[Corey]

When the maximum length went from 40 feet to 45 feet around 1994 the bus manufacturers each had a different approach to minimize scuffing or to tighten a turn radius.

MCI had a tag that turned in response to a turn. From what I understand it was fairly complex and may have had maintenance issues. The Prevost alternative to that was a self unloading tag axle. When the steering wheel was turned to the extreme there was a “cam” that hit a microswitch which in turn dumped tag axle air bag air. It did not lift the axle, just took the pressure from the air bags.

That was followed with a system Prevost called “stabilizators” (I might not be spelling that right) which supplemented the dumping of air with the actuation of a pair of hydraulic cylinders that prevented the bus from squatting down in the rear. That system was used on some conversions but was ultimately dropped.

I don’t think there is any provision now for dumping air bag pressure on the tag axle or doing anything when a sharp turn is required. It can be done manually if the driver desires.

[Archived]

blue bird tried a steerable tag for a while. The first version was steerable which resulted in issues, so we went through and basically disconnected it and it then just free floated and would turn as you turned. The MCI does not turn as tight in the steer axle. The reason we do not lift the tag for the most part. As stated it takes a long time to lift the tag and we usually have plenty of tread on tires when we age out the tires. So unless we turn a lot of tight turns the amount of scuffing is minamial typically. Over the years there has been a lot of diffraction the speed of the actual lift of the tags…..

[Fred F.]

My 45′ MCI with steerable tag turns tighter than my 40′ XL (non independent front suspension) did with the tag lifted. Still, at 42′ I think the MCI has a slightly bigger turning radius than an H-3 45 with the tag unloaded. Of course the steering tag looks cool and gets comments whenever I’m backing into a site.

The rear steering gear is ZIF, and yes, the rear wheels turn only about 35% of the angle of the front wheels. I’ve had no maintenance issues but was warned to keep an eye on the protective boots and to follow the maintenance schedule.

[Tim]

I normally lift the tag on our SOB coach when I need better mobility like in a tight parking lot or campground. The tag unloads in about 30 seconds but needs a good minute or two to fully lift. Lifting the tag also increases traction on the drive axle due to the extra weight. We needed this in the snow and mud this winter.

[Larry & Diane]

Another important point to bring up about the Prevost tag axle is that it is truly unique. If you look in the parts book, you will see that it is “horseshoe shaped” to fit over the driveline, allowing for shorter driveline and the ability to reduce over hang by getting driveline and engine/transmission closer than any other manufacturer.

[Bob]

Everybody that has had a coach for a long time has developed his or her driving style and as long as it has worked for them I see no need to change it.

While I don’t lift the tag unless the turn I am going to make is exceptionally sharp I have used the tag lift primarily to improve traction. When we lived in Western NY snow during the time of year we travelled was a given. I found our coach would do well in snow, but there were instances when we stopped and the warm tires melted a small depression under them making a restart difficult and usually accompanied with wheel spin. I got into the habit of flipping the tag axle lever at the first sign of slippage from a stop.