This discourse starts with a CJ but quickly moves to cover trucks as well.

Merl wrote: Anybody out there with a stock suspension CJ flatfender and non-stock wheels and tires? I'm toying with the idea of going to a 15x7 or 15x8 wheel and either 30x9.5 or 31x10.5 tires. What I need to know is will the 31x10.5 tires fit without rubbing problems? I've got no plans to do any kind of lift at this time. I am also assuming that the tire width will make a difference in the wheel offset...won't it? FWIW, I'd probably keep my old NDTs and wheels, so with no lift I can switch from modern to stock (and back) as the mood strikes me. Seems like the best of both worlds now that I think about it! <g>

Matt Phillimore wrote: My 48 pickup has 31 X 10.5's on it, with the stock suspension. I think they're pretty similar, but I don't have a CJ, so what do I know? Anyway... only problem I had with them was the left tire rubbing on the badly outside of frame mounted power steering box.

Merl wrote: Thanks Matt. I looked high and low for a pic of your PU in Rick's gallery but I didn't see it. I also heard from 2A owner Arne Anderson, http://weber.u.washington.edu/~arndog/ who tells me the 30x9.5 should fit the CJ very comparably to the NDTs.

I've got another wheel question that those with modern Jeep savy might be able to answer...

I've got a set of later model 15" stock Jeep rims on my parts Jeep with balding radials on them. Does anyone know how wide these would be? I'm wondering if the 30x9.5 radials would fit on these rims... I'm guessing they are 15x6.

Richard Grover wrote: Stock Willys truck wheels are 16x5; wagons had 16x4.5. The later CJ wheels (1970's) are 15x6 and work fine on a Willys pickup (I have some) and probably do fine on a CJ-2A. Also, I have some 15x8 aftermarket wheels, but they are probably too wide. I'm trying to get some decent 16x5 rims so I can go stock when I feel like it.

Stock tires were 16x7.00 or 16x7.50 bias ply (may have even been as narrow as 16x6.50 on some vehicles). If you still have the 16" rims, you can still get these tires for about $90 each, which is cheaper than radials.

There are pictures of 31x10.50's on the 15x8 rims on my truck - A1 in the Gallery. They stick out past the fender and throw lots of mud, on those rare occasions when I can find it in Arizona. I have mounted 31x10.50's on the 15x6 rims, but they look a little too wide for that rim. You can also find 30x9.50 radials that are a good fit on the 15x6 wheels. My brother is running them on his 62 Scout, which also has the 5 on 5 1/2" lug pattern.

BF Goodrich makes a 33x9.50 that my friend at Discount Tire is trying to get me to try. He doesn't have them in stock, but can get them. I said I'd bring the Willys down with some of the 15x6 wheels. He'll mount them up and put them on the front. If they rub the steering, I walk away, but if they don't, he expects me to buy a set. Heck, if they work OK, I want them. Keep my belly up off those rocks.

Rick www.public.asu.edu/~grover/willys

PS. I know the original question was about CJ-2A, but they had the same tall narrow rims and tires originally, so this may be relevant. Also, this may be of interest to other list members with Willys other than 2A's.

If you look through the Gallery, you can see lots of narrow tires on stock rims. You'll also see several rigs running wider tires like 31x10.50's. I apologize to the CJ-2A, 3A & B, etc. folks, I only collect Utility vehicle pictures. There were already a bunch of CJ sites when I started mine and there wasn't a decent Utility vehicle site on the whole web. Tom Wanamaker started the Willys Internet Truck Club about the same time as I started my site.

Rick LeBlanc wrote: I had LT 7.5x16's with stock springs on my 2a before I tore it to smithereens (spell check going berserk). Almost 30" tall with no additional mods required. Of course these were on the stock skinny wheels. The unsprung weight of 15x7" rims and 31" tires might be too much for the stock springs and shocks. Try 6" alloy rims, with a little negative offset to help turning radius, and 30x9.5" radials. These are fairly large tires in person, Goodyear MT's almost look stock if you put the letters inside.

