Raising a tow bar connection point?

[Cdn-Tx]

I plan on flat towing a 03 Miata. The normal Miata base plate (Roadmaster) exits the grill opening. To limit the amount of receiver drop I need I’m thinking of making L shaped brackets to raise the car end mounting points about 6 inches. Some of the Roadmaster base plates use brackets like this but are the styles that connect under the bumper, not through the grill opening. I can’t see why it shouldn’t work well. If I raise the cars mounting point by 6 inches and lower the Discovery’s receiver by 2 inches the tow bar should almost be level. Has anyone had any experience mounting like this? BTW Tow bar is a 5250 Falcon

[Route 66]

One consideration is that the 6" bracket may apply to much leverage to the mounting points and create a stress failure.

[Cdn-Tx]

Quote:

Originally Posted by Route 66 One consideration is that the 6" bracket may apply to much leverage to the mounting points and create a stress failure.

Yea I thought of that but the fact that other mounts which look to be no more ridged than the Miata mount (base plate) use a L shaped bracket. I think the Chevy Caviler Roadmaster mount for instance swings up about 7 inches. Heavier car than a Miata. Not sure I’d do it on a car weighing 5000 lbs but a Miata is under 2500 lbs.

[Arch Hoagland]

I tow my 1991 Miata 4 down and haven't done a thing to adjust the height. I've towed it about 10,000 miles without a problem.
I use a Roadmaster base and towbar. I also tow a Lexus RX300 with the same setup.
My Miata weighs 2,400 lbs.

[KIX]

If it would help your situation Demco makes a 6" receiver drop (or raise)

[tinman1]

Kix is correct - I have seen a couple of receiver drops with approximately 3" drop. It might be worth considering.

[teddyu]

Raised my connection point on a 2007 then a 2010 Cobalt by 6". Designed and had made L brackets that slide into my Demco baseplate connection points. The L brackets are re-enforced by plates on each side of the insert that rest on top of the baseplate connection. This design utilizes the whole connection bracket to take the added stress. The L brackets are bolted in place. Once a year, I remove the adapter, checked for cracking, re-painting, lubricating, then re-installing. Just my two cents

[azloafer]

Is this what you maight need?
Drop Hitch Receivers by Blue Ox on Sale

[Cdn-Tx]

Quote:

Originally Posted by teddyu Raised my connection point on a 2007 then a 2010 Cobalt by 6". Designed and had made L brackets that slide into my Demco baseplate connection points. The L brackets are re-enforced by plates on each side of the insert that rest on top of the baseplate connection. This design utilizes the whole connection bracket to take the added stress. The L brackets are bolted in place. Once a year, I remove the adapter, checked for cracking, re-painting, lubricating, then re-installing. Just my two cents

That’s exactly what I was thinking of doing. As best I can tell the main failure regarding flat towing is roll-under during quick stops or on uneven ground. That is when you will most likely bend base plates, tow bars and maybe even the chassis of the toad. That’s why the tow bar manufactures want them as level as possible. One option is to drop the receiver but from a Discovery receiver to the mount points on a Miata is about 9 inches of drop. I’m trying to limit the amount of drop to minimize the receiver smack on steep inclines which we have a number of here where I live and our main destination next summer. I will build (not buy) a 2-inch dropped receiver and by making L brackets that raise the car end by about 6-inches I should be within an inch of level.

[Cdn-Tx]

Quote:

Originally Posted by Arch Hoagland I tow my 1991 Miata 4 down and haven't done a thing to adjust the height. I've towed it about 10,000 miles without a problem. I use a Roadmaster base and towbar. I also tow a Lexus RX300 with the same setup. My Miata weighs 2,400 lbs.

While web-surfing last night I stumbled onto a guy that flat-towed a Miata connected to a stock Roadhouse base plate. He dropped his coach end receiver as much as he could without constantly smacking the ground on inclines (he has significant overhang in back) and still ended up with considerable angle to the tow bar. One day he had a panic stop….the coach reared up….the Miata nosed down and the result was a bent base plate. Speaks to the rigidity of a Miata as it somehow didn’t bend the chassis, just the mounting points (which are half-inch thick). That is why the bar manufacturers want their products as level as possible.

I know I can’t get enough receiver drop to get a level tow bar and not opting for a different toad so my only logical solution is to raise the mounting point of the stock Roadmaster plate. I sure if I build it using basic engineering intelligence; good solid welds; and inspect everything closely for the first 10,000 miles it should work out Ok.

The way the Roadhouse Falcon’s cross brace interlocks with the quick disconnects it distributes any force on one side onto both mount locations. The bar and the mounts are very ridged side to side due to the triangulation of the bar when pinned in place. Up and down it’s only as tough as the 2 pieces of ½ inch thick plate and that’s why you will bend a base plate if it noses under.

[Batman_777]

I use a 2" receiver drop turned upside down to achieve a 2" rise for a high towed vehicle. Works great..

The tow bar angle should not exceed 4" (Ideal is flat or level)

If the vehicle being towed is too low and creates a greater than 4" rise to the tow vehicle's hitch, you run the risk of the towed vehicle pushing up on the hitch and lifting the hitch and or causing damage to the base plate.


If the towed vehicle is too high and creates a greater than 4" drop to the tow vehicle's hitch, you run the risk of the towed vehicle's front end coming off the ground (lifting up) in a fast stop.

The link below provided above by azloafer shows exactly what I use.

http://www.pplmotorhomes.com/parts/r...?source=google

[Cdn-Tx]

Quote:

Originally Posted by Batman_777 I use a 2" receiver drop turned upside down to achieve a 2" rise for a high towed vehicle. Works great.. The tow bar angle should not exceed 4" (Ideal is flat or level) If the vehicle being towed is too low and creates a greater than 4" rise to the tow vehicle's hitch, you run the risk of the towed vehicle pushing up on the hitch and lifting the hitch and or causing damage to the base plate. If the towed vehicle is too high and creates a greater than 4" drop to the tow vehicle's hitch, you run the risk of the towed vehicle's front end coming off the ground (lifting up) in a fast stop.

Exactly why I’m shooting for as level as I can be. And brakes on the toad help as well. Even 2500 LBS multiplies under inertia and you get that pushing against stuff and things can happen you’d think impossible.

[teddyu]

A little to add to my last post. The Cobalt connections are 13" above the road surface and the receiver on the MH is 22" above the road surface. I initially dropped the ball as far a possible, but the ball would drag on the slightest of inclines. Decided to raise the Cobalt 6" and use a 4" drop from the receiver. Not the best solution but it's close to level.

[Arch Hoagland]

I've had a couple panic stops with the Miata behind (and two other toads) and all is well. And I've been over a lot of those large bumps that cause the coach to heave up and down, you know...the ones where you check the rear view camera to see if the toad made it through.
I inspect my base plates, etc several times a year as I read and seen pictures of baseplate failures. All is well.