J10/20 Project Question - Tires / Wheels

[Miltrucks]

Getting back into anther FSJ project after being away from the hobby for awhile (military trucks)

Have an 82 J10 that I am converting back to a J20 Quadratrac setup (D60/44 8 lug)

Planning on dropping a Detroit in the rear 60 and a TrueTrac in the front 44. Looking at a 4" lift.

Question: What is the best tire/wheel combo to run with this and what is the 8 lug bolt pattern / backspacing? Looking at going with probably 33x12.5 tires. I am assuming 16.5? (there were no rims on the axles I bought from the local yard)

Primary street with light offroad use.

Any thoughts, opinions, ideas, information would be appreciated.

Thanks,

Eric. (aka Miltrucks)
www.MilitaryOffroad.com (http://www.MilitaryOffroad.com)

[J10/J20 Project]

Not sure the back spacing on the rims sorry.
I think that would be a great combo for lockers if you wheeled it more. For an occational wheeler I would just throw in a couple Power-Trax lockers unless your doing the regearing yourself and saving some big money.
Are you going to run the part-time kit in the T-case?
You will also need the pre 80's down pipe for the exhaust. for the switch in the drop of the front driveshaft from driver to pass. drop.
33 not sure about I'm running 245/75/16 now but will do a SOA soon so tire size should go up to about 35's

[jode]

I have a 76 J20 - it came stock with the 16.5 wheels

I haven't measured backspacing yet.

I intend to try to run 15" rims on it as nobody has yet come up with a satisfactory reason why it wont work. Everyone says that the front rims will hit the steering arm or something, but that doesn't seem to make sense since the front is just a standard D44. The rear 15s will fit over the D60 drums from everything I have heard. I'm not trying to be stubborn on it, but I just haven;t heard a single (explained in detail) reason why 15" rims wont work on a J20 axle.
If you can go 15" rims, the selection of used tires is WAY larger. Finding a used off-sized tire could be difficult.

Also, I dunno if J10/J20 Project know something I don't about your project, but you shouldnt have to deal with swapping differential sides unless you are swapping a late J20 drivetrain into a early J10 truck or vice versa - just find a J20 that matches your differential and you are good to go.

[J10/J20 Project]

Jode,
I think the 15's won't clear the calipers. The (J20) rotors and hub's are about a 1/4" bigger than the standard 44's.
On the models he stated an 82's truck with a 70's drivetrain the 80's where drivers drop diff and center rear. The Q/T set up is Pass. side drop and about 7" offset to the right in the rear. For this he will need a Y pipe from a 70's model to clear the driveline from the exhaust. When I did my swap I went with the Dana 20 also a pass. drop as the Q/T so all I had to do was swap the bearings, hub and rotor over.

[jode]

OK - I didnt see where he had stated that he was swapping the stuff into a 70s rig. You are correct that in that situation, he needs extra work done. Sure would be easier to Originally posted by jode:
just find a J20 that matches your differential and you are good to go.So if the 15's won't clear the bigger calipers, all I need to do is use the calipers, rotors, etc off my 76 wag on the 76 J20 axle right? And then I am good to go?

[J10/J20 Project]

The calipers are the same. The backing plate's are just a bit bigger also with the rotor's and hub and bearing. So I'm not sure it would work without trying it first hand.

[ November 29, 2003, 08:08 PM: Message edited by: J10/J20 Project ]

[jode]

Are you saying the rhubs and bearings are different too?
Strange, cuase whenever anybody getsinto the "what's the diff between the D44 HD and the D44" topic, the answer always seems to be that there is really no difference. Seems to me like not being able to run 15" rims, along with differnet rotors, hubs, bearings, etc is a pretty big difference...

[J10/J20 Project]

there is nothing different in the axle housings between the J20 and the J10 there the same part #. except the 6 lug vs 8. The difference between the 2 are the J20's have a different backing plate, bigger bearings, and different hub and rotor being bigger and 8 lug. If you have a J20 already just jack up one side then find someone with a 8 lug 15" bolt it up and see what happen's.

