Community Forums

deandec · 03-04-2014, 02:26 PM

Hello all. I know there are some folks on this board that have rigs similar to mine.

It is a 1995 Magna, 38 foot DP that originally had 10R-22.5 tires installed by Country Coach.

Has anyone installed a 295/75-22.5 size tire on the rear duals of a similar rig?

If so, are you happy with the result?

If not, did you replace with yet another size tire?

Ron Burgundy · 03-07-2014, 01:16 AM

Yes! Did exactly that on my 1992 affinity (also a gillig) a few months ago. I am very happy with the results.... Good ride quality, more common tire size allowed more tread options, and increased load rating. In my mind, it was and is a no brainer....can't really think of any reason not to go this route. Good luck!

deandec · 03-07-2014, 08:54 AM

Ron, thank you for sharing your experience. I have yet to measure the clearance at the duals, but it seemed to be doable.

I really would like to install a tire that does not require max air pressure to carry the rated front axle load. The 295/75R will accomplish that mission.

Ron Burgundy · 03-09-2014, 04:19 PM

Excellent! Let me know how it goes!

deandec · 03-10-2014, 10:57 AM

Well, I did the replacement on the steer axle. The rear axle can run for a few thousand miles more. 295 on the front with 10R on the rear.

Ron Burgundy · 03-11-2014, 07:38 PM

Out of curiosity, what's your weight front and rear and what pressure are you running in the tires. I'm almost exactly 20,000 rear and 10,000 front and am running 105 psi..... Considering dialing it down a bit.

deandec · 03-12-2014, 11:05 AM

My rig weighs 11,360 front (also is the axle rating) and 18,800 rear (20,320 axle rating).

With the 10R-22.5 tires the chart says I am ok on the front with no margin and the tires at 115psi. 115psi is also the maximum inflation for the tire. (I have to inflate the tire with a 6 gallon pancake compressor to get the 115psi into the tire.)

On the rears, the chart says I can run at 90psi for my 18,800# load but can achieve a 2,000# cushion by running at 115psi. So the 10R is fine for the rear. I run the rears at 95psi.

Of course, I understand that 20,000# is the max legal carrying weight for a rear axle.

Ron Burgundy · 03-12-2014, 09:07 PM

Gotcha. What about with the 295's on the front? Dialed that in yet?

deandec · 03-13-2014, 10:12 AM

Grand total of 1 mile on the new fronts.

I have to drive more than 50 miles at highway speed to break the Equal balancing powder bags loose. Then I will know what I have for performance.

336muffin · 03-13-2014, 10:22 AM

For the steer tire, you might want to check ou the Michilan XCoach.

deandec · 11-30-2015, 12:43 PM

Quote:

Originally Posted by Ron Burgundy

Gotcha. What about with the 295's on the front? Dialed that in yet?

Well, I now have about 4,000 miles on the Front 295's at 100 psi.

They seem to be perfect.

Now shopping for the rears. If I go 295's there, I will have only one size tire on the whole rig. That seems to be the answer although more expensive.

That is what I will do.

Ron Burgundy · 11-30-2015, 10:53 PM

I don't think you will regret the 295s. I'm continuing to be pleased with the set up.

deandec · 12-07-2015, 11:11 AM

After lots of vacillating and a bit of better research, my final decision was to stay with 10R 22.5 Toyo M170 tires on the drive axle.

The reasons were:

$50 per tire less cost with the 10R 22.5.

19 pounds lighter per tire than the Toyo M154 295R optional tires so perhaps best fuel efficiency decision.

The 10R tires have the same Revs/Mile and Inflated Diameter as the current Toyo M137 295's on the Steer axle.

The 10R tires already provide a 20 psi inflation cushion. More than I use at the rear axle.

295/75R options were 1.2 Inches wider than the 10R tires so the gap between rear duals would be reduced significantly.

I carry an unmounted 10R spare tire that can replaced all of my tires in a pinch with few problems.

Since we age out tires rather than wear out tires, I calculated no gains from the heavier and wider rear tire option for the additional cost.

It is done.

Thanks for all the assistance in this process.

Ron Burgundy · 12-07-2015, 11:02 PM

Good reasoning and enjoy the new tires!

One factor that played into my decision that probably wouldn't apply to most folks is the aggressive tread pattern options available in the 295 size. Most trips I take involve a significant amount of snow driving. I have Ohtsu brand tires with an open lug tread pattern on my drive axle...similar to what is used on off road log trucks. If I recall correctly, this wasn't available in the 10r size.
If I wasn't driving in the snow on a regular basis, I probably would have gone with a highway tread, possibly pushing me to the 10r size.