Technical Buick drum/scrub radius question

I’m working on my ’33 pickup. I want to send my front axle and hardware to the chrome shop but I have two axles to choose from; a 46” wide and a 47 1/2” wide, both forged. I was thinking of using a Wilson Welding Buick brake conversion kit - their backing plates, hubs and converted drums. Of course it occurred to me that the big Buick brakes may push the wheel mounting surface out affecting both the tire position in the fender and the scrub radius.
Nothing is carved in stone at this point, I have plenty of options, however I don’t have front fenders yet so I can’t mock everything up, stand back and look like I usually do. With California looking at closing all chrome shops by 2023, I want to get at least my big parts done now. Small parts could be shipped to an out of state source but I don’t want to end up having to ship an axle, wishbones, bumpers, etc.
Has anyone built a ‘33-34 with the WW brakes? What width axle? Do the Buick brakes widen the front tread width like some disc conversions do?

 

Closing all shops?! I'm all for being environmentally responsible but that's bullwhip. And up here the powers that be like to mimic California's madness...

Edit: another spelling error due to auto correct. "Bullwhip" should read Bull Shit...

 

The photos show a ‘35 Pickup with what may be early Ford Lockheed brakes and a ‘33 Roadster with a Wilson Brakes setup.
One is good, the other is the most extreme example of poor scrub I’ve ever seen. It’s all in the wheels and their offset, I think you can make it work with either axle.

 

I'm using Buick drums with them mounted on the outside of F1 hubs and with '40 type 16" wheels.
This only moves the wheel outboard by about 1/8" maximum over the original F1 drums.
15" wheels require a lot of offset to clear the Buick fins.

 

NO CHROME IN 2 YEARS ??

 

Wilson's hubs are basically a copy of of Ford's "outside" flange hub and as such doesn't move the WMS outward. Use something like a Merc wheel that fits the drum and the scrub is good.



Add spacers/wheel adapters and you end up looking goofy like the pic in the previous post.

 

Scrub ,like a few other things on some hot rods is really messed up do too builders misunderstanding of engineering of how front ends work. Some that make the mistake of high scrub ,will defend there mistake to the point of foolish.
Out set of front wheel from the factory design screws up the feel an safety of steering** WHY below.;

By placing the wheel out more from its designed point,<kingpin line down too road an tire tread patch on road inter act point=scrub/ leverage of wheel on kingpin.
What happens as the wheel/tire goes out more,adding scrub!:
Is the extra leverage of more scrub adds more and move violent action to each input movement from braking an bumps=control drops off for driver.
That is fact above,but some who say things like> "I been driving for years ,an my car, you say is wrong,is just fine an no prob."< Yes ,they do believe that is true to them! They have fully BS there own head into thinking all old cars feel a bit bad=So feel nothing wrong,just a old design.
It's the same with bump steer that was built in by a builder that has very little understanding of that as well.
These mistakes are often defended too death, by some that drive with them on there hot rod.
It is very hard to get passed a wrong belief, based on misunderstandings and even more so if they have had the belief for a long time. Even faced with the engineering facts! Is not enough,so we see the same mistakes being copied or done over and over { they saw it that way in a photo so it must be right}

 

This is how I set up my roadster. 46" axle , MT Car products 39 Lincoln backing plates , Wilson Welding hubs, 62 Buick drums. 5" wide wheel with 3" BS. But I don't have fenders I think that by running a 6" wide wheel with 4" BS would have improved scrub radius (at least visually ) I'm not sure that this will help you. Bill

 

Yeah, they forget chrome is needed in many industrial processes, aerospace and well.............life in general

 

