Getting Blown Around

[Eric]

As we start our trek north from Nashville Tn To Grand Island Nebraska last years wind trouble comes to mind. A small breeze, a semi, even an S&S unit passing us usually launches the bus across the road with a pretty good amound of force. Any thoughts? The suspension seems to all check out is it just our size?

1985 Neoplan An440

[Len Silva]

I don't know anything about the Neoplan, but it definitely should not behave that way.

Front end alignment

Front radius bushings (if you have them)

Rear alignment

Rear radius bushings

Shocks,  Proper ride height

Tire pressure, especially if over inflated

[Eric]

Tires I check Religiously rears @ 100psi and fronts @ 115 every stop everytime! I have no "play in my steering and all seems tight. Airbags are new and keep the axles equadistant from the body. how does one check the shocks on something this big? can't exactly bounce on the hood and see it wave or anything the look recent as they are bright blue and shiny but i guess looks can be wrong! how would one check rear alignment without taking it to a shop? will a bus "dogtrail" like an old car? Thanks in advance!

[lostagain]

Your tire pressures seem high to me. I don't know how much your coach weighs though. Have you checked the tire manufacturer's web site for proper inflation according to each axle's weight? If your tires are indeed too hard, it would wander on the highway.

JC

[Eric]

I have them inflated per Neoplans Specs stamped on the bus if i go by manufacures weight rating i would be running 85 and 90psi but the tires show a pretty good bulge at the bottom when they are that low. kinda scary really!

[kyle4501]

Use the load / inflation pressure charts for your tires & have the bus weighed per axle & side to side. Very important information to have. If you are overloaded on one side, it will cause problems too.
Neoplan's specs are for the expected loading resulting from a load of passangers, I doubt you are that heavy. Get the weight on each wheel assembly & you won't have to guess.

Then take it to a good shop that understands buses and is willing to work with you to fine tune the front end alignment.

I know it isn't a bus, but my suburban was more than a handfull when pulling the TT. I checked & reset the hitch & equalizer bars. It didn't help much if any. (It drove perfect without the TT)

Finally, I took it in to have the alignment checked. It was within spec. I told the shop owner what it was doing & he looked closely at the tires. The technician didn't want to change anything, but the owner had him made a very small adjustment. I was skeptical, but, WOW!, What a difference! Steady as a rock, almost like being on rails. I was fortunate to have found a shop owner who really understands the subtleties in the alignment settings.

Oh yeah, the first thing the shop owner did was check the tire pressures.

[lostagain]

I bet Neoplan specs those pressures based on a loaded coach right at GVW. Does it weigh that much now? Experiment with a little less pressure and see how it behaves in a side wind.

JC

[Len Silva]

My first guess is that your tires are significantly over inflated.  The only way to set them accurately is to weigh each axle and set them per the tire manufacturer's charts.  Unless you are very heavy, probably more like 70-80 in front and 80-90 in the rear.

As far as alignment, toe in is probably the most critical.  If you don't have the manufacturer's specs, I think 1/4" to 3/8" minimum.  You probably don't have any control over caster and camber and unless it has been wrecked, they are probably OK.

Radius rod bushings are hard to check, if you are not sure of their condition, it's probably better to replace them all.  On my 4104, I found that finally replacing the rear bushings made the biggest difference in skittishness.

[Eric]

Thanks Everyone! We currently weigh 33k with GVRW being 38k I have been weighed axle to axle and side to side for load balancing purposes. Let me ask when the pressure on my tires is at the rated psi by the mfgr. the seem to "bulge" at the bottom is that "ok"?

[lostagain]

Yes it is OK. Radial tires are designed to do that. Mine are at 70 psi all around with bulges at the bottom. I check them often for temperature, and even in the hot summer on the freeway, they are allright.

JC

[kyle4501]

I'm sure the bulge was there when the manuf determined the load charts. If it was better to run at max pressure for all loads, the tire manufacturer wouldn't have created the load chart.

Radials often bulge more than seems necessary.

If it was me, I'd try an afternoon trip with the reduced pressures & see if it makes a difference.

[Eric]

Ok I'm going to drop the pressure down and give it a whirl! Thanks Everyone!

[Rick 74 MC-8]

Make sure there is clearance between the duels.  I'm sure there will be but if they are touthing they heat up and blow very quick




                                                           Rick 74 MC-8

[Utahclaimjumper]

My 06 is 85 rears and 90 fronts with a much better ride as a result.>>>Dan

[Chopper Scott]

I had a  right steer tire that was cupping on the inside edge. It wasn't bad unless you really looked at it. Maybe just the inside inch or so. It made the bus wander somewhat and really made a guy busy in conditions you described. I swapped a tag (same tire and such) with the front steer and it made a HUGE difference!!! Before the swap I could tell when they were coming up on me. Just something I noticed.