Tires are getting old... time to make some decisions (3 Viewers)

[COS80]

I've read a million threads and spoken to some vendors and installers, but I'd still like some direct input from owners. I bought my 97 with the intent to run bigger tires, and I intend to regear, so the tire fitment has to be gotten right. It came with a 2" Iron Man lift and 33" tires, and it works well; however, the tires are eight years old and starting to harden, so it's time to finalize my plan.

Here's some more specs that are probably germane to the discussion:

1. Brakes - new calipers, rotors, EBC Greenstuffs, ABS & LSPV deleted, extended hoses
2. Caster bushings and sway bar extensions
3. Rear Whiteline extra-HD sway bar, factory front
4. Supercharged

I'm mostly narrowed down to 37s with 3.5" Dobinson VT springs and something to move the front axle forward (radius arms or the Red Line axle relo plates). Why 37s? Because I've read 100 posts from people saying they regretted their 35s and wished they'd done 37s, and I have found circumstances, more than a few times, where a taller tire would have made a big difference, so I see their point. The goal is to fit those 37s with the least amount of lift and no fender cutting; to set it up to reliably run just about anything but the most extreme trails. The truck weighs 2,800/3,100 lbs. front/rear. I'll do all the necessary supporting mods, like drop brackets, control arms, RCV axles, etc.

Here are my remaining questions:

1. Can less than 3.5" lift accommodate 37s with no trimming and absolutely no tire interference with the body?
2. What 17" wheel specs would be best, assuming a 37X12.50? I've tried and tried to find the answer to this question with no luck.
3. Is hydraulic ram steering required for 37s, or is the 105-series sector shaft upgrade sufficient?
4. Are 37s actually a step too far to maintain factory-like reliability? Put another way, what else is necessary to run 37s without sacrificing reliability?

On the other hand, are 35s actually the "sweet spot", as I've also seen stated 100 times? If so, how little lift can be gotten away with for 35s with the same restrictions as (1)? How much of that "extra" stuff needed for 37s is unnecessary for 35s?

 

[TXMeatball]

I have OME J springs with a 20mm spacer in front. Think it's 3.5"? From my research that's kind of the minimum you want for 37s. Articulation will be limited from the tires stuffing the wells. Need extended bump stops. Body lift would help.
Think the biggest cost for 37s that isn't included (typically) with 35s is having to regear. My friend has an 80 with slinky on 37s; still factory 4.10. Useable, but would not recommend for something you'd drive regularly. I've taken mine across the country with factory gearing/35s and don't have many complaints.
What you'll need for 35s and 37s regardless: Adjustable front panhard, caster correction (radius arms or drop brackets), rear adjustable panhard or panhard bracket. And all the other stuff like extended brake lines, sway bar drop brackets, etc.

 

[baldilocks]

Going from 35” to 37” tires made a very noticeable difference in all facets of drivability on and off road for me. On road it feels more sluggish and heavy. I was pleasantly surprised at the off road performance difference that just one more inch of tire between the ground and the truck can make with regards to getting hung up. Also the larger radius of the 37 helps to smooth out the lumps and bumps makes it less dramatic popping up onto ledges and also the larger foot print.

Unless you drive your 80 every day I doubt you would ever know whether or not 37’s cause more wear and tear to the point of increased maintenance frequency or degraded reliability. If you are a wheeler then maintenance and longevity of parts is a different ball game anyway.

37’s and the 3.5vt’s were made for each other it seems as they are a popular combo. As for no sheet metal contact, proper bump stop tuning will handle that.

All 37’s are not made in the same mold therefor wheel back spacing can be a subjective subject…… I ran 37” super swamper trXus MT’s on stock 80 wheels using a 1” spacer behind the 8” wide wheel effectively giving it a 3.5” backspace. This worked great with a 2” bump stop drop because the tire, although having a 12.5 section width, only has 9.5” wide tread which makes for a rather rounded shape that would tuck up into the rounded inner front fenders nicely.

