Saturday, September 26, 2009

New Skins for the Mighty Binder

Eight new drive tires. Actually, they're "takeoffs" from a brand new truck. These are the "full size" (11R24.5) tires, and the buyer of the truck wanted low profile tires (275/80R24.5). So, we got 'em cheap - relatively speaking, since they run close to $500/ea. We usually run recaps for drive tires because our trucks - with the heavy knuckle boom cranes putting a lot of weight on the steer axle - go through steer tires pretty regularly. They get capped with drive treads. Our trailers all run odd small sizes to be closer to the ground, so we don't use 22.5 or 24.5 wheels at all on our trailers. So, I was pretty fortunate to get "virgin rubber." Caps are ok - but after the carcass has been capped more than once, it's a gamble for long term survival. Most of the blown tires we all see on the road are usually the result of the tire going flat due to a nail - then failing as the sidewalls get too hot and the tread separates from the carcass. If you check your tires in the morning, catch a nail right off the bat - well, you might blow that tire before you're ready to stop for a break. No way to tell - unless you run one of the tire monitoring and/or tire equalizing systems.

The last tire I blew was on a trailer - and it didn't get pulled off in time to be recapped. It just wore down to the steel belts on a flat spot, and let go with a sigh. The tread never separated - I was able to drive another thirty miles to the next town and get it replaced the next morning. It just happened that the flat spot was hidden during my check and during the weekend inspection to find worn tires in the yard.

These babies have some tread on them, too. Yep, that's a quarter buried in there. Retreads aren't even close to having that kind of tread depth. So, this is gonna be a big change in how the Mighty Binder handles. That much extra rubber compared to the tires that came off will mean a smoother ride for sure, but it's gonna feel like the whole rear end "squirms." A tire with little tread doesn't give or flex as much - it's just simple torque. The sheer forces applied to the tire with more tread will work that tread and sidewall more than the ones without, because the moment arm of the new tire is at least an inch longer than the old. The same thing happens when we get new steer tires - the front end doesn't seem as planted, and it seems to take more steering input to turn than before. Side forces can make the new tires roll over a bit more.

So, Monday I'll be a bit unsettled because my truck won't respond quite the way it used to, but I'll be enjoying having the harsh edges of expansion joints and potholes smoothed out with the additional rubber. Ridin' and glidin,' I tell ya.


Anonymous said...

If I remember correctly your speedometer will read slow too, maybe not a lot, but when you're crowding five miles over it'll be close.

Silly me, truckers never do that. ;-)

Jeffro said...

It's been reading fast - it's got to show about 71 or 72 to actually hit 70, so it will actually be closer to correct.

Of course I don't speed. Hah. Especially not in IL, land of the 55mph truck. I better quit, I suspect my eyes are turning brown the more I blather on....

RT said...

My car got hit with tread once after it flew off a truck that was passing by me.

Not fun. I'm especially careful during the hot, humid months. My local highway is littered with tread a lot of the time.

threecollie said...

We hear them do down on the Thruway every now and then...the first time I thought a cannon had gone off. Wow!
Glad you have new ones.

threecollie said...

Go, I mean go, not do