I like to deflate my tires on the tow rig and trailer to 13 psi for a big increase in flotation on heavy rigs. I've heard you will damage the steel belted sidewalls in the 19.5's and 22.5's if you run low psi. If you keep speeds down and only run a few miles at most will this damage these "big rig" style tires? How about 20 psi--probably would not even budge with these heavy thick sidewalls so anyone have experience airing down these style tires? Reason I ask is all the F-450's and F550's we have been looking into and up come with these bigger rims. Not sure if you can fit 17's or 18's or even 20's--are they made in these bolt patterns for these trucks. Going to try 17.5's on the trailer--looking for some nice rims but I can't seem to find any in a convention 8 x 6.5" bolt pattern.

Jason :)

back in 98 I ran a service truck around Orlando, we would run the tires low for going on job sites

after shelling 2 sets we had to air them up to 80, running them at 40psi on a 14K truck wasn't to good but I ran them at 40 all the time, in the sand right up to 80mph on the highway

they last a while, but.....

Were you driving on the street also at 40 psi or "off-road" only at slower speeds? I understand that these also don't have safety beads as I'm familiar with airing down 16.5's at Pismo beach and Glamis over the years. Gennerally as long as you are on level ground and keep sharp turns to a minimum I have found that at 13 psi I was gennerally safe and have run as low as 11 psi (in the morning after setting at 13 psi but hot from coming off the highway).

Jason :)

do not air down a 225/75R19.5
that tire and its sidewall design WILL come apart when you reair it up, and could possibly kill you. most of the other ones wont blow up like the above mentioned one. seen to many of those in person blow up.

What is it that is different than other sizes? Does brand matter? Are there certain ones more that can be aired down? Don't need more than 2500 lbs capacity on the highway aired up.

Jason :)

boom.

I agree, BOOM, i work on medium-heavyduty trucks all day. Anything in the .5 size (except for some rare 16.5's and 22.5 alcoa front dump wheels) do not have safety beads and are easy to debead.

Also the extra stiff sidewalls do NOT like to flex @ low pressures, as others said, they will come apart.

Not only that, do you have a REAL compressor that can get these tires to their 110-140 , yes some 17.5's hold 140, max operating pressure?

Well we don't have these tires yet...trucks we are looking at will come with them. I'm hoping we can use conventional 17" rims or larger if they will clear the brakes and have the correct bolt pattern wheels available etc. We already have the 17.5 tires for the trailer. We needed low or at least as short a tire as possible that had at least 2500 lbs capacity per tire and preferably a big margin above. The guys we pit with have 17.5's on their semi trailer so I had advised not to get this size but that is what was bought for the race hauler. The compressor in the trailer will go to 175 psi and we have C02 bottles with 200 lb regulators and adapters to use the nitrogen regulator that goes to 1000 psi. We have nitrogen in the trailer too! Won't be a problem to air back up but getting the a 30000 lb truck and trailer stuck in soft dirt or sand will be a problem!

I aired down my duals on my motorhome in the sand and it didn't help whatsoever.

You have to air down the fronts too! Does no good to try and push from the rear if the front just plows and bogs you down. You have to float all the way around. That goes for the trailer too!

It really doesn't matter if you air down the fronts or not if you can't get the damn thing to move because it's too heavy.

If it didn't move in the sand in must have already been "stuck" in the sand. In sand (or even conditions like snow) airing down allows u too float on top of the surface and you move instead of bogging down and not moving. You can even run a psi like 10 psi or higher in your sand rail paddle tires and have a hard time climbing the steep dunes and then you let a bunch of air out and can crawl up the same hill at an idle in first gear that you could not climb before with a 30 MPH or higher run at before airing down. Well I'm gathering that the rims will need to be changed to some 20's so something similar. Anyone know if 18's will clear the brakes...I'm guessing 17's won't clear the brakes on the F-450/550's the brakes look huge!

Jason :)

I aired down my 245/75 19.5 Hancooks (very aggressive tread) to 50psi on my F350 towing our 18K 40ft toyhauler out of some deep sand and was afraid to go any lower with that weight on them. The tires are rated for 110psi and over 4500lbs. I also aired down all of the trailer tires to about 20-25psi which probably helped more than anything. It took forever to air all of those tires back up to drive on the highway.

Iv been looking all over trying to find a tire and wheel package that I could air down for the dunes. I cant find a 20" dually wheel off the shelf. Stazworks will custom make some steel 20" wheels for a pretty resonable price. The route im going is 22" wheels (22.5 shaved down and a direct bolt on for the 08 450 bolt pattern) then I can run some toyo or nitto tires in the 35" or 37" range and can still air them down.

Does anyone know what the smallest wheel is that will fit on a F-450 or F-550? Just wondering if 17", 18" or 19" wheels if available in the correct bolt pattern will work or do we need to focus our search on 20's or bigger? It does not appear the 19.5's are going to work for us if we need to go thru soft dirt or sand :( I don't recall exactly but I think the rotors I remember seeing listed at 15.5 " diameter!!!

ttt

Does anyone know what the smallest wheel is that will fit on a F-450 or F-550? Just wondering if 17", 18" or 19" wheels if available in the correct bolt pattern will work or do we need to focus our search on 20's or bigger? It does not appear the 19.5's are going to work for us if we need to go thru soft dirt or sand :( I don't recall exactly but I think the rotors I remember seeing listed at 15.5 " diameter!!!
what, you don't own a tape measure?

well, the problem is that if you are OK or prefer 17" rimmed tires then you don't need one of the 4500/5500/450/550 trucks.

Not to mention that the 17" tires aren't available in load range f,g, or h like on the 19.5s. you'd lower the load capacity of your truck, just get a 1 ton truck, they have the same engines!

Did you know that the new 4500/5500 dodge trucks have a governed speed limit of 75mph because that is the max speed rating of all the 19.5 tires?

Did you know that the new 4500/5500 trucks have a governed speed limit of 75mph because that is the max speed rating of all the 19.5 tires?

Not all of them. From the 4500 specs page on the Chevy site: "Road speed governor, controlled by the speed rating of the tires ordered, which will be less than or equal to 85 mph" (Listed as standard equiptment, lower speeds optional).

http://www.chevrolet.com/mediumduty/kodiak/c4500/features/

Pete

I own at least a dozen tape measures but there aren't a lot of F-450/550's within about 10 miles or so from my work lol! Even with the listed rotor diameters there may be heat/splash shields etc. so even if I measure my insides of my 17 and 18" wheels on my current trucks this still may not fit. We need the tow capacity of the F-450/550 trucks to legally tow our triple axle tow haulers and race haulers. I believe the highest rated F-350 is a dually with the diesel and auto with 4.30 gears which I'm not certain I want that ratio (I think the 450/550's are worse ratio wise) is rated to tow 17,200 lbs. We need 17,999 for the toy hauler and 24000 lbs for the race hauler. Tire capacity even with only E rated 16" is above 3400 lbs which is more than adequate. We rarely have much over 10000 lbs on the rear of the dually. Getting the large trailers and trucks unburied in soft sand or dirt would be a pain if we can't deflate the tires to help the truck float itself.