47-59 Switching from tubed to tubeless tires.

[DieselDog1]

It’s my first time posting as a new member of this forum; greetings to all.

I’d like to tap into the vast knowledge base of the members for guidance.

I have an ALL ORIGINAL ’54 GMC 100. It has the original non-split rim rims on it, 6.50:16 tubed tires. I’m tired of having to pay big money for the NOT SO GOOD, Coker or Classic tires and crappy Chinese made tubes.

I’d like to know if there is something I can do to seal the rivets so the rim would be air-tight and be able to buy tubeless quality light truck tires and run those instead.

An old man who owns a tire shop here told me he thought the rims would OK and not leak and if they did that he could stick in a tube in the tubeless tire and it would be fine. He also mentioned another option, that I could take the rims somewhere and have the area around the rivets sandblasted and then apply epoxy around them to seal.

I’ve heard that there might be a compound that could be used to do this, or a business that I could send my rims to that would do this.

I DO NOT want to buy replacement rims as my goal is to keep the old truck as original as possible.

Thanks in advance, Michael

[mongocanfly]

welcome..!!!
truck is a beaut.!!!!!!!
if your old tire guy feels like it will work, then give it a shot
Dad ran tubeless tires with tubes for yrs
bigger issue you may have is finding tires that are tall and skinny to keep the look you already have... ( never looked for or bought any, so i dont know whats available )

[Rickysnickers]

Welcome! Very nice truck

[nvrdone]

falken shows a 6:50/16 tubless tire available thru Discount /America's tire.
Also, a 225 / 75/16 is todays metric equivelent in a radial tire.
Good luck

[mr48chev]

You will have to buy radial tubes for the radial tires. I don't know how good these are but the price is pretty good. https://www.amazon.com/Doberman-75R1.../dp/B07XYHKFG3 Actually there are several listings there. If you don't use Amazon you can still find a brand and find a source.

[JDarby]

Originally Posted by DieselDog1

It’s my first time posting as a new member of this forum; greetings to all.

I’d like to tap into the vast knowledge base of the members for guidance.

I have an ALL ORIGINAL ’54 GMC 100. It has the original non-split rim rims on it, 6.50:16 tubed tires. I’m tired of having to pay big money for the NOT SO GOOD, Coker or Classic tires and crappy Chinese made tubes.

I’d like to know if there is something I can do to seal the rivets so the rim would be air-tight and be able to buy tubeless quality light truck tires and run those instead.

An old man who owns a tire shop here told me he thought the rims would OK and not leak and if they did that he could stick in a tube in the tubeless tire and it would be fine. He also mentioned another option, that I could take the rims somewhere and have the area around the rivets sandblasted and then apply epoxy around them to seal.

I’ve heard that there might be a compound that could be used to do this, or a business that I could send my rims to that would do this.

I DO NOT want to buy replacement rims as my goal is to keep the old truck as original as possible.

Thanks in advance, Michael

Hello and Welcome,

I too am new to this group and wanted to tell you I have 55 1st series GMC 100 5 window short bed custom cab that could be the twin of yours!

Don't see many of these, yours looks GREAT!!!

Mine is a Texas truck and in solid shape currently in the begining stages of a RestoMod build.

What motor is in your truck and is it a hydromatic?

Jeff

[DieselDog1]

Thanks Greg; I didn't know about the special radial tubes, I'll mention that to my old man tire guy.

[DieselDog1]

I did some research on metric tire size equivalents. What I came up with that's not too much bigger but was within an inch or less was the 215/85/16.

I took one of the old mans new tires of that size and we held it up to the spare and it was REAL close!

[DieselDog1]

Originally Posted by JDarby

Hello and Welcome,

I too am new to this group and wanted to tell you I have 55 1st series GMC 100 5 window short bed custom cab that could be the twin of yours!

Don't see many of these, yours looks GREAT!!!

Mine is a Texas truck and in solid shape currently in the begining stages of a RestoMod build.

What motor is in your truck and is it a hydromatic?