My tires needed replacing and due to COVID I was unable to find more of these trXus MT’s for sale anywhere so I bought a set of Mickey Thompson Baja MTZ in 37x12.5r17 and bought 4 beadlock wheels in 17x8.5r17 with 3.5” backspace. The wheel set up was basically the same as the stock wheels with 1” spacer but due to the fact that this new tire has a wider tread and much more square shoulder I lost at least and inch of up travel because the tire would contact the fender under the right conditions during hard compression. This forced me to drop the bump stops further.



If you plan to do some moderate to advanced (but not insane) rock crawling a few times per year or deep mud and snow the 37’s will be appreciated enough to out weigh any of the “negative” affects of running a bigger, heavier tire on the road.

It seems like you are aware of the extra bits, including a front DC driveline, that will be required when stepping up to the taller lift and 37’s so I won’t go into that.

A 37 will contact the front fender lip directly rear of the tire without longer arms or the redline relocation plates. But since you’d be lifting taller, a set of the proper delta arms would solve three issues in one swoop. You may get away with no trimming of the rear fender lips if the trailing arms are stock length. If your rear arms are longer than stock then it’s likely that minor trimming of the fender lip directly behind the tire will be necessary due to tire to sheet metal interference under full or near full compression. I can tell what my experience has been but you will still be into some hours of fitting and fussing trials.

Hydro assist is very nice off road especially on bigger rocks. The hydraulic cylinder also acts as a very good steering stabilizer in fact too good for over the road driving. On the road my steering feels numb. There is basically zero feed back from the road and the steering wheel needs a little help re-centering after a turn. At idle the 80 series PS steering pump doesn’t put out quite enough pressure and flow to call the steering “good” but just off idle all is good. I’d only do hydro assist if your rig see’s tough rock crawling and not too many road miles per year unless you are a knucklehead like me and are willing to put up with the on road short comings to enjoy sweetness off road even if you really only need it a few times per year. I think the 105 sector shaft is up to the job on it’s own from a strength standpoint. The hydro assist would be for the extra assist.

If you have not reinforced your frame at the steering box and front track bar mounting point it would be a good idea to do so before you go out there with your newly set up rig and start enjoying her new potential that encourages you to go further and try harder trails. The hydro assist does relieve this area of some stress but reinforcements are still a good idea because eventually cracks will happen.

 

[BuzzAZ]

I went back and forth between 35 and 37 and landed on 35’s. No real noticeable difference on road between the 35 and 33’s they replaced - if anything it drives a little nicer. Off road the extra clearance has been nice and the 2” Dobi lift has worked perfectly. You have more width options with 35’s (10.50, 11.50, 12.50, maybe more) whereas the 37’s that I was looking at were all at least 12.50. Lastly, going over 3” of lift seems to have the potential of opening up a can of worms, and I just didn’t want to deal with it. The reality for me is the 37’s weren’t going to take me anywhere the 35’s won’t.

 

[residualboulders]

I went with Dobinson's 2 1/5" VT Springs and 35s. Ride quality was great. It was very sluggish with 35s. I regeared to 4.88 which was a really nice improvement. Loved it with that setup, but it was so similar to my 200 build. So, I decided to mix it up. 37's went on last week.

Current set up:
Dobinson's 3.5" VT springs
MRA Shocks
Delta VS Sway Bar Drop Kits
Delta VS Panhard Drop
Iron man control arm drop bracket
Icon 17" Rebound Pro Wheels
Spidertrax 1.5" Spacer
Longer Toyota brake lines
Yokohama Geolander G003 37x12.5R17

No rubbing at all with daily driving. 3.5 VT springs are a bit firmer but it still rides really nice. I suspect once the snow melts and I can get it out on some trails I'll be needing to trim some of the flare inside the wheel well. We will see. These tires mounted with weight on them measure around 36.5.

