Tire Pressure

[Jon Wehrenberg]

Jim,

Your question suggests we are gear heads and the Prouds are not. I have mixed feelings about how to answer your question because it might seem like we are trying to stereotype POG and Prouds members.

When I was in the Prouds in the early 90's, Prevost put on technical seminars at the FMCA pre-convention rallies the Prouds always had. Those seminars were in depth, highly detailed, and were well attended. Based on that I think that there are members of both groups that if not gearheads, they are certainly interested in the mechanical aspects of the coach. I remember in particular a physician from Pennsylvania that seemed capable of tearing any part of the bus into its smallest components and reassembling it. He could engage any Detroit Diesel tech in a discussion of the internals of our engines. Conversely, I am certain we have members that could care less about anything mechanical on the bus and they participate in POG because it is still a social group that does know how to have fun.

What has changed is that over the years since then the internet came into being, and through forums like ours we got into discussions about mechanical stuff. Don't forget, a lot of the posts on our forum are "social" as opposed to technical. We talk about rallies, campground recommendations, where to eat, and having impromptu get togethers, such as not only mini rallies, but folks just coming together for a meal or a weekend. I don't know if the Prouds have a forum, but I can say with certainty that we have friends we have never met, but we have talked to via the forum for a long time so unlike our experience with the Prouds where we never felt welcomed, I think most who come to the rallies are already welcomed as part of the group.

If you want to draw a distinction between the Prouds and POG here's one that might be suitable as another topic and is not intented to be a jab at one or another.

The Prouds had their technical seminars and it was a guy thing. But during a Prouds rally there were times when the guys had to clean up, dress up and accompany their well dressed ladies to a fancy dinner or some other upscale event.

POG is biased towards the guys, and I can tell you that we may be ignoring the ladies. We clearly do not have enough activities for them, and we don't give them a chance to dress up and see us dressed up and not working on someone's coach. BTW, I prefer to not dress up, but if it makes Lady Di happy to see me suited up I suppose I could for one night. She don't read this stuff so I can say stuff like this.

Did I open a can of worms?

[travelite]

The steer tires are rotating along the direction of the turn and they define the turning circle and have the easier time of it insofar as scrub, the drive axle wheels are the privoting point that describes the other point on the chord of the described turning circle. The tag axle wheels are outside the turning circle and are have a (sideways) component more at an angle to the tangent and 'dragged' (or forced to distort) more sideways than the wheels on the steer and drive axles. This is why they are 'scrubbed' significantly more. They are at the opposite end from the fulcrumm (the drive axle). It is sufficient enough to cause widening of the turning circle and the reason for 'lifting' or removing weight from the tag. It is also the reason for steerable tags that tighten the turn circle by removing this geometric issue, as on the recent Newells, and at various times M.A.N., Daimler-Benzes, Setras, Tatras, and others on some of their commercial bus offerings over the years. Interesting to some may be the reasoning for, and physical constraints against, that invalidated Ackerman steering (where the steer wheels were articulated to describle the two different turning radii, but failed to take into account the greater slip angle(s) of weighted outside tire (and is related to tuning based on specific tire characteristics). Other more distantly related topics we could discuss informally at POG9 might include the geometry behind what is/was known as zero (and plus or minus) point steering, the geometry behind unequal length wishbone suspension systems, camber, caster, toe-in etc.. Or, I can keep my big mouth shut (probably best).

I would add that with the tag not lifted, the pivot point is at some place between the drive and the tag. With the tag raised, the pivot point is at the drive axle. Another way of saying this is that the effective wheelbase is longer with the tag down. This is why the turning radius is shorter with the tag lifted.

[Kenneth Brewer]

I would add that with the tag not lifted, the pivot point is at some place between the drive and the tag. With the tag raised, the pivot point is at the drive axle. Another way of saying this is that the effective wheelbase is longer with the tag down. This is why the turning radius is shorter with the tag lifted.

Yes, stated in other words. Your point is perhaps better made than mine was. Thank you.

[Kenneth Brewer]

Did I open a can of worms?

Friends don't do things like that to friends, I think. I have never even been to a large POG event; it is on you if I have to dress up now to attend a POG social event.

[Jon Wehrenberg]

I thought everyone was aware the night of the charity auction is a black tie affair.

I have a large selection of black ties that compliment my T shirt and jeans.

[truk4u]

The original A-1 in a suit, I gotta see that!

[rfoster]

I thought The only black ties A-1 had are the one he uses on wires and are made of plastic.

I continue to Live and Learn

[Yankee802]

You guys are not helping my paranoia about driving my coach.

[Jon Wehrenberg]

Check your fluid levels, check your belts, check your tire pressures, do a DOT brake check, and drive it like you stole it.

[rbohm]

Hello all, first post, just got our first Prevost, 95 XL-45 entertainer, needs some TLC but amazed on how it drove. I'm used to driving a Freightliner Columbia with a 12.7 Detroit and a 10 speed autoshift. This Prevost is going to be a fun "truck" to drive I can tell from my initial 1000 mile drive home with it last week. Reason for the reply, I was trying to get the tires up to recommended pressures last week for the trip, found that I was running into a lot of the same questions that were brought up in this thread, but what I'm looking forward to installing soon will be a tire pressure monitor system like I have in my Freightliner: www.tirepressuremonitor.com I'm sure that there are other systems out there, might even be something that the newer coaches are installing as "stock", but for the money, this is a very good system for the money and it works well! forget the tire guage, the computer does the work for you. I have some other issues that I've come across to make this coach work for our application so i'll post in another thread. I never thought I would "enjoy" driving a "bus", but I can see that this is going to be the start of an expensive habit! Thanks and I look forward to the info offered on the site. Robert in Kansas