Check my math -under car clearance

[Just puttering]

Blasted... I was just about ready to send this and got a BSOD!!

I did no math... Just a picture to try and get a idea of my clearance!

If I have a ramp that is 25 feet long and rises 2.5 feet, will a 90" wheel base 4inch ride height roadster clear??

How much would you think putting 500 pounds of people and stuff in the car would change the ride height?

If it wont clear, I could always put rubber mat on both ends to raise the car as it goes over the break point (I don't like this idea but if I must....)

Thanks

[Al_C]

No. If my math is correct, you need another 1/2 inch of clearance. Irrespective of extra weight in the car, you would need 4.5 inches to clear it.

[Rdone585]

I also came to the same value. Realize this has many assumptions but on paper given the input as shown above, 4.5" is needed to clear the pinch point in the center of the vehicle. The assumptions are:
* the ramp is flat and doesn't flex
* both the ramp and the upper portion are on the same grade (i.e. the angle at the pinch point is 5.7 degrees)

Some things that could help:
* If the ramp is curved so the pinch point is less than 5.7 degrees
* if the upper level is sloped down (as many garages are, i.e., lower near the ramp than further inward)
* If the upper level is a trailer, the sometimes the tongue of the trailer can be lifted to less the angle at the pinch point

Another point of interest that often is the first challenge - the nose of the car rubbing on the ramp prior to the front wheels contacting the ramp.

[Just puttering]

I did some calculating - (if this is correct)
45" by 4.5" triangle gives 5.7 deg angle. I then double it, so I have 11.4 deg under the car.
45" by 4" triangle gives 5.08 deg angle. so 10.1
300" by 28" triangle gives 5.3 deg.

We are pouring a slab with a driveway up to it. I am trying to keep the slab as low as possible but have to have drainage around it.
The nose hitting on the other end.... not much I can do about that, I can go at an angle at that end!

They dug the footings yesterday, I have to go see what the height is today.

I know I should have run all the calcs before. Thank you all for letting me think this through on the forum!!

I think I may have clearance??? I was just running through my mind, I dont want to have to put something on the driveway to lessen the angle to get the car past!!

193524

[Al_C]

I like Rdone's ideas. The problem is that your ramp is rising at 1.2 inches/foot. You have to get that number down. Can you make the ramp longer? Does it have to rise 2 1/2 feet? Or, slope the garage and/or raise ride height. (I'm sure that will go over well...)