The Stovebolt Site Forums The Parking Lot Big Bolts 700/20 to 900/20 tires

Hey guys,
I have a set of wheels that have 700/20 tires on them so I assume that the rim is 6" wide. So my question is can I put 900/20 tires on these rims?

Thanks,
Jeff

I am not sure why you want 9.00x20 tires unless it is to increase speed or slow engine down. You could put 9.00x20 tires on but I do not think it is recommended. 8.25x20 would be more suitable I would think.

You could call your local tire dealer and ask them what they would recommend. i.e. Les Schwab or Big "O", Firestone or Goodyear...

I did take them over to the local Firestone (they were they only ones that would touch the old split rims) and they were about to change them then some fellow came along and said they couldn't do it due liability. But the other guy seemed to think it was fine - short version=they didn't to them. I was just wondering if it really was dangerous or if it was like the thing where Wal-Mart will only put the factory sized tires on your vehicle.

The tires are going on a 41 G506. I got a good deal on the gripper tread that I wanted. I'm not looking to go faster, because frankly, I think even 45mph is a little scarey in those things as it is. Also, ( I know alot of guys hate this)it has a 350 with a SM 465, so the drivetrain will handle it.

I have 900/20's on my G506 but they are on a wider rim. I do have a spare with a 900 on an original 6" rim so it can be done but you can see the the profile is wrong because the 6" rim sucks the bead section in too much.

I'm saving up (cost more than the truck did) for the 750/20 NDT's to put on the correct six inch wide rims I bought. I don't like the final drive ratio (too tall) with the 900 tires and also at full lock my left front tire rubs on the drag link because of its wider than stock width.I put a bigger 261 six in my truck to handle the taller ratio but all in all I think the truck and myself will be happier with 750's on it and I agree 45 mph in a 506 feels like 145 mph in most anything else, LMAO!

9:00 x 20 would have originally been put on 7" rims. Your 6" are really too narrow and wouldn't seat correctly against the rim edge. If they were 6:50 you could fudge enough but I would not do it on your rims. I agree that the 8:25x20 is as large as you should attempt with your rims.

From memory this is what I recall and I feel confident enough to suggest it.

5.5" = 7:00 tire
6.0" = 7.50
6.5" = 8:25
7.0" = 9:00
7.5" = 10:00

You can confirm this at any of the major repop tire companies websites.

Got tubeless 22.5" rims for my '37 GMC(10 on 7.25, modern running gear), 5.5" wide, 9 x 22.5 fit nicely.

My '46 has 20 x 5.0 rims and the factory specs call for 6.50-7.0 on the front & 7.50-8.25 max on the rear. Would be a good idea to get an actual measure on the width before spending any bucks.

I would like to see some pictures of the rims up close.

Are the rims split in the middle making a 2 piece rim?

Or do they have a single locking ring on outside edge or do they have 2 rings on the outside edge?

There is a web site that has which rims are the widow makers and which are safe enough to deal with.

What is the lug pattern, number of lugs and bolt circle dimension?

The more info you start with the more someone out here can be of help.

" 5.5" wide, 9 x 22.5 fit nicely."

I'm certain if you check with the Tire & Rim Association that will not be recommended.

I don't know how you measured the width but it really makes a difference. It must be taken from between the flanges of where the tires would seat against the tire. Rims are generally stamped on the underside with the size also.

5.5" is way too narrow for a 9:00 tire regardless of whether it goes on the rim or not.
Proper tire size must be taken into consideration especially on a dual tire setup because of the necessary clearance required between the tire sidewalls. That, proper inflation and the spacer ring if so equipped are important safety issues to avoid heat from friction of tires rubbing together.

I ended up finding a tire shop and had them put on. He said he would not do them for a heavy truck. He said "guys" used to do this and have problems with tire failure do to too much pressure on the bead (running them on 20k/30k GVW trucks) He said it shouldn't be an issue on a 10k truck that would be used to tool around town. It will be lucky to see 100 miles a year because its not as cool to drive as it looks.

Sleeve,
What do you think of the brakes on your truck? I put all new on mine, and I still need a couple of miles to stop -LOL

For 9.00X20 tires the minimum rim width is 6.75 and recommended width is 7.5.

Minimum Dual spacing is 11.70, thats center of inside dual to center of outside dual.

Also take into consideration Wheel offset for proper tire clearance.

Sleeve,
What do you think of the brakes on your truck? I put all new on mine, and I still need a couple of miles to stop -LOL [/quote]



Actually with a new hydrovac in it I'm impressed at how well my truck stops. My 45 one and a half ton stops quicker than my 51 half ton and both have new shoes and turned drums!

I have had my share of "throw out the anchor trucks" over the years. :>)

That info until a couple weeks ago was in the Accuride wheel catalog... then they updated the catalog
http://www.accuridewheels.com/pdf/ProductsWheelsCatalogComplete.pdf
Now on page 47 it only shows rim width allowed for tire size for tubeless wheels not the old 20". Note that there is a preferred rim width and an alternate or two.
The allowed rim width for tire size comes from The Tire and Rim Association, Inc. published in "The Year Book" and it only cost $99....
http://www.us-tra.org/publications.html

Here it is
http://www.stovebolt.com/techtips/wheels/

I believe Ed's wheels are actually 5.25" wide between the lips, they're the very same wheels I'm running on my truck, and I also have 9R22.5 tires on them.
A 9R22.5 tire is supposed to be on a 6", 6.75" or 7.5" rim, not a 5.25".

Here are a few shots of them on a 5.25" rim.
http://rides.webshots.com/photo/2317319550080251109EeoORc
http://rides.webshots.com/photo/2493413700080251109bWLBHL
I mounted them myself with absolutely no trouble, they slipped on as easy as could be. Looks like they have sufficient clearance between the duals and I expect loaded they will still.
Again, I know it's not recommended but it can work and 9R22.5 is the smallest 22.5" tire available these days.

Grigg

I dont want to hijack the topic but I have a similer question.

I;m window shopping for tires on my g 506

the rims are the origonal rims, can I put 8.25 x20 tires on those rims and is there a problem with going to 8.25 radials?

8.25 radials are 14 ply tires, any problems going with a 14 ply radial

another question, I have access to m135 rims with 900 20 tires. thye fit the truck but is there any problems putting 8.25 20 tires on these rims?

if I had a choice between the origonal rims and the m135 rims which would be a better choice for both the truck (g506) and the 8.25 radial tires

What tires fit what rims is determined in part by the rim width, what rim widths are you considering?

I'm unclear if 20" radial tires will fit the old tube type wheels, part of that answer is the bead seat angle, the new tires MUST match the angle of the old. Check the Accuride catalog link above for some more info on that.

Grigg

I dont have any specs on rim width. they are rims off of m135's

I checked for the pdf file, it does not come up when I click in the highlited title. I get thier main website and have searched it for a pdf file and found none.

I'm not sure what an m135 is and the truck may or may not have the original wheels on it. Even if original might be a few different width options when new. Only sure bet on what width you're dealing with is to measure and or find it stamped on the wheels in question.

Here's the new link to the Accuride catalog, found it on their website:
http://www.accuridecorp.com/files/2012/10/Accuride-Wheels-Product-Catalog-Summer-2011.pdf
Page 38 shows the 5* and the 15* bead seat wheels, be sure the tire matches the wheel you have (likely 5*).

Grigg

M135 was the 2.5 ton that replaced the wartime trucks until the M35 came into production. Did the wheels work? I thought they had the big six bolt pattern.