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Tire Size and Gearing

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47-old-red View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 47-old-red Quote  Post ReplyReply Direct Link To This Post Topic: Tire Size and Gearing
    Posted: 23 Mar. 2020 at 12:16pm
Hi all

So our jeeps, stock, require a 6.00-16 tire.

i really want to go with a 7.00 or maybe even a 7.50 ground clearance and all that good stuff.

but the gearing and little 4cyl probably wont like it...
if hill climbing or passengers are involved, it requires 4 low pretty quick as it is....

I was wondering what you all drive (tire and gearing wise) and how you like it?




thanks!


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Post Options Post Options   Thanks (0) Thanks(0)   Quote RSR_MK Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar. 2020 at 1:10pm
Well I’m running 600’s on two 2A’s, a few with 650’s and an M-38 with 700’s

For the tire performance I like the 700’s the best. Seem to have a better grip ( running NDT for 600 and 700 )

As far as gearing, I like them all, just different reasons. You can putt around in the pasture l little better on the smaller tires. Most of my driving is on the farm and gravel roads close by and the only one with an overdrive has the 700’s on it. I rarely use the overdrive. Would be better paired up with the 600’s. 

Mike

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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar. 2020 at 2:19pm
P235/75R-15's 28.6" tall 9.3" wide on a 6 x 15 wheel 5.38 gears with a 30% ATV OD My engine will be producing more then the factory rating.

Prior build my dads in the early 60's had 8.45 x 15 on stock wheels 28" tall with 5.38's had no trouble doing 60mph +. I drove it in High school for 3 years. Still have the tires and wheels.
Chug A Lug
1948 2A Body Customized
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47-old-red View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 47-old-red Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar. 2020 at 8:47pm
cool thanks!

yeah for some of the logging roads out here i can baraaaarely climb the steep hills in hi-2nd gear
so i cant imagine that changing too much with taller tires.
in 4 low it powers right up in 3rd gear
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Post Options Post Options   Thanks (0) Thanks(0)   Quote jeepsterjim Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar. 2020 at 9:05pm
though not easy nor cheap, if you want to run 7:50's and still need lower gears, convert your T-90 to a T-90C.  Gives you a lower 1st and 2nd gear. pretty much a plug n play.  Check out Novaks on it.  You can use use your existing case even.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote RA472A Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar. 2020 at 11:15pm
I run stock 7.00 on my M38 and 6.00 on the 2A.  Both are great on the rocks and roots of the Naches trail and anything in between.  Neither are worth a darn on snow.  Chains required.  A friend of mine went with the 7.50 's on his M38A1 and not very happy.  Just too big of a tire for that jeep.  I like to think the stock design was pretty much "spot on".  The M38 putted right up Hell's Revenge in Moab just like the other big tire, big rigs.  I do think the 6.50 x 16 Super traction would be a nice fit for a stock 2A/3A though just for the tread design.  I would not trade the bias ply sidewall for a radial at all for mountain trails.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Fltfndr Quote  Post ReplyReply Direct Link To This Post Posted: 23 Mar. 2020 at 11:50pm
If you can figure out the percentage difference in tire height between sizes, you should be able to confirm the change in gear ratios.. If for instance your new tires provide a 10% increase in tire height, your differential ratios will be reduced by that amount. Example:  5.38 ration with tire size increased by 10% results in a 4.38 ratio
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Mark W. Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar. 2020 at 12:30am
Easy peasy just use the Willys Speed calculator


use the stock OD tab to see what a 30% OD will do.

you can also type in your own numbers in the boxes to get more exact results.

For instance with my 28.6" tall tires 5.38's and a 30% OD the calculator tells me in 3rd gear my engine will be turning 2655 rpm at 60mph.
Chug A Lug
1948 2A Body Customized
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Spinnas Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar. 2020 at 7:40am
I run 7.50-16 and it drives pretty good. Recently I went through the axles and replaced everything but the gears and shafts, world of difference cause now it rolls with very little effort. Up next I plan on going through the trans and adding T90C gears like mentioned above for that lower 1st and 2nd gear, along with going through the t-case and adding an OD. When I get to the motor I have a Kaiser supersonic ready for it. I wheel mine and drive it up to 55mph on the road and it will only get better from where I started. Never had it on any big mountain grades but had pulled some hills getting to wheeling spots without trouble.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote drm101 Quote  Post ReplyReply Direct Link To This Post Posted: 24 Mar. 2020 at 8:56am
I run the 6.50 x 16 Super Traxions with stock suspension/engine/driveline/wheels. Turning radius is better with a 6.00. I had to adjust the stops to keep tires off fenders in front. If you run spacers or different wheels your turning radius will be better, but be careful increasing tire size, especially if you like tight trails.  
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BD1 Quote  Post ReplyReply Direct Link To This Post Posted: 25 Mar. 2020 at 9:45am
How are the 6.5 x 16 Super Traxions for general purpose winter driving?  I'm definitely going to need something better for that than the 6.00 x 16 NDTs that are on it now. 
BD
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 25 Mar. 2020 at 11:53am
I run Super Traxion 6.50 x 16 LT tires and have no problem in snow. Ice is always a problem for any kind of tire, so slow down.

