Randall Young wrote:
>
> Jeffrey :
>
> Well, just to add the voice of dissent, I have both front and rear ADDCO
>swaybars on my TR3, purchased from J.C.Whitney, and I've been quite pleased
>with the combination. My original goal was to eliminate the situation where
>the inside rear wheel "tops out" against the frame in a hard corner, which
>makes the rear end skip sideways. The roll bars did an excellent job of that.
> As originally installed, with rubber at all points, the oversteer was a bit
>more than I like, so the end link bushings on the front bar have been upgraded
>to poly. (There are other approaches to tuning, including using springs in
>the end links.)
Good to hear that, since I just bought front and rear bars from Mark
Bradakis.
> Considering that I took 1st in class at the autoX in Portland (probably
>because I was placed in the wrong class), I must be doing something right <g>
Nah, nah, Randall, it was raw skill what did it. <congratulations!>
> A Panhard rod will not help with axle tramp, you need something more like the
>'traction bars' so popular with the American muscle car set a few years back.
>I'll bet the curved leaf springs used on later TR4s would also help, but I
>haven't tried them.
On this I agree--a Panhard rod is mostly to properly locate the axle
laterally, i.e., to keep it from shifting sideways. For virtually all of
the live axle Triumphs, the leaf springs do a satisfactory job in
locating the axle laterally, as long as the spring bushings are in good
shape. It's hard to get the springs to twist sufficiently to misplace
the axle.
To further amplify for Jeffrey's sake, axle tramp refers to springs
wrapping themselves up parallel to the direction of travel due to torque
reaction of the axle assembly. A Panhard rod does nothing to correct
that. The only solution for axle tramp is to have asymmetrical springs
made or to install traction bars, as Randall mentions. The traction
(ladder) bars forcibly restrain the axle and therefore reduce spring
wrap-up.
I may have missed an earlier message, but, Jeffrey, do you have American
iron under the hood? Truth is, my earlier TR4 produced about 120 hp, and
I never experienced anything resembling noticeable axle tramp. With
enough horsepower, it's certainly possible, but one would also have to
have very large, sticky tires installed. More or less standard tires
would break loose, relieving the axle torque reaction to some degree. It
could be that the problem is related to tired bushings, tired springs,
or both.
You don't mention symptoms of the problem, but if enough power is
applied to springs in good shape, they still behave like what they
are--springs. They wrap and unwrap under large power input, because they
oscillate. The rapid wrapping and unwrapping of the springs causes the
axle to literally hop up and down, resulting in a considerable loss of
power to the ground. If you're not applying an excessive amount of
torque, it may simply be that the rear shocks and/or springs and
bushings are worn out and are allowing an excessive amount of spring
oscillation.
BTW, if you still believe that the problem is related to lateral
movement of the axle, a Watts link is a far better solution to the
problem than a Panhard rod, since a Panhard rod changes the axle lateral
location upon axle bump/rebound travel, whereas a Watts link does not.
Cheers.
--
Michael D. Porter
Roswell, NM
[mailto: mporter@zianet.com]
`70 GT6+ (being refurbished, slowly)
`71 GT6 Mk. III (organ donor)
`72 GT6 Mk. III (daily driver)
`64 TR4 (awaiting intensive care)
|