Speedster Question

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Model T Ford Forum: Forum 2017: Speedster Question
Top of pagePrevious messageNext messageBottom of page Link to this message  By Bryce Putnam Peoria AZ on Thursday, October 19, 2017 - 09:17 am:

I have a new to me speedster the front has been lowered, reversed eye leaf spring, removed leafs, 2 drop axle.
My question is the wishbone is bent down a few degrees about 6 back from where it bolts to the front axle.
Why?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Thursday, October 19, 2017 - 09:26 am:

Likely to keep alignment as with dropped axle the geometry of stock is changed.

As long as the axle pitch is correct , i.e. the wheel spindles are pitched 5 1/2 degrees to the rear then handling and steering won't be affected by the re shaped wishbone.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Don A on Thursday, October 19, 2017 - 09:43 am:

I agree with Dan. The wishbone dictates caster. To maintain proper caster, the wishbone may had to be bent to properly meet up with the mount on the pan. Also, the new location of the wishbone might have interfered with the tie rod and/or drag link. Sometimes the wishbone has to be bent to avoid contact or the tie rod is modified with offsets to miss the wishbone. Making one modification (dropped axle) can affect other crucial components.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Thursday, October 19, 2017 - 03:14 pm:

The geometry of the front end gets funny, and difficult to understand why?
I have had several speedsters over the years. Most of them lowered a fair amount. Most of them, wound up with more than spec caster, which I generally like in a speedster. It helps the car go down the road steady and straight at the higher speeds most speedsters are driven. ONE of them, however, didn't work out so well that way. It turned out, that at low speeds, the car steered just fine. But at anything over 20 mph? it only wanted to go straight ahead. I had put the car together in a last minute effort to make it to an Endurance Run, I had not had time to debug the car first. So I did 200 miles with a car that steered like an antique Mack truck. I completed the Run, but my shoulders ached for days.
That car, I had to put a sizable kink in the wishbone to pull the caster back to near normal (still a little extra). After that, it handled fine.
What I don't understand, is why none of the others that were similarly lowered did not require such an adjustment?
Enjoy the car! After you fix the steering.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem S.E. Michigan on Thursday, October 19, 2017 - 03:57 pm:

Wayne,

Maybe the others had 5:1 steering gears? I had to put 5:1 gears in mine for the very reasons you state.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dana A. Crosby in Glendale, Az on Thursday, October 19, 2017 - 08:47 pm:

Bryce, we can discuss it this weekend in Jacumba. The cumulative Speedster brain power/experience will be T-rific. I too will learn some things.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bryce Putnam Peoria AZ on Friday, October 20, 2017 - 09:03 am:

Thanks Dan & Don makes sense, Wayne mine pulled a little to the right, looking at the right side saw that the wishbone was bent and thought I had found the problem but no both sides the same.
Dana see you there!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jerry VanOoteghem S.E. Michigan on Friday, October 20, 2017 - 12:20 pm:

Bryce,

Maybe that's still your problem. Is your wishbone bent on one side only? I think we're all assuming both arms are bent equally, suggesting a purposeful adjustment.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Friday, October 20, 2017 - 06:22 pm:

A slight pull to the right is common, and MIGHT be nothing more than the crown of the road you are driving on. Model Ts with their simple geometry and not precise kingpin to wheel centering ("not precise" is a huge understatement!) are more prone to pulling toward any downhill force. The crown of an average road is enough to annoy some people. On a nice empty quiet road (preferably in the country), drive on the wrong side of the road for a ways (be British!). On the other side of the crown, the car should pull slightly to the left if everything is as it should be.
If that doesn't explain it, and the pull to the right is consistent, it becomes a more difficult problem. A tendency to pull to one side is more a factor of the camber than either toe-in or caster. Toe-in and caster are fairly easy to adjust. Camber, not so easy. A flaw in the camber geometry can be the result of an imperceptible bend in the heavy forged axle itself, or of a difference or defect in one ore both spindles, or even mismatched wheel bearings (one side ball, other side roller). (I ran into that one one time!)
Tweaking the heavy forged front axle is a task best left to one of the few individuals that have the proper tools and KNOW how to to do it. Nearly ALL modern shops will make it worse, not better.
The other common cause is that not all spindles are exactly alike. Some angle the wheel further under the king pin than do others. Very careful measuring can show if that is the case. Sometimes, finding a spindle that better matches the other side is the best and easiest fix. Sometimes, a slight tweak in the axle can even be compensated for by balanced mismatching of slightly different spindles.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Wayne Sheldon, Grass Valley, CA on Friday, October 20, 2017 - 06:41 pm:

Jerry V O, I wouldn't argue either way about the 5 to 1 or 4 to 1 steering. I rarely even check to see what it is. A few of the Ts I have had over the years I did know were in fact 4 to 1. And I always liked 4 to 1 steering in a model T. One, the '25 TT I had many years ago, I think was 5 to 1. I just never think about it. I sit behind the wheel. I drive. When I need to turn, I turn the steering wheel enough that it takes me where I want to go. I never think about what the ratio is.
That one T that had too much caster? It was different. I could sit still on asphalt, and crank the wheel from kink to kink. Park in a parking lot? Driving ten to fifteen miles an hour, steered just fine. At right about 20 mph? It turned into an antique Mack truck. It would take all my might to force the steering wheel even half way to kink. Seriously, my shoulders ached for days after that drive. Two days after the Run (I let my shoulders rest one day), I took a few measurements, created a cardboard guide to follow for the amount to take back from the caster. I removed the wishbone, and carefully, one side at a time, tweaked the end of the wishbone. Rechecked the caster (about double model T spec, where a few speedsters I had before worked the way I liked), and the car handles like a dream!


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