My tires don't have a problem with mud as long as it isn't too deep, they don't clean out as well as NDT's in mud.

47-old-red said: "but the gearing and little 4cyl probably wont like it...
if hill climbing or passengers are involved, it requires 4 low pretty quick as it is...."

In my opinion, the 6.50 x 16 LT tire does an all around good job with going up and down street and highway hills regardless of the passenger load with speed of up to 45 mph. Sure, you might have to downshift to second getting up some of the steeper grades, but that doesn't usually happen unless it is a long grade. I generally don't drive over 45 mph and limit my highway driving to short distances so that I don't have a bunch of traffic pile up behind me.

If you are climbing hills offroad, you should probably be in low-range anyway. Stopping to shift to low-range in the middle of a hill climb is a no-no. Too many things could go wrong.

If you run locking hubs my advice is to lock them in when you leave the pavement even if you haven't shifted the transfer case into four wheel drive yet. If you don't lock the hubs in when you leave the pavement, by the time you need four wheel drive, it will be too late.



Edited by SE Kansas 46 CJ-2A - 25 Mar. 2020 at 11:57am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote BD1 Quote  Post ReplyReply Direct Link To This Post Posted: 25 Mar. 2020 at 6:21pm
Thanks for the reply. I am pretty familiar with driving on snow and ice, and up here we lock the hubs in October 1st and maybe unlock them April 30 if conditions are clear. I still have 24" of snow in the yard today.  tDon't even get me started on stories of the Rue de Nord, and north of that, the Le Grande Project road east from James Bay into real caribou country. 
I'm not planning on any "off road" stuff in the winter unless I'm on the 4x4 John Deere with Trygg peg chains. 
The NDTs do OK on unplowed ground with soft earth under the snow. The real issue comes during hunting season when it's still above 0 deg F and we're getting home from the woods driving on hard packed plowed snowy roads. The NDTs can barely make the rise into my garage. IMHO the best tires for winter road driving really don't look at all like "traditional" snow tires. They have longitudinal grooves, no cross grooves at all, lots of siping and rubber that stays very soft, even when it's very cold. My daily driver company truck wears Michelin TX M/3s, and they are the cats *** on snowy paved roads and up to maybe 6" on unplowed roads. They do totally fail at off road with soft earth under the snow. I think nothing of getting in that truck for the weekly 150 mile drive to work on a winter Monday morning, but if I get a foot off the hard surface underneath I am needing a tow.
Ideally I would love a tire that looks like the Super Traxion if it stays soft enough at 0 deg, and even better if it could be studded. There's quite a few traditional "snow tires" that come close, but very few that are listed to go on a 16" rim narrower than 6".  Has anyone had any luck putting something like 215/85R16s on the skinny KH rims? Would I need to use tubes on the KH rims?
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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 25 Mar. 2020 at 7:54pm
Originally posted by BD1 BD1 wrote:

Thanks for the reply. I am pretty familiar with driving on snow and ice, and up here we lock the hubs in October 1st and maybe unlock them April 30 if conditions are clear. I still have 24" of snow in the yard today.  tDon't even get me started on stories of the Rue de Nord, and north of that, the Le Grande Project road east from James Bay into real caribou country. 
I'm not planning on any "off road" stuff in the winter unless I'm on the 4x4 John Deere with Trygg peg chains. 
The NDTs do OK on unplowed ground with soft earth under the snow. The real issue comes during hunting season when it's still above 0 deg F and we're getting home from the woods driving on hard packed plowed snowy roads. The NDTs can barely make the rise into my garage. IMHO the best tires for winter road driving really don't look at all like "traditional" snow tires. They have longitudinal grooves, no cross grooves at all, lots of siping and rubber that stays very soft, even when it's very cold. My daily driver company truck wears Michelin TX M/3s, and they are the cats *** on snowy paved roads and up to maybe 6" on unplowed roads. They do totally fail at off road with soft earth under the snow. I think nothing of getting in that truck for the weekly 150 mile drive to work on a winter Monday morning, but if I get a foot off the hard surface underneath I am needing a tow.
Ideally I would love a tire that looks like the Super Traxion if it stays soft enough at 0 deg, and even better if it could be studded. There's quite a few traditional "snow tires" that come close, but very few that are listed to go on a 16" rim narrower than 6".  Has anyone had any luck putting something like 215/85R16s on the skinny KH rims? Would I need to use tubes on the KH rims?


My reply was directed to 47-old-red, but what you said was very interesting.

