34x10.5-R17 Tires with 4Runner "Snowflake" wheels

Hey all,

I got some Toyo AT3 34x10.5-R17 tires put on the Taco and I went with a 17x8.5 0 Offset wheel. I am now starting to question my wheel choice since the tire isn't wide like a 285. I am thinking I should have gone with the 4Runner Snowflake wheels (+15mm offset ) to minimize scrub radius as much as possible.

I got an alignment done, but not at an off-road specific shop. He knew exactly what I was talking about when I asked for ~3.5 or so of caster and there were a couple other off-road vehicles in the shop, so I had faith. Numbers look good post alignment.

I am wondering if going with a +15mm offset will increase tire clearance by the same amount or if it will be a somewhat negligible difference in scrub radius? (15mm is about 0.59 inches)

Currently, does my cab mount clearance look too tight? I definitely rub some plastic, but that can be trimmed. Trying to avoid a CMC.

For those interested, the tire measures just a hair over 33” mounted @ 35PSI. It measures about 32.5” on the truck @ 31PSI. More like a 33” than a 34” for sure. This tire is just a tad wider than 265/75r16 (+0.08" wider according to tire calculator).

Driver:
Passenger:

 

I’d say just go ahead and just get the CMC if you can. It’s pretty hard clearing larger (33”+) without doing one. I mean, all our trucks vary slightly, so I’m not saying that it is impossible to get away without doing one. But it will open up a lot of options and it is a pretty straightforward modification.

the other thing is that your selected tire size and width are somewhat less common here. There are loads of people running 255/80/17, 285/70/17, and even 285/75/17 ( also a skinny 34”) but your tires are ever so slightly more narrow than your average 33 or 34. That should work in your favor.

I see you already have the Dobson upper control arms. If you did not already have those, I might suggest the SPC upper control arms to gain some clearance flexibility and adjustment.

I just feel like if you already like those tires and wheels the easiest step and probably eventual step that you will more than likely make somewhere down the line would be just to do a cab mount chop.

I think the guys running 255/80/17 have the best chance of clearing a 33 without needing to do a CMC.

by way of comparison, here’s a picture of my 285/75/17’s on a 17” x 8.5” -10mm SCS F5 and a CMC.

 

What is your suspension setup?

 

Parts are listed in my signature. The front 650 lbs 6120's on not on the tallest clip.

 

Thank you for the reply! I guess I was trying to avoid the CMC if I can. My main question is if having a +15mm offset instead of 0mm would reduce the scrub radius enough to clear them without a CMC. I feel like I am pretty close on the passenger side to clearing it even with 0 offset wheels. After much research, I haven't been able to find out how much cab mount clearance is "enough" to not rub in all circumstances. I watched a video where one person claimed that "2 fingers" is enough....very scientific. =)

I of course like the wheels I chose, but in all honesty I would rather do the Snowflake wheels and avoid a CMC.....if having that more positive offset actually cures the rubbing.

 

Correct me if I'm wrong, but wouldn't you want to go with a negative offset wheel if you are trying to insure no cab mount interference? I thought that a positive offset wheel moved the centerline of the tire in towards the body and negative offset wheels moved the tire centerline out (poke).

 

This is a common misconception. A more negative offset helps you run wider tires so you can clear the upper control arm, but actually decreases body mount clearance because it increases scrub radius. Ideally, you want to run just enough offset so your tires clear the UCA and that's it. The more positive the offset, the less scrub radius, the more body mount clearance you get.

People run more negative offset wheels for the looks as well, but from a technical standpoint that actually reduces clearance.

Unfortunately, there aren't a ton of wheel choices in 17inch size with an ideal positive offset if you are trying to stay around 4.75 to 5 inch backspacing. It seems the OEM wheels are actually some of the better choices.

Tinkerer's Adventure has a good video explaining this in more detail:

 

After doing a bit more research, I am wondering if I can get away with higher than +15mm offset.

TRD Sport wheels are 17x7.5 +30mm offset (5.5" backspace). People clear 265/70/R17 no problem with these on stock suspension. 34x10.5-R17 tires are basically the same width (.25" wider based on real world measurements)

TRD OR Wheels are 16x7 +25mm offset (5" backspace).

My UCAs claim to also have a little more room for tires than stock UCAs.

It stands to reason I could go with a 17x8 +20mm offset wheel (~5.28" backspace) and clear the Dobinsons UCAs while minimizing scrub radius as much as possible.

Thoughts?