MVP The Herb Farm wrote: Sorry Merl, if this thread is straying a bit. I just picked up a like-new set of 32x11.5 radials and I am now looking for some used steel wheels, I was thinking 15x10 (would 15x8 work?) with the 5 on 5 1/2 pattern for my '53 Wagon with SOA. Anyone tried this??? Want to burst my bubble??? If I'm going to rub when not going straight, is a wheel spacer available/advisable as a cure? I know braking power is going to be reduced with this set-up, so I'm keeping my wimpy tires for hwy traveling. Any comments/advice is appreciated.

Frank Sanborn wrote: I have a set of 32x11.50-15 BFG AT's on 15x8 wheels and they fit just fine. Right now they are on my '76 CJ-5, but I have had them on my CJ-2A with stock suspension. They work fine going down the road, but rub during full-lock when turning and would rub if you got "crossed up" off road.

D. Blackner wrote: Hey guys, I am very curious as to your reasons for wanting bigger tires. I have the original 16 in. wheels and am planning on keeping the skinny tires. This way the speedometer will be right and there will be less friction, thus better power and milage. What are the advantages to having big tires other than the big foot look?

Merl wrote: In my case it isn't so much for the larger tire, its for a *modern* tire (read that as steel belted radials). The tires I'm considering, 30x9.5(15"), are actually very close to the diameter of the 6"x16" NDTs that came stock on it so my speedometer will still be accurate. My goal is for a stock-ish Jeep that I can take on trail OR street, and be able to flat-tow halfway across the state at 60-70mph without worrying about the tires. If my only intended use was slow off-road, I wouldn't be worried about it and I'd have *retread* NDTs. I think a lot of it is the intended use combined with personal preference. There are a lot of folks that pay big bucks to get that "big foot" look for no good reason other than its just what they wanted. Call me indecisive, but I like both looks. Its the functionality issue that's pushing me towards the radials.

Jerry Adams wrote: That was my consideration as well - I wanted tires that are easy to find and buy at a reasonable price. I wound up writing a small program that let me investigate the effects of tire size on drive force, motor RPM, road speed, etc. for my '2A. I did a lot of "spade work" finding actual manufacture's data for the rolling radius, circumference, revolutions per mile, etc. Lots of fun, really. I came up with 235-75R15 as a good compromise for size that is readily available. Because of the repairs I made to the frame, I don't do really serious off road stuff, and they work fine for what I do. Serious off-roaders will undoubtedly want something different, and the full up restorations would of course want the 16" "grave digger" tires.

On the subject of lower gears, Turner sells an input shaft and cluster gear (they must be purchased as a set) that gives first, second and reverse gears in a T90 about 19.2% lower ratios than the ones that came stock from the factory. I had to rebuild my transmission, transfer case and both axles, so I had ample opportunity to make changes. Because I do drive my jeep on road quite a bit, I wanted to have a setup that let me drive on the highway at a reasonable motor RPM, but still be ample for the modest off road work I do. After a great deal of number crunching, I came up with the following:

TIRES: General Grabber AP radicals in size 235-75R15 on 7" wide rims.

AXLES:

Front - Spicer 25 with 4.27:1 open differential.

Rear - Dan a 44 with 4.27:1 open differential (money was a problem)

TRANSMISSION: Wagner T90A with special input shaft and cluster gear to give a 19.2% lower ratio in 1st, 2nd, and reverse.

TRANSFER CASE: Spicer 18 with the "large" intermediate shaft.

The above gives me about the same performance off road, but a much lower engine ROM in third (high) gear for better on road use:

GEAR RATIO TABLE

REMARKS: CJ2A with original factory configuration.

AXLE RATIO: 5.86:1 TRANSFER CASE LO: 2.460:1 HI: 1.000:1

TIRE SIZE: 6.00 X 16 TIRE DIAMETER: 28.0 INCHES REVOLUTIONS PER MILE: 720.29

ENGINE RPM AT 55 MPH IN HIGH RANGE 3RD (HIGHWAY CRUSE): 3869.1

MAX ENGINE RPM: 4000 MAX SUSTAINED RPM: 3600 MAX TORQUE AT: 2000 RPM.