Jeff

Thanks Jeff; This truck was originally purchased directly from the Pontiac truck plant in Michigan. The owner than brought the truck to northern commiefornia and it spent it's time between Redding, Chico, Oroville and Paradise.

The original owner then became my Dad's best hunting and fishing buddy and I starting riding in it when I was about 6 years old.

Unfortunately, the original owner passed away in 1984 and his widow gave his truck to my Dad and he had it until he died in 2014, so it was then passed on to me.

So needless to say, this vehicle has a lot of meaning to me and history. This is why I want to keep it just like it is-only updating it to make the truck safe and reliable to drive.

The truck has a 4 speed (granny first) transmission, the original 248 6 cylinder and oil bath air-cleaner, and still on 6 volt.

Top speed is 55 because it's so low geared.

I'll send some more picts of these features

[geezer#99]

Awesome old ride!
I’d think you don’t put a lot of miles on it so tires and tubes shouldn’t be much headache.
Besides Coker there’s these two places for tires and tubes.


https://www.universaltire.com/


https://www.lucasclassictires.com/

[JDarby]

Originally Posted by DieselDog1

Thanks Jeff; This truck was originally purchased directly from the Pontiac truck plant in Michigan. The owner than brought the truck to northern commiefornia and it spent it's time between Redding, Chico, Oroville and Paradise.

The original owner then became my Dad's best hunting and fishing buddy and I starting riding in it when I was about 6 years old.

Unfortunately, the original owner passed away in 1984 and his widow gave his truck to my Dad and he had it until he died in 2014, so it was then passed on to me.

So needless to say, this vehicle has a lot of meaning to me and history. This is why I want to keep it just like it is-only updating it to make the truck safe and reliable to drive.

The truck has a 4 speed (granny first) transmission, the original 248 6 cylinder and oil bath air-cleaner, and still on 6 volt.

Top speed is 55 because it's so low geared.

I'll send some more picts of these features

Awe man such a great story!!

Thats the beauty of the hobby right there I think, the "Story" and yours is a very rich one with all your family history!

And yes keep the pic coming please

I'm so bad about that but will take some pic's and post my project hopefully soon.

Your truck looks like it has been well cared for its entire life!

I would venture to say that your truck has a SM420 with a non-syncro 1st granny gear.

My truck had a tranny like that, the hydromatic was along gone when I purchased the truck back in 79' and it was paired with a 270.

So sorry I sold the 270 off years ago but that is where my head was at at the time and after that there was no going back!

I had visions of my dream HotRod.

Jeff

[mongocanfly]

Dieseldog , a taller tire will help some with your highway mph ,rpm, and low gearing

[DieselDog1]

I took some fairly precise measurements of the existing spare tire which interestingly enough appears to have a 1968 date code on it and is a re-cap, so here's what the comparison was to a 215/85/16 measurements:


Spare tire: 215/85/16:
Diameter 29 3/4" 30.4"
Tread width 7 1/2" 8.5"
Rim 16" 16"
Sidewall Height 6 1/4" 7.2"
Circumference 92 3/4" 95.5"

So while a slightly larger tire, I think it's pretty close.

What say you all?

[1project2many]

I have some detailed information and some experiences to share which may help. I am currently using tubeless tires without tubes on 1936 wheels. I have also used tubeless tires without tubes on stock Task Force wheels. In both cases the wheels held air and my concerns that I would see leaks around the rivets were unfounded. I had more trouble finding valve stems that would seal properly. Snap-in valve stems need to be fairly snug to prevent leaks. Those old tubes didn't have the same type stems and the outside of the wheels was much more likely to rust. I have used both silicone RTV and bead sealer around valve stems to help seal them properly. Additional issues can come up when the bead of the wheel is excessively rusted and pitted. Tubeless tires rely on pressure between the tire and wheel to create a sealing surface. Now here's where stuff gets a little tricky.

