I have steel ramps, but they are very short and suitable for my [low]
I am considering making ramps from wooden boards. Specifically,
picture a ramp that looks like a letter I in cross section. The wide
part of the I is a 2x8. On the top and bottom of the I, there would be
2x4s. The "I", of course, would be laid flat for use.
Here's the ascii graphic:
The 2x4s would be screwed to the 2x8 with wood screws, and reinforced
My question is, what would be the strength of this ramp if it was,
say, 8 ft long. Specifically, how much load could I place in the
middle for some reasonably low deflection (like 1-2 inches).
It is simply a 3x3-1/2 beam for estimating purposes. You can forget the
2x8 in the horizontal as it is conservative to do so.
I don't have a link ottomh, but a google will find any number of beam
Use SYP or fir for higher modulus and, of course, be sure it is
Depending on length and weight desired, going w/ 2x6 tapered some for
the ends might be more suitable at the expense of a little more
Why not just take the 2 X 8's and test them. Put them on a block of some
kind on the ground and roll whatever you plan to use them for onto them and
observe the deflection. This would be simple and just cost the price of a
I have seen a number of ramps that have a metal end on them specifically
designed for a ramp. I think that would be much more compace and work better
than your proposed 2 X 4 ends. I don't know where to purchase them, but
they are out there because I have seen them in use many times.
On Thu, 25 Oct 2007 11:45:15 -0400, "Lee Michaels"
Even your local borg will probably have aluminum "ramp ends" for 2x8
and 2x10 lumber. They can be secured to a trailer or truck tailgate
by means of holes in the aluminum pieces and pins that go through
those holes and into matching holes you drill in the trailer or
tailgate. The 2x8 version has worked fine for me with 8 foot lumber
for lawnmowers and snow throwers (heaviest item is about 160lbs). I
never drilled holes in the tailgate of my 18 year old truck and I
don't plan to drill holes in the tailgate of the new truck either ;-)
Just FYI, the 1989 Nissan pickup was better built (both assembly and
design) than the 2008 Tacoma is. The wind noise was lower (after 18
years) than the new one and the speedometer was more accurate. The
Tacoma reads 5% high (factory spec is +/- 7%). That 5% error will
take away 5% of the warranty coverage (3000 miles of a 60000 mile
warranty). It's all drive-by-wire and the only physical correction is
a slightly larger tire size (70 series -> 80 series is 5% increase).
The dealer hasn't done anything yet, except the usual "Im sorry. What
would make you happy?" and then not following up. The dealer will get
one more chance at fixing it, then I'll file a "Lemon Law" complaint
(also covers things that reduce the value of the vehicle) - which they
must respond to in writing. At least the error will be documented for
any future warranty claims...
I didn't drill holes in my tailgate either. What I do do though, is use
cargo straps wrapped around each ramp and secured to the bumper to keep
the ramps from slipping off. It wakes you up real fast when a ramp slips
out while you're backing a riding mower out of the truck...
If the dealer hasn't done anything call the regional factory rep. The
calibration is an easy adjustment with a proper scan tool and would take
a competent tech about 5 minutes if they just go by tire measurements
and 10 minutes if they measure the actual rolling radius of the tires.
I thought that sagulator was a PC program. It is great! I have it
bookmarked and am now experimenting!!!
Looks like with 2x4x, the deflection of a 1,000 lbs load in the middle
will be about 2 inches, which is too much.
However, with 2x6s, the deflection will only be 0.36 inches, and 0.7
inches with 2,000 lbs center load.
So, it seems, that a ramp made to the shape of letter I, could easily
let me deal with 2,000 lbs wheeled loads. (such as a dolly on casters)
Well, when you're dealing with that kind of loads, don't forget the
supporting ends, joint strength and fasteners, point loading of a caster
on the 2x ramp, the downward force of the load back down the ramp
running over whatever is in the way, the load limit on a truck tailgate,
etc., etc., etc., ...
For what I expect would be better strength, rigidity and protection from
potential defects in dimensional lumber, try making a glued and screwed
box beam. Something like a top surface layer of three layers of 3/4"
plywood, two or three 2x4 members inside the box, and another layer of
3/4" ply on the bottom. You'd need two sheets of 3/4" ply, six 2x4s and
a lot of glue and screws to make two 1' wide ramps. If you want cleats
at the sides to help keep wheels from running off, apply strips of 1x2
to the top surface along the edges.
Bad ASCII art:
## ## ##
## ## ##
## ## ##
BTW, the extruded aluminum ramp ends are called "Ramparts" and sold many
places including Depot and Lowe's.
I think that it is going to be kind of big. But I will think about
it. By the way, I heeded your advice and bought the HF load balancer a
year ago. I will check those ramparts, I am sure that I will need
them. But maybe I will make them.
A box beam of plywood and 2X's would make an excellent ramp, but
you've got the functions of the plywood and sawn lumber reversed. The
plywood should be the vertical webs and the 2X's the top and bottom
plates. The 2X's carry the tension and compression loads; the plywood
resists the shear between the tension and compression members.
The 2x's could be replaced with ply as well, however using the 2x4s just
makes construction easier. The main point is in putting engineered
lumber i.e. plywood in the positions of stress, eliminating the
potential for an undetected flaw in the dimensional lumber from causing
a catastrophic failure. Indeed, the engineered I joists for building
construction have begun to shift to engineered lumber for the top and
bottom chords of the I joists in place of the earlier dimensional
But there is stress in both the webs and flanges. With a little care
in selecting the 2Xs you're unlikely to have a problem using them in
tension or compression for the bottom and top plates. Any hidden
defects, or overloading, are much more likely to cause a failure along
the grain if they're subject to shear. The criss-cross grain of the
plywood makes it the better choice for carrying the shear in the webs.
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