After the rebuild, the numbers look like this:

GEAR RATIO TABLE

REMARKS: Jennifer Jeep

AXLE RATIO: 4.27:1 TRANSFER CASE LO: 2.460:1 HI: 1.000:1

TIRE SIZE: 235/75 R15 TIRE DIAMETER: 28.9 INCHES

REVOLUTIONS PER MILE: 697.86

ENGINE RPM AT 55 MPH IN HIGH RANGE 3RD (HIGHWAY CRUSE): 2731.5

MAX ENGINE RPM: 4000 MAX SUSTAINED RPM: 3600 MAX TORQUE AT: 2000 RPM.

Most of the above is self explanatory, with the possible exception of the column labeled "Drive Force at Max Torque" This is the data that will probably be of the most interest to jeepers. I used the published data for my "Go Devil" motor, which gave the maximum torque as 105 foot-pounds at 2,000 RPM. From this, it is easy to calculate the torque available to a single shaft that has the total gear reduction of the differential, transmission and transfer case for all of the possible gear combinations. This is the value given under "Axle Torque at Max Torque." (The max torque refers to the torque available from the motor - ie 105 ft lbs.). In the real jeep, this torque would be divided and available at either two or four wheels, but for the sake of making the calculations easy, the table assumes all of the output from the system would be applied to a single "axle" shaft.

The "Drive Force" is derived by dividing the available torque by the rolling radius of the given tire, and is the actual force in pounds that it would take to exactly counterbalance the axle torque with a lever of the same length as the rolling radius. This is the amount of force available to drive the vehicle forward or backwards. Note that this assumes a tire with 100% tractive effort, ie one that never ever slips or spins. As we all know, tires do slip, and there are a good number of jeepers who have spent a lot of money on locking differentials, limited slip differentials, etc. in a effort to minimize tire slip. However, no locker or other device that does not add a gear reduction to the chain can provide more driving force than the above calculations. Also, no provision is made for friction losses.

The "Max Sustained RPM" is an arbitrary value picked by me as what I would use for a "red line" with my motor. I seldom let it get that high, as it sounds like the poor little flat head is about to pop off the block about then. I try to drive with the motor RPM at about 2,000. Yes, I did install a tach...

From all of the above gibberish, it is shown that I can cruse down the road at a much lower RPM than stock, but I am paying only a small penalty in (about 2.6% less in Low Range First Gear) terms of the "Drive Force" that is available to push my jeep along.

Well, that's what I went through in selecting the tires and ratios for my jeep. It was a lot of fun! I hope some of you find this helpful, or at least interesting.

Merl wrote: Once again, Jerry comes up with an interesting and in-depth post. Couple of questions...

I thought the 2A's original axle ratio was 5.38:1. I'm curious where you found the figure of 5.86:1.

My NDTs are 7.00 x 16 and the diameter measures at a little over 29", so accounting for tread wear I figured it was classified as 30" tire. Do you know how the diameter measurement is taken? Is it taken mounted and inflated or otherwise? If the measurement mechanism is the same today as it was 50 years ago, the 30x9.5 tires would actually put my chassis 1" taller than stock? Cool.

I'm curious to know how your L-head performs in 3rd gear in high range. Comparing the stock numbers in combination with a 25% overdrive, this should provide a TOTAL MULT of 4.395 in 3rd gear hi-range, where yours is 4.27. I know that my L-head struggles when I'm doing 55 (in OD) up a long overpass, and shifting out of OD changes my ratio to 5.38, er-ah 5.86 which is usually enough to get me over the top at a reasonable speed. (Using 5.38 for the axle ratio puts the stock+OD 3rd gear ratio at 4.035, noticeably lower/weaker than your modified configuration.) What I'm getting at is do you experience any big disadvantage on the road with your ranges spread out over just 3 gears?

Jerry Adams wrote: Oh, dear... You caught a big fat typo!!! Strange I never noticed it, as the information I sent out was the basis for all of my decisions about tire size and ratios, etc. I re-ran the numbers. Here's the data for a '2A with the correct axle ratio:

GEAR RATIO TABLE

REMARKS: CJ2A IN STANDARD FACTORY CONFIGURATION - CORRECTED AXLE RATIO!

