Scamp Axle - Leading vs Trailing

[Brian B-P]

Originally Posted by Thomas G.

When I think of the spectrum of trailers with electric brakes, on one end I see triple axle equipment trailers hauling bulldozers and on the other extreme end, I see 13 foot FG campers. So, for me, basic need, basic controller.

Tom, I assume that you mean basic in features, rather than in core functionality. A timer-based control isn't just basic, it's bad.

Originally Posted by RogerDat

Thanks for the feedback. One of the things that is sort of frustrating is trying to separate the really important features from the marketing hype so as to avoid the tendancy to purchase way more "features" than one needs due to lack of experience.

My opinion, as a descending-order list...

• Really important: proportional to degree of vehicle braking, such as by measuring acceleration (not timed)
• Important: works well (electronic accelerometers rather than pendulum)
• Valuable: easy-to-use controls and displays to set gain, manually apply brakes, turn any features on and off, show status (e.g. connected to trailer brakes)
• Good: features such as "boost", holding while stopped
• Nice: convenient mounting and electrical connections
• Not important: fancy displays (but remember that easy-to-use was "valuable")
• Almost irrelevant: price (the best is a couple percent of a decent trailer more expensive than junk)

I think Tom's Primus provides all of the characteristics that I listed, although I am not familiar with the controls and displays. At a glance, it looks like an original Prodigy in this respect.

[Brian B-P]

Originally Posted by Thomas G.

Yea, I'd be interested to hear what I'm missing.

I know that my camera and smart phone have about a thousand features that I don't use, but somehow I muddle on.

Didn't you know? You can ask your phone what you're missing by not having the latest brake controller!

[Thomas G.]

Originally Posted by Brian B-P

Tom, I assume that you mean basic in features, rather than in core functionality. A timer-based control isn't just basic, it's bad.

Right, I wouldn't consider a timed controller. By basic, I meant in the Tekonsha hierarchy

I think Tom's Primus provides all of the characteristics that I listed, although I am not familiar with the controls and displays. At a glance, it looks like an original Prodigy in this respect.

I think that you are right.

[Brian B-P]

Originally Posted by Thomas G.

Right, I wouldn't consider a timed controller. By basic, I meant in the Tekonsha hierarchy.

A few years ago, Tekonsha offered a range of timer-based controls. I think it's interesting that they have completely abandoned them... but they are still offered under the same company's Reese brand, where there are no proportional controls!

[RogerDat]

Originally Posted by Brian B-P

A few years ago, Tekonsha offered a range of timer-based controls. I think it's interesting that they have completely abandoned them... but they are still offered under the same company's Reese brand, where there are no proportional controls!

Only "good" thing I can see about timed is they can be mounted in any position. And maybe if the trailer is a very heavy dual axle where you always want the trailer to take more of the braking load than the TV rather than spread it evenly between the two. But from my reading the boost settings on proportional handle that need.

Even Draw Tite web site says that proportional have come down so much in price that the price difference is pretty slim.

On eTrailer for about $30 more than the cheapest timed you can get a primus. The price difference for name brand timed is more like $15. The P2 looks like it comes with the plug kit, connectors and a bit of mounting hardware for $30 more.

This thread someone put forth a little bit of literary effort to explain why it would be foolish to go with timed. Especially since emergency stopping situation is the biggest reason I have for brakes on a 13 ft. I can slow down, brake early, drive according to terrain and conditions, what I can't do is control everything else on the road.

FAQ: Timer Vs. Proportional Brake Controllers - Diesel Place : Chevrolet and GMC Diesel Truck Forums

Thanks for the feed back, I asked my phone and it just kept prompting me to give it an update.

[RogerDat]

I actually heard a reasoned argument against proportional brake controllers today. Bear in mind I'm just the person digging up information. Don't shoot the messenger.

The argument is as follows, if TV is skidding how much inertia is the proportional controller getting? None. So when you really need the trailer brakes to kick in while you try and manage the skid it's not going to happen.

Angle and adjustment. If bumped with a leg or knee they don't auto recalibrate so it is possible to have the controller detecting it's "new" position as a small amount of decelaration causing lite but non-stop braking.

