do you know what the heritage wheel with 1.25 spidertrax spacers total offset is? My previous 200, I had method wheels +18 offset without spacers and was able to run 295/70r18 which I’d like to do with my current 200.

 

[kcjaz]

They will fit with no problem, but I am not sure how specific you are trying to get or what you are trying to test with other methods. For peace of mind I can show you via the calculator how they would work compared to your current setup and a setup that is common for others.

Comparing them to your current tires, the inner and outer sidewall doesn't change because the width is still the same, but the top of the tire will be 0.55" closer to the inner fender.
View attachment 3080159

Your new 285/75 would be nearly identical to running Rock Warriors with a 1" spacers, a fairly common setup for people here. Your tire would only be 0.02" closer to the inner suspension and frame (which is essentially no difference).

View attachment 3080160

You would clear just fine with 285/75/17 at that offset.

Thanks. I know this is pretty common setup so I should be ok with minimum to no issues. My question was really more “in general.” Part of me keeps thinking about 35” tires and what I’d be getting into and how I’d physically make sure it works.

 

[1Maverick]

Thanks. I know this is pretty common setup so I should be ok with minimum to no issues. My question was really more “in general.” Part of me keeps thinking about 35” tires and what I’d be getting into and how I’d physically make sure it works.

I’ve had 35/12.50r18 KO2(not true 35”) on my previous 200 but I was running Method offset +18 wheels and had to do a BMC. It will still rub a little at full lock. It still tucked inside the fender when compressed…just barely. For a proper 35” fitment, a Tundra swap would be ideal. Also, 35” tires are not real comfortable on the highway if your Cruiser spends over 90% on pavement. If you can get a 295/70r18 to fit, that’s a really good tire setup. Running 17” 25+ offset wheels, the 285/75r17 is still a good option.

 

[montegofd3s]

Do you know what the heritage wheel with 1.25 spidertrax spacers total offset is? My previous 200, I had method wheels +18 offset without spacers and was able to run 295/70r18 which I’d like to do with my current 200.

I believe the heritage rims are the standard stock offset of +60mm so running those with a 1.25" spacer puts you 0.4" closer inboard than running the +18 offset you had before.

 

[linuxgod]

Jason what 34” tires are you thinking? It’s a bit dependent on the fully inflated tire size (which can vary a bit) and the alignment settings (in particular caster).

In my experience Nitto Ridge Grappler 34s will fit on +25 offset wheels (like my Icons) but you will have some rubbing to alleviate (or live with). You’ll need to remove you front mud flaps, you’ll need to use a heat gun on the back side of the inner plastic fender liner and also hammer the bracket behind the plastic liner that the mud flaps mounted to so it makes a smoother arc. You will almost certainly rub the KDSS arm and the sway bar on the passengers side (but just at full lock). I did a KDSS relo bracket to alleviate this though if you go this route you should also consider moving the sway bar end links to the outside of the cradle. I can give you details on that but it’ll significantly reduce the sway bar end link angles that the KDSS relo creates. You may need to run caster on the higher end (3 degrees or more) if you’re too close to the body mount but I didn’t have this issue.

I’m on 34s no rubbing now with the above setup. I also have an SPC UCA but I’m assuming you’re not on the OEM UCA at this point. I will go 35s next time. They require a body mount chop and taller bump stops.

(As far as wheel offset goes, the more offset you have the wider the arc the tire takes when you turn. Lower offsets require more effort to fit a tire because the “corners” of the tire (during an arc) are more likely yo contract stuff. This is why people running 34” tires on Rock Warrior wheels sometimes can avoid some of the above minor modifications that I had to do). But lower offsets get you further from the KDSS arm and the UCA, which will help reduce or eliminate rubbing there. It’s a trade off. You can go +0 offset and you won’t need a KDSS relo for 34s (or maybe even 35s) but then you will probably smash the fender on a hard bump.)

 

[kcjaz]

Jason what 34” tires are you thinking? It’s a bit dependent on the fully inflated tire size (which can vary a bit) and the alignment settings (in particular caster).

In my experience Nitto Ridge Grappler 34s will fit on +25 offset wheels (like my Icons) but you will have some rubbing to alleviate (or live with). You’ll need to remove you front mud flaps, you’ll need to use a heat gun on the back side of the inner plastic fender liner and also hammer the bracket behind the plastic liner that the mud flaps mounted to so it makes a smoother arc. You will almost certainly rub the KDSS arm and the sway bar on the passengers side (but just at full lock). I did a KDSS relo bracket to alleviate this though if you go this route you should also consider moving the sway bar end links to the outside of the cradle. I can give you details on that but it’ll significantly reduce the sway bar end link angles that the KDSS relo creates. You may need to run caster on the higher end (3 degrees or more) if you’re too close to the body mount but I didn’t have this issue.

