DIY car loading ramps??

Stampie said:

Starting off with the quoted numbers above.

With a wheelbase of 256 inches by raising the front wheels 8 inches you only change the angle 1.79 degrees.  That 1.79 degrees lowers the rear attachment point by 3.56 inches.  Let's round off to the attachment point height being 31.5 inches tall.  While looking at things last night the problem isn't the angle of approach.  It's the high center.  The high center angle for a Miata is 11.52 degrees.  Add our tilt of 1.79 degrees and we get a ramp angle of 13.31 degrees.  That ramp angle with a attachment point height of 31.5 inches gives us ramps 137 inches  long.  Now SKJSS stated that his deck height was 32 inches instead of the 35 quoted above.  That would get an attachment height of 28.5 inches and then a ramp of 124 inches which is right at the 10 foot ramp desired.  As you can see anything that can be done to lower that rear attachment point helps a lot. 

I would append that to say "anything that lowers the rear attachment point OR RAISES THE CAR helps a lot.", which is why I suggested blocking the suspension at full droop earlier.  It's quick, cheap, easy, and yields lots of benefits which is what GRM is all about.  It's not like the car needs suspension movement while being transported.  :shrug: 

Stampie said:

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My thought is a redeck from the rear of the wheel wells back.  If you make that a dovetail of 10 degrees it gets your new attachment point 20 inches lower.  If the tubs are 6 inches that gives you a deck height of 41 inches and a rear attachment height of 21 inches without having to raise the front.  At that point 10 foot ramps gives you 10.1 degrees and 8 foot ramps give you 12.6 degrees.  This allows you to pull up put on some ramps and unload without having to screw around raising things and wondering if you are being safe.

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 I don't know if he would need to redeck the full length of the bed.  If he just had small ramps before and after the wheel tubs that cleared the approach/high center/departure angles that would be good enough and certainly a lot easier.  Then again, if he DID redeck the full length he could build in storage beneath if, including storage for two long ramps, so there's that.  

Stampie said:

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My extra special Christmas thought is make that new rear overhang hinged at the front.  Put a simple hand operated jack to raise the rear of it.  Then as long is your angle of approach is over 10/12 degrees you can get a very low car up on the rear overhang, jack it up, and have a total flat bed that you never have to worry about high centering.

Anyone want to check my numbers?

 Hmmm, that is a very interesting idea.  Not sure how much would need to be made bendable/flexible for that to work.  Maybe just exhaust and wiring?  

In reply to JBinMD :

When I said redeck from the rear of the wheel wells back I meant just the back 9.5 feet.  That would still leave the front half of the bed intact.

Also yes raising the car would help loads but then you're adding extra work.  My goal would be to make it as easy as possible to arrive, unload, and race.  That said my first car trailer required that we remove the trailer wheels to load and unload.  Do as I say not as I do kinda thing.

Don't forget that I have very little mechanical skills. I'm thinking if I get those ramps that raise the front of the truck 15" that'll help.  From there maybe a couple of 10' ramps with some overlap and vertical support will do the trick.  To help with high centering I can use 2x6 wood in front of the rear wheels to raise it up. 

This video shows a similar truck with the bed off. It looks like any dovetailing of the bed/frame would have to start a good deal behind the rear wheels to account for the rear spring perch.

I did find a few listing for 13' 1000lb capacity aluminum ramps for $250 each. Maybe 3 of those? 2 reinforced ones to load the car on the back, and one cut in 4 pieces on the deck to get up and over your wheel tubs.

In reply to SKJSS (formerly Klayfish) :

If you raise the front wheels of the truck 15" it will lower the rear of the bed 6.6". 
 

If you build ramps over the wheel tubs it will help the high centering.

In reply to MrJoshua :

Those 13' ramps are excellent.  They are gonna be pretty heavy to lift, and difficult to stow.

