1986 K30 Big Dooley in need of bigger tires.

[Countrian]

I just recently bought this 1986 K30 dually 454/TH400 with 3.73 gears. It has a Rough Country 6" lift. I believe it has the stock wheels and tires. It desperately needs bigger tires to fill some of the gap. I've done some searching and seems that it can fit 35" tires. I'm thinking of running 35x12.50 Toyo MT's. Will there be enough room for good flex in the truck? What kind of spacer setup am I going to need to make sure the dually tires don't rub each other or the frame? I'm new to the dually scene and haven't been able to find a lot of info for this specific setup. I'm also on the fence about buying new rims or just keeping the rims on it. I really like the rat hole rim style, but havent found many I really like. I was thinking about running 20" wheels with the 35's. I was gonna take it to a performance 4x4 shop and get their opinion, but I work offshore and I still have 2 weeks. I'd like to get as much info before I get home and take it. Any info is appreciated. Thanks in advance!

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[jmbcary44]

buying 6 or 4? it should make a huge difference on cost. if 6 then get something that will still fit on that rear side by side, I think 35s up front with 6 inches of lift should be fine, I would definitely check the steering and suspension components though as they could be more of an issue than rubbing

edit---just saw you said six so wait for black Friday sales, it will be here soon

nice truck looks very clean

 

[Countrian]

Thanks, it has 27500 original miles. It was an emergency response vehicle for a fire department. Everything looks good up front, real solid. I'm gonna go with all 6 tires. Just not sure how or if I can fit all of that tire on the rear.

 

[68post]

Thanks, it has 27500 original miles. It was an emergency response vehicle for a fire department. Everything looks good up front, real solid. I'm gonna go with all 6 tires. Just not sure how or if I can fit all of that tire on the rear.

Any pics of the big guy with new skins yet ?

 

[bucket]

If nothing has happened yet, you will need about a 3 inch spacer on the rear. Dually trucks look great with all that meat out back too!

 

[68post]

They don't get traction without a posi at all . Duallies are not great on a slick surface in stock form. I had a '85 C30 cab & chassis with a 14' box - even loaded there was no traction ( 2+ ton in box). A Detroit Locker made all the difference.
Whipped my '83 K30 5/4 off the light bad in the snow after installation of the locker.( '83 had : 305's /4.56 gears/no locker/Hi-perf 350 ). Both using a SM465 trans.

I also almost slid backwards down the hill in the snow pushing cars in my 2000 3500HD cab and chassis, (10,500 - empty bed center), it had 6 great straight rib 19.5 highway tires and an open rear diff too. Worst truck ever on snow 'n ice.


( of course - doesn't apply in Miss )

 

[bucket]

Agreed, I've only ever spent time behind the wheel of one dually truck that was actually good in snow. I assume there was a locker of some kind installed. All the others have been not so great, including my own.

 

[CSFJ]

Those 2 extra tires really screw with the available contact pressure between the tire and the ground.

 

[68post]

Those 2 extra tires really screw with the available contact pressure between the tire and the ground.

They sure do, but the '90 3+3 V3500 I just sold did fine in 4wd. It's the 2wd that has such a problem, the '90 had plenty of weight in it and got us out of some tight spots.

I did have a '85 cab chassis box truck that sucked in snow , but a Detroit locker install cured it. (and four aggressive tires to replace 4 very good straight tread tires)

 

[Countrian]

Any pics of the big guy with new skins yet ?

No still no tires yet. I've been working on other upgrades while I search for the right tires. Carb rebuild, Radio and speakers, sound deadening, rewiring the halogens and spot lights, and a Dakota digital gauge cluster.

Now I find myself ready for tires and still no definitive answers! So here I am again to get yall's opinion on solutions I have. Since this truck is a cab and chassis with a 14 bolt corporate rear and Dana 60 front. With 255/85R16 tires, theres about an inch of clearance between the tires and springs and frame on the rear. I really want 900R16 tires to just put on the rims I have now, so I dont have to mess with spacers. I've run across a few tires, but I can't get any good review information. Does anyone have any good real world, first hand knowledge on these tires I have listed? I drive on the road a lot, mostly because the small not so offroad friendly tires I have on it now, but I do tend to take it on the interstate and highways a few hours to events and other trips. Should I go with one of these or 255/85R16 Toyos? ( the small tires have grown on me a little, lets you see how awesome the drive train is! haha )

Tire #1 Michelin, XL 900R16 $2800 for 7 shipped CON= Low speed rating maybe 63 MPH? I like to go fast...
Tire #2 STA, super traxion tread E 900R16 $1800 for 7 shipped CON= Not DoT approved, not sure why...
https://simpletire.com/specialty-tires-of-america-9.0016lt-lt285-tires
Tire #3 Cordovan, Power King premium traction 900R16 $1400 shipped CON= Cant find any good tech data on the tires.
https://simpletire.com/cordovan-9.0016lt-nr50-tires

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Forgot to take a better picture of how close the tires are, and i'm on the rig now.
Thanks in advance!

 

[GMSaint]

Edited by staffBeing disrespectful like that lands you a ban, no questions asked.

 

[89Suburban]

Somebody ban this jackass. I'm not near a computer.

 

[highdesertrange]

boy I would like to see that post. anyhow if it were me I would lower the truck down a little I have a 3.5" lift on my 78 dually and the 255/85R 16 fill the wheel wheels fine. if you put any wider of a tire on you will run into problems with the fronts too. they will rub on the drag link unless you cut down on the turning radius. highdesertranger

 

[Camar068]

Thx for taking care of it Admins.

 

[Countrian]

if you put any wider of a tire on you will run into problems with the fronts too highdesertranger

Yeah, that's why I want to go with the 900R16 which is a 255/100R16 no wider just taller. Just don't want to waste money on tires, that I'm gonna hate.