The Stovebolt Site Forums The Shop Area Driveline Those dang tire size one more time.

Here we go again. It used to be easy, but now 65 years later, trying to determine what
width, aspect ratio, tread design will look and work good on a Stovebolt is a real pain in
the ars. There doesn’t appear to be any one chart that will convert the original
recommended size of tire to a modern size. And when you don’t have a recommended
tire size that makes it even harder. Looking at the original tire size in the owner’s manual
and resto pack, draws a blank. The only base size given for this particular truck is 15-6
which only tells me it’s a 15” rim and it’s a 6ply tire.

In addition my old 3604 is never gonna haul anything more than a sheet of plywood or
bag of groceries so I don’t need 6 or 8 ply rating which translates to a rough rider, which
by the way is what I’ve been trying to escape from for the last ten years.
Choosing a tire for your ride is, in my case at least, a one shot deal. Once I put a grand
into rubber I can’t afford to discard them and go looking for a tire that’s better suited to
my needs. In other words, it’s gotta be right the first time round.

The question is, has anyone ever figured this out?????


dg

Denny;

Here is a chart that may help.

Vintage Tire Chart

The "15-6" in your owners manual may refer to a 15" diameter rim with a 6" width.

SimS

Probably a nominal width rounded up to the nearest inch, since
the original rims were 5.50".

With the half dozen different themes that the tire industry
has gone thru over the past 60 years it's really muddies the
water, and I'm not sure if I have it figured out yet.

Parts manual lists a 7.00x15 and 7.50x15 for the 3/4-ton
trucks thru '54.
Those were not standard sizes that the tire mfg's offered.
6.70x15, 7.10x15, 7.60x15, would have been standard sizes
back in the 50's.
Almost every conversion chart has a different interpretation
of what the original tire size should be converted to.

I'm pretty much convinced that the brand is gonna be Michelin
and since I have no intention of ever hauling a load with
this truck ever again so I really don't need a 'D' or 'E'
rated tire, but an LT A/S tire looks to be about the best
choice.
I have thought about a Passenger rated tire also but haven't
looked at any specs.
The Michelin LTX A/S in a 225/70R16 seems to be about as close
as I can come to the correct size if the Ford rim will accept
it.
And once more, this truck will never see mud or snow, very
rarely be in rain for more than a few minutes and a sheet of
plywood or bag of salt will probably be the biggest load it
will ever see. What I'm looking for now is ride and highway
comfort.

Denny Graham
Sandwich, IL

Denny,
I feel your pain! That's why I started a thread in the one tons about the Excelsior tires. Yesterday I stopped in a rim manufacture to see about making a 19" rim for my truck. I came up with that measurement by the true diameter of my 17" rim with the bead and lock ring. I'm going to take an old 17" rim to him and see what they say. I know a lot of truck enthusiast would be interested in a period looking tubeless rim that would have the same overall diameter as the old rim and bias ply tire. Reaching for the stars but you never know until you ask

Denny, 7.00x15 and 7.50 were 6 and 8 ply light truck tires in those days. 6.70x15, 7.10x15 and 7.60x15 were 4 ply passenger tires. A 1954 Chev would have come with 6.70x15 a Pontiac with 7.10x15 and an Olds and Buick with 7.60x15. A Caddy would have had 8.20x15. We sold BF Goodrich in those days and I changed a jillion of them on an old Henderson manual tire changer.

Life was simple on those days and people just couldn't believe that we often had over 100 tires in stock.

Ok, that explains it. I always dealt with car tires for the
cars that I owned and when I was working in the Sinclair station.

Now, can you tell me what sort of Michelin for the highway
would come close to looking about the same as those 7.50x15
tires that were the base tires for the AD 3604's?
I was hopin' Bill would jump in here cuz he's worked in the
trade just up till recently.

DG

I'd personally go for a 7:00-15 Denny. I think that it being a bit narrower makes for easier steering at slow speeds. If you where hauling a load maybe the 7:50 would be appropriate. I don't see the need for a wider tread width. Just my 2 cents worth.

I agree that you don't need more width. I would discuss it with a Michelin dealer...not a bunch of kids at Walmart with all kind of certification patches. I have run these on a Jeep Cherokee parts runner. I would think that our parts runner gets about the same kind of use your pickup sees. Only a little more power. Its the last year of the 4 Liter 6.

http://www.michelinman.com/US/en/tires/products/defender.html

In Europe they have a 205 80R15, but I don't think they are available here. They stand up a little taller than the 70 aspect.

