I assume that you used static conditions and not dynamic for your
calculations, which changes the equations entirely. And remember it is not
just the distance between the bearings , but the offset from the center line
of the ball joints to the center line of each bearing. That is the lever
arm.In addition you probably assumed that the coach was travelling in a
straight line which of course it seldom is. When turning at speed the loads
changes dramatically on all bearings.
>All of this is interesting to me, and I'd be interested in hard numbers to
>go along with the discussion. Numbers such as how far apart are the two
>bearings, where is the weight of the coach applied relative to the two
>bearings using stock wheels, and how much offset is there in the offset
>wheels. Just for giggles, I made some assumptions about those numbers,
>disregarded any kind of variables you would get from moving down the road
>(such as variations in side loading, hitting bumps, crashing into things,
>etc.), and did some calculations.
>The assumptions I used are:
> 1) each front wheel sees 2500# of weight - this is approximate, perhaps a
>little on the high side, perhaps not;
> 2) the bearings are spaced 3" apart - a quess, but close enough for me for
>now, and a nice round number;
> 3) the design of all the components (tire, wheel, hub, etc.) makes the
>point where the weight of the coach is applied to be exactly in the middle
>of those bearings, or 1 1/2" from each bearing;
> 4) the offset from the offset wheels amounts to 4", so that the point where
>the weight is applied is 4" out from where it is with the stock wheels, or 2
>1/2" out from the outer bearing (4" - 1 1/2 = 2 1/2").
>My calculations:
>Stock wheels: both bearings see 1250# (2500# divided by 2).
>Offset wheels: the inner bearing sees 2083#, and the outer bearing sees
>4583# (the math for this is more complicated, but uses the 2500#, the 3"
>bearing spacing, and the 2 1/2" dimension noted above. A diagram would be
>needed to help explain things).
>For me, I can see that the bearings are subjected to more of a load with the
>offset wheels, but I don't believe that it's on the magnitude of what I've
>seen posted previously. And not just one of the bearings sees a greater
>load: they both do. As to whether the greater load exceeds the capacity of
>the bearing or not, I don't believe that it does, but it does use up some of
>the margin of safety.
>Time to get back to work!
>Robin
>
>
>
>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
calculations, which changes the equations entirely. And remember it is not
just the distance between the bearings , but the offset from the center line
of the ball joints to the center line of each bearing. That is the lever
arm.In addition you probably assumed that the coach was travelling in a
straight line which of course it seldom is. When turning at speed the loads
changes dramatically on all bearings.
>All of this is interesting to me, and I'd be interested in hard numbers to
>go along with the discussion. Numbers such as how far apart are the two
>bearings, where is the weight of the coach applied relative to the two
>bearings using stock wheels, and how much offset is there in the offset
>wheels. Just for giggles, I made some assumptions about those numbers,
>disregarded any kind of variables you would get from moving down the road
>(such as variations in side loading, hitting bumps, crashing into things,
>etc.), and did some calculations.
>The assumptions I used are:
> 1) each front wheel sees 2500# of weight - this is approximate, perhaps a
>little on the high side, perhaps not;
> 2) the bearings are spaced 3" apart - a quess, but close enough for me for
>now, and a nice round number;
> 3) the design of all the components (tire, wheel, hub, etc.) makes the
>point where the weight of the coach is applied to be exactly in the middle
>of those bearings, or 1 1/2" from each bearing;
> 4) the offset from the offset wheels amounts to 4", so that the point where
>the weight is applied is 4" out from where it is with the stock wheels, or 2
>1/2" out from the outer bearing (4" - 1 1/2 = 2 1/2").
>My calculations:
>Stock wheels: both bearings see 1250# (2500# divided by 2).
>Offset wheels: the inner bearing sees 2083#, and the outer bearing sees
>4583# (the math for this is more complicated, but uses the 2500#, the 3"
>bearing spacing, and the 2 1/2" dimension noted above. A diagram would be
>needed to help explain things).
>For me, I can see that the bearings are subjected to more of a load with the
>offset wheels, but I don't believe that it's on the magnitude of what I've
>seen posted previously. And not just one of the bearings sees a greater
>load: they both do. As to whether the greater load exceeds the capacity of
>the bearing or not, I don't believe that it does, but it does use up some of
>the margin of safety.
>Time to get back to work!
>Robin
>
>
>
>
>
>
>
Tom & Marg Warner
Vernon Center NY
1976 palmbeach
