[tracer]

I took a look at the company flatbed trucks at our terminal and was surprised to see 99.9% of drive tires on them were ... 11R24.5, mostly GoodYear and Michelin. My current low profile Yokohamas 295/75R22.5 are reaching a point of 512 revs per mile where I'm doing 1,394 RPM at 60 MPH (too high for my Cat). I've been looking at the GoodYear G372A 11R24.5 which spins 471 times per mile. With 3.73 rears this would put me at 1,282 RPM at 60 MPH or 1,400 at 65.5 MPH. I know a lot of flatbed guys here use tall rubber... Question: how badly will this affect my steering if I lose the low profile tires and put on the 11R24.5? The sticker on the side of my truck cab says, "Your tire is 295/75R22.5".

I'm afraid the switch might screw up all the angles in the steering again. When I bought the truck it had 11R22.5 tires and steering considerably improved after I switched back to the "factory size" of 295/75R22.5s...

[sgreer78]

I don't see why it would do anything to your steering at all. You'll mainly notice that it won't pull as good as it did with LP22.5's because of the height difference, thus changing your overall gearing so to speak.

[heavyhaulerss]

I went from low pro 22.5 to 11r 22.5 & it may be slower pulling hills, but it gave me about 5 mph more top end.

[tracer]

Originally Posted by sgreer78

I don't see why it would do anything to your steering at all. You'll mainly notice that it won't pull as good as it did with LP22.5's because of the height difference, thus changing your overall gearing so to speak.

the side sticker on the door frame says, "your tire is 295/R7522.5". and when i went from 11r22.5 to low profile 295s, steering improved. with 22.5 tires the truck was following the grade or arch of the road, pulling to one side when the shoulder was lower than the center of the highway. i thought it was mis-alignment at first, but after many all-wheel alignments nothing changed. steering became normal only i returned to the original tire size mentioned on the door frame sticker - 295/R7522.5.

hence my fears about switching to "tall rubber"...

by the way, i talked to the tire guy in the shop this morning and he said their flatbed division trucks that have 24.5 tires are ... "probably 10 years old". he said, "we went away from that and are using 11r22.5 tires on all newer trucks now." makes one wonder if using tall rubber is a good idea...

[sgreer78]

Either way, the cost involved in going from LP22.5's to 11R24.5's would be ridiculous. It would probably be cheaper to just have your rears changed out to 3.55's or 3.42's.

[GMAN]

I prefer 24.5 tires. By the time you buy new wheels and tires you will spend a lot of money. I have one truck that has the low pro 22.5's that gets better fuel mileage than the truck that has the tall rubber. I think the difference has as much to do with gearing and aerodynamics than the tire size. If you decide to go with the tall rubber you might check to see if you can find someone who wants to go to the smaller wheels and is willing to trade wheels with you.

[moe]

Unless you already have the wheels(24.5) if you are ready for a new set of tires I would go with 11R22.5's The expense of new wheels off sets the benifits of the 24.5's I have a friend who made that change(from low pro 22.5's) and he was quite happy with the improvement. I run 11R24.5's and I believe that is the best size for your money. They cost a little more but they last longer, for two reasons, more rubber means less heat and if you run heavy loads thats important and less revs per mile adds up. Another positive aspect is the difference in height, many times a flat bed ends up on construction sites where just a little bit higher can make a big difference and if you ever do any of your own work it helps to be able to get under the truck. If you always run light loads in a dry van then there really isn't much benifit to 24.5's...... by the way 11R.22.5's are about the same height as low-pro 24.5's. .... They are close enough to run side by side if need be, I have had to do this from time to time on my trailers in emergency situations.

