tag axels

I would think that if the tag steers, the pivot point for a sharp turn is on the drive axle versus between the tag and the drive and that the tag tire would not scrape like a fixed tag in a sharp turn.

I always lift the tag during a sharp turn so I already have both of those advantages.

A steerable tag can't make the turning radius tighter. That's determined by the cut of the steer axle and the distance from the steer to the drive axle (with either a steerable tag or a lifted tag).

Lifting or steerable its about the turning radius, and as said above it will be the same. Not having had a steerable I can only guess. The passive nature of the steering , automaticly locking straight at some set speed, is less to think about.
My lifting axle has two driver controlled settings , off or on . If on it lifts the axle every time you drop below 2nd gear. Not needed in stop and go traffic so I leave it off and only turn on during tight maneuvering corners. So I guess I do have to think about it more. It really wouldn't be a major decision point for me ... Having a tag period .. Is

I've never driven anything with a lift/steerable tag axle.

Maybe you could drive a few and see the difference for yourself?

I wonder if the added expense and maintenance is worth it over a fixed axle?

I watched Andy Pargh (the gadget guru) test drive a Newell Coach that offers a steerable tag which Newell has produced since 2004. Andy has a whole line of video's on RV's.

I think the advantage of a steerable tag is that the tag can carry the load in tight turns. Most coaches with liftable tags will lift all the way. Ours will partially lift releasing most of the weight on the tag. If I'm not mistaken, the H3 Prevost chassis tag does not lift all the way, the XL Prevost chassis lifts all the way.

Like Roadpilot above, I only lift my tag on tight turns, especially when reversing. I'm curious on a steerable tag if there is more maintenance involved. Do they get out of alignment?, etc.

Safe travels,
MM.

I'm a firm believer in the KISS rule. That's the main reason why I do not think the added complexity (more moving parts) of a IFS front axle is worth the supposable better handling.

Maybe on a bus that gets lots of miles the better tire wear might make the added complexity of a steerable axle worth it. Since we do not wear our tires out before they age out... is steerable really an advantage? I have not seen extra wear on my lifting tag tires and I do not lift it unless I'll be making multiple sharp turns. I actually put my tag tires on the front at 5 years so I could inspect the insides of the four tires and since the tag tires had not been doing much this gave the front tires a rest by putting on the tag... 75 psi instead of 115 psi.

I think you will find the rigs with steerable tags have lots of weight on the tag axle... as much as 14,000 lbs. They also are pushing 24,000 lbs on the drive axle so do you really want to raise that to 38,000 lbs with a lift-able tag? Adding 6,500 lbs to my 20,000 drive axle is not that big of an increase but it is the reason I rarely raise mine plus they are only 44" apart. A steerable tag has all of the moving parts of a solid front axle and alignment requirements.

I doubt my turning radius is any difference if I raise or not. I pretty sure four tires with 20,000 lbs on them will slide the two tires with only 6500 lbs on them in a turn. I DO NOT leave my lifting switch turned on as it's going to raise the axle as soon as the tranny down shifts into 2nd even if I'm not turning.

My tag....probably like most... has a switch with two positions. When turned off the tag never lifts and when turned on will automatically lift when the speed drops below 5 to 10 mph and in reverse. The problem with the auto use is that the tag uses a lot of air and takes a while to left clear of the ground. The extra 8,000 lbs of wt transferred to the drive axle causes the rear of the coach to drop until pressure rebuilds the ride height.

I honestly can not see much difference in turning radius either way but having it up certainly eliminates the tag tires skidding sideways. What I did notice is backing into my driveway with the tag up the rear can drag on the up-slope more than I like.

Steerable tag...guess it would be OK but it would not be on my list one way or the other.

Now I almost never use the lift unless it's really tight maneuvering.

I would keep it simple and use a fixed position, non-steering tag axle, if the tandem is standard spaced. If it is a spread axle tandem, then a lifting tag axle may be helpful. I've not seen any spread axle tandems on motorhomes though. Seen plenty spread axles on flatbed semi trailers.

Look at all the semis and trailers out there. Essentially NONE of them have steerable tags or tandems. Ever watch a trailer jackknife into a place? Those rear tandems are going in a circle, not moving! They are literally going sideways! I run those trailers. Still get close to 200,000 miles on retreads back there! So, I think the steerable tag is marketing hype, not reality.

I don't think you can buy a 42'-45' DP that doesn't at least have a liftable tag and many more lower end units now have a steerable tag. I believe it is now standard on the Dutch Star and like others have mentioned a steerable tag used to be found only on higher end coach's. I do lift my tag quite often when turning tight as I hate the sound of the tag tires scrubbing.

I'm not convinced a steerable tag is worth the expense and maintenance costs. Not to mention when it breaks. My tag is semi lift able, still drags a bit. However, these tires will age out long before the tread is gone.