I now use a Jeep Cherokee with 16". As soon as the whatever name tires get a little more worn, I'm gonna buy Michelins for it. I have Michelins on my Town and Country as well as my 2015 3500HD.

In the Defender this appears to be all that is available:
205/60R16 25.7"
215/65R16 27"
235/65R16 28"
I want the tallest tire that still looks right for the 3/4-ton
truck. I also need that with my 4.10 gear if I'm gonna keep
up with traffic.
The Cooper 8.75/r16.5 Lt (why were they still using the old
pre-1965 number system?) tires look correct for my truck.
Also, the Power King bias ply tires that I first used on the
truck were 7.00x15 mounted on the split rims with tubes and
flaps.
Looking at the two numbers would suggest they were different
diameter tires yet they are both about 30" tall.
http://www.pbase.com/dennygraham/image/160943154

So, after much research on Michelin tires, I've found that
none are made that will give me the narrow tread. There are
no series 80's. There are series 70 and 75 available that
will give me the 30 inch tall tire that I want but the width
is much wider than what I've got on the truck now.
I've zeroed in on about a half dozen which I have to compare
then try to find a dealer that will get them for me.
There are two passenger tires, P245/70R16 just differnt load/speed ratings.
Then there are six Light Truck tires, LT225/75R26E and
245/75R16E just with different load/speed ratings.
I need to download the sheets on them to see what the tread
patterns are on them, haven't got time now.

I'm just about to throw in the towel and give Corky a call
to see what he can come up with.
dg

Denny, My 2 cents also. I had p255 70 16 on my 3600 . They were on 16x8" rims they were 30 " tall and at the time I still had the 4:56 rear. Recently I was able to get a 4:10 and swapped the rims to the 8 lug fords 16 x6" and mounted p215 85 16 on them. same height 30 " I looked around for something less than 8 ply in that size but didnt see them. They steer nice but ride rough. I usually haul 6 bales of hay and 3 feed bags so I dont need the 10 ply either. good luck in your search.

Denny, I'm confused. Are you looking for 15" tires or are you looking at 16" tires for your Ford Wheels. If you are looking for 16", I think 215 is about the narrowest you will find in a Michelin SUV tire. 8.75R16.5 is not an old size. It is a truck tire designed to run at 80 psi. A 16.5 tire will not fit a 16" wheel. In fact it will have a warning on the sidewall stating that it will not fit a 16" wheel.

I will probably be putting 215 70R16 on my Jeep pretty soon. I would rather have 205 but 215 will work.

215 is about as narrow as you'll find in any truck tire these days, except maybe for s few hard to get oddball LT sizes in 195 and 205 for 15" wheels for the panel version of the Dodge Caravan.
The 8.75R16.5 isn't necessarily old, but it is obsolete as far as a common truck tire size. It's almost impossible to get a 16.5 tire anywhere without special ordering it anymore.

I'm confused Ken, did I post somewhere that I was using 15"
rims? I thought I'd made it clear that the Ford rims were 16".

And that's probably why the old code Bill. They had a hard
time finding 16.5" even back when I bought these tires.

In a Michelin series 70 there is only one 215 16" tire and
that's only gonna give me a 27.86" tall tire, not big enough.
I gotta go very close to or over 30". Which as I posted, takes
me into a wider tire such as the P245/70R16.

In the series 75 tires they make several LT225/75R16 just
under 30" and LT245/75R16 just over 30".
The later is the ones I'm leaning toward.

Denny Graham

The first couple of posts mentioned 15". I thought you were "debating between 15 and the Ford 16" you bought. I think the Ford wheels are a good choice. However, I'm not sure you would be pleased with LT tires. Here are the specs.
LT245/75R16 30.5" 9.8" 17/32" 7.5" 6.5-8" E 3042 lbs 80 psi 44 lbs 683

I run LT Michelins on my 3500HD. But this is the kind of things that I do with my GMC.

https://plus.google.com/11263693037...5156051106&oid=112636930370126476644

The old cabover weighs 16,000. The trailer has 17.5 tires.
235/75/17.5 6005 lbs (single)18 ply Load Range J 10k super single

I wasn't near the rating of my tires anywhere, but it rides rough. I don't think that is what you are looking for. The pickup tires are recommended at 80psi and the trailer 120 psi.