[ November 29, 2003, 08:41 PM: Message edited by: J10/J20 Project ]

[Bob Barry]

The smaller rotors won't work with the larger 8-lug J-20 front hub.

I'd suggest going with a set of 16" rims; the selection for this size in that range is pretty extensive, though the sizes are sometimes given in Metric (i.e. 275/75-16 or something like that).

[Elliott]

You didn't say you were going to wheel hard, but all the same if you're dropping some money on tires and rims you should know that on a 16.5" rim they have a different bead design and if you air down it will break a bead easy.

[Miltrucks]

Great discussion here guys. Thanks for all the feedback.

To try to clarify a couple of points....

The vehicle is an 82 (360, 727, 208, with a front 44 and rear 20). I am putting the drivetrain from a late 70's J20 (401, TH400, QT, 60 rear and front 44)

Exhaust is a custom dual setup from the manifolds back to I don't think there will be problems with the pass side TC output.

Current diff is driver side on front and center on rear (think its a 727/208 setup). Going to Quadratrac will require a pass side front diff and the rear offset 60. The axles I am putting in were from a late 70's QT unit, so no problems there.

I have heard of the differences on the 44 vs the 44HD just being different on the outer ends. Mine is already set up correctly, so I am just keeping it 8 lug.

Am not going to do the PT conversion on the QT - leaving it FT 4WD. I have a couple of vehicles with the FT setup and IMO it's one of the best setups that I have found. Only thing better is a 6x6 :)

I mentioned only light off-road use. I have a Grand Wagoneer (6" lift, 35's, Detroit/TruTrac, QT, 44's, 401) that I have for severe off-road use. And when that get's stuck I can go get it with my 5 ton military Wrecker. This will be for farm use and light duty towing (under 10K lbs).

Sounds like the biggest question is still the wheels. 16" or 16.5". I don't really like the design of the 16.5s due to the bead lip issue, but I don't have any experience with civilian 16". Is that design like the 15 or the 16.5?

Anyone running aftermarket wheels on their rig (8 lug) that can share experiences?

Keep the discussion coming!

Thanks,

Eric. (aka Miltrucks)
www.MilitaryOffroad.com (http://www.MilitaryOffroad.com)
www.Ohio4x4.com (http://www.Ohio4x4.com)

[joe]

Depending on the year but most J20's could be had with either 16 or 16.5 wheels. I would stick with 16's because it leaves you open for more tire options. 16.5 wheels and tires are an odd size today with limited choices.

[Bob Barry]

The 16" tire has a safety-bead like the 15" tires. I'm running that size civilian rim with my military XML.

[jode]

Thanks to all the contruibutors for finally clearing this mystery up for me. I kept on getting one line answers as to why the 15" rims wouldn't work, and, pardon me for being a cynic, I just couldn't buy into it without some actual data to support it. Now I know - thanks.

So Bob - what is the overall diameter of those XMLs you are running? And where is a good source to pick them up - and what size/backspacing are you running on those civvy rims?

[Tad]

iirc Bob's site says they are 38x13's on 16x10's, not sure on the backspacing.

[Bob Barry]

Well, I just got a TSL 38.5"x15.5" 16.5" tire as a spare, and it is noticeably smaller than my 325/85-16's. So I'd say that the XML works out to be equivalent to about a 39.5"x15.5" Super Swamper. It measures an even 38" tall with worn tread, and 13" even across the tread.

[jode]

So who sells Michelin XMLs?

[Bob Barry]

Ah; there's a number of canadian surplus tire stores that do, if you're not interested in paying the $750/tire price that they get for them through Michelin tire dealers. Of course, there is the discount they offer to members of military vehicle clubs; in which case, the price is only $380/tire. See the following link for details:

http://www.garbee.net/~cabell/michelintires.htm

http://www.garbee.net/~cabell/photos5.htm

http://www.d-90.com/tire/mich.html

[jode]

Thanks for the links bob

Phew :eek: - nice and cheap :(