AXLE RATIO: 5.38:1 TRANSFER CASE LO: 2.460:1 HI: 1.000:1

TIRE SIZE: 6.00 X 16 TIRE DIAMETER: 28.00INCHES

REVOLUTIONS PER MILE: 720.29

ENGINE RPM AT 55 MPH IN HIGH RANGE 3RD (HIGHWAY CRUSE): 3552.2

MAX ENGINE RPM: 4000 MAX SUSTAINED RPM: 3600 MAX TORQUE AT: 2000 RPM.

And, again for comparison, the final values for my jeep:

GEAR RATIO TABLE

REMARKS: Jennifer Jeep

AXLE RATIO: 4.27:1 TRANSFER CASE LO: 2.460:1 HI: 1.000:1

TIRE SIZE: 235/75 R15 TIRE DIAMETER: 28.90INCHES

REVOLUTIONS PER MILE: 697.86

ENGINE RPM AT 55 MPH IN HIGH RANGE 3RD (HIGHWAY CRUSE): 2731.5

MAX ENGINE RPM: 4000 MAX SUSTAINED RPM: 3600 MAX TORQUE AT: 2000 RPM.

With the correct axle ratio, it now seems that I have slightly *more* drive force (about 6%) available with the new configuration than with the original.

Thanks for spotting the typo... Strange, but I never caught it before!!!!

Jerry Adams wrote: I converted my jeep to 12 volts so I could mount a winch. I got a 0-4000 RPM tach from J. C. Whitney. All of the tachs in the local parts houses went up to 8,000 RPM or more. Since my little flat head red lines at 4,000 RPM, that meant that half the range would be wasted. When I saw the low RPM tach in JCW, I ordered it. I have been more than satisfied with it, and the readings I get from it agree very well with the calculations I made regarding gear ratios, tire sizes, etc. I can calibrate my speedometer courtesy of the local California Highway Patrol. They have a little trailer that they park by the side of the road that has a radar unit attached to a *big* LCD readout. It displays your speed as you approach it. They use it as a gentle reminder. If you see the trailer parked someplace, better start slowing down, as the police will be there in a few days handing out tickets.

I used the trailer to find out my true road speed for a couple of indicated speeds on my speedometer. After that, I was able to compare the known speed with the tach readings. This helped to verify my calculations for the tires, axle ratios, etc.

As to whether or not a 12V tach would work on 6V, it all depends. Most of the analog tach circuits I have seen use some form of integration to determine how far up the needle goes. To cut out the technical stuff, I would expect that such a circuit would not read accurately on a 6 volt circuit. Some of the digital tachs use an analog integrator followed by a digital conversion stage, and they would probably not read right either. Sorry, but I don't know much about how the different gages are implemented, so I have no recommendation beyond checking some catalogs. They use to make 6V tachs, as I had one on an old WM300 once. Unfortunately, it took an external mercury battery as a reference, which kept running down. Finally I neglected to replace the battery for too long, and the "juice" got into the innards, ruining it.

Chad Welch wrote: Jerry: I wish I had your head, w/cold, and you had a better one. There are several of you out there that can really humble a guy. Any way, several E-MAILS ago some one wrote about a shaky/wobbly front end. I let my alligator mouth get a head of my humming bird a__ and said "Ya mine does the same, I just don't drive it over 40 mph. Well fortunately several of you said no way my front end is tight regardless of speed and you can balance tires with or without tubes. So, I have replaced my tie rods, ends, tubes, etc. I purchased new 600x16 ndt tires a couple of months ago(I didn't replace them). My front end is TIGHT now cost less than $100.00 w/shipping(Turner 4x4). I also found a guy that balanced my tires with what looked like a 60's vintage Snap-On spin balancer(I offered to buy the thing on the spot, no luck but I'll try again:-)). Spin balanced the tries ON the jeep. My little jewel runs like a top now. Moral of the story: Listen to the folks on "Willys Tech" and heed the quote by Mr. Royce at the end of Jerry's notes!!!!! Thanks for keeping my head out of the sand!!

Kevin Dorris wrote: Hello, What common wheels fit the Willys bolt pattern? Jeep? What years? Ford?.Thanks.

