The Stovebolt Site Forums The Shop Area Driveline Never seen this here about disc brakes

I saw this on the instructions for a disc brake conversion from Chevs of the 40's. I've never seen this mentioned in any of the discussions about disc brake conversions for AD or Task Force trucks on Stovebolt. Is this a major concern? I'm looking for more of an explanation regarding bent tie rods and "built in" bend - I'm not sure what this means. Any thoughts on this? Thanks.

A WORD TO THE WISE

You now have a front braking system far superior to the original installation. Because of this it is strongly advised that the front end supporting and locating system is adequate to absorb the increased braking loads. Since normal braking action may tend to spread the forward edges of the tires apart it is essential that you check for bent tie rods at regular intervals. This "spreading" of the front wheels results in a compressive type of loading on the tie rod and any "built in" bend may cause tie rod failure under severe braking.

I can lock mine up if I want to. Disc brakes can't apply a higher force than that. It sounds a bit silly to me.

I don't know what data they have that there are "increased braking loads". I'm sure they have none. Disc brakes don't stress any components. The only data ever documented is that disc's heat up less. Thus not as much fade. Other than that, the truck does not know what system is stopping it. There are good advantages to disc brakes. On dry flat roads, they really don't stop better.

I assume this vendor was making an attempt to be an armchair lawyer trying to dodge liability of some sort.
A Jr. Engineer that learned the word compressive loading. Did not accomplish anything except loss of credibility.

Never heard that front edge of tires "spread" during braking. I assume the "built in" refers to a component that is already "bent" from stopping with drums and would therefor be aggravated by adding disc brakes. All hogwash. Don't worry about any of that.

About 66% of stopping "load" is taken by front brakes due mostly to weight transfer and front end motor weight.

The relatively small size of tie rods, their diameter to length ratio, tells you that they do not see large "bending" loads from steering the truck, pot holes, bumps or braking.
We've heard the term "bent tie rod" in our lives. Those are from impact on a rock, log, curb, etc.

The max load on all the parts in question would be at wheel lock up. While power disk brakes might be easier or occur with less effort on the driver’s input. Lock up is the same forces no matter the brake used. A good drum brake should be able to lock the wheels at will........with some serious driver effort.

I would agree that the whole suspension and steering system should be looked at during any restoration or upgrade. Sloppy king pins, loose steering box or worn out spring shackles can make any emergency stop a real adventure.

Given that there is toe-in on these trucks, I would surmise that there would be a tendency for the tires to be forced inward not outward, but then I ain't got one of them fancy engineering degrees. Besides that, trains are obsolete anyway.

It's far more likely that some of the non-stock wheel and tire combinations most resto-rodders use would overstress a stock tie rod system than any sort of brake setup could. Wider than stock wheels with the offset necessary to allow big tires to turn without interfering with the frame, springs, etc. will load the tie rods and possibly bend them, or running into a pothole or rubbing a curb with more leverage on the spindle can also cause forces sufficient to bend steering components.
Jerry