Any idea how this affects a racer/speedster?

[Rob]

This addition is on the Ford Special racer at THF. It’s only on the right spring, and appears to limit possibly the upward flex of the spring? Anyone familiar with anything similar on other T’s? My guess is this is to help hold curves on tracks, since it’s on the right side only. This is the 410 c.i. racer that beat the Blitzen Benz in a one mile match race at Detroit (fairgrounds 1 mile dirt track) in 1911:

[Kerry]

Looks like a good way to break a spring leaf, shackle or the perch, no movement in the suspension by locking up the spring shackles.

[DanTreace]

Shackle locks have been used on racers.

Here is older post.
Rob. I think you have shown the ‘grandfather’ of shackle locks!


http://www.mtfca.com/discus/messages/11 ... 1281336285

[AndyClary]

You lock one shackle to help the rocking back and forth to a minimum. You can also use a simple panhard bar.

And

[Wayne Sheldon]

A probable issue with the model T's "go-cart" steering, is that at higher speeds on corners, the shackles allow the axle to shift sideways which in turn alters the relative position between the axle and pitman arm, which again in turn changes the direction the wheels are aiming the car.
Having years ago (thank you Ed A et al!) had the opportunity to do quite a number of laps at speed on a real dirt track (even though mine was the slowest car there!), I can tell you that that shifting of the front end can get a bit dicey. It took a couple laps for me to get used to it, and anticipating the steering shift, allow for it from the beginning of the turn. Once into a longer turn (like an oval's "U"), centrifugal force pushes the car to one side and holds it there until the turn has ended. Unless one has a bit more power, and begins to slide the rear wheels around! Then the force reverses, and the driver must again compensate for it.
It feels somewhat wicked when driving model T racing cars at racing speeds. And it takes a little bit to adapt to it. I never had much trouble with it on any of my speedsters, as most people that really enjoy driving model T speedsters also seem to be able to do.
Serious racers however, often have some sort of shackle lock on one side, or a Panhard bar, to limit that side to side motion and avoid the potential instability it can cause. Letting them float on a speedster driven at moderate speeds may be okay? However, in serious racing, that minor drift could turn into disaster!

[Allan]

I deliberately locked a shackle on my speedster front and rear axle. It acts like a panhard bar to stop the car flopping about on the springs.

Allan from down under.

[Rob]

This device looks like it let the spring depress, but not rise at speed. I wish I had taken more detailed photos. It is oval, so not a lock, but allows shackle movement in one direction (downward spring action).

[slang250]

The Fronty Catalogs from back in the 20's had these brackets for Model T's.

[David Mazza]

Hi Steve! Any update on the Aldrich roadster?

[Gen3AntiqueAuto]

Stops "bump steer"

[Billy Vrana]

Seems like it would prevent body roll while cornering, only letting the shackle go so far, but not limiting on compression, I like the idea,

[TRDxB2]

Best to read various articles related to the purpose of panhard bar, sway bars, steering stabilizers etc

Some older discussion https://www.mtfca.com/discus/messages/1 ... 1312792242
and the one on going with this one Panhard Bars on a Model T viewtopic.php?f=2&t=39405