SKJSS (formerly Klayfish) said:

Don't forget that I have very little mechanical skills. I'm thinking if I get those ramps that raise the front of the truck 15" that'll help.  From there maybe a couple of 10' ramps with some overlap and vertical support will do the trick.  To help with high centering I can use 2x6 wood in front of the rear wheels to raise it up. 

Ok I'll do the math on this.

Raising the front wheels changes the angle to 3.36 degrees.  That lowers the rear attachment point 6.68 inches.  For safety error let's say 6.5 inches.  If rear deck height  is 35 inches that brings you down to 28.5 inches for the rear attachment point which means 124 inches ramp length.  Again right at the 10 foot length for a ramp.  Do you really want to jack up the front 15 inches everytime you load or unload?

In reply to MrJoshua :

I could see airbagging the rear to not only eliminate that issue but also help in angles.  Basically it comes down to do a lot of work once to make things right or do a some work every time to make it dealable.

Looking at that frame more that's just begging for a hydraulic tow truck bed to be attached and berk all this screwing around.

15" is a long way to have to lift the front end of a truck that heavy.  It's a lot of work, and potentially dangerous. 
 

You could accomplish the same thing by letting the air out of the rear tires, then refilling them after loading (that's a pain, but so is lifting the front)

The maximum amount airbags could lower the rear is 6" before the tires hit the bottom of the wheel tubs (which would be more at the rear of the overhang). 
 

If you are serious about cutting the wheel tubs off and flattening them with plate, then air bags won't be able to lower the truck at all.

SV reX said:

The maximum amount airbags could lower the rear is 6" before the tires hit the bottom of the wheel tubs (which would be more at the rear of the overhang). 
 

If you are serious about cutting the wheel tubs off and flattening them with plate, then air bags won't be able to lower the truck at all.

In reply to SV reX :

You didn't hit in reply to so I'll assume you're not replying to me.  Especially since I've never suggested that and my calculations include the 6 inch wheel wells.

In reply to Stampie :

Good assumption. I wasn't responding to you. Just a data point. 
 

OP previous mentioned trying to cut off the tubs.

In reply to Stampie :

I'm sure it adds a small amount of extra work but I think it would be *very* little work for a significant benefit.  The process to load the car would be something like... 

1) raise one end of car.  

2) place an appropriate length of 2x4/pipe/etc between the outer half of the lower arm and a hard point like the subframe/strut tower/inner pivot of the upper arm/etc to prevent suspension compression, and 

3) lower car.  

Repeat for other end of car.  Unloading would be the reverse order.  

How long do you think that process would take in time and money?  I would be surprised if it took more than 5 minutes to perform and $20 In materials.  How much would you estimate it would cost in time and materials to dovetail the rear 9' of the truck or build a pivoting rear deck?  I'm not saying that what I suggested is the best way to do it because honestly I think your ideas are a much better long-term solution, but since he expressed a desire to be budget conscious I think raising the car a couple of inches would certainly simplify his ramp situation and buy him some time to decide which way to go in modifying the truck.  I would like to throw out one last modification:  if he uses your idea to redeck the rear of the truck, instead of making it 6" higher all the way to the back I think it would be even better if he took whatever angle his ramps end up being (say 16*?), divide it by two, and make deck ramps starting at the rear edge of the deck at 32" high going forwards at 8* until they reach 6" high and then continue horizontally to the wheel tubs.  That way the rear deck height is 32" instead of 38", and the half angle wheel-tub-ramps will minimize the high centering that he has to deal with.  Does all of that make sense, or should I try to explain it better and/or draw a picture?  
 

SV reX said:

In reply to MrJoshua :

Those 13' ramps are excellent.  They are gonna be pretty heavy to lift, and difficult to stow.

Agree on the heavy, but one can stow in the stock location. Maybe that area could be modified for 2? IF that is possible, AND 13 feet would be long enough to work without lifting/lowering the truck, that's the easy button. 

In reply to JBinMD :

In my redeck of the rear it would be a dovetail type with a 10 degree angle going down that would start at the rear of the wheel humps.  That would give about a 21 inch height at the far end where the ramps would attach.  That make sense?  I like pictures.  Hell I'm just a redneck born and raised in SC and then graduated to FL man.

