[glen]

Harry,

Happy Birthday.

All the answers to your questions are in your Prevost Manual.

https://techpub.prevostcar.com/en/manuals?filters%5Bvehicle_families_id%5D=2&filters%5Bvehicle_models_id%5D=4&filters%5Bsearch_units%5D=&filters%5Bsearch_serial%5D=&filters%5Bmodel_year%5D=1990&filters%5Btype%5D=all&filters%5Btitle%5D=&filters%5Blanguage%5D=

[Tim]

Harry that manual, from what I see, doesn’t cover our DDEC11 8V92TA motors. Just the 50’s and 60 series.

Maybe the turning radius is the same. Have all the manuals on mine and haven’t seen a turning radius listed. I’ always heard just drive until you hear glass and smell chit.

[Archived]

Hi guys,

I didn’t find the wheel cut in the manual but I’ll take another pass at it later tonight. I have the Build Sheet for my bus but it’s not listed. I’ve been through my manual and didn’t see it there either. I’ll look again when I next visit The Beave!

Thanks for your help,

Harry

[Tim]

And I am just curious as hell about who would ask that question, and then if they got the answer exactly what good it would do knowing that?

Is this a joke?

[Archived]

Who gives a crap.

[Archived]

Wow, such hostility…

The reason I asked is I was watching a video about backing a motor home. It talked about how you turn and back up differently based on wheel cut.

In the video they were talking about 45, 50 and greater wheel cuts and how you adjust where you start tuning based on that information. That’s why I asked the question?

Harry

[Per]

Harry, just my opinion, but if we’re you, I would collect the bus manuals from where ever and live with them. There is some good info in there, might be better than the way you seem to be going about knowledge gathering.

[Andy]

I Don’t do it often Harry but check every once in a while, raise your tag axle and it seems to make turning or backing into a spot a little easier or at least doesn’t scuff those high dollar back tag tires as much. These boogers don’t turn very well or not as good as your cars for sure.

[Archived]

Harry … couldn’t you just measure the “turning cut”? If its even in any Prevost material it would likely be in a technical manual or in Prevost’s marketing materials from back in the day.

While knowing the “turning cut” might be interesting, the cut is what it is. You have an straight front axle (SFA) and your “turning cut” is less than my independent front suspension (IFS) coach. The wheel base on your XL (40′) is a little shorter than on my XLV (45′); but the difference is not five feet. You have to live with the “turning cut”, and most importantly learn what your coach can and can’t do in tight situations.

You can watch all the videos you want, but the only way to learn to successfully and safely drive your coach (including backing it up) is to practice, practice, practice. (I tried to find an old Miller Beer TV commercial with Paul Hornung getting into a stretch limousine with three babes and when asked how it came to be that he was such a successful college and NFL football player as well as apparently so successful with beautiful women he simply answered as he closed the door to the limo … “Practice, Practice, Practice”. Remember that one Tommy?)

I’m lucky in that we live in a kinda (but not awfully) narrow town road that is level and straight in front of the house. The kinda long concrete drive way is I think only 14′ wide but most importantly it is almost perfectly perpendicular to the town road. At the end of the concrete driveway I have to jog the coach to the pax side to get around the race shop to get the coach in its parking spot. These challenges forces me to be a better motorcoach backer upper.

After we had the coach for a while, I discovered that when we got home from being out with the coach the neighbors would gather and watch me back it in; they had a pool going based on how many times I would change direction to get it backed in right. Last night I came home from the race track in the dark (no trailer, had unhooked the toad), was alone, and backed the coach down the driveway in a single move (but not into the parking spot, too dark alone, will do that in a few minutes). I couldn’t do that three years ago. With a reasonable amount of practice, practice, practice I’ve been able to back the coach and 26′ enclosed trailer (w/5′ tongue) into the trailer’s parking spot next to where the coach parks in a single move. The neighbors quit having the pool.

If you’re having difficulty backing the bus and want to learn you need to practice, practice, practice. Start with an open parking lot and cones or markers. Practice various maneuvers. Backing up from the right, then the left, try some “S-turns”. Try turning while going forward with the wheel over to the lock and see how tight the turn is, watch where the back tires track. Do that going forward and backward. If you’re going to be backing into the same location often, that’s where I would practice. I think you’re going to keep the coach at an RV resort. I suspect this time of the year they don’t have lots of spots rented, so ask the resort if you can spend a couple of hours practicing backing into various sites.

You should have a “coach” to help when you start out; someone who has either driven truck (long straight truck or semi), school bus, big motorhome, or farms or grew up on a farm. I’ve found that when trying to back up the bus and big trailer at the race track, my most helpful spotter is a farmer … no ambiguous hand gestures, weird looks, unnecessary conversion … just the information I need to know very concisely, accurately, and timely. If you’ve never been on a farm (and I didn’t grew up on a farm), trust me … they have to maneuver some of the weirdest, most awkward pieces of machinery into and out of the most unusual situations; often at night with no lights.

