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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: IMABUSBOY on August 27, 2015, 06:54:14 PM

Title: Tag axle for or aft, which is best?
Post by: IMABUSBOY on August 27, 2015, 06:54:14 PM
I would like to know what you all think is better for ride and stability or other considerations, the tag in front of the drive axle like the eagle or behind tag behind the drive like an mci. Thanks, Danny
Title: Re: Tag axle for or aft, which is best?
Post by: kyle4501 on August 27, 2015, 07:31:15 PM
If behind the drive axle = longer drive shaft which allows longer u-joint life.
In front of drive axle = shorter drive shaft & accelerated wear of u-joints - drop box is likely required which also has power limitations.

Tag in rear - add pressure on tag & you increase pressure on steer
Tag in front - add pressure on tag & you decrease pressure on steer

Probably the tag in front will provide a better ride, just comes at a price. 
Title: Re: Tag axle for or aft, which is best?
Post by: eagle19952 on August 27, 2015, 07:48:21 PM
if the driveline angle is within parameter/design and engineering limits the life expectancy of the u joint is not a concern...
Title: Re: Tag axle for or aft, which is best?
Post by: luvrbus on August 27, 2015, 08:12:11 PM
Your talking about 2 different suspensions, the Eagle is superior in handling and ride than a MCI 9 the Eagle has independent front suspension compared to the MCI 9 straight axle.Drop boxes and U joints are not a problem with maintenance on a Eagle or a MCI
Title: Re: Tag axle for or aft, which is best?
Post by: TomC on August 27, 2015, 09:23:46 PM
To simplify drive trains, many buses have gone to tag behind drive axle (if it is in front of the drive axle, it is called a pusher axle) mainly to give more room for the 6 cylinder inline engines used on all the buses now. I know the Eagle ones porpoised more then the 5, 10 or 15. Good luck, TomC
Title: Re: Tag axle for or aft, which is best?
Post by: bevans6 on August 28, 2015, 05:13:15 AM
I always thought the Eagle axle in front of the drives was called a "bogie".  Anyway, the way I think of it the tag like an MCI has will transfer weight to the front axle and reduce porpoising while the bogie will take weight off the front axle and improve the ride that way.  I don't think it makes much difference, I wouldn't choose a bus based on it.

Brian
Title: Re: Tag axle for or aft, which is best?
Post by: bigred on August 28, 2015, 05:49:53 AM
Worst part is the turning radius .Withe the boogie in front ,it really adds feet to the turning radius.I also have been told that you can not use an air seat.Trailways ordered some with air seats and the drivers were putting 2x4's under them to prop them in place!
Title: Re: Tag axle for or aft, which is best?
Post by: luvrbus on August 28, 2015, 05:59:38 AM
Eagles don't porpoise when the adjustment and shocks are maintain they used the bogie in front of the drivers for more luggage bay capacity and the bogies are independent also no axle across the body like a MCI tag.

Turning radius on a 40 ft Eagle is not bad about the same as MCI and Prevost the Eagle was 45ft the MCI 9 was 46ft the Prevost was 43ft the Gm 4905 is the worse 49ft with no tag or bogie.lol the turning radius on a 35 ft MCI 5 is the same as a 40ft Eagle the 4106 GM is close at 43 ft  

The 45 ft Eagle has terrible turning radius I have own both the MCI and Eagle I have a 45 ft D MCi now with the follow tag that or a steer tag is the way to go on a 45 ft bus FWIW both MCI and Eagle were owned by GH and then Dial Soap,it all gets down to what bus you like I am like Ian on BNO the Eagles just have more curb appeal to me   
Title: Re: Tag axle for or aft, which is best?
Post by: TomC on August 28, 2015, 06:41:44 AM
Maybe it's different in bus terms. I understand that any non driven axle in the rear is a bogie. At least with commercial trucks, if the bogie is behind the drive axle, it is a tag axle. If the bogie is in front of the drive axle, it is a pusher axle. A tandem drive 3 axle is called a 6X4. Now non driven axles, whether it be a tag or pusher are getting looked at again since a single drive axle is more fuel efficient than a tandem drive. Single drive axle on a 3 axle is called a 6X2. To compensate for traction problems on a 6X2, electronic air suspension dump systems are used. If the drive axle is slipping detected by the ABS system, the non driven axle will dump air forcing more air into the drive axle-up to the legal rating of 20,000lbs. Works very well as demonstrated at Meritors proving grounds in Mich. in winter. Good Luck, TomC
Title: Re: Tag axle for or aft, which is best?
Post by: luvrbus on August 28, 2015, 06:47:45 AM
Could be Tom but Eagle has listed it as bogie since 1968 in their books and sells literature.
I was told it came from a railroad term the wheels in front of the drive wheels on a locomotive 
Title: Re: Tag axle for or aft, which is best?
Post by: bigred on August 29, 2015, 06:17:35 AM
I'm with you Luverbus on the curb appeal!!I have a Prevost but as I have said before ,I'm a closet Eagle man.I know that Eagles have their share of problems as does any buses,but there is nothing as stately as as a Silver Eagle bus especially if it was wearing the Greyhound uniform!!
Title: Re: Tag axle for or aft, which is best?
Post by: kyle4501 on August 29, 2015, 06:16:53 PM
The PD4501 was a 40 foot bus with a rear tag axle that carried as much weight as the drive. The turn radius was under 42 feet.

As nice as Eagles are. . . . , a Scenicruiser has 'em all beat when it comes to curb appeal.   ;D  8)
Title: Re: Tag axle for or aft, which is best?
Post by: Iceni John on August 29, 2015, 07:05:34 PM
Quote from: luvrbus on August 28, 2015, 06:47:45 AM
Could be Tom but Eagle has listed it as bogie since 1968 in their books and sells literature.
I was told it came from a railroad term the wheels in front of the drive wheels on a locomotive 
It's ironic that the usual American railroad term for a pivoting four-wheel assembly is a truck, but the Brits call that a bogie.   Over there a road truck is a lorry, or maybe a pantechnicon, artic, HGV or juggernaut !

Maybe we should call them idler wheels if they're on buses ?

John
Title: Re: Tag axle for or aft, which is best?
Post by: Scott & Heather on August 29, 2015, 07:06:45 PM
Meh, sometimes I wish I could just delete my tag


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