I would be interested to know why small lift axles are used on certain units - mainly it seems for bulker work.
I was told years ago there was no reason but the units have a lower road tax… weight distribution is the same. One driver told me the small tyres were very expensive compared with standard size… so that doesn’t seem to add up.
There must be a reason and i’d just like to know. Anyone who drives one please let me know.
Weight saving.
Star down under.:
Weight saving.
+1…
Tiddly tyres = mo’ money.
More chassis space for hydraulic tanks, blowing equipment etc.
Beau Nydel:
More chassis space for hydraulic tanks, blowing equipment etc.
Ah yes that makes sense. The hydraulic oil tank for the tipper/bulker must take up extra space.
Also more space for bigger diesel tanks when there was a marked diff in price between NI and ROI.
Fill in ROI then on boat and run about GB on cheaper derv.
On 3day “trip work” your filling up again when back on boat through Dublin so run all week+ on cheaper derv!!!
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Big Truck:
Also more space for bigger diesel tanks when there was a marked diff in price between NI and ROI.
Fill in ROI then on boat and run about GB on cheaper derv.
On 3day “trip work” your filling up again when back on boat through Dublin so run all week+ on cheaper derv!!!
That’s true - now i recall a lot of the European trucks have the small lift axle hidden by a panel and also large diesel tanks either side.
Star down under.:
Weight saving.
I don’t know the answer but I would say this ^
I’ve never had one myself, but I was told by an owner driver who used to have one that he got rid at the first opportunity. Claimed that the smaller wheels used to put more strain on the wheel bearings when maneuvering, dragging them sideways as they weren’t a steer axle.
Even now I’m not sure if this is bs. It’s got just enough plausibility that it might be true though. I’m not in a position to judge. Maybe someone actually knows one way or another?
I’ve never used them, and never really looked into it, but always wondered,…
How does a smaller wheel, still carry the same weight? There must be a weight penalty, which must be offset by something else…
WhiteTruckMan:
I’ve never had one myself, but I was told by an owner driver who used to have one that he got rid at the first opportunity. Claimed that the smaller wheels used to put more strain on the wheel bearings when maneuvering, dragging them sideways as they weren’t a steer axle.Even now I’m not sure if this is bs. It’s got just enough plausibility that it might be true though. I’m not in a position to judge. Maybe someone actually knows one way or another?
Only had experience of them working at Daf. Can’t recall many wheel bearing failures but forever changing the discs on them due to cracks.
WhiteTruckMan:
I’ve never had one myself, but I was told by an owner driver who used to have one that he got rid at the first opportunity. Claimed that the smaller wheels used to put more strain on the wheel bearings when maneuvering, dragging them sideways as they weren’t a steer axle.Even now I’m not sure if this is bs. It’s got just enough plausibility that it might be true though. I’m not in a position to judge. Maybe someone actually knows one way or another?
Standard fare here and many other places in the world, is bogie drive. Front wheel bearing wear is not a major issue in Australia.
It’s for weight saving so that you can carry more payload, which is paid on the weight you’re carrying.
I think on my truck if you add up all the axle weights you get to 50.5t but obviously you can only load it so that you’re not more than 44t. This gives flexibility on where the load is positioned.
So by having an axle that can carry say 4t instead of 7.5t you lose some of that flexibility on where the load is positioned, but that’s less of an issue with bulk jobs but you might gain half a ton for your payload.
And doesn’t everyone lift a none steering axle when loaded and manoeuvring?
md1987:
WhiteTruckMan:
I’ve never had one myself, but I was told by an owner driver who used to have one that he got rid at the first opportunity. Claimed that the smaller wheels used to put more strain on the wheel bearings when maneuvering, dragging them sideways as they weren’t a steer axle.Even now I’m not sure if this is bs. It’s got just enough plausibility that it might be true though. I’m not in a position to judge. Maybe someone actually knows one way or another?
Only had experience of them working at Daf. Can’t recall many wheel bearing failures but forever changing the discs on them due to cracks.
Thx for your reply. I appreciate your response. Forgive my curiosity… from what you have written you are a technician. Why should the tag axle have disc brakes? If there are disc brakes on the front and main rear axle - why should the tag axle have discs. Cracks appear due to cooling issue. Somehow the heat is not dissipated properly. In design the braking requirement is considered and should take place on front axle and main rear axle where the most weight is.
the nodding donkey:
I’ve never used them, and never really looked into it, but always wondered,…How does a smaller wheel, still carry the same weight? There must be a weight penalty, which must be offset by something else…
I thank you all for your responses. Presumably if a unit with a front and rear axle can take 40T… then the requirement for a tag axle is only 4T - instead of 8T. [8T per axle is weight per axle i have understood].
So from our responses it seems that the small tag axle offer more chassis space for either a bulker hydraulic tank or large fuel tanks which is what many European trucks seem to have fitted.
jessejazza:
md1987:
WhiteTruckMan:
I’ve never had one myself, but I was told by an owner driver who used to have one that he got rid at the first opportunity. Claimed that the smaller wheels used to put more strain on the wheel bearings when maneuvering, dragging them sideways as they weren’t a steer axle.Even now I’m not sure if this is bs. It’s got just enough plausibility that it might be true though. I’m not in a position to judge. Maybe someone actually knows one way or another?
Only had experience of them working at Daf. Can’t recall many wheel bearing failures but forever changing the discs on them due to cracks.
Thx for your reply. I appreciate your response. Forgive my curiosity… from what you have written you are a technician. Why should the tag axle have disc brakes? If there are disc brakes on the front and main rear axle - why should the tag axle have discs. Cracks appear due to cooling issue. Somehow the heat is not dissipated properly. In design the braking requirement is considered and should take place on front axle and main rear axle where the most weight is.
Disc brakes are pretty much the norm now, there would be no reason not to fit them to the tag/lift axles really.
On drums heat dissipation would be far worse.
Daf discs crack for fun generally anyway. They were basically the same size components you’ll find on a 7.5tonner front axle brake setup. So they took quite a bit of stick fully loaded.
Typical small mid lift max axle weights limits are typically between 4.6 and 5.5 tons, there might be the odd one higher or lower, MANs are at the higher end possibly because the tyre/wheel is slightly larger than on other makes.
Obviously this makes 5th wheel positioning more important than on tractors with full size mid lifts to avoid overloading that axle, but 5th wheel positioning is more important than some realise or care to make safe handling, especially cornering in the wet.
Interesting to hear about Dafs cracking the mid lift discs, that rang a bell, colleague’s Daf needed new mid lift pads at 90k, MAN still has 70% of original mid lift pads left @ 580k, half of both mileages will have been at close to max GVW so mid lifts will have spent the same percentage of time in use at similar weights and usage, irregular drivers tend also to drive the things empty with the mid lift down 
^^^ just checked the brake lining display on my 22 plate with 184k km on the clock, 99% middle axle! That’s because with a fridge carrying 26 pallets you have 6 pallets behind the trailer rear axle so the midlift very rarely drops even with for example 26 pallets of ice cubes on.
^^^ but then it also benefits from having a pro at the wheel…does he use it a lot when you’re off mate 
…i’ll get me coat and wear me gum shield when i see you next 
Juddian:
^^^ but then it also benefits from having a pro at the wheel…does he use it a lot when you’re off mate
