Changing Tire Size

[Charlie-Ellie]

Please chime in: I have a 98 Ford B700 with 11R22.5 tires/rims... I have an opportunity to pick up some 24.5 Chrome rimes with brand new tires at a steal of a price, Will i have any issues changing the size of rims/tires

Thanks in advance for any information.

Charlie Mac and Ellie!

[Charlie-Ellie]

I found an earlier thread with some input, I will have to check to see which type rim i have, I have not checked, My Bus is being picked up Jan 11, I am working offshore until Jan 10th. Just being excited about starting My Conversion... talking to mechanics out here at work a fellow worker has an 18 wheeler with chrome rims 24.5 and Brand New Tires he said I could have for FREE!!! I would Love to be able to use them.

[deftone]

You are changing the drive ratios by changing the tire diameter, so your speedo will be a little off but otherwise not much difference if you can get them to fit I guess.

There is a calculator online that you can input tire sizes and it will give you the difference in speed etc.

[Brad_SwiftFur]

Basically you'll have to check 2 things. First, if your bus and the wheels have the same bolt pattern ... 10 lugs is pretty standard. If so ...

You'll need to compare to see if the wheels and your bus are "Hub piloted" or "Stud piloted". The former typically use nuts with a "washer" made into them, the latter use tapered nuts (and a similarly tapered hole in the wheel). No, they are not interchangeable. Over time the stud piloted wheels can begin to crack around the nuts, as it's a pretty small contact area; the hub piloted wheels have a much larger nut-contact surface and are much less likely to do this. It's not a major problem; it is something to be aware of and watch out for.

[Charlie-Ellie]

The 24.5 rims are on an 18 wheeler Truck... If that gives any information without me being on land to actually go check.

[Brad_SwiftFur]

Buses and trucks both used stud piloted wheels and hub piloted wheels. Typically older vehicles used the stud piloted, newer vehicles use the hub piloted. Pics will help greatly.

[Deezl Smoke]

Ok, firstly, chrome wheels suck. They rust and flake like you would not believe.
Second, you will have to know the actual tire size numbers to know the diameter of the new ones. A low profile 24.5 is available and common to run. So you may not change any ratios worth mentioning if the 24.5s are really close to the same diameter as your 11R22.5s, which are a good solid tire and on the tall side of the 22.5 wheel.

As mentioned, you'll need to know stud pilot (budd) or hub pilot wheel mounting style. They do not interchange. Hub pilot which is what 99% of all newer rigs will be, you put both wheels on the hub and use one set of 10 nuts to hold both wheels an.
BUDD, or stud pilot, you put the inner wheel on and install 10 double sides long nuts called "thimbles" to hold it on. Tighten the thimbles. Then install the outer wheel and use 10 large diameter budd nuts to hold it on.

The budd style has gone out of favor, and though they are still serviced and will be for some time, they will get harder and harder to service as time wears on.

I like free stuff as well as the next guy, but new tires for free? I would be careful to check the date codes on the tires. The tires may very well be unsafe. Can not tell until you see them and get some detailed info.
A 285/75R24.5 is close in diameter to most 11R22.5s. If however the 24.5s are 11R24.5, you'll end up with a speedometer error of enough to get you a ticket without correction.

[REDD]

Originally Posted by Charlie-Ellie

I found an earlier thread with some input, I will have to check to see which type rim i have, I have not checked, My Bus is being picked up Jan 11, I am working offshore until Jan 10th. Just being excited about starting My Conversion... talking to mechanics out here at work a fellow worker has an 18 wheeler with chrome rims 24.5 and Brand New Tires he said I could have for FREE!!! I would Love to be able to use them.

Are they actually chrome or polished aluminum that look chrome?
An aluminum alloy rim will be a lot thicker and you may have to change the studs to longer ones....

[roach711]

The width of the new tires can be an issue too. Wider tires may rub together and wear through sidewalls quickly.

[milkmania]

For that price... Snap them up!
If you can't use them, Someone on here can...
I'd drive down and haul a u-haul back from Louisiana if they fit mine.


Just sayin'

[Charlie-Ellie]

Well ****.... Call in the dogs and piss on the fire...The Man sold the truck with the 24.5" rims/tires on it. I wasnt home working offshore. he said he couldnt wait until Jan 10 for me.

Thanks Guys for all the info, and the help! maybe next time.

[Charlie-Ellie]

After getting bus home, and seeing for myself, my tire size on my Bus is 10R 20's.
Also... my bus is a 1989... not a 1998.
But the bus is in really great shape, still a good deal for$2000 bucks

[milkmania]

Originally Posted by Charlie-Ellie

After getting bus home, and seeing for myself, my tire size on my Bus is 10R 20's.
Also... my bus is a 1989... not a 1998.
But the bus is in really great shape, still a good deal for$2000 bucks

My 10R 20's are still stamped US GOVT

[Haugyland]

This site has always been helpful.

https://www.miata.net/garage/tirecalc.html

You want to try and stay within a few percent of your current rolling diameter. It wont address potential rubbing issues you may have while turning - but should be a good resource for overall tire sizes.

[ol trunt]

Ditto that. The diameter change becomes quite significant after +/- 5% and will really mess up spedo, ABS, odometer and fuel injection operation. Jack