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colo.kids · 05-06-2012, 12:25 PM

As I posted earlier we are new owners of a 2004 Inspire and traded in our 2003 Itasca, which had a Freightliner chassis. Driving the "new" MH I at first thought a tire was out of balance due to vibrations above 60 mph, but now wonder if the steering box is too loose or there are suspension bushing issues. I also think the shocks are bad as there is lots of porpoising and bottoming out on dips in the roadway. Even at slower speeds the transfer of road roughness is IMO severe. The CC has 55000 miles.

Is this behavior characteristic of this suspension system vs the Freightliner, or is something amiss?

Thanks for your thoughts?

dons2346 · 05-06-2012, 01:54 PM

You mention "tire was out of balance due to vibrations above 60 mph". I can tell you from experience that a tire that appears in perfect balance can go out of round at highway speeds and you will get a vibration. The only way to find this out is to have them balanced on the coach by spinning them up to the RPM than they would see at and above 60MPH and watching the tire for runout. Not a lot of tire places will do it that way but it is the only way.

If you are bottoming out, you could have three problems, all a cheap fix.

First thing to check is your ride height and make sure it is in spec.

I think that coach came with the red adjustable Koni shocks. If so, they were probably set at the factory on the soft setting. Adjust them up to the firmest setting.

The last thing is tire pressure. CC recommends the max pressure for the tires as they do not know how an owner would load the coach. Therefore, they assume worst case. Have your coach weighed and adjust the pressures accordingly. That alone will make a huge difference in ride quality.

colo.kids · 05-07-2012, 07:52 AM

I will weigh the coach asap and adjust tire pressure accordingly. I am trying to find out how to adjust the shocks, which are Koni, as a first step. I hope they are not needing replacement as they are $$$. The tire rebalance is of course easy and that will be done for sure.

Thanks for the recommendations,and I am glad you did not say something like, "these coaches at that mileage are known to require major front end work for worn bushings and linkages."

dons2346 · 05-07-2012, 08:34 AM

Well, my chassis is pretty much the same as yours and I have 99,000 miles on it. The only thing,other than normal lube, is to change out the Konis to Road King. Huge difference but big bux. It was worth it to me.

You can find out how to adjust the Koni shock here http://www.koni-na.com/pdf/tech.pdf

B Bob · 05-07-2012, 06:55 PM

dons2346 is giving you some good tips colorado kids. Our coach has 102,000 miles and or original equipment Koni's work well. It is possible to bottom out our front end but hard. I suspect what don said will work. Get your tires balanced to see if that cuts out the vibrations. I have owned our coach close to three years and never balanced the tires. They are very smooth at 60.

I don't know where you live but our roads in California have really become terrible. On smooth roads our coach is like a magic carpet. Glides almost noislessly down the road at 60-65. But when the roads get bad the noise goes up a LOT!!!! I have tried lots of different air pressure settings. The noise is about the same. So I go with the factory settings as the handling is better.

KIX · 05-07-2012, 07:10 PM

We have had success in balancing using Dynabeads. They can be installed without breaking the tire down off the wheel. The8ir website will advise how much to use.
Tire Balancing Products

colo.kids · 05-07-2012, 08:30 PM

It seems the consensus is that it is a tire balance issue and I will proceed accordingly. Thanks to all those who offered suggestions.

dons2346 · 05-07-2012, 08:43 PM

Quote:

Originally Posted by KIX

We have had success in balancing using Dynabeads. They can be installed without breaking the tire down off the wheel. The8ir website will advise how much to use.
Tire Balancing Products

Balance is one thing, going out of round at speed is another. Balancing beads will do nothing to correct an about of round condition.

A tire can be in prefect balance and still go out of round at speed. I know, I went through this with an original tire and it took a good truck shop to find it. Bob Dickman in JC spent two days playing with changing tires, remounting tires, changing the inside dual wheels, etc. and never solved the problem as they do not spin the tires on the coach or do any run out checks.

If there is some shimmy, it could also be alignment.

KIX · 05-07-2012, 08:58 PM

Quote:

Originally Posted by dons2346

Balance is one thing, going out of round at speed is another. Balancing beads will do nothing to correct an about of round condition.

A tire can be in prefect balance and still go out of round at speed. I know, I went through this with an original tire and it took a good truck shop to find it. Bob Dickman in JC spent two days playing with changing tires, remounting tires, changing the inside dual wheels, etc. and never solved the problem as they do not spin the tires on the coach or do any run out checks.

If there is some shimmy, it could also be alignment.

Did I say something about balancing beads curing an out of round tire issue???

Smitty77 · 05-08-2012, 10:09 PM

IMO, good input from the gang. I'll add the input from my research of our 04 Allure. Our front end would sometimes bottom out, and yes I too felt the front took too long to stop bouncing. These are the Koni SP1 Adjustable shocks, that many (including Koni) felt were undersized for these rigs. Set our front to the highest setting of ride height spec range. And our shocks to the highest setting too. Was better, but still not what I wanted.

I added Road Kings, very pleased. I had a credit from the first owner, or I probably would have gone with the newer Koni SP3, third generation Adjustable. I would have started these a settin 3, fronts, and seen how I liked the ride.

Best of luck,
Smitty

dons2346 · 05-08-2012, 10:44 PM

Road Kings are what I installed. Light years ahead of Koni for a heavy coach.

colo.kids · 06-07-2012, 08:52 AM

I thought I should bring this post full circle for closure. For the most part the issues have been resolved by adjusting the ride height (which was about 1.5 inches too low due to a bent valve bracket), installing new shocks (Koni), and adjusting air pressure in the tires. The coach now rides and drives great, though there remains more road feel in the steering wheel than I am accustomed to (but have been told that is characteristic of IFS compared to solid axle setups like my previous Freightliner/Winnebago)

Thanks for all the suggestions and interest.

Smitty77 · 06-10-2012, 09:26 AM

Thanks for the update, that is always good to hear the way things final out... Glad your adjustments have worked...

Down the road (pun intended), do a look into the Super Steer Motion Control Units, not a very expensive addition, and they have worked well for us.

We also added Centramatics on all axles, as part of our base line purchase. If you bought the Koni SP3 adjustable shocks, tuning the firmness settings can also help on the road feel. One gent with a 36' Allure of your era, has his rears set to setting four, and his fronts set to setting 3. He finds that to work well for his coach, but he admits he likes a firmer 'controlled ride' vs floating...

Go have some fun

!
Smitty

colo.kids · 06-10-2012, 04:58 PM

Thanks Smitty. I am somewhat aware of MCUs but have little knowledge of Centramatics. They sound like a good alternative to a re-balance of the front tires, which runs $120. I assume you feel they are worth the cost.