K5 wheel and tire questions

pigsammy

New member
I am looking for a new wheel/tire set up for my recently purchased 91 k5. It currently sits on 35 12.50 15's. Truck drives ok with these but will need gears soon. There is minor rubbing on the rear inner fender with mild offroading. Previous owner stated the suspension was stock, and I see no obvious modification, but I am not sure.

I am interested in the Kenda 35 10.50 17 tires.

Does anyone know if the Vision D window 17x8 wheels will fit a K5?
( My concern is the backspacing, which is 1/4 -1/2 inch greater than stock 3.5)
Or does anyone have a 17 wheel that works on their k5?

Any input on the Kendas would be welcome also!
 
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nitro_rat

Observer
Any wheel with more backspace than stock is going to compound your rubbing problem on the rear. It will probably cause problems in the front too depending on tires.

If your suspension is stock, you will have two leaves in the front pack and the pack will have "negative" arch (it will be bowed up in the center at the axle). It was possible to order a three leaf HD pack. This pack will also have negative arch. The rear will either be 4+1 or 5+1 with a slight positive arch. It will be really stuffed with 35's and the corners of the front fenders will have to be hacked off to keep it from rubbing when the wheels are turned.

Post up some pics of your setup and I can tell what you have for sure.

33x12.50 15's on 15x8 wheels with standard offset (4.5"?) work pretty good on stock trucks. Trim the front fenders (not noticeable) and don't worry about the slight sidewall rubbing on the inner fender in the back when flexed. A 2" lift will make things better (Tough Country ez rides front and back). You can probably flex 35's with that setup. The 2" springs are about twice as expensive as the 4" ones though.

The Suburban in my sig is on 2" Tough Country HD's (it's a diesel) in the front with a custom pack in the back. Ride is better than stock and the geometry didn't change enough to mess up the steering, etc. Most guys go right to the 4@ or 6" lift but then you have to worry about pinion angle, driveshafts, steering, brake lines, etc.

As far as 17" wheels go, Cragar used to do a "Soft 8" that was available in the correct offset. Not really current on that stuff as the only reason I would run 17" wheels is if I had to for brake clearance. There was a kit you could get to put Hummer H3 brakes on your axle (intended for H3 SAS kits) and that would require a 17" wheel but I never seriously considered it...
 

rayra

Expedition Leader
seconding nitro's remarks. Your limiter is chiefly the bottom edges of the front wheel well / fenders and the tub rub contact at max turn. 33s would work fine and negate the need for re-gearing.

/85 C-10, never put anything bigger than 33s, and usually 31s, never had any trouble, but also didn't off-road it too hard. Was mostly a dirt bike hauler. I put some Rough Country coils and add a leafs on it, got maybe 1.5" out of that. As some RS5000 shocks. All I ever bothered to do to it, went everywhere I needed to go in SW deserts
 

pigsammy

New member
Thanks for the replies!

I'm 3rd owner, first life as a fire dept truck. Primary use is hunting and forest service rd exploration and camping. This truck may move to our cabin in Colorado at some point also. I have an 89 suburban 2500 that I also use this way. Just ran across this and couldn't pass it up. Probably because I stay on this forum too much!

Front springs are 3 leaf and flat so prob HD . Rears are 5+1. The rubbing in the rear was noted to me by previous owner. The paint is barely gone in a small area. Twisting a bit in the ditch reveals a very small contact area at the inside upper tread/shoulder junction. Maybe just lower a bump stop or try zero rates? Should be a minor issue as I don't intend to wheel it hard. Mainly hunt club/forest service rd use.

Previous owner also trimmed lower front of front fender prepping for a bumper that didn't happen. Really not noticeable.

I have always preferred a slightly skinnier tire. They seem to work better for easing along in the mud here (GA) while hog hunting ( not a bogger) and ride well also. My thoughts were also that a 10.50 -11.50 tire would allow some clearance for that rear inner fender. In a 35 these sizes are easier to find in 17's. There are some options in 16 as well while maintaining a 34-35 inch tire. Hoping the larger rim diameter would help avoid tie rod end interference as long as backspace is an extra 1/2" or less. Never had 35's on my trucks, but this one came that way and seems to work pretty well, just needs new tires.Tires are not stuffed too badly.
I will have to get and post pics. That would be much easier.

Truck actually drives well, but overdrive is not really useable with 3.08's. I have a set of 373 axles to go through and put under it. Gear ratio calculators suggest that 4.10's would work well also, and may be preferred if truck moves to Colorado.

I've enjoyed this site and learned a tremendous amount here. Thanks again to everyone.
 

nitro_rat

Observer
I would go with 4.10 or 4.56 if you do something other than the 3.73 axles you have. Maybe swap them in and build the 3.08 axles at your leisure.

