Community Forums

TexasTwoStep · 11-21-2015, 05:50 AM

I have 17.5" wheels with Michelin tires and Dexter disc brakes and have been having trouble with tires which Dexter says is a result of having my controller set too aggressively. Just curious as to what settings you run with.

rockintom · 11-21-2015, 07:28 AM

6.0 on my 2014 Chevy ITBC. rockin'

Rburke8 · 11-21-2015, 09:51 AM

Mine is set at 4.0, seems to work just fine. I also have the 17.5 Michelin tires, triple axle.

Sent from my iPad using iRV2 - RV Forum

2013 Excel Wild Cargo -41GKE
2013 Chevrolet Silverado LTZ 3500HD Dually

CARLnJANIS · 11-21-2015, 10:33 AM

Tex,
What tire trouble are you having?

I expect you already know this but different things such as weight, tire wear and the weather affect braking and tire wear. The only way to properly adjust the gain on the controller is to do a towing adjustment. I followed the instruction in the F450 owners manual. Set the gain to 6 and accelerated the truck and trailer to about 20 - 25 mph and used the manual control lever to apply maximum braking for that setting. The trailer brakes slowed the truck and trailer, but barely. I raised the gain up one increment and tested it again. I did this until the brakes locked up and I left two skid marks. I then backed off the gain setting one increment at a time until the brakes stopped locking.

We can only take a few trips a year and I still check the controller gain before each trip.

JDT · 11-21-2015, 11:19 AM

6.5 works for me. I have the 17.5 wheels and discs also. I have been using that setting for 4 years and no issues at all with the tires. Could it be something else causing your tire problems?

TexasTwoStep · 11-22-2015, 06:08 AM

I had trouble with tires on the front axle wearing flat in a couple of places. One was a new tire that I had replaced with the same problem a year ago. Took it to dealer in Albuq. and they checked out the brake system and couldn't find anything wrong. They called Dexter and they said I had the controller set too aggressively and that I should set it between 2 and 3. I had it set on 5 before.
The thread to the most recent episode is below.

http://www.irv2.com/forums/f116/shocks-266051.html

The episode a year ago is here:
http://www.irv2.com/forums/f116/your...es-223666.html

CARLnJANIS · 11-22-2015, 01:18 PM

Gary,
IMHO and limited knowledge, it seems your trailer is riding nose high or your trailer weight distribution is to the rear. I looked at the tires on your previous posts and I've seen this before on 18-wheeler trailer tires when the driver has to lock the trailer brakes in an emergency. The flat spot and shredded rubber is not from normal braking. If I were to venture a guess, when you brake on a downhill grade, there is not as much weight on the front axle as the back. Given the controller and brake system sends the same amount of braking force to all the disks or hubs, the front axle brakes will lock and the rear axles will have to work harder to slow the trailer. If this is the case, adjusting your settings will not correct the problem.

This is how I would troubleshoot it.

First, park your truck and trailer on a level surface and measure the frame to the ground to see if the trailer is close to level. If not level, get it adjusted before the next step.

Second, take your truck and trailer with your normal loading and find a scale that has multiple platforms on the scale that weighs the steering, drive, and trailer axles separately. Pull up onto the scale and pull forward until the truck is off the scale and each trailer axle is on a different platform. This will give the weight of each axle. If the axle weights are not within a reasonable difference, rearrange your load accordingly.

If you still have a problem, then I would look at the brake system.

When we go on our summer getaways to Creede, CO, we are packed to the gills. Both the truck and trailer are loaded to capacity. At the beginning of last year's trip, we were hauling 30,160 lbs. through the Raton and La Veta passes. The truck handled both the up and down sides with ease and didn't leave any tire skid marks on the road.

TexasTwoStep · 11-23-2015, 06:42 AM

Quote:

Originally Posted by CARLnJANIS

Gary,
IMHO and limited knowledge, it seems your trailer is riding nose high or your trailer weight distribution is to the rear. I looked at the tires on your previous posts and I've seen this before on 18-wheeler trailer tires when the driver has to lock the trailer brakes in an emergency. The flat spot and shredded rubber is not from normal braking. If I were to venture a guess, when you brake on a downhill grade, there is not as much weight on the front axle as the back. Given the controller and brake system sends the same amount of braking force to all the disks or hubs, the front axle brakes will lock and the rear axles will have to work harder to slow the trailer. If this is the case, adjusting your settings will not correct the problem.

This is how I would troubleshoot it.

First, park your truck and trailer on a level surface and measure the frame to the ground to see if the trailer is close to level. If not level, get it adjusted before the next step.

Second, take your truck and trailer with your normal loading and find a scale that has multiple platforms on the scale that weighs the steering, drive, and trailer axles separately. Pull up onto the scale and pull forward until the truck is off the scale and each trailer axle is on a different platform. This will give the weight of each axle. If the axle weights are not within a reasonable difference, rearrange your load accordingly.

If you still have a problem, then I would look at the brake system.

When we go on our summer getaways to Creede, CO, we are packed to the gills. Both the truck and trailer are loaded to capacity. At the beginning of last year's trip, we were hauling 30,160 lbs. through the Raton and La Veta passes. The truck handled both the up and down sides with ease and didn't leave any tire skid marks on the road.

Thanks for the information. I weighed the rig on the way home:front axle 6,160 lbs. and rear axle 5,900lbs. My trailer is slightly nose high but I have clearance at the underside of the 5er at the bed rail of 6 3/4 inches, both at front and rear. I am at the lowest setting on my hitch, I could go down one more notch on the pin box (putting it at the very top notch) and my settings under the rig are at the top holes.I guess I could move my pin to the top notch, but am afraid it would lower my clearance too much since I boondock camp in some remote places. I am uncomfortable with my controller at 2.5 although it seems to stop ok.

