Does anyone know why tippers and ro-ro’s still tend to use spring suspension?
The only reasons I can guess at is either
1 air bags would be more prone to failure with large amounts of weight deposited quickly
2 a sudden air bag failure when tipping could cause it to roll over
Does anyone know why they don’t use air other than my guesses above?
Some of the tippers do have air suspension,I was loading at a quarry and sat there waiting for the shock.I waited and waited the guy in the tower blew his bummer (horn) then came out demanding to know what I was waiting for.Well you all know how understanding and laid back those guys are.I honestly didnt know that 14 tons had been dropped on me.If I was in a motor with steel springs I would have been tossed about the cab like a cork.
I can’t speak about tipper’s but our RO-RO use’s a pair of ram’s that push onto the springs to keep the front from lifting when hooking up a heavy bin.
Mabye that wouldn’t be possible if it was fitted with bags.
I don’t think it’s that the airbags would go more often than leaves - although some of the ■■■■ places they go, they could get damaged or perish due to the mud - as much as a broken leaf is cheaper to repair / replace and get the truck back on the road.
Armstrong is the man in the know.
Foden offered air susspension on 8 wheelers from the early 90s only ever saw one though.
kr79:
Foden offered air susspension on 8 wheelers from the early 90s only ever saw one though.
Yep, had 1 while working for T. Baden Hardstaffs early 90’s. G916YJF 8wheel crane lorry then M819JFP same sort of motor. The latter is still about on some fairground work and is now white 
We got ro ro’s on steel but most of the drags have air now. Used to be cheaper tax but not now for ours. Don’t know why 
Anything to do with off road and tipping stability on loose ground?
Never had a tipper with air susp but did have one with rubber susp, couldn’t articulate and maintain equal grip anywhere like an upside down single spring double drive bogie (Leyland Constructor had the latter and would go almost anywhere the track layer could).
Although the Norde sus dosent give much its probably the lowest maintenance bogie there is and certainly the lightest ,the MAN bogie is excellent for off road conditions, again low maintenance keep the trunion bearings greased ,my cousins 8 wheeler MAN had trunion bearings in 17 years of opencast pits tips and quarries fit only for dumpers and nothing else, a part from spring leaves which break depending on the type of work,the down side is the MAN can be very heavy unladened {12 tonne plus unlike the 10 tonne ish foden }but will grip very well,the older generation say the non reactive sus gives excellent grip but very high wear/maintenance such as rievers and early B series,in my opinion air cant transfer in and out of the bags quick enough on a double drive in off road conditions resulting in traction loss ,as for air sus when tipping the best way is to let it go or at least when tipping on rough ground or tipping bales or OA ect.
I agree with Dan that the Norde/Rydwell/Foden back end was brilliant in that virtually nothing wore out, the Elephant’s Feet were changed sometimes, however I also agree that they were not ideal for site work etc due to the inflexibility of the design. The Sed Aks and older Foden’s we ran with balance beam and springs were better off road, until it came to Test Time! Virtually every bush and bearing would be worn out. I guess that the single inverted spring like Scammell and Leyland was best apart from the weight penalty?
Pete.
The simple answer really is air just hasn’t taken off in this market. You would think it’d give you major advantages in being able to level off the wagon before tipping if the ground wasn’t perfectly flat, but still you’ll find pram springs lead in this sector. Maybe it is a reliablity issue, I really don’t know.
Juddian:
Anything to do with off road and tipping stability on loose ground?Never had a tipper with air susp but did have one with rubber susp, couldn’t articulate and maintain equal grip anywhere like an upside down single spring double drive bogie (Leyland Constructor had the latter and would go almost anywhere the track layer could).
Leyland’s floating axles had a lot to answer for with that. My dads Constructor 24-23 was fantastic and really would go anywhere. The DAFs still use a very similar system and it shows, Any DAF or Scania drivers mention Difflocks in the quarries and the Volvo lads are unpacking the ropes, either for a tow or to hang themselves 
Air bags dont get anywhere near Hendrickson Norde suspension on rough ground.
The shockers end up doing most of the work and fail in no time.
Most decent tippers have reduction axles and “hard suspension”
dew:
The simple answer really is air just hasn’t taken off in this market. You would think it’d give you major advantages in being able to level off the wagon before tipping if the ground wasn’t perfectly flat, but still you’ll find pram springs lead in this sector. Maybe it is a reliablity issue, I really don’t know.Dead right you dont really know ,levelling the wagon before tipping?what do you think happens when you pull forward? or if load dosent move ? over you go!
Dan Punchard:
dew:
The simple answer really is air just hasn’t taken off in this market. You would think it’d give you major advantages in being able to level off the wagon before tipping if the ground wasn’t perfectly flat, but still you’ll find pram springs lead in this sector. Maybe it is a reliablity issue, I really don’t know.Dead right you dont really know ,levelling the wagon before tipping?what do you think happens when you pull forward? or if load dosent move ? over you go!
I don’t mean trying to tip on a 45 degree angle ffs, I just mean on a rough ground you could flatten the truck off before the body went up, ■■■■ sight more stable to tip than if it’s leaning off. If the load doesn’t move your in trouble no matter what springs are attached to the wheels, if your lucky all it does is lift the front axle off the ground, which is scary enough by itself, or the ram goes and the whole lot goes over sideways for a lie down.
I have quite a bit of experience with tippers, so it’s an educated guess