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kyle cj5

New Wheels and Tires for a 1967 Jeep CJ-5 Restoration

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Hey Moses

I am in the process of restoring a 1967 jeep cj5, I have replaced the drum brakes with disc front and back. I now would like to put new wheels and tires on 

I purchased a AR23 16x8 wheel and slid it onto the front axle all looked ok until I turned the wheel in ward and noticed I would not have enough space for 

any size tire. It looks like any new tire would rub on the suspension spring. Could you help me with what I am missing?

 

Thanks!

Kyle Cj5

 

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Hi, kyle cj5...The three wheel concerns involved would be rim width, rim diameter and the rim backspacing.  If you're trying to achieve the equivalent of OEM Jeep 16" wheels from the day, those rims were a maximum of 6" wide.  (Willys/Kaiser era Jeep rims were as narrow as 4.5" or 5" in 16" diameter.)   In general, Jeep 4x4 tires of that vintage were only 6.00 or 6.50x16, never larger than 7.00x16.  (7.50x16 was for heftier GVW vehicles, not Jeep CJs and lighter 4x4s.)  

Note: A stock 1967 Jeep CJ-5 Universal four-cylinder model came standard with 6.00x16 tires on 4.5"x16" rims, for a total wheel/tire diameter of only 28-inches!  There were slightly larger 5" x 16" optional wheels for 6.50x16 tires.  V-6 models used 5" to 6" wide by 15" diameter wheels.

These were closed knuckle, narrow track width front axles.  The traditional (late 'sixties forward) aftermarket oversized tires, fitted on a vintage Jeep CJ chassis, were on 15" rims.  Tires were typically 30" or 31" diameter with a maximum 10.5" tire width on an 8" wide x 15" diameter rim.  These steel (often chromed) aftermarket rims had negative offset (shallow backspacing) and used Jeep-type centers with the correct size center hole.  

Tidbit:  Earlier than this, some converted to 15" wheels, using Lincoln 5-on-5-1/2" type 15" wheels with their center holes cut larger to clear the Jeep wheel hubs; on these applications, a tire size was chosen to fit the chassis and springs; sizes like 6.70 or 7.10 x 15 were common.  Jeep CJs of your vintage often had 7.00x15 light truck type Goodyear Suburbanite tires.  My folks bought a '64 Jeep CJ-5 new that came stock with the optional Goodyear Suburbanite 7.00x15 tires on 4.5" x 15" rims. 

With a closed knuckle front axle, wider 15" aftermarket wheel and tire sizes could also rub the springs at the left and right extremes.  One solution has been setting the stops for the steering knuckles so that the tire will not rub.  I've done this when the adjustment was only minor, but the down side is less turning angle and a bigger turning radius.

You'll need to decide how much steering turn angle you are willing to sacrifice in the interest of bigger tires.  A wheel style with more negative offset (shallower backspacing) will help, and that is a typical solution for fitting oversized tires on a leaf spring 4x4.  Again, the classic 8" wide X 15" aftermarket wheels for a Jeep CJ with a full-floating front axle had negative offset or shallower backspacing.  This increases track width and also pushes the wheel rim section away from the springs for greater clearance.  You could accomplish this with narrower 16" wheels and the correct backspacing.

Note:  Some use wheel spacers between the wheel hubs and wheel rims to create a wider track width and provide more tire-to-spring or frame clearance.  I avoid using spacers and prefer getting wheel rims with the right diameter, width and backspacing to safely fit a suitable, safe tire size.

To solve your problem, you will be taking wheel sizes, backspacing depths and tire sizes into consideration.  I would sacrifice as little steering angle as possible if you decide to readjust the steering knuckle stop screws.

I encourage others to jump into this topic with their personal experiences and specific suggestions on tire size/wheel designs that will work safely...Keep in mind that this is a 1967 Jeep CJ-5 with a closed knuckle Spicer front axle.

Moses

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Moses, Haven't quite wrapped my head around backspacing and offset when it comes to wheels. Looking at 2 different wheels first has a back space of 3.75 with a -19 offset. The second one has a 4.03 backspace with a -12 offset. Its my understanding that the 1st one would be better for my 66 cj5 because it pushes the wheel out form the springs, hows the offset come into play. Looking at 15 x 8 with 5x5.5

Thanks

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Hi, Monty...Yes, you do need to be concerned about tire clearance at the springs on a vintage Jeep CJ.  The shallower backspacing (3.75" or less provides more negative wheel offset) would be preferred for your application especially in a wider 8" rim width.  4.03" would be for late model Jeep applications with unit hub wheel bearings.  Make sure the 3.75" negative offset is ample enough, these wheels typically fit '76-up CJs. 

Here are wheels that specifically fit your Jeep CJ although a quick look at the specifications does not indicate the backspacing:

https://www.quadratec.com/categories/jeep_wheels/steel_wheels?f[0]=sm_wheel_size%3A15x8&f[1]=sm_wheel_bolt_pattern%3A5 on 5.5"

I would dig deeper into the wheels offered at the link above.  Pick a wheel you like and go to the manufacturer's website to determine backspacing specifications for that particular wheel.  Ultimately, you should ask your tire store to trial fit the wheels/tires before buying them.  Most stores, like Discount Tire where I trade, will be price competitive or match the pricing on wheels.  The tire size/width/diameter is the wild card.  Typically, the vintage Jeep vehicles were candidates for 30" x 9.5 x 15 tires on a 7- or 8-inch wide rim.  Beyond this may require a 2" lift for 31" x 10.5" x 15.  Try the wheel/tire package before committing.  I've had success with modern 31" diameter range radial LT tires on a 16" x 7" rim size.

The real issue is your tire/wheel combination and whether the diameter and tread width of the tires will clear the springs.  With your Jeep's full-floating front axle and stout rear axle bearing support (semi-floating with Spicer 44 stamina), you have little concern beyond the tire clearance at the front springs and the amount of acceptable stick-out from the fenders.  One issue with closed knuckle axles is the modest caster angle, which makes the steering axis inclination different than the post-1975 CJs.  When possible, I add positive caster angle to my early Jeep front wheel alignments.

Cycle/twist the axles with a floor jack to make sure tires will clear over the range of wheel travel and lock-to-lock steering.  If tires steer into the springs very slightly, one solution is to reset the axle/steering stops at the steering knuckles.  This reduces the front wheels' turning angle and the vehicle's turning radius, so it must be done prudently.

Keep in mind that any increase in tire diameter will demand a speedometer correction.  This can be done by changing the speedometer drive pinion at the transfer case.  Tooth count on the speedometer pinion determines the speed readout.

Let us know how this turns out for your 1966 Jeep CJ!

Moses

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