How much BUS HP do I need for a 16000GVM?

[Pedro_The_Swift]

Is there a technical reason for tag axles other than weight?
are discs (like with the Volvo B7R) worth chasing?

[donh54]

Is there a technical reason for tag axles other than weight?
are discs (like with the Volvo B7R) worth chasing?

The extra weight carrying is usually the main issue. Comfort is an added bonus, as the extra axle helps smooth out the ride.
You do need to be aware that tag (or "lazy") axles make it very easy to lose traction with the drive axle on loose surfaces or going over undulating ground.

For keeping up with highway traffic at 16T gvm I would suggest at least 280/300 horsepower ("real", not European)

Disc brakes will always out-perform drums, but it depends on the application as to whether it is cost-effective. Town running with lots of stop-start I'd go for discs. Long distance stuff, I wouldn't consider them a deal breaker.

[incisor]

Lots of questions floating around pete

[V8Ian]

Sorry, I'm a bit late to the party, Pedro.
How many ponies? Too much is never enough. I can recall when the average interstate prime mover had 180 -230 hp, nowadays even a garbage truck has 250 hp!
When I bought mine I was looking for 350hp, ended up with 360.
The Euros, as Don said, don't have the grunt of the Yanks, but nor do they have the thirst.
Driven sensibly, a bus towing a large 4X4 should give similar economy to a 4X4 towing a big 'van.
Generally, a highway coach will be a better buy than a route service bus. They've had an easier life, not stopping and starting every 100 yards and been navigated by more sympathetic drivers.
For my money, you can't go past S cam drums.

[Bigbjorn]

S cam brakes for ease of repair and reliability. As much horsepower as can be fitted in. What is in the one or ones you have been looking at? What size bus have you been looking at? How many bums? There are still good highway coaches around with 92 series Detroits in. These are long lasting and reliable, start easily in all weathers and get their ass into gear very smartly with excellent torque available from clutch engagement (800 rpm) up. Tag axles on forty footers and up were to get more legal load aka more bums on seats. As has been mentioned you can get dry bogged with tag axles. If you are going onto the dirt much with one then a Detroit locker in the drive axle is good to have. Amateurs often have a steep learning curve with bus transmissions mounted at the rear sometimes sideways or angled with long whippy linkage. Allison auto is to be preferred.

[gavinwibrow]

S cam brakes for ease of repair and reliability. As much horsepower as can be fitted in. What is in the one or ones you have been looking at? What size bus have you been looking at? How many bums? There are still good highway coaches around with 92 series Detroits in. These are long lasting and reliable, start easily in all weathers and get their ass into gear very smartly with excellent torque available from clutch engagement (800 rpm) up. Tag axles on forty footers and up were to get more legal load aka more bums on seats. As has been mentioned you can get dry bogged with tag axles. If you are going onto the dirt much with one then a Detroit locker in the drive axle is good to have. Amateurs often have a steep learning curve with bus transmissions mounted at the rear sometimes sideways or angled with long whippy linkage. Allison auto is to be preferred.

Concur with all this, inc DD6v92 donks.
One thing to watch - some caravan parks don't like tags cos they rip up the bitumen on the driveways, and with air suspension a single axle is more than enuff for the average RV. I'd also go for an auto for the older years - don't believe that most of your running will be open highway.
Pulling a 4.5T triaxle trailer with 4WD on board, my ex greyhound single rear axle DD6V92 and V730 auto trans used to get at worst 3 mpg at 100kmph

[Homestar]

Looking for something to tow the Disco with Pete rather than the other way around now? 😊

[Blknight.aus]

Scam drums, and FFS get the meritor style ones with the drum over the hub not the retarded suzi setup where the drum is inside the hub ala pre 2010 landy disc brakes.

the money you'll save when it comes time to swap out brakes in time alone is phenomenal. (and because the parts strip out so quickly doing bearing work is quicker easier as they are lighter to pull out)

[Bigbjorn]

Concur with all this, inc DD6v92 donks.
One thing to watch - some caravan parks don't like tags cos they rip up the bitumen on the driveways, and with air suspension a single axle is more than enuff for the average RV. I'd also go for an auto for the older years - don't believe that most of your running will be open highway.
Pulling a 4.5T triaxle trailer with 4WD on board, my ex greyhound single rear axle DD6V92 and V730 auto trans used to get at worst 3 mpg at 100kmph

The 6V92TA series were rated at 335 hp @ 2100. They can be tickled up to marine spec of around 400 hp @ 2300. Seem to live OK at that rating in boats. Clutch engagement torque @ 800 rpm was 720 ft/lb or 976 Nm. Maximum torque is 957 ft/lb @ 1300 rpm.

[djam1]

I live in a bus with a tag axle it’s an Austral bodied MAN
I tow a Defender on a trailer all up this weighs over 20 tonne
The bus has a MAN D2566 that was originally 280 hp with a 12 speed ZF
Not sure how many ponies there are left but towing the trailer up hills involves gear changing and slowing down
I think a few more horses would be better
Oh and 2.5-3 km a litre at upto 115 kmh