Fitting 285/70r17 without CMC via proper alignment/UCAs

Been searching around and I can't really find any definitive answer to this...

I've just completed a 6112/5160 lift with 285/70r17 tires on -10 offset wheels (yes not ideal for clearance but I prefer the look).

I was planning on getting a CMC which will cost around $300, but I'm wondering if anybody has been able to clear tires of this size on this offset just by aligning properly and using aftermarket UCAs... SPCs or maybe even a non-adjustable option.

Basically... if I allocate money towards UCAs and can push my caster much further on the LCA adjustments (since the UCAs should correct the camber issues that come with doing that on stock UCAs), would it be likely to fit my tires in full stuff or is the CMC probably inevitable no matter what?

Thanks

 

Seems to vary a lot truck-to-truck. I just installed -10 offset wheels (SCS F5) with 285 70 17 tires (KO2s). I have a little rubbing on the cab mount when wheels are turned and suspension flexed. I have an appointment to get my SPC UCAs realigned on Thursday, pushing the wheel forward.

I can check back in, but I'm expecting the alignment to fix what little rubbing problems I'm having - although did have to trim the rear part of the wheel well, and remove the splash guards up front.

 

It depends on how you use the truck. If you want to drive around town a CMC “may” not be necessary. Driving Offroad full lock in uneven terrain, don’t be surprised it rubs.

Sounds like you already purchased the wheels and tires. Have you tried going full lock in reverse?

 

I know you aren't talking about 35s but this topic is discussed ad nauseum in the 35s thread:

https://www.tacomaworld.com/threads...-those-that-wheel-and-love-alignments.594309/

tldr yes but it's highly dependent on wheel backspacing and it's going to take a decent alignment shop, since you already own the wheels you're limited on your backspacing. you didn't mention how thick the wheels were (are they 8, 8.5 or 9) but assuming you're running 17x8.5 -10, you're probably SOL without a CMC IMO.

 

Enough caster and alignment will get you close but you will eventually get the CMC but you can get away with it for a bit for regular and mild offroad. I had the SCS -10 setup when I first started ( 17x9) and 285/70/17.

I would def consider the UCA. at first it will pull it back to the wheel well but if you get around 3 degrees it will give you room then previous replies apply when you go offroad. The worst case is you could cut off the part of the cab mount and then weld on a plate later on. I've seen this done in a crunch before.

 

I use it as an adventure rig... a lot of wheeling and sometimes a little faster than I should in the desert. Definitely need to to clear at full stuff. I do not rub at all in reverse at full lock, I only rub when hitting bumps.

 

Yep they're 17x18.5 -10, Circuit Offroad Hayford. Does the wheel width make that much of a difference?

 

Believe it or not, all trucks are not the same. When manufacturing pretty much anything, you have +- tolerances. Those tolerances eventually stack up (every part has a tolerance and they are additive) and by the time you get to the wheel/cab mount clearance, you can have a big difference. This is why tires still have an adjustment for alignment. If all vehicles were perfect, there would be no need for any adjustments of any type.
So, might fit, might not.

 

If you don’t rub on cab mount you’ll rub somewhere else. The mixed reports are from people who don’t fully flex out the front suspension at all steering angles.

It is possible to “not rub” on pavement but rub often when actually wheeling.

 

Yep. There's really not much margin for larger tires in the wheel well so every millimeter matters. Backspacing makes a huge difference and you have ~12% more backspacing than you would at 4".

 

Alright, I'll take your word for it's necessity. A reputable shop near me will do it for $300... not a terrible price in 2023.

 

I don't have CMC with 285/75/16 with aftermarket UCA's but I have 0mm offset wheels which is huge with this equation. I have rokblokz mudflaps on too.

 

No CMC No rubbing
285/17/70
Lifted 3”
Icon Delta joint UCA
Zero offset wheels

 

Get the cmc. If you plan to take it off road you will rub the mount. I know there are people who say they dont rub, but you will if you plan to off road with it.