[tracer]

Originally Posted by moe

Unless you already have the wheels(24.5) if you are ready for a new set of tires I would go with 11R22.5's The expense of new wheels off sets the benifits of the 24.5's I have a friend who made that change(from low pro 22.5's) and he was quite happy with the improvement. I run 11R24.5's and I believe that is the best size for your money. They cost a little more but they last longer, for two reasons, more rubber means less heat and if you run heavy loads thats important and less revs per mile adds up. Another positive aspect is the difference in height, many times a flat bed ends up on construction sites where just a little bit higher can make a big difference and if you ever do any of your own work it helps to be able to get under the truck. If you always run light loads in a dry van then there really isn't much benifit to 24.5's...... by the way 11R.22.5's are about the same height as low-pro 24.5's. .... They are close enough to run side by side if need be, I have had to do this from time to time on my trailers in emergency situations.

I grew up under metric system, so for some strange reason I didn't realize a 24.5" tire needs a bigger rim I thought just the tire was bigger than a 22.5". Of course, now that I know that, it'd be too expensive to change from 22.5 to 24.5 because of having to get the new set of rims. I'd go back to 22.5"s but when I had Michelin XZA 3 11R22.5" as steers, the truck steered much worse than with the current Michelin XZA3 275/80R22.5.

The 22.5" tire was 6 mm wider, had a slightly bigger radius (19.3" as opposed to 18.6"), weighed 5 lbs more and spinned 502 times per mile, as opposed to 518 with the current LP. Everything else was the same. I have no clue why steering was affected in such a positive way when I put on 295s on the steers. Any ideas?

[tracer]

Originally Posted by GMAN

I prefer 24.5 tires. By the time you buy new wheels and tires you will spend a lot of money. I have one truck that has the low pro 22.5's that gets better fuel mileage than the truck that has the tall rubber. I think the difference has as much to do with gearing and aerodynamics than the tire size. If you decide to go with the tall rubber you might check to see if you can find someone who wants to go to the smaller wheels and is willing to trade wheels with you.

Here's a small table that sums up the differences between my Bad Tire and the Good Tire If anyone has any idea on why the truck was pulling towards the ditch when the Bad Tires were on, pls let me know. When I put the Good Tires on, the truck's steering became perfect (all-wheel alignment was done twice when the Bad Tires were on).

BAD TIRE
Michelin 11R22.5" XZA-3
Diameter: 41.3"
Loaded radius: 19.3"
Sidewall: 9.4" (41.3 - 22.5 / 2)
Width: 11.1"
Weight: 117.7 lbs
RPM: 502

GOOD TIRE
Michelin 275/80R22.5 XZA-3
Diameter: 40.1"
Loaded radius: 18.6"
Sidewall: 8.8" (40.1 - 22.5 / 2)
Width: 10.9"
Weight: 112.9 lbs
RPM: 518


I know when I changed from 15" rims and tires on my car to 16" ones, steering became much more sensitive. The 16" tire had the same diameter but a shorter sidewall and bigger width. I think a steer tire's width is the factor that affects truck's steering. Weight is probably important too.

[bob h]

Originally Posted by tracer

Here's a small table that sums up the differences between my Bad Tire and the Good Tire If anyone has any idea on why the truck was pulling towards the ditch when the Bad Tires were on, pls let me know. When I put the Good Tires on, the truck's steering became perfect (all-wheel alignment was done twice when the Bad Tires were on).

BAD TIRE
Michelin 11R22.5" XZA-3
Diameter: 41.3"
Loaded radius: 19.3"
Sidewall: 9.4" (41.3 - 22.5 / 2)
Width: 11.1"
Weight: 117.7 lbs
RPM: 502

GOOD TIRE
Michelin 275/80R22.5 XZA-3
Diameter: 40.1"
Loaded radius: 18.6"
Sidewall: 8.8" (40.1 - 22.5 / 2)
Width: 10.9"
Weight: 112.9 lbs
RPM: 518


I know when I changed from 15" rims and tires on my car to 16" ones, steering became much more sensitive. The 16" tire had the same diameter but a shorter sidewall and bigger width. I think a steer tire's width is the factor that affects truck's steering. Weight is probably important too.

Low profile tires have less sidewall flex.