It was in Auto Expo 2012, when three Indian manufacturers – Ashok Leyland, Tata and AMW launched 37T rigid trucks, claiming first in India. 5 axles, 9 speed gear box for a haulage truck were a kind of first in Indian CV scene.This segment has some specific advantages like
- Highest payload for a rigid truck, which is upto 24T.
- Lower toll rates as compared to equivalent cargo carrying capacity of a tractor trailer.
- Regular skilled driver unlike a specially skilled driver for a tractor trailer.
- Lowest Ton KMPL – which means has the lowest cost of transporting goods.
These advantages will make 37T truck segment will grow in future and will be a must have product for truck manufacturers as well. These trucks are preferred in applications like
- Market Load
- Construction Materials
- Mining applications – Surface transport
- Tipping applications
- Agri Products
- Industrial Goods
- POL Tanker
- Chemical Tanker
- Edible Oil Tanker
Though there were common features, there was a difference in the position of 6T single tyre rear axle. A single tyre 6T axle by virtue of placement its called as Tag axle or Pusher axle. When the axle is placed in-front of drive axle its called pusher axle and if its behind its called tag axle.
Both Ashok Leyland and AMW had pusher lift axle and Tata had the tag lift axle. Later Mahindra launched Truxo 37 with tag lift axle,and subsequently Bharat Benz and Volvo Eicher started to offer pusher lift axle. Now things were really interesting, as each position of axle has its own merits and demerits and honestly there wasn’t global bench marking as well.
Globally there are lot of options available for placing an axle for a given load rating– we even have pusher lift axle tippers, tractors, which are application specific products, unlike India where a single truck configuration is sold to many applications. Of course we are also maturing, as we have application specific products in 31T rigid haulage truck like we have both options of twin steerable front axle and pusher lift axle. But in this case of 37T trucks, this being the first time, there were discussions among Customers, as each company claimed superiority over its design.We try to bring some of facts behind the same.
- Primary advantage of pusher lift axles in 37T trucks is the even weight distribution and gives a uniform load balance. This is experienced both during braking and acceleration. This solution is suitable for concrete pumps and larger truck-mounted cranes that need uniform axle load distribution and operate as special vehicles.
- Having a pusher lift axle, the same needs to be lifted during reversing otherwise will plough asphalt and scrub concrete, and will scuff tire treads. This will also impose high lateral stress on wheels and chassis components.
- Manually or automatically this needs to be lifted each time, otherwise you will require reverse-steering axles, whose geometry automatically shifts from forward to reverse and back again as the driver shifts gears.
- Since the pusher axle is a dead axle it tends to move tandem with the live axle which is just behind it. Also any play in the axle arm will lead to excessive tyre wear.
- The primary advantage of tag lift axle is reduced turning circle diameter and effectively will be around 1.5m lesser than pusher lift axles. This was one of the advantage promoted by Tata LPT3723.
- Also when weighed in a weigh bridge, the shorter weigh bridges can be utilised, unlike a full length weigh bridge required for pusher lift axle trucks. The tag axles can be lifted and weighed in a regular weigh bridge.
- With respect to demerits in tag lift axles, there were cases of frame cracks when operated with lifted condition
- Also in case of Tippler application, the loading bed wasn’t suitable for this design.
- Bellow punctures, were a common sight due to stone throw from live axles ahead of it. This led to run the truck with axle lifted condition leaving more stress on the frames and eventually leading to frame cracks.
- Rear most axle being with a single tyre, limits the rear over hang and may not be suitable for an extended RoH.
Considering various market feedback and sentiments, Tata has now switched to pusher lift axle and offering both variants – Tag and Pusher lift axle options in its LPT 3718, leaving only Mahindra Blazo 37 with tag lift axle. These are current market conditions, and we couldn’t see a clear application advantage of axle positions as in the case of 31T.
This segment will be emerging as a fast growing haulage truck segment, and eventually volumes will multiply in the forthcoming years. Going by the market feedback and acceptance for pusher axles, we may see good number of pusher lift axle products in this segment.