JBA UCA Wheel/Tire Clearance Questions - 4.75BS 17"x8.5" -

I have been doing a lot of research on tire and wheel combinations for the first gen. I have not been able to find a definitive answer to my questions after a couple weeks of searching.

Maybe I am bad at searching. Maybe I just need to be spoon fed. My entire front end is removed. The front fell off. I can't measure but I want to order my wheel/tire combo.

Question 1: With 17" wheels what is the interference point with the upper control arm when running 4.75" backspacing. Is it the wheel itself or is it the tire?

Question 2: Do the JBA Upper Control Arms provide additional clearance?

I'm still a week out from having my front end put back together but I've been looking into wheel tire combinations in the mean time. I have my heart set on some 17x8.5 +0mm / 4.75" backspacing wheels. I'm just concerned about UCA clearance as that seems to be the biggest issue with larger wheel/tire combinations from my research.

Spacers are a non negotiable for me. Will not run them.

Thank you in advance.

Currently pressing out the bearings. Taking some ingenuity.

 

With how much lift? What size tire? You're giving us too few variables here.

To my knowledge, there isn't a clearance issue. 4.75" BS seems to be the sweet spot for both RC/AC and the DC. OEM BS is 5.0". 4.5" BS with no spacer will put the outside of an 8.5" wheel just about flush with OEM fender flare, I had some rub with 275/70R17 and 2" lift with the wheel you're referencing below. See my signature. My UCA are set at OEM setting, basically.

Totally get it on the spacers. I won't run them either. There's a thread around here somewhere on spacers and wheel fitment. Here: https://www.tundras.com/threads/let-me-see-your-wheels.126855/

It'll show you a few backspaces.

General lift info and what to expect, backspacing, several warnings etc., see the Suspension section here: https://www.tundras.com/threads/so-you-wanna-buy-just-bought-a-1st-gen-tundra-eh.115928/

 

Currently have 1.75" OME springs on Bilstein 5200s set to the lowest setting. I would love to fit a 295/70/17 - Keep in mind my fenders are non existent, I have 100 grinding discs and 50 pounds of welding wire. I am purely asking about clearance with suspension components.

My main concern is clearance with the upper control arm and where it falls into the mix depending wheel diameter, width and backspacking/offset, as I noticed a lot of people mentioning it without really giving me any data.

Where did you have rub?

I would expect that size to start getting into pinch welds and really threaten the frame rail at full lock. However, that is based on absolutely no real world experience with this platform.

Thanks for the response.

 

Here's where I cut the OEM flaps to compensate: https://www.tundras.com/threads/1st-gen-mud-flap-splash-guard-mods-for-larger-tires-lift.133574/

My flaps had just a small kiss of rub in the same spots you see rubbed-out on those flaps. And cutting, as shown, solved my issue. My tire profile is pretty aggressive though IMO.

Those flaps are actually from @FirstGenVol's truck, so the rubbing you see are from his 285/70r17 KO2s. He says he only rubs the frame a bit at full lock in reverse. Other than rubbing his front flaps.

I personally wouldn't recommend going to 295/70r17. You won't gain any significant amount of added ability, and that extra half inch isn't buying you shit in the looks department. Furthermore, the hit you're going to take in mpg and performance isn't worth it.

265/70r17 (31.6") I can see being tempting for some folks for added performance, knowing OEM 265/65r17 at 30.6" seems inadequate.
275/70r17 (32.2") looks aggressive and substantial, grabs as much as I'll ever need.
285/70r17 (32.7") looks beefy and large, it's a lot of member's preferred choice at 17" and shouldn't rub more than flaps or kiss frame at full lock on your AC or RC.
295/70r17 (33.3") ... maybe you have a reason, I see no point other than bragging rights and loss of driveability.

 

You won't have issues rubbing the upper control arm. With SPC uppers, SCS 17" wheels and 285/70/17 I lightly rub the fender liners occasionally. Only in reverse at low speed. It's really not an issue.

A proper alignment will help reduce rubbing.