What will help your rear tub clearance is wheel spacers or a wider axle. A 6 lug 14 bolt SF out of a 88-98 (GMT400) 4x4 (the 2wd version is same width as your existing axle) will get the rear track width to match the front.

Sounds like your suspension is original and the trim the PO did on the is keeping the 35's from getting mangled by the front fenders. If you check over on ck5 I think I did a fender trim how-to years ago, same user name over there.

315/75r16's run a little smaller than a 35x12.50 and are easier to fit in most cases. There is a 315 in a 17" fitment also (315/70?) that would probably yield a similar result.
 

pigsammy

New member
Pics!
Hope these are helpful.
Most should be self-explanatory.
Worn out, dry rotting 35x12.50x15 Mud Terrains.
The photo of the tie rod end is where I am worried about interference if backspacing is increased and the wheel is moved in. Possibly a larger diameter wheel would move the rim out and clear better? I may just have to order a wheel and give it a try.

The axles i have are 8 lug 14 bolt rears, both 373. One from a 79 4x4 pickup and one under a 97 yukon 4x4.
Front is 8 lug 10 bolt also pre 87 and geared 373.
Other option is regearing the 10 bolts under it now to 4.11. Not anticipating any heavy wheeling use. Current rear is open and would like some type lsd, have had no issues with my other trucks and g80.
 

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nitro_rat

Observer
Have you verified the rear is open? A worn out G80 acts like it's open...

If it is open, I might be tempted to throw some 4.56's and a spartan locker at it. Actually, two spartan lockers!

I can't load the side shot in full size on my phone but it looks like you may have a front add-a-leaf.

I would throw the 2" tough country ez-rides and some 5100's at it. it will sit just a little higher and should help with the saggy rear. You could also do an ORD 2-1/2" shackle flip in the rear instead of the springs. You may have to fiddle with your pinion angle if you go that way.
 

zoomad75

Observer
Looks fairly stock as the suspension goes. Without doing some type of lift the 35's are going to rub up front. Nitro-rat is right on the money for the suggestion of 2" tough country springs and the ORD shackle flip out back.

I'm running 315/75-16 tires with 4" springs up front and a 4" ORD flip out back. The front tires can still rub under full stuff on mine, so they probably will with less lift and the same size tires.
 

rayra

Expedition Leader
Id probably consider some positive offset rims, if you want to stick with that width of tire. But you are correct in mentioning narrower tires. Two ways to deal with mud, flotation or cutting down thru it with narrower tires. But add snow to the mix or slushy roads in CO you'll probably want wider. A bigger contact patch, anyway. Going with the offset will solve the rear well rub, but might worsen contact with the front well rear/bottom lip. There's a couple inches there that can be trimmed back before you reach the footwell.
 

pigsammy

New member
Thanks for the replies. Two of the current tires are in bad enough shape that I'm hesitant to get it far from the house. I have two tires and wheels on the way to replace them so i can use it a bit and see what it needs. I'm going to give the larger 17 wheels and 35x10.50 a shot. I'll update when I know a bit more, but hope that some this works ok and will suffice for now to allow me to use it hunting this winter. Then I can finalize tire size and get regearing completed. If this one goes to Colorado I envision a dedicated set of tires for winter use. I'll seek input on the best tires for that at that time, we don't get a lot of experience in snow here in Georgia!
 

rayra

Expedition Leader
well get a proper rated Mud/Snow tire, so the tread will self-clean. Lot of folks seem to go with 'mud terrain' in general, but they're a lot noisier on the road the 95% of the time you aren't in mud and snow.
Another important thing to consider in your tire clearance issues is leaving room for snow chains. Got to have some clearance for those too. You might really want to come down to 33x10.50. That or start looking into suspension lift options. You'll really need more tire clearance with the fenders and wheel tubs.
 

pigsammy

New member
Excellent point about chains! Our drive comes out on pavement about 1/2 mile from the chain area for La Veta Pass. I'll remember to get tires for winter use that allow clearance for chains, whether it's this K5 or the Suburban that we take out there.
 

jeep-N-montero

Expedition Leader
For skinny tires you have 35x10.50r17, 34x10.50r17, 33x10.50r15, 255/85r16, and a few others, but all of them can be mounted on a 7 inch wide wheel.
 

nitro_rat

Observer
I had 33x10.50r15's on a K10 Suburban for about a week. BFG A/T's. They were really squirmy at all times and downright dangerous in snow/ice. Bought a set of Cooper Discoverer AT3's in 31x10.50 to replace them. The Coopers were excellent!
 
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