Topic: 39.5's on toyota drivetrain

[superyota]

I have had 2 different opportunities to trade my 37'' MTR's for 39.5 iroks.  Both times I have changed my mind because I don't think the toyota drive train will hold up to it, and the truck works great the way it sits now, so i'm not sure if I want to dump a ton more money into it just to run 39's.  Anyone have first hand experience with running bigger than a 37?  what up grades have you done, and what had broke?  I have a 85 reg. cab pickup, 22re, dual stock tcases, 5.29's, spooled v6 rear, and aussie locked 4cyl front, hydro assist, and gusseted top and bottom front axle, and 30 spline bobby longs with hub gears.  
The only other upgrades I can think of without going 1 tons is 5th stud addition, hub studs and dowls, upgrade the outputs, cryo the gears, upgrade rear axles to chromo, and 4.7's in rear case to take some of the stress off everything else.  I'm just not sure if this is all necessary.  I drive my truck pretty hard, and its been holding up great with the 37's.  I don't want to go 39's and start breaking all the time, or have to change my driving style to compensate.  
Any input would be great.

[crazykooter]

Call me eddie.  A built front with longs and gussets will handle them no problem.  The big issue with the 40" tires is steering. 

[superyota [OP]]

Call me eddie.  A built front with longs and gussets will handle them no problem.  The big issue with the 40" tires is steering. 

hey josh, I'm not worried about the front axle as much as the tcases.  I figuered I would have to do the hub kit to add more dowls to it so they don't shear off, and I for got to add I have hydro assist and the front axle is gusseted.  I'm just don't know if its going to take its toll on the duals.

[Dingman.]

I know a couple people who had 42"s on their yota axles. With no real problems, but they arnt the type of drivers who hit rev limiter, while the truck is bouncing trying to make it up an obstacle.

And many many more who have 40"s.  I ran 39.5" iroks in the snow and smashed on it pretty decently never had an issue.

You have a good set of on road/off road tires that should give you plenty of miles.   Dont mistakenly think the iroks will be the same.  My $0.02

[CSR73]

The owner of my old truck switched from the 36" Irok radials I bought to 39.5's.... as far as I know, he hasn't broken anything.  4.88's, Detroits front and rear, 30 spline Longs, duals (both 21 spline 2.28).

40's and 'yota stuff would last for me.  I'm very easy with the skinny pedal.  Comes from wheelin' locked Samurai axles with 33's, I guess.

[superyota [OP]]

yea, thats what i'm afraid of.  I'm not to easy on it, and I like the way I drive and have fun.  I don't want to have to putt around and be easy on it just to run a bigger tire.  If i could could get away with minimum mods like, hub studs, 5th knuckle stud, etc(the cheaper upgrades), i'd do it.  but getting into the tcases again and having to tear them apart and dump money into shafts for them just doesn't sound to appeasing to me right now.

[1980yota]

Just look at the places you normally go to. Ask yourself would the extra inch of ground clearance allow me to go over obsticals I wouldnt be able to go over now? Then decide if you want to do all that is necessary to run them. I personally am going with 38's because I think they will be just small enough to ensure that I wont be breaking every trip and they will give me plenty of ground clearance for the stuff I wheel.

[jrock]

This... again....

Eddie, your driving habits will be fine with larger tires. As long as you fix that hopping problem You will probably break ring gears and pinion before anything else. And you have experience in that Just do it and save your old tires for me.

[Steve_925]

i have 39.5s, had a mini front axle for a while with them. no hub studs, no cromo hub gears, stock out puts, 5.29s, reg 4 stud arms, 3" spacers and drove it very hard. only thing i every broke was the steering arm pin. i've always had an fj80 rear axle so im not sure how long the 8" R&P would hold up. i now have an 80 front axle wich still has an 8" 3rd that been holding up fine. you will def need 4.7s, i use lo lo all the time. my next upgrade is outputs, then im golden.
on another note austin(with the yellow first gen) does 90% of the stuff i do with little struggle on 37" mtrs. my opinion is really dont need 40s on a wheel base like yours

[punchyyoter85]

i have a friend that runns them on his stock axles just trussed, hassent had any problems yet

[twistedtoy92]

It all depends on how you are on the skinny pedal.... I blew both stock birfs in one HARD night of wheeling at the dunes. I wont run my 39.5's till I have 30 spline longs.

