Sorry... Should say R/Ts.
These tyres have a tread pattern that appears to be directional, in that it looks different depending on which way round the tyre is fitted, although from what I could see in photos there isn't a marking on the sidewall indicating a rotation direction.

I can find plenty of photos showing Humvees with the front tyres fitted so that the tread matches, and plenty where it doesn't. What's going on? Factory fitting seems to be with them matching, but does it just not matter which way round they go? Thanks.

I think, and it's merely an educated guess, the idea behind this phenomenon could have the same roots as changing direction of tank tracks. The weight of the tank results in inner side of the track gets more usage and the thread starts to dissapear in that area. Changing the direction of the track reestablishes the vehicle footprint grip.

Mario

Interesting, and made me look again and realise that it seems that when the treads are matching it is usually with the centre chevron pointing down, as in the top photo. Most photos with them mismatched seem to show the right (looking head on) tyre reversed... But not all. Then there's a photo of one on the AM General production line with them both pointing up... Maybe my photo sample is just completely misrepresenting things.

HMMWV tires are non directional. They can/are installed either direction. Some try to install the tire w the date code on the outside. This would result in the V going different directions on each side, but this doesn't always happen. It's pretty random unless the NCO at the maintance shop is really OCD.

Bruce, thanks for taking the time to respond. Seems odd the tyre is designed like that, but I guess we'd need someone from GoodYear to answer for that.
I'm guessing most modellers will play safe and put them on the same way round.

I'm actually at Ft Riley with the 1st Infantry Division. The TMs will refer to them as ND or non directional. Maintance would be a nightmare if you had to remount tires all the time - especially with the run flat inserts. Think about it. The maintance guys here work on thousands of HMMWVs here and rotation of tires is an X pattern, no concern about direction. That would be a pain in the butt.

The only reason for the angled V pattern is to divert water at high speeds on paved roads to avoid hydro planning. It doesn't matter which direction they angle.