Tube type tires rely on the tube expanding to press the tire beads against the wheel. The tire does not have to seal against the wheel and in fact has to allow some air to leak out while the tube expands so the tube can fully contact the tire. Tubeless tires are just the opposite. Tubeless tires have to seal against the wheel before inflation, at least enough so you can begin to build air pressure while inflating the tire. Tubeless tire wheels are different than tube tires and it's important to understand the difference.

This is a picture of a wheel for tubeless tire.



Notice the raised portion of the wheel inboard of the bead surface? This is what causes a tire to "POP" when it is first inflated after being mounted on the wheel. It is what the tire repairman must force the tire to "pop" over with a bead breaker when dismounting the tire. And it is what holds the tire bead against the wheel when the the tire is flat.

This is a tube type wheel:



Notice there is no raised area near the bead surface? This means there is nothing to seal the tire against the wheel when the tire is flat. And this can be a huge issue. For example, if your tire goes flat while the truck is parked, the tire literally falls inside the wheel leaving a massive gap between the tire and wheel. You're not just going to hook up a compressor and air that thing up. You have to find some way to get the tire to contact the wheel while delivering enough air to cause the tire to fully contact the wheel on both sides. If your tire is a bit narrow at the bead surface and does not naturally expand enough to contact the wheel? Same battle. Somehow you need to get the tire expanded and get enough air into the tire to make the tire contact the wheel so it will seal due to air pressure. And what if the pressure gets low while you're driving? It's possible that a turn or bump or sidewall hit is enough to temporarily break the seal and suddenly the tire is flat. That fast.

What can make this issue a bit more complicated is that bias-ply tires traditionally have stiff sidewalls while radials have more flexible sidewalls. This doesn't mean that one type tire works better in tubeless operation, but that it's important to match tire and wheel so they fit together as snugly as possible before inflation. How do you find this without a "try before you buy?" I'm not really sure.

Long story short is that you are better off using tubes in the tires when you're using tube type wheels if you can afford it. Radial tubes for radial tires due to the additional flexibility and movement of the tire. My experience is that bias-ply tires work with either tube type but folks in the know recommend bias tubes for bias tires.

Good luck.

[DieselDog1]

Thanks 1project2many, that's some really great info! BTW, I like your catchy handle-it's pretty much the story of my life too!

The old man owner of the tire shop I'm using said that he thinks the rivets won't be a problem either. He told me that if it is, then he'll throw in a tube made to be run in radial tires.

On the pitting, I'm not sure what the inside of the rims look like yet since the tires are still on them. If there is extensive pitting there, maybe take them somewhere and get them vapor blasted to clean them up and smooth them a bit?

On the valve stems not sealing properly, is it that the holes are too large to fit tubeless stems properly?

I'll speak to the old tire guy about what you've written here and see what remedies there might be in addition to what you've said here.

THANK YOU again, your experience and insight have been extremley valuable and helpful to me! Mike.

[geezer#99]

If you have a problem with the rivets possibly leaking, I’ve used duct tape over them. Firmly put the tape in place using a screen door spline tool like this example. The tape will never move. I’ve used duct tape to keep stick on wheel weights in place too.


https://www.homedepot.com/p/Screen-T...IFE2/319030509

[1project2many]

On the pitting, I'm not sure what the inside of the rims look like yet since the tires are still on them. If there is extensive pitting there, maybe take them somewhere and get them vapor blasted to clean them up and smooth them a bit?

On the valve stems not sealing properly, is it that the holes are too large to fit tubeless stems properly?

If the bead surface is badly rusted you could try blasting the wheels then painting. They do need to be de-rustified in some way even if you aren't planning to use paint. I have spread gobs of bead sealer on the bead after removing rust to achieve a seal. It's crude but effective.

In regards to the valve stems, the thickness of the steel could be different, the hole diameter could be different, or you may find pitting around the edge of the hole. The rules for the two different types of tires and wheels are different so be prepared to solve unexpected issues.

[geezer#99]

I’ve used bolt in style stems to help sealing.


https://www.summitracing.com/parts/bsp-999900

Kudos for the great post with pics on rim differences 1project!