RR8R improvements

[franktr]

I have a 2006 Cheetah and believe it is a rr8r chassis. I have about 44000 miles and the front tires have uneven wear. The front tires are a different brand than the rears so maybe this happened before. I bought the coach used. The rear tires need to be replaced due to age so I am going to change all 6 tires and have the front end aligned. I have been reading a lot about shock replacements but manly on the rr4r chassis. My ride is good to me but the coach pull to the right and feels a little loose in the steering. So new shocks? And is there a sway bar or steering stabilizer I should install? Thanks. I am thinking just get it all done once.

[jacwjames]

When I first bought our coach in 2008 the front tires had a bad wear pattern and a vibration in the front while driving. Once I had a complete service and inspection done I took it and had a front end alignment. My axle actually has to be bent to fix the alignement. Cost ~$400.

I then 2 new Bridgestone R250 tires. Have ~50K miles on the front tires and they still look like new, will probably rotate them to the rear to get a couple more years on them.

[jrusselltx]

You didn't give the brand of front tires, but the Goodyear RV tire has a known problem of "rivering" when used on the front. My 2007 had that problem with the fronts, the rears were fine. Caused a lot of bouncing and wandering going down the road until they were replaced.

[franktr]

Originally Posted by jrusselltx

You didn't give the brand of front tires, but the Goodyear RV tire has a known problem of "rivering" when used on the front. My 2007 had that problem with the fronts, the rears were fine. Caused a lot of bouncing and wandering going down the road until they were replaced.

I do have Goodyears in the front about 6 years old and Saliun in the rear about the same. As I said I will replace all with either Michelin or Toyo still on the fence and would like some input on shocks.

Thanks

[CampDaven]

Originally Posted by franktr

I do have Goodyears in the front about 6 years old and Saliun in the rear about the same. As I said I will replace all with either Michelin or Toyo still on the fence and would like some input on shocks.



Thanks

My opinion is that you should start with new tires that have pressures set per the appropriate inflation table, AFTER doing a 4-corner weigh-in. Then see how it rides and handles. It may be just fine!
I have an 08 RR10S chassis that acted like yours. The above was all that was needed. I still have a slight right tendency but only on crowned roads. And I don't expect any issues with shocks until I am way past 100K miles.
I am among many that wish Roadmaster still made these amazing chassis!
Best wishes


Dave and Nola, RV Mutants

[franktr]

Originally Posted by CampDaven

My opinion is that you should start with new tires that have pressures set per the appropriate inflation table, AFTER doing a 4-corner weigh-in. Then see how it rides and handles. It may be just fine!
I have an 08 RR10S chassis that acted like yours. The above was all that was needed. I still have a slight right tendency but only on crowned roads. And I don't expect any issues with shocks until I am way past 100K miles.
I am among many that wish Roadmaster still made these amazing chassis!
Best wishes


Dave and Nola, RV Mutants

Thanks. I did weight mine but front and rear not all four corners and around 10K front and 20k rear so I have 90 psi in all tires. Can or should you put a steering stabilizer on this chassis?

[CampDaven]

Originally Posted by franktr

Can or should you put a steering stabilizer on this chassis?

You can, but you need to try the simple stuff before reaching for a mechanical bandaid that will only partially mask the real cause.
If you are heavier on one front tire than the other it can do weird things. I adjusted the load to get a closer balance and put 10psi in the heavier front side. A big difference AFTER a weigh-in and new tires. Alignment check too


Dave and Nola, RV Mutants

[96 Wideglide]

Originally Posted by CampDaven

You can, but you need to try the simple stuff before reaching for a mechanical bandaid that will only partially mask the real cause.
If you are heavier on one front tire than the other it can do weird things. I adjusted the load to get a closer balance and put 10psi in the heavier front side. A big difference AFTER a weigh-in and new tires. Alignment check too


Dave and Nola, RV Mutants

That's not recommended. All tires on the same axle should be air'ed equally.
If the heavy side needed an extra 10psi, the lighter side should get that extra 10psi as well !

[Dennis_K]

Originally Posted by franktr

I have a 2006 Cheetah and believe it is a rr8r chassis. I have about 44000 miles and the front tires have uneven wear. The front tires are a different brand than the rears so maybe this happened before. I bought the coach used. The rear tires need to be replaced due to age so I am going to change all 6 tires and have the front end aligned. I have been reading a lot about shock replacements but manly on the rr4r chassis. My ride is good to me but the coach pull to the right and feels a little loose in the steering. So new shocks? And is there a sway bar or steering stabilizer I should install? Thanks. I am thinking just get it all done once.

X2 on the Goodyear tire issue. I replace my fronts at 20,000 miles. At 30,000 the rears are doing it too so the problem is not limited to the fronts.

If your shocks are original then you definitely need new shocks. I replaced mine at 12,000 miles, I recommend the Koni FSD units.

For looseness in the steering you need to read the threads in this forum titled "Steering Box Play- Sheppard M100 SHIM or Swap for a TRW ?" and "Wandering, sway bars, alignment, ride height, oh my!!". I have done both and my coach drives very nice now.

Don't add a steering stabilizer until you get everything else corrected. They mask the other issues.

[Gdawgs]

Guess I'm lucky. I have the RR10R and I to wish that chassis was still around. I'm running GY 295's all around. Factory setting is 85 PSI on tag and drive axle and 100 PSI on the front tires. I'm slowly increasing the front pressure after seeing a little more wear on the edges at 20K miles, rears are wearing fine. Coach runs very smooth and straight as an arrow at highway speeds and sometimes I'm at 80MPH before I realize it. It's so stable and dead silent. Can't hear the motor, wind noise and only hear the Allison shifting at low speeds. Maybe I need to have another coffee and have my ears checked.

[CampDaven]

Originally Posted by Dennis_K

If your shocks are original then you definitely need new shocks. I replaced mine at 12,000 miles, I recommend the Koni FSD units.



.

Not necessarily!
My 09 RR10S shocks have 60K miles and are perfect, and expect over 100K. Don't know what they are. Must be unique to the older Roadmaster? I don't think your Knight has that chassis. Am I right? Or possibly the RR4R?



Dave and Nola, RV Mutants

[96 Wideglide]

Originally Posted by Gdawgs

Guess I'm lucky. I have the RR10R and I to wish that chassis was still around. I'm running GY 295's all around. Factory setting is 85 PSI on tag and drive axle and 100 PSI on the front tires. I'm slowly increasing the front pressure after seeing a little more wear on the edges at 20K miles, rears are wearing fine. Coach runs very smooth and straight as an arrow at highway speeds and sometimes I'm at 80MPH before I realize it. It's so stable and dead silent. Can't hear the motor, wind noise and only hear the Allison shifting at low speeds. Maybe I need to have another coffee and have my ears checked.

Have you ever run it across a scale?

Little surprised your steers only require 100psi, when mine require 115. Is your water tank in the front bay, directly behind your fuel tank?

[Steve Ownby]

Originally Posted by 96 Wideglide

Have you ever run it across a scale?



Little surprised your steers only require 100psi, when mine require 115. Is your water tank in the front bay, directly behind your fuel tank?

The difference is, his has a 13k steer axle and you have a 14.6k. Same tire size.

[Gdawgs]

Originally Posted by 96 Wideglide

Have you ever run it across a scale?

Little surprised your steers only require 100psi, when mine require 115. Is your water tank in the front bay, directly behind your fuel tank?

Factory calls for 100 PSI. I'm running 105 for a while and will probably settle around 108-110. Fully loaded I'm right at 40K lbs. TMS runs about 115 on the front with ambient temps in the 80's and tire temps in the 80's also.