You’re going to be tempted to “lift the tag” because you read somewhere or someone told you to lift the tag when you’re maneuvering in tight spots. BUT before you “lift the tag”, you MUST stand next to the rear axles and have someone “lift the tag” for you. You MUST see how the coach behaves when you “lift the tag”. First the coach will drop (because when you lift the tag you’re dumping air from the tag axle air bags and all the weight gets shifted to the drive axle bags, it takes a while for the drive axle bags to go back to full ride height). If you “lift the tag” and immediately start backing across a crown in the road or driveway or over a curb or high spot you could catch the drive shaft loop because the coach is low. If you feel the need to “lift the tag”, WAIT for the coach to return to ride height in the rear. I don’t lift my tag for two reasons: (1) one of the pivots is corroded tight and one side won’t lift and (2) even if both sides lifted I have enough grade changes I won’t want to wait to get to ride height or risk something on the underside of the coach hitting something.

Once you’ve worked with your coach, practiced, and got your “learners permit” you’ll often want to have a “spotter” when backing up. That often falls to your companion, partner, or spouse depending your personal situation. You need to practice, practice, practice with your spotter. BEFORE you need to back in, you need to explain clearly to your spotter what you want him or her to watch for. How you are going to communicate. Put the spotter in the driver’s seat so the spotter clearly understands you CANNOT see shit behind you. Explain to the spotter that you WILL NOT move the coach unless you can see the spotter … when you can’t see the spotter because the spotter is standing behind the coach or persists in walking along the front bumper in your blind spot, one toot of the air horn should mean “I can’t f’g see you!!!!”.

Hopefully the videos you are watching will show the usefully and effective hand gestures that the spotters are giving.

We use handheld Motorola race radios to communicate between driver and spotter. You can get inexpensive walkie-talkie’s or even use cell phones on speaker if you don’t have easy access to radios.

I read a post once about a couple that backed a huge M/H into a really tight site with a minimum of hand gestures and only one or two word phrases without any vulgar language, screaming, hollering, or air horn blasting. That is your goal.

Its very important for you and your spotter to understand the geometry to how the coach behaves. It all comes down to geometry. You will learn by doing. That is the only way.

Good luck! Keep us posted. And IBP can be reached at 800-468-5287 if you need them.

[Dick]

Harry, prior to picking up my bus, I watched similar videos regarding how the wheel cut affects turning and learned how a few degrees of cut seems to make a difference on when to initiate a turn. Yes, it’s geometry!

While I can’t answer your specific question, I can tell you that taking some time practicing in an empty, well lined parking lot and having a spotter assist, is a good way to get to know the characteristics of your bus. When I took delivery, I drove around the Marathon parking lot quite a few times and randomly selected spaces to back into. I started with the easier spots and worked my way up to the ones that seemed a bit more difficult. I had a spotter in the passenger seat when starting a turn who went outside when I was backing. It was a helpful learning exercise.

[Archived]

One thing that has helped me, especially when I’m by myself, is using the big red/orange cones for markers.

I get out and determine where I need to go and place the cones (3) at the back or side depending on what area is risky. This has helped me tremendously.

In sharp turns I do raise the tag.

Mark

PS. Happy Birthday Harry, my nephew’s b-day is today too (born in ’71).

[Dan]

Happy birthday Harry! Today is mine as well and our anniversary too boot! Going from our Beaver Bus model year, 1992 to current Bus, model 1999, 2000 Marathon we really don’t feel much difference between beam andor independent front turning radius/wheel cut. As you turn, pivot point in bus rear us between drive tire and tag tire. Lifting the tag gives a bit better turning for two reasons. One it slightly changes your geometry. Second, lifting weight off tag whether it comes off the ground surface or not takes weight off of tag so your pivot point changes to drive tire. Difference between Beam Axle vs IFS at least on a 40 footer is negligent. As above stated earlier, practice makes for more experience. Rules we follow when backing.

Don’t, but if you must

a spotter is helpful

Never guess. If you need to get out to see where your backside is get out

Once you’ve made contact with a fixed object, get out and assess what you do next to minimize damage

[Jim/Chris]

Thanks for your posts gentlemen and the information you passed along. It’s the old “practice makes perfect” isn’t it. I’ll have to find a place to practice and a spotter.

Harry

[Archived]

Harry,

Some time ago someone asked the very same question just with a different terminology, “Turning Radius.” If I can find my design manual it has a diagram of all the wheel tracks when making a turn with a 40′ bus. If memory serves me, and that could be questioned, the turning radius is 45′. So to make a 90 degree turn would require two 40 acres fields! or 90′.

[Kirby]

Hey Jim, I don’t know how I missed your post but I sure did… I’ve never known anyone born on October 30th? I always thought when I was born they established Halloween! It just goes to show that October 30th was a very good day. And I fully agree “if you’re backing and you’re not sure, get out and look”!

Hi ExpressBus, I was going through the books that came with my coach today and I didn’t find anything that’s helpful. I’ve become friendly with a guy at Prevost parts and I’ll give him a shout tomorrow. He’ll know or can get me the information.

Thanks,

Harry