So I am looking for some new tires for my 79. I know that just because a tire is labeled a certain size doesn't mean it actually measures that. Like a 36 super swamper I am looking at measures closer to 37. With that being said is it supposed to be that size when fully inflated and on the truck or does the weight of the truck push them down some? Example. I have a worn out set of gumbo monster mudders on my truck right now mainly for mock up purposes. They are 16/38.5's. When fully inflated and off the truck they measure 38. When on the truck they squash down to 36.5. Is this because they are old worn out tires or is this what is to be expected because of the weight of the truck?

 

If they measure 38 when off the truck they will measure 38 on the truck. It may flat spot when weight of truck is on it but it does not lose size. It will still measure at least 38 side to side instead of up and down.

 

And if they are worn down you lost some size there as well

 

made a rambling video.......................

 

Tires will loose a bit of height when mounted on the truck because the weight will balloon them a little bit. You shouldn't loose more than a 1/2" or so though. My 38.5x16" TSLs brand new mounted on 16.5x9.75" rims measured 38.5" tall by about 15" wide. Once installed on the truck they were about 37.5-38" tall.

Also, gumbo was around when ground hawgs were originally made, and were always on the short side regardless of what they were advertised to be.

Edit: Just read your thread about 39.5" tires. If I ran them they would hit the front edge of the front fenders. Maybe with some other offset and rim width they'd work? I like my 38.5s though, very proportionate.

-"Mudfighter" (Nick lol)