[-Jake-]

im running 39.5 iroks.  I've got 30 spline longs and his hub gears, tg's trunnion eliminator and stock dual transfers.  4.7s in the rear case would be nice.  but i havent broke anything yet.  i dont drive like a retard either tho...

edit:
I went from 37s to the 39.5s as well.  if you plan on driving it on the street then stick with the 37s.  I've about decided to make mine a trailer only rig.

[superyota [OP]]

i have 39.5s, had a mini front axle for a while with them. no hub studs, no cromo hub gears, stock out puts, 5.29s, reg 4 stud arms, 3" spacers and drove it very hard. only thing i every broke was the steering arm pin. i've always had an fj80 rear axle so im not sure how long the 8" R&P would hold up. i now have an 80 front axle wich still has an 8" 3rd that been holding up fine. you will def need 4.7s, i use lo lo all the time. my next upgrade is outputs, then im golden.
on another note austin(with the yellow first gen) does 90% of the stuff i do with little struggle on 37" mtrs. my opinion is really dont need 40s on a wheel base like yours

the two obstacles that really bugged me were not being able to make it up soup bowl, which you were there for, and also back door.  I'm not sure if its more the wheel base, bed catching on rocks, or tire size, but i was thinking a larger tire might help.  I'm starting to think I need to be happy with the 37's and look into maybe doing something else to help me out.

[Steve_925]

the two obstacles that really bugged me were not being able to make it up soup bowl, which you were there for, and also back door.  I'm not sure if its more the wheel base, bed catching on rocks, or tire size, but i was thinking a larger tire might help.  I'm starting to think I need to be happy with the 37's and look into maybe doing something else to help me out.

link it!!

[superyota [OP]]

lol! don't tempt me.

[sweetmeat]

you would do fine with 39s. everybody in our club does exactly that. Except me that is I'm busy spending money on everything else besides my truck. But always remember this, the lighter the better

[bigarms23]

how much street driving are you going to be doing on the 39s but i think your front axle should be strong enough for the 39s

[superyota [OP]]

It's not so much the axle's i'm worried about, it's more the tcases and r&p.

[crazykooter]

Your gonna be fine with tcases and r&p's.  If they were set up correctly then your good to go.  Since your on 37s now a jump to 40s is nothing imo.  Dont under est. how strong these toy setups can be.  Just look a marlins old ftoy.  That thing got abused and never broke. 

[jrock]

the two obstacles that really bugged me were not being able to make it up soup bowl, which you were there for, and also back door.  I'm not sure if its more the wheel base, bed catching on rocks, or tire size, but i was thinking a larger tire might help.  I'm starting to think I need to be happy with the 37's and look into maybe doing something else to help me out.

It was your tail!!!!!!!!!!!!!!!!!!!!!!!!!!!!! BOB IT!!!!

[superyota [OP]]

hey steve, is austin's yellow first gen bobbed?

[jrock]

Yes,

[awhotrods]

I just upgraded to 39.5" IROK Radials, sheared a bobby long 30 spline in half driving it on the trailer.  Personally I think toyota axles shouldn't run on anything bigger than a 33" tire. 

[swillbuilt400]

I Have been running 39.5 for about three years on toyota axles and the things I recomend are fifth studs, V6 ring and pinion front and rear and drive flanges.  I think you will be fine with 5.29 and duals.

[superyota [OP]]

I just upgraded to 39.5" IROK Radials, sheared a bobby long 30 spline in half driving it on the trailer.  Personally I think toyota axles shouldn't run on anything bigger than a 33" tire. 

I take  it your packed and ready to go.  let me know what time  you guys are leaving.  we might try to catch you.

[jrock]

I take  it your packed and ready to go.  let me know what time  you guys are leaving.  we might try to catch you.

You can do it.

PS. Those Iroks come with one bias tire. You can't run, or not suppose to run, on the same axle with a radial.

[superyota [OP]]

PS. Those Iroks come with one bias tire. You can't run, or not suppose to run, on the same axle with a radial.

I talked to Rob, he said 4 radials and 1 brand new radial. all are radials.  Yotatough has a set with one bias, but thats not the set I'm talking about.  I'm sticking with 37's.  I like being able to drive hard and have the peace of mind that i'm not going to break something serious like a output.  I'll use my buggy for the bigger tires.

[jrock]

Your buggy on 44" TSLs

[superyota [OP]]

find me a set of 44's and i'll run them.  42's to 44's would be perfect for it.  once the civic is sold, thats what i'm going to start setting money aside for, if I have any after the baby is born

[jrock]

And what of your dad's super cab  Sell the buggy and build the super