Many TV's have a dash very close to the max angle a proportional controller can compensate for, if one does not take this into account inferior performance may be the results. Mounted with only a few degrees of pendulum movement possible they don't work as well.

Not sure if I agree with all that but figured it was worth sharing.

The other suggestion which did make sense is keep my old 4 bolt idler hubs to use as a spare in the event one of mine goes out on the road, not common enough to count on getting a replacement quickly. With bearings greased and ready to go I would lose brakes but would be able to get back on the road.

[Brian B-P]

Originally Posted by RogerDat

... if TV is skidding how much inertia is the proportional controller getting? None. So when you really need the trailer brakes to kick in while you try and manage the skid it's not going to happen.

If a vehicle is skidding, that does not mean it is not decelerating. Does this argument mean the brakes are locked up and tires are sliding because the driver is trying to brake beyond the available traction? If, so the proportional controller is doing exactly the right thing by applying enough power to brake the trailer to match the deceleration achieved, not applying too much power for the available traction and locking up the trailer's tires as well.

Originally Posted by RogerDat

Angle and adjustment. If bumped with a leg or knee they don't auto recalibrate so it is possible to have the controller detecting it's "new" position as a small amount of decelaration causing lite but non-stop braking.

So mount the controller properly! This is like saying a poorly positioned gearshift could get bumped and bump the vehicle out of gear, so we should skip the transmission and have only one gear.

Originally Posted by RogerDat

Many TV's have a dash very close to the max angle a proportional controller can compensate for, if one does not take this into account inferior performance may be the results. Mounted with only a few degrees of pendulum movement possible they don't work as well.

Again, just mount it properly.

Modern proportional controllers don't have a pendulum; they use two-axis accelerometers (like the bits inside a modern video game controller, such as the ones introduced with the Nintendo Wii).

[Jared J]

If the tow vehicle is skidding with full brakes and zero deceleration, then it doesn't matter if the controller is braking the trailer or not. At that point, I would really consider my odds for bailing out.

My prodigy is at a steep angle and applies plenty of braking.

As for being bumped to a different angle, it senses force. Feel free to take mine from an easy 45* and lay it flat, nothing will change.

[ruscal]

Regarding skiding trailer: It would depend on whether the skid was sliding sideways or skidding forwards due to too much braking. If you were trying to stop in a straight line and the trailer tires were skidding due to the controller applying too much brake, the lessened traction would cause the controller to see the inertia go down and apply more braking, which would just make the wheels skid more. That is assuming that the controller tries to cause the most inertia by applying more braking force. They may not work that way, I don't know. I adjust my controller so it won't lock up the trailer tires during panic stops with slightly dirty or wet conditions, and it seems to handle just fine.
In the second scenario where you overcooked a corner and the trailer was hung out sliding sideways, I doubt the inertia device would know what was happening unless your forward deceleration was enough to come into play.
braking may not be desired in that case anyway, as it could actually cause more lateral forces or break loose the tires more. I would probably try not to decelerate during a skid like that just from personal experience.
Russ

[Jared J]

He said tow vehicle skidding, not trailer. If the tow vehicle is skidding and the controller can't sense it, that means you aren't slowing down. If you aren't slowing down, there is zero grip, and if there's zero grip, who cares if the trailer brakes apply or not? Completely irrelevant.

[Brian B-P]

Originally Posted by ruscal

If you were trying to stop in a straight line and the trailer tires were skidding due to the controller applying too much brake, the lessened traction would cause the controller to see the inertia go down and apply more braking, which would just make the wheels skid more. That is assuming that the controller tries to cause the most inertia by applying more braking force. They may not work that way, I don't know.

No, they don't work that way. They respond only to deceleration, so less deceleration (not less "inertia") means less power applied to the trailer brakes.

Originally Posted by ruscal

In the second scenario where you overcooked a corner and the trailer was hung out sliding sideways, I doubt the inertia device would know what was happening unless your forward deceleration was enough to come into play.
braking may not be desired in that case anyway, as it could actually cause more lateral forces or break loose the tires more. I would probably try not to decelerate during a skid like that just from personal experience.

