Double decker suspension upgrade

[Gertie]

We are about to add another level to our converted full size bus. Is it necessary to upgrade the suspension to accomodate the extra weight?

[jctrembly]

Originally Posted by Gertie

We are about to add another level to our converted full size bus. Is it necessary to upgrade the suspension to accomodate the extra weight?

Look at your bus data tag.

If your Front Axle is 10 or 12K lbs
And you Rear Axle is 20k or so

Stay under those and your fine, if you go above your axle rating, something on your bus is going to break at some point and it won't be pretty. In fact it could be very very not pretty.

Beside, if you go over your axle weight limit you may be over your road legal weight limit.

Currently, your bus springs and so forth are set up to carry your max axle limit. They only thing that may help is some type of sway bar.

Do replace your shocks, they are always over looked unless leaking and you may be pleasantly surprised at there cost.

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[Njsurf73]

Originally Posted by jctrembly

Look at your bus data tag.

If your Front Axle is 10 or 12K lbs
And you Rear Axle is 20k or so

Stay under those and your fine, if you go above your axle rating, something on your bus is going to break at some point and it won't be pretty. In fact it could be very very not pretty.

Beside, if you go over your axle weight limit you may be over your road legal weight limit.

Currently, your bus springs and so forth are set up to carry your max axle limit. They only thing that may help is some type of sway bar.

Do replace your shocks, they are always over looked unless leaking and you may be pleasantly surprised at there cost.

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+1 on the sway bar. You are going to be a bit too heavy.

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[cowlitzcoach]

I would suggest that before you do anything you take your bus to a scale and determine exactly how much your bus weighs currently.

You need to determine how much weight is on each axle right now. Until you determine that number you won't know who much more weight you can put on each axle before you are overweight.

Most full size school buses have more than enough reserve capacity to load on a lot of weight. But some buses, the FE buses in particular, can be relatively heavy when they are empty.

A guy I know built up a Blue Bird All American FE with a Cat 3208. After I had seen some pictures of how he built it out I asked how much weight was on each axle. I asked because it looked like he was weight biased too much towards the front .

After he got back from the scales he started to tear stuff out and reposition a lot of stuff. He had almost 13,000 lbs. on the front axle and just over 11,000 lbs. on the rear axle. In other words he was almost 3,000 lbs. over weight on his steer axle and had less than half the weight he could have had on the drive axle.

Regardless of who made the chassis under your bus and no matter who made the axles on your bus, the front axle will always be your limiting factor mainly because it has single wheels instead of duals. There was a reason why the GM Futurliners had dual wheels on the steer axle.

If you determine that your current suspension and axles are rated to carry as much more weight as you are planning to add I would also add some auxiliary air helper springs and heftier sway bars to take care the leans your bus will have while going through a corner or when the wind is blowing past you in a different direction from your direction of travel.

Good luck!

[jctrembly]

Well said cowlitzcoach . Your 100% right air helper springs would be an easy add on. Main thing like you said is staying under your axle weight and proper weight distribution.

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