 

[COS80]

Going from 35” to 37” tires made a very noticeable difference in all facets of drivability on and off road for me. On road it feels more sluggish and heavy. I was pleasantly surprised at the off road performance difference that just one more inch of tire between the ground and the truck can make with regards to getting hung up. Also the larger radius of the 37 helps to smooth out the lumps and bumps makes it less dramatic popping up onto ledges and also the larger foot print.

Unless you drive your 80 every day I doubt you would ever know whether or not 37’s cause more wear and tear to the point of increased maintenance frequency or degraded reliability. If you are a wheeler then maintenance and longevity of parts is a different ball game anyway.

37’s and the 3.5vt’s were made for each other it seems as they are a popular combo. As for no sheet metal contact, proper bump stop tuning will handle that.

All 37’s are not made in the same mold therefor wheel back spacing can be a subjective subject…… I ran 37” super swamper trXus MT’s on stock 80 wheels using a 1” spacer behind the 8” wide wheel effectively giving it a 3.5” backspace. This worked great with a 2” bump stop drop because the tire, although having a 12.5 section width, only has 9.5” wide tread which makes for a rather rounded shape that would tuck up into the rounded inner front fenders nicely.

My tires needed replacing and due to COVID I was unable to find more of these trXus MT’s for sale anywhere so I bought a set of Mickey Thompson Baja MTZ in 37x12.5r17 and bought 4 beadlock wheels in 17x8.5r17 with 3.5” backspace. The wheel set up was basically the same as the stock wheels with 1” spacer but due to the fact that this new tire has a wider tread and much more square shoulder I lost at least and inch of up travel because the tire would contact the fender under the right conditions during hard compression. This forced me to drop the bump stops further.

If you plan to do some moderate to advanced (but not insane) rock crawling a few times per year or deep mud and snow the 37’s will be appreciated enough to out weigh any of the “negative” affects of running a bigger, heavier tire on the road.

It seems like you are aware of the extra bits, including a front DC driveline, that will be required when stepping up to the taller lift and 37’s so I won’t go into that.

A 37 will contact the front fender lip directly rear of the tire without longer arms or the redline relocation plates. But since you’d be lifting taller, a set of the proper delta arms would solve three issues in one swoop. You may get away with no trimming of the rear fender lips if the trailing arms are stock length. If your rear arms are longer than stock then it’s likely that minor trimming of the fender lip directly behind the tire will be necessary due to tire to sheet metal interference under full or near full compression. I can tell what my experience has been but you will still be into some hours of fitting and fussing trials.

Hydro assist is very nice off road especially on bigger rocks. The hydraulic cylinder also acts as a very good steering stabilizer in fact too good for over the road driving. On the road my steering feels numb. There is basically zero feed back from the road and the steering wheel needs a little help re-centering after a turn. At idle the 80 series PS steering pump doesn’t put out quite enough pressure and flow to call the steering “good” but just off idle all is good. I’d only do hydro assist if your rig see’s tough rock crawling and not too many road miles per year unless you are a knucklehead like me and are willing to put up with the on road short comings to enjoy sweetness off road even if you really only need it a few times per year. I think the 105 sector shaft is up to the job on it’s own from a strength standpoint. The hydro assist would be for the extra assist.

If you have not reinforced your frame at the steering box and front track bar mounting point it would be a good idea to do so before you go out there with your newly set up rig and start enjoying her new potential that encourages you to go further and try harder trails. The hydro assist does relieve this area of some stress but reinforcements are still a good idea because eventually cracks will happen.

This is an excellent post, thank you!

My truck doesn't get used much on the road, but it does get driven to the trail, and will continue to be, so I am willing to give up street manners for trail performance, but it has too remain streetable. When I said "reliability" I meant more from the point of view of "doesn't break down any easier" than the wear and town point of view.

Your experience with backspacing: was the spacer necessary or would that have solved your issue with the newer, wider tire? I understand they were different wheel - theoretically.

