Community Forums

trx430ex · 11-18-2017, 05:24 PM

With SMI brakes

Was wondering, if anyone else was running this combo?

Toad will be E350 @ 6000 pounds. Would not mind full lock on toad in emergency stop.

BFlinn181 · 11-18-2017, 07:14 PM

Locking up the toad brakes could cause the toad to skid off to the low side of a crowned road and jackknife. ABS prevents skidding and I don't think you'd stop any faster with the toad's brakes locked up.

powercat_ras · 11-18-2017, 09:33 PM

The ABS function might be enabled if the E350 or other type of towed vehicle was towed with the Ignition Key in the Run position to power the Engine Control / AntiLock Electronics. The AntiLock system also has a pump integrated into the ABS actuator box with all the brake lines running thru it that is also only powered with the ignition key in the Run position.

The normal way that vehicles are set up for flat towing there is no antilock action when the brakes are applied on the towed vehicle by the braking assist.

The assisted braking on the towed vehicle is supposed to be set so that the brakes on the toad are not applied so that they lock on pavement. The usual procedure is to set them up so that they just start to lock up on unpaved surface under very hard braking.

twinboat · 11-18-2017, 10:28 PM

You would rather have a skidding 6000 weight behind you ?

You do know that rolling friction is better then sliding friction. Ask any drag racer.

Gary RVRoamer · 11-19-2017, 08:00 AM

I would think that would be the normal situation for towing. The toad would have to be actively monitoring wheel speeds with its ABS computer to get any anti-lock capability. When towing 4-down, most vehicles have the toad ignition off, disabling its computers, which would almost surely include the ABS.

I wonder if your SMI can even apply enough pressure to cause a lock up on a firm dry surface. Anybody have any experience with this? I've seen toad brakes lock up on gravel or sand, but not sure about surfaces with better traction.

twinboat · 11-19-2017, 09:48 AM

Quote:

Originally Posted by Gary RVRoamer

I would think that would be the normal situation for towing. The toad would have to be actively monitoring wheel speeds with its ABS computer to get any anti-lock capability. When towing 4-down, most vehicles have the toad ignition off, disabling its computers, which would almost surely include the ABS.

I wonder if your SMI can even apply enough pressure to cause a lock up on a firm dry surface. Anybody have any experience with this? I've seen toad brakes lock up on gravel or sand, but not sure about surfaces with better traction.

I agree that the antilock system is disabled while towing, but it seems the OP WANTS the toad to lock up the wheels in a panic stop.

Sweetbriar · 11-19-2017, 11:23 AM

I don't think the toad brakes would lock up even if it's anti-lock system was active. The SMI system uses proportional braking which will maintain the toad's rate of deceleration so that it does not drag or push the coach during braking. Taking this into consideration and the inherent slower deceleration of the heavier coach, even in a panic stop, the setup is in effect anti-lock.

To enable the toad's anti-lock the key would need to be in the run position but still no guarantee it will work correctly.

And run the weight numbers for the Tiffin. The E350 @ 6000 pounds might be exceeding its limits.

trx430ex · 11-19-2017, 07:46 PM

Always so much to learn, everyday, thanks guys.
The driver's side ABS sensor on the toad is fried, so the van is ABS free for the last 8 years. Didn't even think about the power being off. Like being in full control of 6000 pounds, I like to drive. I don't ever want to be in that situation but if I get thrown into the extreme. I want to know the toad will actually help the rig stop.

But,, the reason I chose SMI brakes is that they power up the vacum assist of the power brakes on the toad, creating "active" braking. Unlike the Blue-Ox, passive pedal pushing with key off.

With the toad braking harder than the coach, it would also pull the tail of the coach back down into level braking. That would provide better steering control, and braking on the coach itself. Everything squats to level, with good control.

Replacing hitch on RV with 10K Reese, 5/8 "locking", and 1/2 "locking" pins on toad.

powercat_ras · 11-19-2017, 08:48 PM

The weak point after you reinforce the things you mention in your last post would seem to be the tow bar, base plate, and base plate frame attachment point with what you are trying to do in terms of having much more of the braking done by the towed vehicle than what is the standard way that is followed by vast majority of RV users.

trx430ex · 11-19-2017, 09:04 PM

Thanks Powercat, May throw a weld on that toad, in addition to the bolts.

After 10K hitch, replaces 5 K hitch. I see what you did there.

If the entire rig can squat at the same time in braking, that would provide much more control.

BFlinn181 · 11-19-2017, 09:39 PM

Quote:

Originally Posted by powercat_ras

The weak point after you reinforce the things you mention in your last post would seem to be the tow bar, base plate, and base plate frame attachment point with what you are trying to do in terms of having much more of the braking done by the towed vehicle than what is the standard way that is followed by vast majority of RV users.

Quote:

Originally Posted by trx430ex

Thanks Powercat, May throw a weld on that toad, in addition to the bolts.

If the entire rig can squat at the same time in braking, that would provide much more control.

Got to agree with powercat_ras, it's not a safe way to set up an RV and Toad. If you're just trying to reduce 'squat' you could buy heavy duty shocks. If you want to improve braking in the RV, install a proportioning valve to balance braking force. Of course if you've got ABS braking, you already have that built in.

In any case, if you go ahead with increasing braking in the Toad, make sure you have a working break-away braking system....and please don't drive in Cincinnati.

trx430ex · 11-19-2017, 09:50 PM

But that is the whole point BF, if the toad can pull the [lack of a better word], the tail down. The coach would stop faster in full on level position.

SMI could answer the question, but it would require legal, for that I do not blame them for keeping silent.

You see, the math works both ways, too light it is not noticed, but go the other way. Too heavy, the math needs to save itself.

BFlinn181 · 11-19-2017, 10:15 PM

I don't know what math you're talking about, but a couple of points: Daily driving only requires emergency braking in very rare incidents. Paying attention, anticipating other's actions, when I was taught over 50 years ago it was called driving defensively. That would make you far safer than setting up your rig so the Toad creates forces to increase braking. It's a theory I'm not sold on because the Toad would be pulling back, very little force would be directed downward. You'd be better served by replacing the 'fried' ABS sensor to increase braking in that vehicle, making it safer when not being towed. Braking systems for Toads are generally meant to reduce the braking need of the additional weight and momentum you're towing, not holding down the rear of the RV.

jrwitt · 11-21-2017, 12:18 PM

I was taught and always heard that when wheels lock up during braking you loose traction. I have heard it described as sliding on a pool of molten rubber. Anyway, isn't the whole purpose of ABS to improve traction rather than letting the brakes lock and slide? If brake lockup was a faster way to stop then why did they invent ABS?