 

295/70r17 - Wider tire, lower ground contact pressure. Taller tire, more clearance. I appreciate your recommendations and the information you have provided. It seems you really have the real world experience with this platform that I don't. However, I believe your recommendations are coming from what works best for your use case. I'm not building a rig that's going to get a lot of miles put on it. I'm certainly not in it for the looks. Like I said, my fenders are non existent. This is a toy/project. I'm doing a flatbed, boat sides and custom fenders. OEM mudflaps, MPG and Image mean nothing to me. I'll add a picture of my current fender to give you an idea of what I am working with. Also tossed in a picture of my old toy, 6" lifted XJ on 38.5x14.50s. Should give you a better understanding of where my brain is.

I really do appreciate you sharing your knowledge however. I was able to learn quite a bit from you. That will be useful when I have a nice one like you. Good looking truck.

What are you running for suspension in the front? What is your wheel width and Offset or Backspace? I am doing a complete overhaul of the front end with all OEM or better parts so it will be getting aligned properly. Thank you for the insight.

 

All details of my build are at the bottom of each of my replies. It updates periodically, so I'll just point you to the dotted line below, check the line following it. Backspace is missing, but you can calculate, 4.75 is ballpark. I'm getting a hair over 2" lift all-around with the setup I'm running at the moment. With the couple of sizes up I'm running, the truck is definitely dragging w/factory gears. Cruise control is holding ineffectively/hunting. Negligible, since I typically don't use it, but worth noting maybe for someone else reading this.

My recommendations are coming from 4-5 years of watching other people's builds on this platform, hearing their input and feedback on options they chose. I'm not myopic or self-focused by any means, though I will speak to my own experience, that's not where advice I chuck out is centered.

My input above still stands. If you're sticking with 17, you're looking at (diameter/width) of ... 275/70r17 (32.2"/10.8"), 285/70r17 (32.7"/11.2"), 295/70r17 (33.3"/11.6"). We're talking half an inch or less of actual width/height from those couple of steps, but I think you'll find you're adding several pounds of rotating mass per wheel for the addition of 0.5" diameter and 0.4" width? I dunno, one of those I'd sacrifice the added burden for serious offroad, the other ... IDGAF. One of my highest priorities would be regearing, else it's going to feel and move like ass, regardless what your final intent is.

Thanks!

 

Man, how's the frame on that thing? That's a lot of rust.

I'm running ICON coilovers. 17x8.5" SCS wheels with 4.3" backspace.

 

I was also curious, as it looks rough...

Here is a reply he made in another thread of his. A reply to you funnily enough.

 

Glad you posted that. I forgot about that thread, and this explains that nagging feeling I was getting.

 

He should be able to run 35’s soon. Those fenders are slowly self clearancing……

 

I have no input on your question, but I'm really excited to see where this goes!

I'd love to have the skill to build a sas truggy someday.

 

It's a learning process. I have my grandfather's Jeep Scrambler in storage that has been waiting for me to gather the skill to properly restore. This rig is helping me gain those skills. Front end is completely rebuilt which was a learning process that doesn't apply to the CJ-8, however now that all the important bits are taken care of I can move on to more fun things. Coming up next is going to be the flatbed build and rock sliders. Also getting rid of the stock rear crossmembers and shock mounts.

 

That explains everything. Keep up the good work.

They won't even exist soon. The weight reduction should help me overcome the terrible gas mileage I am going to get with the extra heavy LT295/70/17s.

 

The ol great northern weight reduction mod. Cheap and effective. Hopefully there’s enough left to keep you rolling for your intended purposes.

 

All the parts that matter are there. Not sure what direction I want to go with the fenders yet. I'd like a little bit of bulge but most the fiberglass options I've found are a bit extreme and also expensive. Leaning towards getting some super cheap repops and modifying them to fit my tire/wheel package. I think with some creative fender rolling I can create some extra space.

 

Do I need to trim my mud flaps?

 

Send it!

 

For anyone who finds this thread in the future this is my current clearance with all 4 cam bolts in the center position. I still need to align it properly, currently it visually has positive camber however I have not put it on the gauge yet.

Wheels - Fifteen52 Offroad Turbomac HD Classic 17x8.5 +0mm

Tires - Mickey Thompson Baja Boss A/T LT295/70R17

 

Looks like current camber is +1.75*

 

Set everything at 0 at got it rolling. Need to put some miles on it and let it all settle for a bit. Gonna need to add some more height to the rear after I build the flatbed for sure.