On steering: Would you say the hydro assist is something that can be delayed for down the road, or is it a necessity and a part of the initial plan?

 

[COS80]

A thought occurred to me today: if 35s will fit with my current lift, I could do 4.88 gears and probably actually improve driveability, and get ~8 years out of the setup; then when it's time for the next tires, do the new lift and 37s, and add underdrive gears in the transfer case. What I found, with the quick search I did over lunch, was 10% underdrive gear, which would take 4.88s to 5.36s. Is that noticeable over 5.29s?

I guess I could also consider just tires for now, but is that hard on these transmissions? I assume it causes premature failure, just like it does in other makes.

I'm waffling because I'll either have to lose the roof rack or rebuild my garage with taller doors to go straight to 37s. Dammit.

 

[ajax1]

I have ran 37s since 08 I would look for a lighter weight 37 over a heavy weight. Do 5.29s or don’t do 37s. I run my truck on i70 all the time able to pull most hills and normal road at 70 to 80mph. Not a race truck but I do pass people. Learn to kick out of overdrive and let her rev before you climb a big hill. On back space I have done 4 and 4.25. If you run stock you might run into rubbing on inner arms in sharp turns. Also stay with 12.50 for easier fitment.
I run 4 inch lift combo of slee rear springs front are Dobinson flexi, bumpers, winch, slee front arms Dobinson rear upper and lowers, slee steering rods, you will bend stock rods in 37s if you wheel, brake lines, 5.29s, arb air locker . Cv front shaft normal rear. Wheels now are Hutchinson double beads and mounting Mickey Thompson Baja boss mt.
If you are going to buy a lift I would look at the slee kit you need all that, and get an idea.
On the steering box I would tell you to upgrade to the 105 when you can, if you keep the front unlocked and don’t force it to turn you shouldn’t have issues, it is when the steering gets bound between a rock and you try to force it to steer. That has been my experience, when I have the truck jammed I don’t force it to steer I let it go and once tire is free then steer.
You also prob want rcv axles up front if your wheeling. The rear stock seem to be pretty tough, the unlocked axles don’t have the twisting issue with arbs. If you have stock lockers carry extra shaft, and mod the one you have installed.

 

[77mustard40]

Not to take a thing away from 37’s but I decided to build for 35’s knowing I would be DD’ing the truck for a few years. Dobs 2.5” VT’s and IMS shocks, DVS 4” arms, DC front DS, pan hard lift bracket, hoses and bump stops, bumpers, winch, sliders and skids. Still with 4.11’s but gears / TC gears up next. Gets to wheel a few days a year and leaves me with a smile every time. Yeah I could build a better wheeler but it’s point and shoot as it is, and great everyday rolling around town.

 

[baldilocks]

This is an excellent post, thank you!

My truck doesn't get used much on the road, but it does get driven to the trail, and will continue to be, so I am willing to give up street manners for trail performance, but it has too remain streetable. When I said "reliability" I meant more from the point of view of "doesn't break down any easier" than the wear and town point of view.

Your experience with backspacing: was the spacer necessary or would that have solved your issue with the newer, wider tire? I understand they were different wheel - theoretically.

On steering: Would you say the hydro assist is something that can be delayed for down the road, or is it a necessity and a part of the initial plan?

If you are thinking and asking questions about this now and the thought of waiting 8 more years doesn’t nauseate you then you either aren’t very desirous of the new set up or you have a train load of patience. Haha

My axles are geared 4:88 and I ran 37’s for about six years before I installed the under drive gears. Underdrive gears made a very noticeable difference but I can’t comment on comparing to 5.29’s. I’m sure the difference would be negligible. Rumor has it 4.88’s might have a bit stronger pinion gear due to it being slightly larger……

I wouldn’t be concerned with transmission wear unless you plan to run it 50k miles per year. At this point of concern, a guy could be talking himself out of building a fun, capable 80.

