[Jimmyjosek]

Hello friends;

I have never seen the chassis of a multi axle bus before. I am sure most of us here too must not have seen one. Had the chance of seeing one during Scania plant inauguration. Posting pics for you. I am sure it will be interesting.

As you can see the original chassis length is short. There are screws and rivets in the middle that are used to extend it.

1. Scania multi axle chassis

2. The bolts and rivets in middle are extended to the desired length

3. Rear side of the chassis

4. View from back

5. The massive 410 hp Scania engine

6. View from the other back. Radiator

7. Steerable rear axle mechanism

[TheARUN]

Its very similar to a Mercedes Benz and Volvo chassis

The point I noted is that Scania takes good care of the chassis while transporting, the sheet protecting the electronics for example. Also good to see an uncovered engine, shows the confidence the manufacturer has that the engine even if left open to the elements will not be affected

Always wondered what was in those boxes mounted mid-way, the plywood boxes! Have seen them on many chassis

[gschandra]

1. Scania multi axle chasis

2. The bolts and rivets in middle are extended to the desired length

3. Rear side of the chasis

4. View from back

5. The massive 410 hp Scania engine

6. View from the other back. Radiator

7. Steerable rear axle mechanism

The 7th photo shown is not of the steerable rear axle mechanism. It shows the torque rods/radius rods of the rear air suspension. These are used to control the braking & accelerating loads and the lateral loads on the axle.

In case of air suspension, air springs/bellows are just like tire tubes which can take only vertical loads. Same is the case with coil springs in cars. So additional rigid links have to be used to resist and control the horizontal and lateral forces.

[audioholic]

Is it the pictures or is there a sag towards the end of the rear of the chassis? Or is it because of the weight at the rear?

Had visited this factory when it was in the final stages of construction. That time only the white Scania Bus was doing rounds around the factory. Will pay a visit sometime soon.

[a4anurag]

Originally Posted by audioholic

Is it the pictures or is there a sag towards the end of the rear of the chassis? Or is it because of the weight at the rear?

There is no sag but it made like that may be to keep the bus near to the ground and have a lower centre of gravity. But I have my doubts on ground clearance towards the engine end though I see engine guard at the base but still.

One thing I have noticed is that Volvo, Mercedes and now Scania are using Michelin as tyres in their fleet. What is that is special with Michelin that all use it?

Originally Posted by TheARUN

Always wondered what was in those boxes mounted mid-way, the plywood boxes! Have seen them on many chassis

It must be having the necessary tools and parts of the vehicle that need to be installed on a later stage. Some electrical components etc etc. Just my guess.

@ Jimmyjosek
Do you have any picture of the chassis from side showing it fully by its length?

Anurag.

[silversteed]

Originally Posted by a4anurag

One thing I have noticed is that Volvo, Mercedes and now Scania are using Michelin as tyres in their fleet. What is that is special with Michelin that all use it?

Michelins are perhaps one of the most comfortable and grippy tyres available. Even the KeSRTC, an STU, uses Michelins on their inter-state buses.

OT: For my car, if not for the higher tread wear owing to the softer compound, I would've gone for Michelin XM1+ instead of Bridgestones. The former has lower tyre noise and better grip

[a4anurag]

Originally Posted by silversteed

Michelins are perhaps one of the most comfortable and grippy tyres available. Even the KeSRTC, an STU, uses Michelins on their inter-state buses.

OT: For my car, if not for the higher tread wear owing to the softer compound, I would've gone for Michelin XM1+ instead of Bridgestones. The former has lower tyre noise and better grip

Nice to manufacturers thinking about grip, safety etc for their buses at least (indirectly passenger safety). I hope passenger safety also will come soon into picture.

The thing that surprises me is these Michelins are softer compound and with such load and speeds maintained by the buses, these tyres go bald faster than normal. I have seen many buses having a near-to-bald tyre on the dead axle. It is risky but no choice as the operators will use the tyre till dead bald.

Anurag.

[1100D]

Pity the driver who has to sit on that chair while delivering the chassis. Its just a normal folding chair attached to a wooden plank. Scania being international, should have done better, even though it would only be used only once.

Or is it a Demo-only Chassis which won't be driven on the roads, to an outside body builder.

[julupani]

Originally Posted by 1100D

Pity the driver who has to sit on that chair while delivering the chassis. Its just a normal folding chair attached to a wooden plank. Scania being international, should have done better, even though it would only be used only once.

Or is it a Demo-only Chassis which won't be driven on the roads, to an outside body builder.

It wont be driven on the roads at all. Its going to be transported by trucks.

And FYI, today there are specific requirements of structure surrounding the driver even in a chassis which is to be driven on the road like having a temp roof, front glass with operational wiper, full seat with seat belt etc. And that structure even has to be certified by the ARAI before it can be used on a chassis.

[Ashley2]

Originally Posted by a4anurag

Nice to manufacturers thinking about grip, safety etc for their buses at least (indirectly passenger safety). I hope passenger safety also will come soon into picture.

There is very less effect in terms of grip, safety for which they are prefered, rather they don't edge out competition on this, as tubeless tyres perse offer better safety compared to tubed radials. But they(Michelin) outperfrom in terms of over all tyre life including retread life. Almost 15% to 20% higher life and that's one reason they are prefered.

Originally Posted by a4anurag

The thing that surprises me is these Michelins are softer compound and with such load and speeds maintained by the buses, these tyres go bald faster than normal. I have seen many buses having a near-to-bald tyre on the dead axle. It is risky but no choice as the operators will use the tyre till dead bald....

That's a specific problem in Volvo pusher axle and they wear much faster than other axles.

[a4anurag]

Originally Posted by Ashley2

That's a specific problem in Volvo pusher axle and they wear much faster than other axles.

Shouldn't the tyres on the driven axle be having more wear and tear as compared to dead axle as the tyres are subjected more towards the forces and load from the engine + transmission?!

Anurag.

[Ashley2]

Originally Posted by a4anurag

Shouldn't the tyres on the driven axle be having more wear and tear as compared to dead axle as the tyres are subjected more towards the forces and load from the engine + transmission?!Anurag.

Pusher axle is subjected to additional load from rear live axle whenever it accelerates/decelerates, and so it needs to keep moving / draging. Also rear live axles have differential to modulate the speed required at both wheel ends when they make a turn which pusher axles are at mercy.

[a4anurag]

Originally Posted by Ashley2

Pusher axle is subjected to additional load from rear live axle whenever it accelerates/decelerates, and so it needs to keep moving / draging. Also rear live axles have differential to modulate the speed required at both wheel ends when they make a turn which pusher axles are at mercy.

Thanks, so that is the reason why the dead axle is having four tyres instead of the two on the driven.

What would have happened if they had placed the engine over the axles (Like Activa ). I know the comparison is funny but just a doubt.

Anurag.

[Ashley2]

Originally Posted by a4anurag

Thanks, so that is the reason why the dead axle is having four tyres instead of the two on the driven...

Dear, dead axle has only 2 tyres in buses.

[MAS]

Originally Posted by a4anurag

Thanks, so that is the reason why the dead axle is having four tyres instead of the two on the driven.

From the last photo it seems that the axle with four tyres is hooked up to the engine/gear box. The dead axle seems to be the last one, closest to the engine. Can anyone help with right information?