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Foretravel Owners' Forum

Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: Elliott on April 22, 2024, 03:37:15 pm

Title: ORED 9R22.5 vs 10R22.5
Post by: Elliott on April 22, 2024, 03:37:15 pm
Hi all,

I'm currently working with Dave Ward on tires for my 1987 GV. I have 9R22.5 Toyo M170z on it currently. He doesn't have a 9R Michelin available but he does have a 10R22.5. My forum sleuthing indicates that Michelin 255/80R22.5 was a good replacement 7 years ago... is that still true?

Also, any comments on the Michelin XZE or XZLE line of tires?

Thanks as always
Title: Re: ORED 9R22.5 vs 10R22.5
Post by: Protech Racing on April 22, 2024, 04:23:07 pm
If you have the Cat with 4 spd like mine . 
          I just removed the 295/75/22.5  from the rear, and installed the 9R.
 Now my cruise RPM  increased to  2350 at 64 true.  From 2200.  So I lost a few MPH cruise speed and slight fuel mileage.
  The 9R is about 38.3 OD.    The 295 is about 39.8 OD .  The 10 R is about 40.1 OD. 
 The 255/80/ is about 38.5 about the same as 9R.
    I would fit the tallest tire  on my bus next time. due to gearing and speed . 
 I would not fit a smaller OD tire ever again.
 Measure your fender wells tho. Mine are 41  and may need trimming a little at the edges.
Title: Re: ORED 9R22.5 vs 10R22.5
Post by: Elliott on April 22, 2024, 05:30:04 pm
Quote from: Protech Racing –
If you have the Cat with 4 spd like mine . 
          I just removed the 295/75/22.5  from the rear, and installed the 9R.
 Now my cruise RPM  increased to  2350 at 64 true.  From 2200.  So I lost a few MPH cruise speed and slight fuel mileage.
  The 9R is about 38.3 OD.    The 295 is about 39.8 OD .  The 10 R is about 40.1 OD. 
 The 255/80/ is about 38.5 about the same as 9R.
    I would fit the tallest tire  on my bus next time. due to gearing and speed . 
 I would not fit a smaller OD tire ever again.
 Measure your fender wells tho. Mine are 41  and may need trimming a little at the edges.
My fender wells measure the same. What size tire are you running on the front?
Title: Re: ORED 9R22.5 vs 10R22.5
Post by: Elliott on April 22, 2024, 05:35:53 pm
I also have a local place that can get me some Toyo M154 tires that are 265/75R22.5 (38.4", almost exact same OD as my M170s). Out the door at $618/tire

Or Dave can get me 275/80R22.5 Michelins which are 40" in diameter at $601/ea + his $90 fee + whatever the shop charges to mount and balance ($50/ea?). So roughly $300 more for the michelins that may be running uncomfortably close to too big for up front.
Title: Re: ORED 9R22.5 vs 10R22.5
Post by: Protech Racing on April 22, 2024, 06:49:06 pm
 I had the 295 X 6 for 5 years, Swapped out the steers last year for 9R .  Steers about the same . maybe a little crisper with e 9R at 90# vs the 295 at 74# .    These buses will be at a light loading  on the tire load /pressure scale .
  Does your tach read the same  at Speed?  I have GPS , true speed.  My  OE speedo read about 9% high .
 I think that my gear is a 4;10 .  Love to have a 3.9
Title: Re: ORED 9R22.5 vs 10R22.5
Post by: wolfe10 on April 23, 2024, 04:02:42 am
Yes, options near in size to the 9R22.5 are Michelin 255/80R22.5 and other's 265/75R22.5.

10R will change effective rear axle ratio (higher road speed for a given engine RPM).
Title: Re: ORED 9R22.5 vs 10R22.5
Post by: Protech Racing on April 23, 2024, 02:03:05 pm
These need more gear. Not less .
Title: Re: ORED 9R22.5 vs 10R22.5
Post by: Elliott on April 23, 2024, 03:58:18 pm
I decided to go with the Toyos. Partly because they're a closer match in diameter and party because the local shop I've been dealing with has been fantastic and I'd like to build that relationship for the future.
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