Maine would be very interesting to visit but I don't think I could stand the winters. Southern Kansas is about as far north as I like to be in the winter and sometimes that is even too cold.   
46 CJ-2A #64462 "Ol' Red"



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Post Options Post Options   Thanks (0) Thanks(0)   Quote BD1 Quote  Post ReplyReply Direct Link To This Post Posted: 26 Mar. 2020 at 6:21am
OK, I hope I didn't come off as too pedantic. I'm an old fart and opinionated in a few areas :). I've found that a lot of what people think about driving in the snow has little to do with my experience. Tire choice included.  Wide tires do not help in most situations. Temperature plays a big roll as well. I think most folks in the south don't realize that the traction is actually pretty good on snow once you get down around 10 deg F and below.  At -20 a packed snow road isn't that much different than a dirt road, and I can drive through 10" of fresh snow pretty easily. It's when the temps get up around 32 that it can be tough going. 4" of wet snow can be enough to make it hard to get anywhere.

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Post Options Post Options   Thanks (0) Thanks(0)   Quote SE Kansas 46 CJ-2A Quote  Post ReplyReply Direct Link To This Post Posted: 26 Mar. 2020 at 7:05am
Originally posted by BD1 BD1 wrote:

OK, I hope I didn't come off as too pedantic. I'm an old fart and opinionated in a few areas :). I've found that a lot of what people think about driving in the snow has little to do with my experience. Tire choice included.  Wide tires do not help in most situations. Temperature plays a big roll as well. I think most folks in the south don't realize that the traction is actually pretty good on snow once you get down around 10 deg F and below.  At -20 a packed snow road isn't that much different than a dirt road, and I can drive through 10" of fresh snow pretty easily. It's when the temps get up around 32 that it can be tough going. 4" of wet snow can be enough to make it hard to get anywhere.



Hey, I understand perfectly...I'm an old fart too.   
46 CJ-2A #64462 "Ol' Red"



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Post Options Post Options   Thanks (0) Thanks(0)   Quote WillysWally Quote  Post ReplyReply Direct Link To This Post Posted: 26 Mar. 2020 at 12:29pm
Good Afternoon Everyone:

When I look at what tires to run on any given rig, the first thing I consider is the mission or how I will use/drive the jeep or other rig.  For example, if she is going to be a hangar queen -- then by all means what ever she came with off of the dealers lot or factory.  On the other hand, in 2012 we had the absolutely unbelievable experience of participating in the MVPA Cross Country, up and down the ALCAN Highway, which was a very different mission than setting in a garage all day.   

My wife and I drove our 1942 Dodge, WC-53, 3/4 Ton Carryall.  Our son drove the 1945 Dodge, WC-52, 3/4 Ton Weapons Carrier.  I equipped both of the with STA, M & S, 14 ply 9.00X16's.  I choose those tires for three reasons. 

First, on these cross country convoys, the column moves regardless of the weather.  NDT's due to their design have a tendency to hydroplane on wet paved roads.  Second, we were going to spend a significant amount of time on dirt/gravel roads, hence the heavier lug.  We were both also pulling trailers.  Of the 4,100 miles the convoy covered, 1,100 of those miles were on unimproved roads.  And finally, I selected the 14 ply version of that tire vs the standard 8 ply to reduce the number of tire failures or flats.

Earlier in this thread the question was raised whether a 2A drive train would stand the using a larger tire -- i.e. the 7.00 vs the 6.00 X16.  Given the previously mentioned 6.00 was the standard on the 2A and the 7.00 was the standard on the M-38, how do the two drive trains compare with each other?  I believe that might answer the mechanical question. 

With only minor internal differences the engines of both are virtually the same -- L134's  As are the transmissions -- T-90s.  I believe that there is a shaft size difference in their respective transfer cases other than that I believe they both are Model 18's.  That leaves the axles.  Both run Dana 25's on the front.  The 2A runs a Dana 41 on the rear and the M-38 runs the Dana 44.  While there has historically been some discussion as to which is better, they both are, or can be geared exactly the same -- i.e. 5.38: 1's.  My comments in this paragraph are not meant to be a definitive, item by item, comparison of the two drivelines.  I am sure that there are folks on this forum that could write volumes from an engineering standpoint in how they actually differ.  The point I am trying to make is that both drive trains are, for all practical purposes, exactly the same, regarding their form, function and overall performance. 

The bottom line for me is that if the drive lines of both are virtually the same, involving the same/similar components, it would only seem logical that either size would work with little or no impact on the respective drive trains mechanically.

It really comes down to your personal preferences.

Just the random thoughts of 'Ole Fart #3!

Regards,

Walter
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ol' Unreliable Quote  Post ReplyReply Direct Link To This Post Posted: 28 Mar. 2020 at 9:51pm
Ol' Unreliable (the Jeep, not me) wears 30x9.50-15 footgear.  It's got the standard original Go-Devil, T-90A, D-18 X-fer, 5.38 axles.  The Go-Devil has always felt quite peppy wherever I go with those tires.  I have driven it to the FCT 3 times--about 100 miles each way--at around 50 mph without blocking too much traffic.  US 24 is wide enough most of the way so people can pass me easily.  Off-road, the all-terrain tires work as well as any other tires.  I don't drive it at all in snow, or rain if I can help it.


Edited by Ol' Unreliable - 28 Mar. 2020 at 9:53pm
There's a reason it's called Ol' Unreliable
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