Dana, you said just what I was thinking, that if the WW setup increased the scrub radius too much then I wouldn’t use them. I don’t have any test data to confirm it but I’m pretty sure that the larger the scrub radius the more likely that the car will have death wobble problems, with all other factors being equal.
I’ve had the WW brakes for a while but I finally have a car that I would like to use them on. I recently acquired a pair of chrome steel wheels that fit nicely over the drums exposing just the innermost fins. They also help keep the scrub point in close to where it should be. At this point all that’s left is to pick an axle that will position the tires in a good place under the fenders.
I sure wish I had the Lincoln backing plates instead of the bulky finned ones but at this point I have what I have.
In regards to the chrome shops, I’ve read several things lately imploring us to contact our congressmen to fight against the proposed closure of the chrome shops in California. I haven’t seen the proposed bill but having lived in Ca all my life, it doesn’t surprise me. It’s low hanging environmental fruit; basically defenseless business owners who can’t afford to put up a viable fight, a “non-essential” business that the public at large doesn’t care about, and a history of repeated environmental violations by a few irresponsible businesses. Sounds like a slam dunk for our disconnected state legislature. So I sent my email and gathered up everything I think I want chromed, just in case….. Besides, it’s getting more expensive every year.

 

As RICH B stated, 15" Merc wheels work well with Buick drums

 

^^^^ Very cool, I like how the wheel covers most of the drum. And the scrub radius isn't objectionable.

 

/\ how did you manage to chrome the king pin bearing on the 37 tube ?

 

I have Buick drums mounted on modified '58 Buick backing plates used with aluminum adapters made by a local machine shop. When I mounted my wheels, the wheels tucked in so far that I added spacers just so that the Buick fins would show up!

 

I'd have to believe that a good part of the dilemma is that all too many guys running Buick drums are more concerned with showing the world that they have Buick drums than how they work or how the car drives.
[/UR

 

^ x 120%

 

Stainless...

 

It's refreshing to see that every one posting here actually knows what 'scrub radius' is....................well, so far anyway.
There's still time...............

 

That shot should show you that there's too much scrub radius. Draw a line through the king pin to the ground, does it fall within the footprint of the tire? Ideally it would be in the center of the tire for zero positive or negative scrub radius, it may just be the angle of the photo but it looks like you've got abut 3" - 4" positive scrub radius. You need a lot more wheel offset to get it within a decent range.

 

A little scrub radius is a good thing................

"At zero scrub radius the general consensus is that it can make a car feel a little unstable at the front end through corners and under hard braking."

 

Isn't scrub radius determined by how long your arm is? Like when you are washing the car and can't reach all the way to the middle of the roof?

 

I totally agree . That's why I mentioned that a 6" wheel with 4" backspacing might help. But this is what I'm stuck with for now . I really notice it when making a sharp turn . Bill

 

As I mentioned earlier, I added spacers just so that the finned drums would be visible. Don't think that scrub radius would be much of a problem.

 

This is an excellent thread on 'scrub radius' with good info from quite a few guys. Read the lot, especially the stuff from @F&J .

https://www.jalopyjournal.com/forum/threads/scrub-radius.1135446/

Front suspension, braking and steering is NOT the place for form over function.........

 

something about the line and load through the centre of the pair of single row TAPER wheel bearings
equal upward load, begs the question, why they are different sizes

 

Yes, and that's why I'm looking at this carefully instead of just bolting it all on and hoping for the best. I'm trying to coordinate the brake swap dimensions (known), wheel choice/offset (known) and axle width (undecided) and end up with the proper position of the tire in the fender, looking from the front and also a decent scrub radius.
I think what I need is the dimension from the front fender crown centerline to the crown centerline of the opposite fender.

 

Steering geometry
According to what I've read on the subject, if the tire center line contacts the pavement outside of the extended kingpin center line it's going to steer hard.

 

I have not seen the polished bearing sold without the kingpin kit
https://www.roadstersupply.com/Polished-37-41-Ford-King-Pin-Kit-p/ahr-60701.htm

Maybe someone will help.

 

The bearing in all kits is steel anyway, just polish them and then shoot alittle clear on them.

 

That would make a lot of sense. Think of it this way................
2 + 2 + ? = x.
This is unsolvable. If you have the final needed answer, x (fender crown to fender crown or required track width), you can work out or adjust the other values to suit. The brake swap dimensions are set if you have chosen which setup you will be using. A combination of wheel offset and axle width can be used to get as close as you can to the required combination of track width and acceptable scrub radius. When you measure the fender crown to fender crown dimension, be aware that you will have a little leeway in or out with where your tire will sit. It may be an idea to measure the acceptable range of tire location in the guards. This will give you some wriggle room with axle width and wheel offset.

Hope this all makes sense..................