I’m on 34s no rubbing now with the above setup. I also have an SPC UCA but I’m assuming you’re not on the OEM UCA at this point. I will go 35s next time. They require a body mount chop and taller bump stops.

(As far as wheel offset goes, the more offset you have the wider the arc the tire takes when you turn. Lower offsets require more effort to fit a tire because the “corners” of the tire (during an arc) are more likely yo contract stuff. This is why people running 34” tires on Rock Warrior wheels sometimes can avoid some of the above minor modifications that I had to do). But lower offsets get you further from the KDSS arm and the UCA, which will help reduce or eliminate rubbing there. It’s a trade off. You can go +0 offset and you won’t need a KDSS relo for 34s (or maybe even 35s) but then you will probably smash the fender on a hard bump.)

I was thinking KO2s but haven't made any hard decision. I don't mind heat gun or hammer mod/adjustments but I'd like to avoid KDSS relo. Maybe that's not that big of a deal. I do have SPC UCAs. I probably really just need to stop hanging around dedicated trail 80's and 40's with 37s+.

 

[TLC2013]

@kcjaz with around a +25mm offset and a good alignment you should be able to fit LT285/75R17 K02's with minimal fuss. On my 200 with 3 degrees Of caster they fit easily and didnt rub the driver side KDSS but needed some massaging at the rear of the front wheel well plus removal of the mud flap. I also dont want to mess with the KDSS relo so I was pleasently surprised to see that this size fit so well with k02s and 25mm offset.

 

[nwfl4runner]

I was thinking KO2s but haven't made any hard decision. I don't mind heat gun or hammer mod/adjustments but I'd like to avoid KDSS relo. Maybe that's not that big of a deal. I do have SPC UCAs. I probably really just need to stop hanging around dedicated trail 80's and 40's with 37s+.

Never. Skip 35s entirely, they’re basically donuts anyway! Come join us in the land of 37s

 

[Heckraiser]

If you're looking for a way to simulate articulation at home, the thorough way is to drop the springs out and cycle the suspension with a jack.

The easy way is to park on a couple ramps arranged thusly:

 

[CharlieS]

Every time I consider going bigger than 34" tires I come to the same conclusion, which is that I should get a dedicated trail rig in addition to the 200. A triple locked 200 on 34s, 17" rims, 2-3 inches of suspension lift, aired down, with proper underbody protection is far more capable than I am. Anything that needs more than that could benefit from front and rear solid axles, larger tires, a differently tuned suspension, etc.

 

[TimCFJ40]

Every time I consider going bigger than 34" tires I come to the same conclusion, which is that I should get a dedicated trail rig in addition to the 200. A triple locked 200 on 34s, 17" rims, 2-3 inches of suspension lift, aired down, with proper underbody protection is far more capable than I am. Anything that needs more than that could benefit from front and rear solid axles, larger tires, a differently tuned suspension, etc.

Having lived through the evolution then devolution of a prior vehicle, I couldn't agree more. Earlier in life I had a decently capable Grand Cherokee that did everything well on 31s then 33s. Then I broke the rear axle in Moab, then did a front and rear axle swap and lockers and 36s, and sacrificed most of the day to day and long distance usability. Then I wheeled the s*** out of it, rolled it, and chopped it into a buggy and bought a tow rig. Pretty soon I longed for the days of a decent little rig on 31s that could comfortably drive long distances, explore off road, and comfortably carry people and stuff wherever. Every time I start to get the itch for bigger tires and more extreme mods, I remember that I can drive my 200 across the country at 90mph, get 13-15mpg, carry the family and all of our stuff, hit decently hard trails, and do it all relatively effortlessly and comfortably. Then I reconsider how good of an all around rig I have, and plan the next adventure keeping my limitations in mind. This keeps me out of the 35" tire game on my last set, and actually kept me on 33s on the last set of tires...

That, and for the cost of extreme mods on the 200, I could build a damn capable trail only rig that I wouldn't cry about if it got broken or beat up...

 

[TimCFJ40]

I realized I went down the rabbit hole without answering the OP's question. I would flex the truck as well as possible with the current tires, then look for how much clearance I had at the critical spots. Then make a judgement call as to whether the additional 1/2" of tire or the 1" of additional tire poke, etc will clear.

 

[linuxgod]

Every time I consider going bigger than 34" tires I come to the same conclusion, which is that I should get a dedicated trail rig in addition to the 200. A triple locked 200 on 34s, 17" rims, 2-3 inches of suspension lift, aired down, with proper underbody protection is far more capable than I am. Anything that needs more than that could benefit from front and rear solid axles, larger tires, a differently tuned suspension, etc.

If I’d had 37s I might have cleared that stupid rock on red cone…

 

[kcjaz]

If I’d had 37s I might have cleared that stupid rock on red cone…

Yeah and maybe even achieved 3 mpg through Nebraska instead of 5…

 

[linuxgod]

Yeah and maybe even achieved 3 mpg through Nebraska instead of 5…

Touché