Fitting 295/70r18s: trimming required for me

[amateurhour]

I finally got around to putting new wheels and tires on the truck. I picked out some Falken Wildpeak AT4Ws on Method 305s with -12 offset that I picked up on sale.

I installed the ucas and leveling spacer before heading to the tire shop.

I had read through AXE”s thread: https://www.chevyzr2.com/threads/method-305-nv-toyo-oc-rt-trail.623/ and I was planning on doing the same wheels and same sized tires, did the same trimming he did before heading to the shop, and I even had the leveling spacer so I should be golden right? Nope, they rubbed hard

Two things were working against me: falkens run big for their size and I added cognitos uca’s that have added castor. I probably wouldn’t have as much trouble if I had gone with 0 offset wheels (stock wouldn’t fit with the ucas) or settled for 285/70s (Falken even has one in D rating) but the tires had been mounted and I pressed forward. I needed to take it a step further if I was going to make any turns with this setup.

The front is easy, you can cut to your heart’s desire up there, add spacers to the bumper, or even mount up a prerunner skid plate.

But the rear is more constrained. Some googling lead me to this guide: https://wheelsasap.com/gmc-at4-oversized-tire-trimming-guide/ A lot of people completely remove this bracket as it gains a bunch of extra space for the tire to tuck into

But there are a bunch of body panels coming together under this bracket and it seems to help tie everything together.

So my solution was to cut down the bracket. It can’t be any worse than having the bracket completely removed, as many do, and with the bulk of it removed it is out of the way of the tire.

 

[amateurhour]

I had to take more off the lower section of the fender flare. You can see the rub marks :

I used one of the bolts from the bracket to help pull back the fender liner. I wonder if a fender liner pull back kit (https://westcottdesigns.net/product/2020-22-gm-1500-fender-liner-pullback-kit/) would be cleaner but this works for now.

With that done it’s tight but it clears. I can’t gain any more space without cutting the crash bar or adding more lift so that’s how it’s going to stay for now.

Overall I’m happy with the results. The truck would probably look better with some power steps, that might be something for next time.

 

[ZR2BIZON]

That stance is 100!
Clean cuts

 

[Koppster]

Thanks for posting this. How do you think you would have fared with the Peak 2.25" kit?

 

[Busa Dave]

You will be needing to do a lot more work on the truck if you plan on driving this truck off road and articulating the suspension fully. This will be painfully evident when the tires are turned, and the suspension goes into compression such as going down an embankment and turning the wheel one way or the other at the bottom. Be careful!

Sometime when making component modifications they all do not play nicely with each other when combined. Been there done that many times over the years.

 

[amateurhour]

You will be needing to do a lot more work on the truck if you plan on driving this truck off road and articulating the suspension fully. This will be painfully evident when the tires are turned, and the suspension goes into compression such as going down an embankment and turning the wheel one way or the other at the bottom. Be careful!

Sometime when making component modifications they all do not play nicely with each other when combined. Been there done that many times over the years.

Absolutely, this should be taken more as a cautionary tale than a triumph. It stuffs into the crash bar when articulating. I’m not willing to remove that safety feature on a vehicle that frequently transports my family. So I’ll just have to resist going full lock when articulating until I change something else. Just like you said: sometimes it works out better than other times.

 

[amateurhour]

Thanks for posting this. How do you think you would have fared with the Peak 2.25" kit?

It would have helped at ride height, maybe even cleared that bracket, but with just 1.25” of flex the tire would be right back where it’s at. The wheel wells are just narrow and that’s difficult to get around. Spacers or negative offset wheels and wide tires move the tires away from the spindle centerline and create a larger arc that can, like in my case, put the tire into the fender.

 

[AXE]

Tires and wheels look good.

So how tall do the 295 Falkens sit? I have the same wheels with 295 Toyo RT Trails that sit about 34.5 inches. No lift or leveling kit. I left that frame support in place and trimmed the plastic and liner. I don't have any rubbing and I've ran offroad quite a bit.

I wonder if the spacer and UCAs charged the geometry enough to push it closer.

I think these trucks each sit a little different too. Seems like some guys say they don't get any rubbing without trimming anything.

I'll bet the next generation 1500 ZR2 is designed such that it can handle bigger tires and wheels. That new Colorado ZR2 Bison is rocking 35s and had a lot of clearance in the wheel well.

 

[amateurhour]

They are listed at the same 34.3 tall as most 295/70s but 12.2 wide compared to most at only 11.8”.
I think the arms move the ball joints rearward to add caster and that rolls the tire right into the cab. The wider tires or reduced backspacing has just too much to fit.

I agree that they are all a little different, tolerance variations add up, even left to right it’s different.

Hopefully they can open up the wheel well in the next generation. Like you mentioned in the Colorado thread I think the 1500 needs a little more refining. Bothe the colorado and the 2500s have 35s but the 1500s have 33s

 

[AXE]

They are listed at the same 34.3 tall as most 295/70s but 12.2 wide compared to most at only 11.8”.
I think the arms move the ball joints rearward to add caster and that rolls the tire right into the cab. The wider tires or reduced backspacing has just too much to fit.

I agree that they are all a little different, tolerance variations add up, even left to right it’s different.

Hopefully they can open up the wheel well in the next generation. Like you mentioned in the Colorado thread I think the 1500 needs a little more refining. Bothe the colorado and the 2500s have 35s but the 1500s have 33s

Yep, I think the other factor is 9 inch rim vs 8.5" stock. That doesn't sound like a lot, but with offset and different a arm geometry, it all adds up.

I notice when I'm backing hard off camber my passenger side rear has rubbed the felt liner a bit. I might trim the edge a little more on that side, but I just looked today after your post and I got about 1/4 x 1'/4 spot where it must make contact. I've noticed my felt liners don't fit quite the same on both sides. You can tweak them just a little.

 

[amateurhour]

Yep, I think the other factor is 9 inch rim vs 8.5" stock. That doesn't sound like a lot, but with offset and different a arm geometry, it all adds up.

I notice when I'm backing hard off camber my passenger side rear has rubbed the felt liner a bit. I might trim the edge a little more on that side, but I just looked today after your post and I got about 1/4 x 1'/4 spot where it must make contact. I've noticed my felt liners don't fit quite the same on both sides. You can tweak them just a little.

Good points. A quarter inch here, another quarter there, etc and pretty soon the tire is stuffed into the crash bar.