[Per]

Charlie,

Your diagram has a fatal flaw. It appears you start the turn at the beginning of the edge of pavement radius return. If you do that your drive and tag wheels on the inside of the curve will definately be riding on whatever material is off the pavement before completing the turn. If its grass and raining, throw in a slight uphill grade and guess what? As soon as the drive wheel on the inside of the turn hits the unpaved surface you will stop. As I understand it the Prevost drive wheels are not posi-traction operation. Therefore the first drive wheel to lose contact with the pavement will be a spinner. Don’t ask how I learned this feature during a check in, raining hard for all afternoon, clay surface off the stone surface, and at a facility in western NC (uphill grades).

You will have to begin your turn further forward from the point of curvature (POC) in order to keep your drive wheels on the pavement. I posted an engineering diagram some time ago which detailed the geometrics of a coach turning sweep area with wheels shown. If I can find it, that is if I did not delete it from my computer, I’ll re-post it again. For a straight front axle 40′ coach the inside turning radius is 45′. One other piece of advice, provided there are no objects in the way of the front bumper, is that with the significant set back of the steer wheels you can start your turn later and allow the front of the bus to overhang the outside of the curve pavement while keeping your steer tire closest to the outside of pavement actually on the pavement. It is spooky the first couple of tries at doing this but with experience comes success.

[Jerry]

Charlie,

Here is a link for your information. It contains information on what geometric factors influence design turning radii. Forget it, I am unable to cut and paste a link here. Do a search of the internet for “Bus turning radius template. The end of the best link will be 2004 Green Book. Go there and spend some time reading and more importantly viewing the template drawings.

[Dan]

Charlie:

Driveway. I have a layout similar to yours, but my surfaces are wider.

Road: 22.5″ of blacktop. There is a gravel shoulder on both sides about 3′ to 4′ wide.

Driveway: 14′-10″. I don’t know the thickness of the concrete off hand, I will check and amend my post. I have original concrete and new concrete from when we built the race shop and bus parking area. The new was pinned to the old. I told the concrete the bus weighed 52,000#. He said “don’t worry”. I put the steer tires at the edge of the old concrete, where the new and old come together, and of course on the new concrete. I put the tags and drive tires in the same places. NO CRACKS. One of the big things to keep in mind when putting lots of weight on concrete is what’s underneath. If there is lots of the proper rock and stone with proper drainage, that makes a HUGE difference.

I’ve added some pictures to give you an idea of what I’m dealing with. I back in from left (west) of the driveway which makes the turn in more than 90 degrees. I do that so I can more easily watch the back of the coach and trailer (as appropriate) when I’m backing in.

I think you need to widen your driveway or at least the first probably 45 to 50 feet. You can’t do much about the road in front of the house that you need to back off of, but you’re only 2′ narrower than what I have to work with. Do you have the same elevacation from the road back through the driveway? We don’t. There is a pronounced drop from the road down the driveway, not as dramatic I understand that Jon Wehrenberg has to deal with, but something I was concerned about.

Not only do I back the 45’/IFS coach into the driveway and often into its parking space in one continuous motion, I also back the 26′ enclosed trailer with a 5′ tongue into its parking stall with the coach. It takes practice and a good understanding of the geometry involved. (BTW its “geometry” and not “physics” when you’re talking backing the coach into tight places … “physics” comes into play when you hit something with the coach like a large rock or mail box or short post you didn’t see or a tall concrete curb you didn’t allow for).

I also don’t lift the tag when I back up or pull out. Two reasons: (1) one of the tag pivot points is frozen/rusted tight and I haven’t gotten around to dealing with that and (2) when you lift the tag, the coach drops and it takes a while for it to come back up. Because of the drop from the road onto the driveway, when I’ve lifted the tag (actually only half of it) I’ve had contact between the driveshaft loop and the road. I can get the job done without lifting the tag for now.

Check to see (1) if the zoning, homeowners association, etc. will allow you to have a coach parked on your property and (2) if you can widen your driveway. Remember you’ll want to park the coach on concrete.

I’m actually looking at widening my driveway by 7.5′ (on the east side, right side of the aerial picture, left side of the shots looking at the parked coach) so that I can leave the coach, coach and trailer, Suburban and trailer, just trailer, or friends coach(es) on the driveway without driving around it onto the grass. Plus I’d have more room to work with when I need to move the trailer in and out of its parking place.

Will a Prevost fit into your work. As you go off on different jobs, try to figure out at each job what you’d do with the coach. Where would you park it, would you have any services, how long of a commute. That will help you really decide if you can use a coach in your work.

One thing I’d suggest is you that you buy a coach with separate washer and dryer. If you’re going to be working out of the coach, you’ll want to do laundry in the coach. We love our separate units when we travel.

Length. We first started out quest looking for a 40’/IFS Liberty. I wanted OTR/bus air, 40′ was shorter for manuvering the trailer, and I’d been told the IFS had a smaller turning radius which would help with the trailer. But then a broker in Florida showed us a 45′ and explained that not all the additional five feet is in the wheelbase (only part of it) and explained the difference in the interior room … and I quickly determined that for the long term the 45′ was better for us. With some practice and help from my wife when we’re in tights situations, we make the 45′ work.

No offense to everyone and anyone who is happy with their 40′ coach, their combo washer/dryer unit, and who don’t see a need for OTR/bus air.

[Davy]

Charlie,

My coach is a 40 footer with IFS.

The documentation that came with it lists wheel base 280″ and Turning radius 37.75″

Good Luck

[Chuck]

One thing everyone needs to realize is while the IFS has shortened the turn radius, that feature is of no benefit if there is no room for the swing of the front end when backing because the front end is almost going sideways. I face this situation with a guard rail right at the edge of the road opposite my driveway. Similarly, when going forward the driver has to be aware the potential for damage is shifted to the center of the coach as the body swings sideways. Campgrounds in particular present a risk in sharp turns when there are large boulders used to define the roads or prevent coaches from cutting corners and running over the grass.

[Davy]

Super helpful. I’m still negotiating this job offer and I’m not too hopeful at this whole point so the saga might end before it begins… That said the feedback and the suggested search to diagrams is very interesting!

[Rudy]

Charlie, never let a job interfere with the enjoyment you will get owning a Prevost. We all reach a point where we find we want something, and initially think we need to justify that desire.

If you want the truth, none of us can justify a coach. They are a dumb investment and an ongoing cost. But I cannot think of anything I have ever purchased that has brought so much satisfaction.

Buy the bus you want and make the driveway fit it.

[Archived]

I’m with Jon… of all the toys we have – we love the bus the most. And BY FAR the most. If you think you will like it… You will LOVE it! Get to getting it and enjoy it!!

[Archived]

Minimum Road Width=A-(0.707 x B)

where:

A = One-half outside curb-to-curb turning diameter.

B = One-half inside trace turning diameter.

This is for equal road widths on both legs though. Probably doesn’t help, but I thought I would throw it out.

[Peter]

I love the support! I will certainly keep you all posted. I have a lot of experience with unjustifiable “toys”, unfortunately, as most do not understand my race car fetish… That said, this purchase was supposed to have *some* practical benefit as I’d actually sleep and eat in this thing… Still negotiating the job, so we will see.

Thanks!

Charlie