I still think you should talk to someone at Michelin. They have an 800 number. I think a SUV tire is what you should be looking at instead of light truck tires. I have SUV tires on my Town and Country, run them at 32 psi and it rides good.

Agree Ken, as I said earlier, never ever gonna haul a load with the old gal, just looking for
the best ride. The problem is width. When I get into non Light Truck tires in the 30"
diameters they have to be pretty wide tires. I'm using this link to what Michelin makes, and
it lists all their tires by rim size:
http://www.michelinman.com/US/en/tires/sizes.html
I've charted out all of the 70 & 75 series tires that fall in between 29.28" to 30.6" by
doubling the aspect ratios and adding the rim diameter. The widths will run between 9.65"
to 10.43".
A P255/70R16 will give me a 30.06 diameter but the width is 10.04” which is getting pretty
wide for a stock 3600 Stove bolt.
It's no wonder I get a blank stare from the salesman at the tire dealers. All they know how
to do is the same thing that I've been doing for two days now. That is, look up the listing on
Michelin's site of the 16” offering. The difference is if you can't give the salesman a year
and model that's in the Michelin data base they're helpless.

I should have known how this was gonna turn out from all those past threads about tires.
Never did read one where the lines were clearly drawn to what tire fits what. I’m limiting my
choice to Michelin’s because I can’t afford to try a half dozen different tire brands and I’ve
heard nothing but good about them. I can’t even imagine what a fiasco this would be if I
was considering five or six other tire manufacturers.

I’m tired, been up all night again running round in circles like a dog chasing his tail. Goin’
back to bed now!

dg

Denny,

215/85R16

It about 31.5" diameter rolling diameter and it looks narrow enough to appear to be original. They are spec's for 5.5"-7.5" inch rim - that is why they are wider diameter and look narrower on the 4.5" wheels.

Mine are Cooper SRM II LT (no longer listed by Cooper).
LT215R85 16" Cooper SRM II radials

They are 10 years old. My Goodyear dealer has 2 or 3 lines of tires in that size. I can look them up - I do not recall if they are LT.

215mm=8.47" (tire width)
75% of 8.47"=6.35" (side wall)
6.35"x 2=12.71" (both side walls)
12.71" + 16"= 28.71" (side wall plus rim)
That's the math that I've been using. Now, I ain't no
mathematician by any means, but that seems to
correspond with the calculators on line.

Here's one calculator which I just looked up:
http://tire-size-conversion.com/tire-size-calculator/

Also at that site are tires by diameter, a long listing of
30" tires, which as Ken mentioned on the first page does list
a series 85 Michelin tire. They have no listing of those
on their site. The site that I'm referencing does show a
Michelin LTX A/S - 215/85R16 tire. This would be great it they are available.
http://tire-size-conversion.com/tires/Michelin/LTX-AS-215-85R16.htm

When you go to look that size tire up all you find are
M/S 2 or A/T 2. Nothing in an A/S or summer tire.

Now, so how did you arrive at 31.5 diameter? The tires that
have been on my truck for the past decade or just short of
a decade and approximately 14-15k miles, are also Cooper
SRM II 8.75xR16.5LT M&S tires:
http://www.pbase.com/dennygraham/image/160954025
They're the ones I want to replace with Michelin's in a 16"
hoping for a better ride, less vibration and at 30" a little
more speed on the highway. The distance those tires roll
inflated to 50psi is:
90.25" divided by 3.1416 = 28.72" rolling diameter.
http://www.pbase.com/dennygraham/image/160954029


dg

I measured my tires on the truck (rolling diameter) - the measurement might be +/- 1/2 inch, but I had someone else check out my measurement.

Note: I corrected the tire size in my previous post.

Cross referencing in my tire guide, 215/85/16 would get you 30.4", nominal. There will be variances from manufacturer to manufacturer, plus different tread types make a difference, too. Moving up on the width, 225/75/16 s 29.3, and a 235/75/16 comes in at 29.9.

Before we switched to super single Michelin about two years ago, I had good luck with Continental and Goodyear. I think they offer a few more sizes than Michelin. Some people have good luck with Bridgestone. My luck with them hasn't been that good. 10 years ago Cooper was a good tire and it was built right here in Texas. Their quality has really changed since they moved production to China. Someone like Discount Tire can probably explain all of your options to you.

