35s vs 37s : steering components

I've read about the strain on the front components when going to 37s from 35s.

Mainly additional wear/strain on tie-rods, PS pump, rack, etc. (Please correct me if this is a misconception)

But if all things were equal and I was moving from a 35" tire that weighed 68lbs to a 37" tire (@64lbs), does it place less stress/wear because of the weigh difference? Or the weight difference doesn't matter because its not about rotational mass and is more about the strain involved in trying to pivot a taller tire?
But if there's less mass to pivot, shouldn't there be less strain on the components doing the steering?

Sorry for speaking in layman terms. Trying to seek a layman's answer. Thanks in advance.

 

I think weight and frictional losses are the biggest battle with bigger tires. So in theory, if you can find a bigger tire with less weight, assuming that the tread pattern doesn’t add significant friction to the ability to turn, it shouldn’t add any more strain. It would be a fairly easy test to measure force required between tie rod and knuckle to rotate tire lock to lock. Repeat with other tires and compare.

usually, people adding bigger tires are taking harder trails and it’s not a 1 to 1 comparison. The death of the rack is more than likely due to the places the truck is taken vs the tire upsize.

 

That’s a good question, and I’m curious to hear other’s thoughts, as well.

@snowsk8air2 @WormSquirts what do you guys think?

 

Strain and geometry.

Big lifts over 3" have terrible tie rod angles. Combined with heavy scrub means you'll wear out racks faster. It's just a fact of life.

I've never changed a rack on a drop bracket truck yet. And they have dead even tie rod angles. Albeit they never really offroad hard.

 

Less rotating mass is good, but now that rotating mass is at a further distance from the pivot point creating a larger moment for forces to act upon thus adding stress even if the larger tire is lighter. That is if you’re looking at things from an engineering point of view.

From my personal experience going 35-37’s here’s what I noticed. Note my wheel/tire combo was about 2lbs heavier per corner. Acceleration loss was negligible, but braking took a very noticeable hit. This is because that extra mass is farther from the point of rotation. After about a year on the 37’s, wheel bearings were still fine (and they were the originals at about 130k miles). I didn’t have any issues with tie rods either. Power steering pump knows no difference between tire sizes, it’s just going to supply pressure based on rpm. The big issues I had with 37’s were with the steering rack. Rack was about 2 years old when I jumped to 37’s and after about 8 months it started skipping teeth pretty frequently.

Things I’ve done in the last year or 2 to help keep things tight and working nicely are the jd fab slide rack paired with a new aftermarket rack. I also did heimed steering at this time. Since doing this the steering has been 100% solid beating the crap out of the truck for the last year. I also more recently did their Howe ps pump kit. This is definitely a nice upgrade to make turning the tires much easier. That said, if I didn’t like to crawl the truck and only did high speed stuff I probably wouldn’t have done it. At speed turning the wheel is easy with the stock pump. Just gets hard when going slow.

 

Thanks man, that’s some great first hand experience. Nice to know acceleration didn’t take too much of a hit. Figured braking would though. If I go to 37’s 17” wheels are a must for a brake upgrade. Looking into swapping for stock 4Runner calipers.

I haven’t had an issue with tie rods or the rack on 35’s. I don’t push it very hard when in a bind because I hear so much about it. Slide rack seems like a worthy upgrade if I go 37’s. Locked up front makes for some super hard turns when slow.

My truck sees a lot of pavement and I’m torn between keeping 35 MTs or going to an all terrain on 37’s. Almost seems dumb to not do a MT on 37’s though. Wonder how the two would stack up offroad…

 

I’ve been running 36s on stock rack for about 5 years and haven’t had any issues. Been bound up a couple of times on the trail but don’t beat on the truck too bad by any means.

 

As someone running the 4Runner brakes as well, they are better than the stock taco ones but definitely have a longer pedal throw than stock. If shopping around I would go with a taco specific kit to maintain pedal feel.

Locked up front as of recently as well and turning the 37’s in the rocks was really difficult. Hence going with the Howe Ps pump. Haven’t crawled the truck since upgrading the pump.

As for tires, if your wheeling benefits from a Mt over an AT, then stick with an Mt.

 

Didn’t know that about the brakes, good to know. Curious to see how the pump does bound up. I know long term plans are a truggy built, which will leave the taco as an oddball, because I’ll probably want an F150 to haul the truggy and use as my daily/workhorse on the land. I just don’t see hauling a truggy with the Tacoma being a joyful experience with long travel and 35 MTs or 37 ATs. Maybe I’ll just leave the taco alone and put the funds towards the truggy haha.

 

My 37s are substantially heavier than my 35s were because I swapped to beadlocks at the same time. My braking is horrible. It wasn't good before either though. I think I will be doing the tundra brake booster/MC and 4runner brakes at some point soon here.

I think the tires blow racks quicker due to the leverage on them, but I'm sure weight plays a part as well. I blew my original rack on 35s after a couple years. I swapped to a brand new Toyota rack just before putting on the 37s, and I blew that rack in around 9 months. Tie rods are still fine. I have the JD slide rack sitting in a box. Was going to put it on my new rack, but now that it's toast, I guess I gotta figure something else out.

I have a majorly bad clunk in the front end that I can't find other than the play in the rack. It's the only thing I can think of. Checked shock bearings, and all uniballs, tierods etc, and there's no play. It's basically undrivable. Just did the rear JD Sua kit too and can't even try it. Anyway, just really frustrated with this truck lately. Everytime I fix something, 2 other things break.

 

That sucks. I hate a mystery clunk. I’m not totally convinced and sold on any of the steering rack upgrades for our trucks. The slide rack addition and pump seem to be working well for folks though.

 

Check the welds on the rack mounting barrels, I cracked both of mine and the symptom was just like play in the rack.

 

Checked everything in that area. Pulled the boots and you can see the shaft of the rack move up and down inside there by a few millimeters.

 

For what it's worth, it would be a good idea to look for the lightest wheels possible. When I made the jump to 35s from 33s the wheels I chose where 7 lbs lighter than what I had on, the 35s are 5 lbs heavier. So with the new set up with 35s, is right around 2 lbs lighter on each corner.

I did feel a difference the first couple of drives, now I'm used to it. Turning and braking felt easier. The ease of turning really shows up when the truck is stationary, or going super low on the trials.