Dave and Robin Samuelson wrote: Well, from what I have heard, it's a 7.00x16 tire/rim and the bolt pattern is 5 on 5 1/2, which is ( I think, due to my research ) common to all willy's / Jeep vehicles. So, in theory, the wheels from my 47 '2A would fit an 85' CJ, 94' wrangler, 98 TJ, Cherokee, GC, and so on. If anyone knows different, then please correct me.

Frank Sanborn wrote: You're close- The 5 on 5 1/2 wheels will fit up to an '86 CJ. YJ, XJ, MJ, and ZJ all use (I believe) a 5 on 4 1/2 wheel. The Full size Jeeps used the 5 on 5 1/2 wheels until about '74 or so, when they switched to a 6 bolt wheel, like a Chevy truck. You also have to be careful because you could get a Ford wheel that is 5 on 5 1/2, but has a smaller center hole, and it won't fit over your hubs, even though the bolt pattern is correct.

Richard Grover wrote: The wheels from a mid-seventies CJ will be 15X6. These will fit a little better on the Willys truck than 15x8's. I traded my 15x8's to a guy for his 16x5's. Different strokes for different folks.

James Roney wrote: Yeah!!! I just got the 16.5 x 8.25 Hummer wheels mounted up with 33's for my CJ. You gotta love those beadlocks. :) I highly recommend that you "try before you buy." Wheel widths, offset, tire bulge, and overall height is a matter of personal taste once you deviate from factory stock. If you see something that you like, copy it exactly, and you'll be happy.

Chuck Pedretti wrote: Just spent last night trying to remove the wheels on my 46 CJ2a, strangest thing the wheels on the right side came off easy got to the other side and all the nuts were froze (I thought). After breaking a couple of sockets and getting nothing but stud spin, I decided to quarter the nuts with an air wheel to get them off. After cutting 8 of them off completely I came to an interesting discovery (try to contain the DUHH's) all the studs on the left side were reverse threaded. Are there any other reverse threaded parts I should know about? I am new to working on vehicles this old (it's got 23 years on me) is this normal? Thanks

Jeff Gent responded: Standard issue for old rigs is left handed studs on the drivers side. Some long ago disproved theory that this helped prevent the lug nuts from coming loose. You can put on right handed lug bolts to avoid this issue in the future. By the way, those little grooves in the side of the nut are the standard indication that this is a left handed nut. You'll see this on almost all gas (propane, acetylene, natural gas) fittings.

James Roney wrote: The lug nuts on the left hand side of the Willys are certainly left hand thread, but I'd be cautious of that "long disproved theory" part.

The theory behind needing LH threads on the LH side is sound, but the application has become unnecessary with the advent of the modern "safety center" wheel. If you take the time to examine the hub ring of any modern stamped steel wheel, you will notice that there is a relief stamped into the flange which deforms elastically (like a spring) when loaded. This deformation allows for minor deflection of the wheel flange without having the self-loosening effect that occurs without it.

This "long disproved" theory was still in application in 1986, and can be seen on the left rear (only) of the F250 w/ DANA 70U. Keep an eye out for Big-rigs with Budd wheels too. Many of those are still LH. (interesting that newer 60 degree conical lug aluminum wheels are OK???)

...bottom line: If you intend to run the original wheels, keep the LH wheel studs, or else check them often.

Scott Little wrote: My truck was missing many lugs and lug nuts, when I was surveying to see how many replacements to purchase I noticed some of the lugs had L's stamped on the end and some had R's stamped on them. Did I get lucky or do others have the L's & R's also???

James Roney wrote: I'm going to try to explain this in words, but without pictures it's more difficult. Try to imagine that all of the lug nuts are loose. In that case, only the bottom of the nut would be in contact with the wheel. Now apply the torque in the dominant direction and see which way the lug nut wants to turn. To accelerate, on the LH side of the Jeep, the axle turns CCW. Since the wheel flange is pushing against the bottom, the nut will want to rotate CW. If that makes sense, then you need to remember that braking forces are vastly higher than driving forces, (especially on the front of a 2wd car!)