Rburke8 · 11-23-2015, 08:15 AM

Quote:

Originally Posted by CARLnJANIS

Gary,
IMHO and limited knowledge, it seems your trailer is riding nose high or your trailer weight distribution is to the rear. I looked at the tires on your previous posts and I've seen this before on 18-wheeler trailer tires when the driver has to lock the trailer brakes in an emergency. The flat spot and shredded rubber is not from normal braking. If I were to venture a guess, when you brake on a downhill grade, there is not as much weight on the front axle as the back. Given the controller and brake system sends the same amount of braking force to all the disks or hubs, the front axle brakes will lock and the rear axles will have to work harder to slow the trailer. If this is the case, adjusting your settings will not correct the problem.

This is how I would troubleshoot it.

First, park your truck and trailer on a level surface and measure the frame to the ground to see if the trailer is close to level. If not level, get it adjusted before the next step.

Second, take your truck and trailer with your normal loading and find a scale that has multiple platforms on the scale that weighs the steering, drive, and trailer axles separately. Pull up onto the scale and pull forward until the truck is off the scale and each trailer axle is on a different platform. This will give the weight of each axle. If the axle weights are not within a reasonable difference, rearrange your load accordingly.

If you still have a problem, then I would look at the brake system.

When we go on our summer getaways to Creede, CO, we are packed to the gills. Both the truck and trailer are loaded to capacity. At the beginning of last year's trip, we were hauling 30,160 lbs. through the Raton and La Veta passes. The truck handled both the up and down sides with ease and didn't leave any tire skid marks on the road.

Carl,

I was very surprised at the weight you stated above. What type of rig do you have and what are using as a tow vehicle? When fully loaded I weighed out at 29,300 lbs and that was with 2 motorcycles, full of fuel, topped off propane tanks and all of my household goods.

Sent from my iPad using iRV2 - RV Forum

2013 Excel Wild Cargo -41GKE
2013 Chevrolet Silverado LTZ 3500HD Dually

CARLnJANIS · 11-23-2015, 04:15 PM

Quote:

Originally Posted by TexasTwoStep

Thanks for the information. I weighed the rig on the way home:front axle 6,160 lbs. and rear axle 5,900lbs. My trailer is slightly nose high but I have clearance at the underside of the 5er at the bed rail of 6 3/4 inches, both at front and rear. I am at the lowest setting on my hitch, I could go down one more notch on the pin box (putting it at the very top notch) and my settings under the rig are at the top holes.I guess I could move my pin to the top notch, but am afraid it would lower my clearance too much since I boondock camp in some remote places. I am uncomfortable with my controller at 2.5 although it seems to stop ok.

Well I'm officially stumped.

Since you stated in a previous post that the brakes were inspected and functioning normally, I can't think of anything else.

It's just not logical that only the brakes on the front axle would lock. Check if the trailer has a proportional valve that can be adjusted.

CARLnJANIS · 11-23-2015, 04:30 PM

Quote:

Originally Posted by Rburke8

Carl,

I was very surprised at the weight you stated above. What type of rig do you have and what are using as a tow vehicle? When fully loaded I weighed out at 29,300 lbs and that was with 2 motorcycles, full of fuel, topped off propane tanks and all of my household goods.

I have a 2013 L36GKE. The GVWR for the trailer is 18,750 lbs. I usually load out the trailer to capacity. My 2012 Ford F450 fully loaded is around 11,000 to 11,500 lbs. and has a GCWR of 30,000 lbs.

TexasTwoStep · 11-25-2015, 05:55 AM

Quote:

Originally Posted by CARLnJANIS

Well I'm officially stumped.

Since you stated in a previous post that the brakes were inspected and functioning normally, I can't think of anything else.

It's just not logical that only the brakes on the front axle would lock. Check if the trailer has a proportional valve that can be adjusted.

I wonder what would happen if I killed the hydraulic line to the front axle brakes. I have heard that friction is a function of weight and not necessarily surface area.

rockintom · 11-25-2015, 08:06 AM

Gary, please don't do anything like that. I would use someone else truck and see how the brake system works (preferably a truck with an add-on controller they are happy with). That'll decide whether you have a trailer or truck problem. Personally I am not totally satisfied with the factory ITBC on my Chevy. To me, it's too late coming one and on light brake applications the trailer brakes don't work at all. Adjusting the gain changes nothing at lower-lighter brake applications. I won't get into details now. That portion of the controller is non adjustable. Many folks go to an add-on brake controller like the P3 for a better/more adjustable braking on the trailer. rockin'

CARLnJANIS · 11-25-2015, 10:59 AM

Gary, I agree emphatically with Rockin'. You may have already done this, I would contact the brake manufacturer and find a factory level authorized repair facility or maybe get in touch with Ralph and maybe he can point you to an exceptional brake shop.

While testing on a different truck could rule out the truck being the cause, there is only one wire going to the brake actuator or pump on the trailer and that in itself would not explain why only one axle locks. Plus one trip down the road in a different truck may not trigger the event. If the front axle locked every time you braked hard, your tires would look like hexagons. This is going to take a person with a lot more brake system experience than me.

This reminds me of story.

A manager, an engineer, and a programmer were on a trip. As they were coming down a steep hill, the brakes failed. They started bouncing back and forth off the guardrail and side of the hill. Half way down they finally stopped. While trying to decide what to do, the manager said, "Let's form a committee, assign tasks, and commission studies of our options up to this point." The engineer said, "We don't have time for that. I will get under the hood, completely redesign and build a better braking system." The programmer said, "That would take forever. Let's just push it back up the hill, come back down and see if it happens again."

By the way, I'm a retired programmer.