> the one I looked at was the plastic tri-fold one on the same page
I have that ramp, it carries up to 200lb. Buster is roughly that weight so we now have to put something under the ramp to support it
(I will take more weight that that, my OH & I have got on it together and jumped around to check it's safe for the dog, LOL, but it bends with Buster on it and he's not happy with it feeling so unstable under him).
However, even with a ramp, does not mean you will be able to get a large dog up the ramp if it has a bad leg :( We needed to get the vet out to Buster, he had hurt his leg, there was no way we would even let him attempt to get up the ramp the way he was limping, too much of a risk of him falling off it, or getting half way up and refusing to move.
Ramps are great, but they are not an easy solution.
As a pup, due to his breed Buster wasn't allowed to jump in/out of the car, so thats why we got the ramp. Unfortunately he has elbow displasia so he still can not jump in/out of the car. He can get in without the ramp (once his front feet are up I can just about heave his rear end in, if I had too), but he can not be allowed to jump out himself, that would be far too much stress for his elbows. A step wouldn't be much good for him either as it would still mean him haivng to put a lot of weight on his front legs to go down the step - with the ramp, they can stand on all legs and walk as they normally would.
So for anybody considering a ramp - a ramp is a solution for the DOG, LOL, not an easy option for the owner! They are heavy, hurt when you drop them on your feet! take up a lot of space and are a complete faff, but if a dog has mobility issues they can help the dog in the car or even up steps that it can no longer cimb ie. maybe steps in/out the door.
While we're on the subject of ramps, if you don't think your dog will happily walk up one, simply leave it folded up, in sight, in the house for a little while (a couple of days maybe). Let the dog get used to the sight/smell of it and in that time it will also start to take on the smell of your home (all in all it will smell/appear less 'strange').
Next, open ramp out, lay flat on floor (in the house), let dog investigate, praise & treat if dog steps on. If dog is not worried, encourage onto ramp, then praise & treat.
Once dog will happliy walk along flat ramp, put it on a slight incline (wedge some books under one end). Once dog is used to that, try having the ramp going out a door with a step. Etc...
Get the dog used the ramp in stages (if it needs it).
If you are worried that you will struggle to help your dog in/out the car, a ramp will help your dog, but it is a faff.
Oh, while I rememebr, the tri-fold ramp in the link dogs-a-babe put up, is the one I have and use it to get the dog in/out the back of a 4x4