Now the search for rubber gets real serious.
http://www.pbase.com/dennygraham/image/160976697
Just gotta wait for the paint to dry, get the stems screwed in
and mount the hub cap clips.
Went to Discount Tire yesterday and my choice of what they can
get are limited to P245/75R16 A/T2 or M/S2. Wanted a summer
or all season P-metric but nothing that will give me 30 to
30.5 out there.
Probably go with the All Terrain as much as I hate to go with
that heavy of a tire. Really wanted some thing a little
lighter that the Light Truck M/S tires on the truck now.

Well..........thanks for all the comments guys, hope those
Michelin's give me some of what I want.
dg

You might want to consider the M/S2 instead of the A/T2. Both are built on the same carcass, only difference is the tread pattern. The M/S2 is more highway friendly. I have the older version of it (which looks like they dropped my size in that line), and am very please with the ride quality and handling, even with running a C load range.

Funny how one can spend the better part of 5 or 6 days on the
internet, at tire sites and still not have a through understanding
of all the terms.
Here all along I've been putting the M/S Mud/Snow tread as the
more aggressive one over the A/T All/Terrain.

I guess I got that idea from descriptions like this:
http://www.offroaders.com/tech/AT-MT-Tires/tire-tech.htm#All_Terrain_Tires_offroaders

And like this:
"M+S, or M&S: Mud and Snow, These are winter tires, with self-
cleaning tread and average traction in muddy or very snowy
conditions, and for low temperatures."

I just can't picture running an A/T or M/S tire on a Cadillac
or Lexus. But of course, even though I might find a 30.5"
tire that would work with them, they also would be a tire
that leaves a 12" wide footprint.
Just because I've got a truck, I don't need a truck tire. As
I've tried to stress to tire shops and in everything that
I've posted, as long as I own this truck it's never going to
carry any more load than one could carry in the trunk of their
family car.
After this past week, I'm just about to say the 'ell with it
and finish out the next 27 years with those lousy Cooper's
that are shaking my teeth out now.

And I still haven't been able to find an explanation of what
the '2' suffix stands for on the Michelin tires, as in A/T2 or M/S2.

Denny Graham
Plumb 'tired' out in Sandwich, IL

Now just to throw another monkey wrench into this mess. As
Bill posted, "You might want to consider the M/S2 instead of
the A/T2." When I look at the tread patterns of the Michelin
tires at Discount Tire, the A/T tread does look a lot more
aggressive, almost like a knobby snow tire. Which contradicts
the info printed in the link that I posted. Think I'd trust
Discount Tire over the "offroaders.com"

There is so much conflicting information out there when it
comes to tires I don't see how anyone can figure it out. Seems
as thought every make, model and year has a special tire
designed for it. And that puts the choices in the thousands.

The guy at Discount tire said there was no 215/85R16 in a
Michelin available so my only choice for a tire the diameter
I was looking for was a 245/75R16. Yet when I got to their
online site it says they have the 215's in stock. Makes me
wonder if they're just trying to unload some 245 tires???
Who do ya trust?
dg

Denny,I am running bfg 215/85/16 on my 59. They are about 30 " tall. Got them thru Sams club. they also had a 235/85/16 which was a little taller. If you are running the 6" wide rims the 70 series may bulge a little and there may be tierod/steering clearances to think about. The bfg are load e and have a quieter highway tread. Just a thought.

Have you tried calling Tire Rack. They are aimed at selling on the internet. but they do have knowledgeable people that answer the phone. It appears that you are in a position to mount your own.

http://www.tirerack.com/content/tirerack/desktop/en/homepage.html?s_kwcid=AL!3756!3!78748013533!e!!g!!tire%20rack&ef_id=VcjXWwAAANiT5Czp:20150810165451:s

I've dealt with Tire Rack in the past, both as an authorized installer and as a customer. Good company, had my order to me pretty quick.
Now, to answer Denny's question about the "2" in the A/T2 and M/S2 tires; Those are the second generation of those tires. The original A/T, which I have had a set of those on a different truck, has been discontinued for a few years now, the M/S has very limited availability, and looks to getting dropped soon itself.

