Freightliner M-2 Chassis Ride

[arthurhugh]

All,

On my 2006 DynaMax DynaQuest 302 ST (Freightliner M2-106 chassis), I am generally very pleased with its ride - with one exception. When cruising down the Interstate at moderate speed (55-65 mph) and I pass over a bridge crossing and if the pavement is not very level and it dips up and down (seems to be usually the case) the Dyna front end will "hobbyhorse" up and down so strongly we can almost be bounced off our seats! It seems to me to be a function of its wheelbase, heavy rear axle loading and long rear overhang that aggravates this condition. I first thought the front shocks must be worn out but they have only 18,000 miles on them. Seems unlikely. The vehicle is otherwise in first class condition, alignment right on and tires well balanced. Has anyone any insight into this "hobbyhorsing" phenomena and what would be a good approach to fixing or reducing it?

Art

[wolfe10]

Art,

Welcome to the FMCA Forum.

Even if shocks are only 18,000 miles old, they may not be the best shock for your application:

They are likely NOT high end shocks such as Koni or Bilstein.

They are likely NOT valved for your specific application (sounds like you need more dampening, particularly on rebound).

I would contact Koni and Bilstein and see what they have to offer for your M-2 chassis and how it differs from the OE shocks you have (suggest you crawl under and determine exactly what front shocks you have before calling them).

Brett

[arthurhugh]

Brett,

Thanks for taking the time to respond.

I have had Bilsteins on my RVs in the past and think they are the best. One problem I have is the DynaQuest chassis is really a Freightliner "truck" chassis M2-106)and it appears there are NO Bilstein listings for this application. So far I have struck out although I agree with you that from shocks are the most likely fix to this problem. The rear suspension is airbags with OE shocks. It seems to be well controlled.

ArtS

[wolfe10]

Art,

Ya, I would pick up the phone and call both Bilstein and Koni and discuss this with them:

Bilstein 858-386-5900. Kevin O’Keefe

Koni (859) 488-0339. Jim Ryan

You can tell them I suggested you call them.

Brett Wolfe

[arthurhugh]

Brett,

I want to thank you for passing to me the two names associated with Koni and Bilstein shocks I needed for my DynaMax. I spoke with Kevin at Bilstein and found him to be a real expert. That is just what I needed because there is no Bilstein listing for my Freighliner M-2 chassis but Kevin knew that the shocks were the same fittment as on a Safari Zanzabar so, based on his advice, I ordered them (no shipping cost, no tax, 89.95 ea) from ShockWarehouse in FL I got them a couple of days later and had them installed today. I am very happy with the improvement in ride. The "porpoising" I spoke of before is at least 50% reduced with no loss of ride comfort.

I hope to say "hello" at the FMCA rally in Winston-Salem NC in two weeks or at the CAT RV rally in Kerrville TX next spring. See you there.

Art Sturgis

[wolfe10]

Glad it worked out, Art.

Ya, Dianne and I will be at the Caterpillar RV Engine Owners Club Rally in Kerrville April 15-20, 2011.

My linkhttp://catrvclub.org/Buckhorn%202012/Buckhorn%20Rally%20Registration.pdf

Will have a couple of maintenance seminars and a lot of fun.

Brett