As to the tapered axle-shaft, they are both RH thread, put you will need a puller even after you take off the big nut. Behind the nut is a tapered axle with a single square key. The key is primarily for alignment purposes, and will shear if the nut is not properly torqued. You'll need to remove those flanges in order to properly repair the brakes. (meaning the 11 inch self energizing ones) There's another thread going on about that one!

Matt wrote: Ok, I could use some measurements, if anyone is willing to make a couple quick ones. I'm trying to figure out if the FC ones will work. Nothing too detailed is needed quite yet. I really just need to know how far out from the bed it is to the mounting surface.

Rick Stivers wrote: Matt, Sorry it took me so long to reply but I've been a little busy. I measured the distance from the bed to the outside edge of the tire carrier and it was 8 3/4". If your going to make a tire carrier, make sure that it has the proper clearance for whatever tires and rims you are running. My truck is running 235/75R15s and the tire clears ok but much larger and I would be rubbing on the fender and bed rail. I believe rim specification (backspacing) would be just as critical as the tire size. Sometime in the past the previous owner moved the tire carrier forward 1 1/2" and down 1 1/4". I think he did this so he would have better visibility over the tire through the side-view mirror. If you need more specific measurement let me know. I was thinking an old brake drum would be a good start for a homemade tire carrier. Rick S.

PS. I use the tire carrier as a storage space for some tow cables. Coiled up they fit over the carrier and the tire holds them in place.

Tom Lee wrote: Hello Willys fans, A few months ago I posted that I had an inner tube failure on my 2a with the original 16" rims and NDT tires. The rubber tore at the base of the valve stem. I had purchased those tires and tubes from Carl Walck only 1 year earlier and had never exposed the valve stems to any hazards such as off- roading. My 2a is a parade queen and seldom leaves the garage. I thought it was an isolated failure and hoped it would not happen again.

I have since sold those tires and wheels to Dave Hatch and upon shipping them I noticed another valve stem was starting to split. I now believe that the valve stem tears because the rubber at the base of the stem is too thin and the valve stem does not fit snugly in the hole in the rim. I am installing another set of original wheels and tires and this time I bought just the tires from Carl and I bought the inner tubes from Phil Nelson's Surplus. The inner tubes from Phil were $10.00 ea. (Carl's were $6.00) and the valve stem is much thicker at the base and fits snugly in the hole in the rim. The tubes from Phil are stamped Goodyear, the tubes from Carl are not. Carl has been very sensitive to the problem and has offered to refund my money after I send him the failed tube. :)

In summary, look for tubes that have Goodyear stamped on them or tubes where the valve stem fits snugly in the hole in the rim. Man, there is nothing worse than walkin' out to the Willy with a few minutes of free time, ready for a little ride, and find a flat tire. Feeling like I just finished an argumentative essay for that Technical Writing class in college.

Ronald L. Cook wrote: Not so much in defense of Walck's but as a matter of fact, you must have a tube in which the valve stem fills the stem hole in the wheel. New production tubes mostly are made to retrofit in tires mounted on tubeless tire type rims, which have a smaller diameter hole for the valve stem. If you use these tubes, you must have the adapter that slips over the stem prior to installing the tube that completely fills the hole. And it is a matter of fact that the older style tubes be they Goodyear or other brands were much stronger at the base of the stem. Usually doubled at least out to about an inch and a quarter diameter. Just some info from experience for all on the list. I would also buy the $10 tubes myself.

David H. Hatch wrote: The narrow ones that Tom Lee mentioned are here, narrow, no taper, too small for the rim hole... http://netnet.net/~oslc/cj2a/tubesmll.JPG

I bought a new tube at a farm supply store here for $5.95, not Good Year, and it has the tapered stem...    http://netnet.net/~oslc/cj2a/tubebig.JPG

Ben Page wrote: Tom, If you're fitting the tubes without using a rim "gaiter" and a "valve protector" then no matter what tube you're using you'll have trouble. I can appreciate your frustration but I use tubes all the time. (As an aside - it's a foolish practice to go anywhere in the Outback with tubeless tyres. They're more trouble than they're worth. But that is another story<smile ) So mate, fit them properly and I doubt you'll have any troubles. If you'd like to send me a private "e" (this thread may not interest most people) please feel free to do so. All the best