You wouldn’t be the first member to raise his garage door opening height, so don’t think it’s a ridiculous concept. Mine happens to be 8 ft tall.

Look at hydro assist like icing on the cake. I was getting by without it and never broke or twisted the stock sector shaft but the frame and track bar bracket did develop several cracks. Once the hydro assist was in service on my 80 I knew there was no going back though.

 

[COS80]

If you are thinking and asking questions about this now and the thought of waiting 8 more years doesn’t nauseate you then you either aren’t very desirous of the new set up or you have a train load of patience. Haha

Worse... got my wife involved in the discussion.

 

[mudgudgeon]

Worse... got my wife involved in the discussion.

You're only interested in making the truck safer right.

Right?

 

[mudgudgeon]

If you are thinking and asking questions about this now and the thought of waiting 8 more years doesn’t nauseate you then you either aren’t very desirous of the new set up or you have a train load of patience. Haha

This.
If 8 years in 35s sounds reasonable, stick with 2" lift and 35s

You're doing less mods, going to stir up less issues with mechanical and handling. So, safer, and less abnormal wear and tear.

The truck will have more manners on road ( with appropriate caster correction) on 2" lift vs 3.5-4" lift. (Ask baldilocks how many rigs he's tipped over).

My cruiser was on stock suspension with 33's until fairly recently. I stuck 2" springs under it before shipping it to US. I haven't done caster correction yet, definitely will. Just that change competent charged thef road manners. It went from being a Cadillac that was relaxing and easy to drive, to being something that needs constant steering input and concentration. Something I'd hesitate to let my wife drive.
I've had 4" lifted rigs before with good caster correction, and sorted suspension, and they still fit that second description.

35's, sliders and a winch will get you anywhere 37's will, just maybe not with the same bragging rights, and mall / rigs n coffee cred.

 

[COS80]

You're only interested in making the truck safer right.

Right?

This all got kicked off because she ran a tire over to the shop for me, and the guy told her, "hey, tell your husband these tires are 8 years old so they're about due for replacement."

I was --->| |<--- this close to ordering parts, and then the price tag came up, and now the period of debate and bargaining is upon us.

Evidently, raising the garage doors is the wrong kind of remodeling.

 

[COS80]

This.
If 8 years in 35s sounds reasonable, stick with 2" lift and 35s

You're doing less mods, going to stir up less issues with mechanical and handling. So, safer, and less abnormal wear and tear.

The truck will have more manners on road ( with appropriate caster correction) on 2" lift vs 3.5-4" lift. (Ask baldilocks how many rigs he's tipped over).

My cruiser was on stock suspension with 33's until fairly recently. I stuck 2" springs under it before shipping it to US. I haven't done caster correction yet, definitely will. Just that change competent charged thef road manners. It went from being a Cadillac that was relaxing and easy to drive, to being something that needs constant steering input and concentration. Something I'd hesitate to let my wife drive.
I've had 4" lifted rigs before with good caster correction, and sorted suspension, and they still fit that second description.

35's, sliders and a winch will get you anywhere 37's will, just maybe not with the same bragging rights, and mall / rigs n coffee cred.

Let me clarify this "eight years" business... I'm assuming new tires would last me approximately what these current tires are lasting me, although they were owned by someone else for six of the eight. I'm going to have no choice but to buy new tires sooner than later - probably this year. If I buy new tires, I'm stuck - I'm not selling a set of barely-used, $2,000 tires for $400 after a year or two to upgrade to what I really want... it'll just have to wait. So I'm trying to concoct a "Plan B" that I can live with, that gets me where I want to be in a while longer, but with relatively the same end game. I'm also on the hunt (wasting my time, I'm sure) for a used set of 33s that aren't ready to be turned into cattle waterers, to try to buy a little more time.