Right, deceleration along the front-to-rear axis of the tow vehicle (the way the controller is mounted) is all that determines deceleration... regardless of any wild thing the trailer might be doing.

I agree that excessive braking is never desirable in combination with turning. Tires have only a limited amount of traction, and whatever you use up braking is not available for turning, and for keeping the trailer on track. Anyone really interested in this aspect of vehicle dynamics might want to search the ever-helpful internet for a description of the "friction circle"... but this wouldn't be the place to get into much more detail on that!

[RogerDat]

Originally Posted by Jared J

He said tow vehicle skidding, not trailer. If the tow vehicle is skidding and the controller can't sense it, that means you aren't slowing down. If you aren't slowing down, there is zero grip, and if there's zero grip, who cares if the trailer brakes apply or not? Completely irrelevant.

I think the idea is one might get some braking from the trailer even if TV was not slowing down enough to be detected by brake controller as need for much braking action. Sort of the opposite of problem of timed controller not able to tell that you just hit the brakes hard for a panic stop. It just does it's "set" thing.

Seems to me that ABS brakes might change the decelaration profile during a skid. At least when I tested them on snow they stayed short of a full on zero traction skid for the most part, providing some pulsing deceleration.

Even on snow there is some traction, water over ice might get down to zero. Or hydroplane situation. But even in a skid there is generally some traction to be had.

Mounting properly to get proper function should be a given, I think point was some folks do, some folks don't, folks that don't are better off with a lesser system but one they have less chance to screw up.

If TV hits ice on bridge first the trailer pushing probably would not be a good thing but... I'm more inclined to think typical driving and panic stop use case the proportional would be better, much better. Just the ability to detect I'm stopped and cut power way down while I continue to hold the brake at a light seems "smart".

So the controllers no longer use the pendulum as a detector? Instead using something like smart phone or game controller to detect deceleration.

[Jared J]

Originally Posted by RogerDat

I think the idea is one might get some braking from the trailer even if TV was not slowing down enough to be detected by brake controller as need for much braking action. Sort of the opposite of problem of timed controller not able to tell that you just hit the brakes hard for a panic stop. It just does it's "set" thing.

Seems to me that ABS brakes might change the decelaration profile during a skid. At least when I tested them on snow they stayed short of a full on zero traction skid for the most part, providing some pulsing deceleration.

Even on snow there is some traction, water over ice might get down to zero. Or hydroplane situation. But even in a skid there is generally some traction to be had.

Mounting properly to get proper function should be a given, I think point was some folks do, some folks don't, folks that don't are better off with a lesser system but one they have less chance to screw up.

If TV hits ice on bridge first the trailer pushing probably would not be a good thing but... I'm more inclined to think typical driving and panic stop use case the proportional would be better, much better. Just the ability to detect I'm stopped and cut power way down while I continue to hold the brake at a light seems "smart".

So the controllers no longer use the pendulum as a detector? Instead using something like smart phone or game controller to detect deceleration.

If the vehicle is slowing down at all, a good controller will know it. I guarantee if you hotwired the brake switch to my prodigy and just let off the gas, it would apply trailer brakes.

Also, it applies slight trailer brakes even if you barely touch the pedal and just activate the switch.

Again, if it isn't sensing deceleration from the tow vehicle, it doesn't matter if it applies trailer brakes or not, nothing is going to help you. A dumb controller would be worse, as it would just stab the brakes on, on the ice.

[RogerDat]

Axle has arrived! Going to drop trailer in shop next week for installation.
Al-Ko had to create a part number for this bracket configuration, if it installs correctly without modification there will be a source here in Mich for "stock bracket" leading arm replacement axles.

[Brian B-P]

Originally Posted by RogerDat

Axle has arrived! Going to drop trailer in shop next week for installation.
Al-Ko had to create a part number for this bracket configuration...