Pulled the trigger to day guys. After all the research I
settled on a set of Michelin LTX215/85R16 115R E1 BSW.
Went to a different tire store today and, no problem,
they'll be in tomorrow afternoon.
Didn't really want a "E" load rated tire but these tires are
used an a lot of the light trucks SUV's and crossovers and
all the reviews have nothing but good to say about the ride.
Height is 30.4", tread is 7", rim is 7". The only complaint
I've got is they are going to be a heavier tire than a
passenger and being a all season Mud and Snow tire the tread
design wraps around the edge, a little more aggressive than I
would have liked for a fair weather street tire.
Gonna wait till Thursday to mount them cuz I want the paint to
cook a few more days.
http://www.pbase.com/dennygraham/image/160976697

No Ken, not gonna mount them my self. I could, but my chinchy
Harbor Freight tire machine is not much more than a toy and is
really hard on the paint job. I'll let them install them on
their new Hunter machine where no tool will touch the rim.

I did some calculation and by going from a 28.75" tire to a
30.4" tire will effectively make my 4.10 gear appear to now
be a 3.87. So I should pick up another five mph or drop my
rpm by about 150 rpm.

Once again, thanks for the input, I've learned a lot about
modern day tires the past week and feel like I know just
what I want from what's available.

Denny Graham
Sandwich, IL

I'm in the market for tires and would like to keep the original six bolt rims on the 1947 3100. I talked with a local tire vendor and he said they couldn't install radial tires on the rims because they don't have a safety bead retainer. The 'Bolt' threads look to be divided on whether this is a good practice or not. As far as radial tubes go, I'd like to avoid them.

Denny, I appreciate all the research you did on tire size. I will likely go with a LT215/85R16 tire; however, finding someone to mount them could be a challenge. The PO had radials mounted on these rims and I haven't experienced any problems with them, but it's time for new rubber.

Is there a definitive answer to the question of mounting radial tires on these stock rims?

Thanks for your advice in advance.....

Do you have another tire dealer nearby?

I have found dealers who would mount that size radial on my original 16" 1954 3100 truck rims - the dealers were will willing to mount the LT radials with or without tubes.

I have had the radials with tubes for over 10 years.

Have seen many radials mounted on older rims. The weakest point
with old rims that were used with for bias ply tires with tubes
is that the center is riveted to the hoop. There is a possibility
that they can leak there. Other than that, here's the take that
Diamond Back Classic Tires has on the subject:
http://www.dbtires.com/rimstress.html

dg

Thanks fellas,

Yes, I have other dealers to check with; however, I've been doing business with this dealer for many years. There's something to be said for 'dealer loyalty' and 'customer service', especially when my wife has a tire problem. I'll keep looking and comparing prices.

You both have far more experience running these old trucks than I do, so I value your opinions and advice. The Diamond Back Classic Tires article is an interesting read. The possibility of a rim failure is there either way. IMHO, I'll error on the safety and handling the radials offer me.....now to find that dealer to mount the new rubber!

Thanks again,

I finally got some new radial tires mounted! The ride is much improved over the old tires and the 30.4" diameter makes 55-60 mph an easy lope, even with the 4:11 rear end. Wow, the wheel wells are really full now!! I bought them from Theisen's, a local farm supply store. They are Kenda Klever 8 ply LT215/85R/16. According to my GPS, the speedometer indicates that I am going 5 mph faster than I really am- oh well at least I know!!!

The guy that mounted them put 50 psi in them. Out of curiosity, what psi are you fellow Bolters running in your radial tires?

Thanks in advance for your replies......

Yer in the ball park on the pressure. And that's about what I'm
experianeing on the GPS with the Michelin LTX215/85R16 115R E1
BSW tires I've got on my 3600 with a 4.10 gear. Got a tack and
it's running right around 2500 rpm at 55 mph.
dg

Same tires as Denny, same pressure @50psi, tires are wearing evenly.

Denny on your 3/4 ton what is the diameter of your rear drums? I have a 1-ton and my drums are 15". Im curious what the opening size is on the back of your new rims (how big a drum will they accomodate)?

Fronts are 11", rears are 12" and there is plenty of clearance.
Without jacking up the truck and removing the rear wheel I can't
give you the exact ID, but as you can see, there is a lot of room:
http://www.pbase.com/dennygraham/image/161548205

dg

OK Thank you

Any concerns running a LT225/85R/16 on the stock four inch wheels?

Those would be too wide for a 4 inch wheel. A 225 would need at least a 6 inch wheel to handle properly.