This thread has pretty much convinced me that I, too, will be firmly in the "I regretted the 35s and had to change to 37s" camp. Right up until this:

Ask baldilocks how many rigs he's tipped over.

@baldilocks How many rigs have you tipped over?

Is a 3.5" lift high enough to be prone to tipover?

 

[mudgudgeon]

The comment about @baldilocks tipping rigs was slightly tongue in cheek because of his long running rebuild thread.

Is a 3.5" lift high enough to be prone to tipover?

Any lift raises the COG and increases the likelihood of a rollover on or off road .
If suspension is not fully dialled in, stability in an 'oh s***' moment can be badly compromised.

There's loads of posts on mud by guys with lifted rigs that have rolled on road but they live in denial on the contribution 4, 6, 7" lift had in these incidents.
We get complacent and have rose colored glasses with these things. Lots of us drive trucks that we would be nervous about letting our wife drive it. This is a truck that has been compromised.

I love the idea of 37s, they look sweet, but the realist in me says 37s would be a benefit in maybe 2% of all the driving I'm ever likely to do, and create too many compromises with the vehicle in lots of ways, too many mods.

Stock suspension and 33 on my current rig took me everywhere I wanted to go, and places lots of people wouldn't contemplate. On a previous rig 2" lift and 35s have taken me some crazy places, and ALL the places I went in an earlier rig with 4" lift and 35s.

Not trying to talk you out of anything, just being devils advocate

 

[mudgudgeon]

Quality tires can be good for 50k+ miles

 

[COS80]

The comment about @baldilocks tipping rigs was slightly tongue in cheek because of his long running rebuild thread.



Any lift raises the COG and increases the likelihood of a rollover on or off road .
If suspension is not fully dialled in, stability in an 'oh s***' moment can be badly compromised.

There's loads of posts on mud by guys with lifted rigs that have rolled on road but they live in denial on the contribution 4, 6, 7" lift had in these incidents.
We get complacent and have rose colored glasses with these things. Lots of us drive trucks that we would be nervous about letting our wife drive it. This is a truck that has been compromised.

I love the idea of 37s, they look sweet, but the realist in me says 37s would be a benefit in maybe 2% of all the driving I'm ever likely to do, and create too many compromises with the vehicle in lots of ways, too many mods.

Stock suspension and 33 on my current rig took me everywhere I wanted to go, and places lots of people wouldn't contemplate. On a previous rig 2" lift and 35s have taken me some crazy places, and ALL the places I went in an earlier rig with 4" lift and 35s.

Not trying to talk you out of anything, just being devils advocate

I appreciate it. I expect there's a cutover point, like anything else, where you go from marginal risk increase to not-so-marginal, and i would have expected it to be higher than 3.5". I accept the marginal risk, but if 3.5" is "above the line", then the 37s plan is out.

 

[ikarus]

I'm in the "35s are the sweet spot" camp for now. Just easy. I would personally go 35s and start slowly making the previously mentioned modifications for 37s slowly and be ready to swap them out for 37s in the future. And take note of trails where an extra inch of clearance make or break your ability to finish the trail.

I threw on 35s with nothing more than a simple 2" Dobinsons lift and have since been adding everything I would need to run 37s.. extended brake lines, Delta 3L arms, Delta panhard bracket etc.

Even with 35s I need to space out my bumpstops a little because I get some rubbing at full stuff.

My observation over the years is that most guys who went big on lifts have scaled them back to find the sweet spot between a low center of gravity and enough ground clearance to wheel it. Seems like 3-4" is a good place to be.

 

[mudgudgeon]

I appreciate it. I expect there's a cutover point, like anything else, where you go from marginal risk increase to not-so-marginal, and i would have expected it to be higher than 3.5". I accept the marginal risk, but if 3.5" is "above the line", then the 37s plan is out.

I don't think there's any clear line where a lift becomes too much. The risk ain't going to be linear either.
The whole package is important. Springs, shocks, caster, pnhard setup, sway bars set up.