Excellent. Since the brackets are unique, it would be nice to see a photo of just the axle (especially the bracket area) before it is complicated and obscured by installation

[RogerDat]

Originally Posted by Brian B-P

Excellent. Since the brackets are unique, it would be nice to see a photo of just the axle (especially the bracket area) before it is complicated and obscured by installation

Good Idea! I'll have to make sure I take a camera with me. Hmmm wonder if I will have the time to spray a dusting of light colored paint around the existing bracket and frame to provide for contrast with the new bracket on the frame for an after picture.

[RogerDat]

First picture you can see where the front (left) end of the bracket is shorter and runs into the drop floor of the scamp. It is welded on that edge as well as to frame above. The bracket is an "outboard" because the long side with the axle attached to it is on the outboard side of the bracket.

Second and third picture are the replacement axle with brake flange. 22 degree down angle. You can see the forward side of the bracket is shorter to accommodate the drop floor.

The new bracket is a not as tall. The original was a "drop" mount or "high" lift. Notice the height of bracket above axle is less on the new axle than the old still attached to the trailer.

This was intentional, based on measuring what height of trailer would have been at down angle of original axle vs 22 degree down angle of new axle. That extra bracket height was getting sort of tall so the standard height bracket was used.

One last minor note, on the new axle you can clearly see the square shaft has the corners running parallel with bracket, shows the "original" position of the axle shaft. Which as prev. post pointed out allows you to figure out what an old axle original down angle was.

[RogerDat]

Ran into a couple of problems.
1). The brackets are welded up through the center of the bracket to the frame through the holes. Looking at the new brackets you can see the oval holes in the top of the bracket.

Getting a grinder on those welds at the bottom of the U with the axle in the way turned out to be difficult, the installer would normally just cut the bracket off parallel to the frame so these buried welds could be ground off BUT since it was not certain that new axle would fit there was a desire to not destroy original axle. So they had to work a grinder into the middle of the bracket to grind them off.

2). Four bolt brake drums were the wrong depth, did not cover the brake pads. Same nominal size as Dexter or Torflex but slightly different off set from the bearing. Not off by much but enough so that different brake drums needed to be ordered. those won't be in until next week.

The good news is the new axle does fit. Trailer sits 3.25 inches higher AND has some suspension again. During removal they wanted to push the old spindle out of the way of the grinder. They said they could shove it several inches with the leverage of a screw driver. Pretty soft.

[stevebaz]

So Roger was the issue combining your old brakes to your new axle or an issue with all new components?

I am probably going to have to address a new axle next year so I am very interested in where you at and where its going. My 1986 has an Al-KO forward swing 4 lug axle. And like you I want to keep it the stock 4 lug wheels.
I am glad your posting this up it helps me alot.
Thank You,
Steve

[RogerDat]

Originally Posted by stevebaz

So Roger was the issue combining your old brakes to your new axle or an issue with all new components?

Steve

Original axle had no brakes.

I figured the added safety for myself of having brakes and the fact that these small campers can be pulled by some pretty small vehicles that would have greater need of trailer brakes made the modest cost of adding in brakes when ordering an axle worth it.

However during the process of ordering the axle it was decided to order the brake drums separate from the axle since Al-Ko did not have 4 bolt drums in stock and a lower priced source of 4 bolt brake drums was known.

What was not known is that the lower priced drums where specific to a proprietary brake/axle system different than the one installed on my axle. Same 7 inch stock dimension hub but with the bearing seat position non-standard. The drum sits too far "in" on the spindle so it does not cover the pads.

Warehouse that had the hubs said they had not sold one of the 4 bolt hubs in years, so willing to sell them cheap, part number not even in system but parts bin labeled with "size". Oops.

Once the correct size is found I may well purchase a spare set of drums and bearings. Except for accidental damage the axle should last at least 10 years or more. I may not be able to even get 4 bolt before that and if there was a break down on the road I would be out of luck replacing that part.

My experience with availability of 4 bolt axle parts is something to balance against cost of new rims and re-fabrication of the spare tire mount on the back. On reflection I could have put a bar/bracket up from the back bumper with studs to fit 5 bolt rim and used original 4 bolt spaced studs mounted through back trailer wall to help mount it. Live and learn I guess.

Still I am excited to see how it tows and rides with the new axle.