If you cut the wheel "tubs" off and then decked it flat.. would you not have rubbing? Seems like they have that shape for a reason.

I started down the path of removing the wheel tubs, but they seem quite happy to stay where they are.  

I can use these to raise the front of the truck.  Ramps

I agree that redecking it or a hydraulic bed is the "best" solution, however both are far beyond my abilities.  I need a solution that is realistic for me to do.  Maybe long term I'll get a shop to dovetail it but for now...  I don't want to break the bank but I don't mind spending the money if it makes things easier for me. And safe.  While it'll take a bit more work, I think some combination of raising the truck and ramps might be my best bet. 

OHSCrifle said:

If you cut the wheel "tubs" off and then decked it flat.. would you not have rubbing? Seems like they have that shape for a reason.

It absolutely will rub. 

Stampie said:

In reply to JBinMD :

In my redeck of the rear it would be a dovetail type with a 10 degree angle going down that would start at the rear of the wheel humps.  That would give about a 21 inch height at the far end where the ramps would attach.  That make sense?  I like pictures.  Hell I'm just a redneck born and raised in SC and then graduated to FL man.

I like this idea, but the math is off a little. 
 

If the dovetail starts at the top of the wheel tubs, it's 41" high. A 10 degree  angle for a run of 9'-6" would mean 11.4" of drop.  That means the height would be 29.6".

But that's not quite right either. The 9'-6" tail is a measurement from the centerline of the axle.  From the rear of the wheel tubs there is about 8'. So the drop would be 9.6" from the 41" leaving 31.4" to the ground.

Steve_Jones said:

SV reX said:

In reply to MrJoshua :

Those 13' ramps are excellent.  They are gonna be pretty heavy to lift, and difficult to stow.

Agree on the heavy, but one can stow in the stock location. Maybe that area could be modified for 2? IF that is possible, AND 13 feet would be long enough to work without lifting/lowering the truck, that's the easy button. 

That's a good point.

The rack underneath could be modified to hold 2 ramps piggybacked.  
 

Alternately the ramp could be modified- cut in half lengthwise and stored in the same location. (I suggested this earlier).  The 2 narrow ramps would still be 16" wide (plenty wide enough).  Another advantage is that they would be lighter.

Either of these is a much easier fabrication than some other ideas.

The truck I looked at didn't have 13' ramps- it had 8' ramps.  So I guess there is some variation in those.

Since the Formula 500 car is only about 650lbs would an engine hoist (with people guiding the car) be an easy button solution?  It's just full size cars that would need ramps. 

In reply to SKJSS (formerly Klayfish) :

I think you'd have some challenges with the engine hoist not having enough vertical lift.  

Since you are gonna have to have some degree of fabrication no matter what you do, I think the easy button is probably to cut a 13' long ramp in half lengthwise and modify the rack under the truck to hold the 2 ramps.  
 

It will work for cars or the F500, and if you decide you want to go further later you could consider adding those ramps for the front of the truck, a hoist boom, or dovetailing the deck.  
 

The ramps will still be nice to have. 

In reply to SV reX :

If b is 114 inches and A is 10 then a = 20.1

I was wondering if that measurement was from the rear of the wheel wells.

If b is 96 and A is 10 then a = 16.9

I cheated and used this page.

http://www.cleavebooks.co.uk/scol/calrtri.htm

EDIT - for the construction types 2/12 pitch is ~9 degrees so you get 2 inches of drop per foot of length.  You know if you need to do easy math.

In reply to SKJSS (formerly Klayfish) :

If you are considering that I might lean towards a   deck mounted lift

Those ramps are actually 13'7" which gives you less than 15 degree slope at 36 inch rise. That's not hateful at all. They're 25 wide so splitting them would be tight, but the weight savings and storage issues might be worth it. If the stock location could fit 2, I'd want 2 un modified ones.