Question ? I want to improve the steering on a very fast Model T (70 plus m.p.h.) designed for touring and not just racing short distances with a more modern steering box mounted on the frame connected to a Model A link mounted on the left hub. Is there a good selection of these boxes and which is best ?. I have non-power steering box from a late 50's Dodge that is not too large and could fit on the frame and still let the hood close to hide it. Any thoughts ?
We have had seven fast Speedsters and they all changed lanes when they hit a bump in the road. We plan to use a Model A steering arm with a ball on the end of it for the push-pull action required by the pitman arm. We are concerned about bump steer. We did have a Franklin system but it went to Australia where it was desperately needed for a more authentic restoration of a famous race car.
Why not just mount a Model A two tooth steering box, modified drag link, steering arms and tie rod. The A steering arms fit the holes in the T spindles. Box brace in frame with plate to mount the steering box. Shorten the drag link and maybe the tie rod. The steering column should not to be hard to shorten too. Trim out the side of hood and fender and build a nice box to hide it if mounted above the frame but you could do the same thing and mount under also, maybe. That last one would depend on where you mounted the box and if it was in the arc of the wheel when you turned.
A "real" steering box mounted on the frame will do the job just fine using the cross drag link arrangement of the T. My old speedster easily capable of really stupid speeds. I drove freeway speeds regularly. The guy I sold it to got a ticket for 92 mph!!
This is all related to why I decided to reproduce the Ross steering box for the T. Currently only in the '26-7 version and I am still testing it. I am completely happy with it.
Ross included a bolt in frame "boxing" brace which I have figured out as well. A new drag link is needed and I have gone with using Model A tie Rod ends and a custom piece of LH-RH threaded tube. I have had a "locking disc" laser cut to connect the steering wheel directly to the existing steering shaft (it drops over the existing 3 pins).
NOW for another option that I have used with total satisfaction!!
I tilted the king pins on a stock T axle inwards 9 degrees.
I then machined up 2 new spindles that had 11 degrees of tilt in them. (On my car these also included front brakes but that is another story.)
The net effect is that the projected line of the kingpin now lines up with the centre of the tire patch on the ground.
The REAL net effect is that my '27 roadster now drives and handles like a modern car. Comfortably safe with two fingers on the steering wheel using the stock T steering box!!!
If the drag link is perfectly level when two people sit in the car you should not get much bump-steer.
If you lock up the left spring shackle you will eliminate all bump steer.
I you use model A steering with the drag link horizontal to the frame (going from steering box to left spindle) you must mount the steering box so the drag link is level, or you will get bump-steer.
If you install rack & pinion steering you must lock up the left spring shackle or you'll not be able to drive it on the freeway.
If you elect to tilt the kingpins, you now no longer need much, if any caster. The car steers as nice reverse as forwards. You also don't need to lock up any shackles.
A level drag link is helpful in all circumstances
Question for Aaron. To lock the shackle will a set screw in the left perch oil hole do the job?
Question for Les- can you elaborate on the kingpin tilt and machined spindles? Is the axle bent to get the 9 degree tilt? Perhaps you could post some photos.
John — here is an easily-made front sprint shackle lock. It has worked well for me.
One probably doesn't need the bottom bolt, and if there was any concern about drilling the axle, one could configure a simple clamp-to-the-flange instead.
Question,.....doesn't "locking one spring shackle" accomplish the same thing as does a Panhard bar?