Maximum driveway incline to still provide clearance?


D

dtomaso1

GT Owner
Dec 6, 2006
184
Phoenix, Arizona
Ok, just when you thought you were asked everything about the fgt. Anyone out there have a general feel for max incline slope and distance needed to clear a stock gt? I am visting a friend's vaction home that has some sort of ski jump driveway, and do not wish to leave the car on the street. Based on what u say, I am laughing at the site of my friend measuring his driveway with a level!!! :rofl

Thx, T
 
Run a lenght of straight 1x4 (or whatever) from where the car's front tire meets the ground to the underside of the leading edge of the chin spoiler. Measure the angle/distance created thereby.

The real issue you may find yourself facing is any 'drainage channel' that may lie between the road and the driveway at his place. Once the GT's front tire(s) drops (drop) into that it's likely going to be 'scrape city' regardless. (Approaching the 'dip' by driving the car at an extreme angle to it probably won't help much by itself.)

To eliminate the clearance issue completely, I'd just ask your friend to have an assortment of 2x6s or the like at the ready so that you can create a 'bridge' between the road surface and his driveway. :wink
 
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It's not the slope, it's the delta in slope.
 
Thanks EP.

Yes, that drainage channel always is a PITA. Those measurement instructions are a big help. Had those same problems with trailer ramps through the years. Like Fenzo says, it's the delta to be aware of as well. I may start out ok only to find the slope picks up. Too muck work for some easy go'in R&R... but better safe then scraped!:frown

Thx, T
 
I've tried this before with other cars, doesn't work well. There are too many variables, including the ride height of your car and the tires you have on it. Short of creating a 3D CAD rendition of that driveway and road, and the underside of your car, the only way to see if it will go is to try it. Usually, you can get over obstacles or driveway aprons by approaching at an angle, instead of straight on. I'd go with Empty Pockets suggestion to ask your friend to have an assortment of planks to fill in the dips or lay down as short ramps.
 
Agree, the old plywood and 2x4 shim trick! ...for kicks though, I'd like to understand more about the geometry from you engineering types... I measured 6 degrees between center of front tire patch and tip of spoiler. So a continuous 6% slope could be accommodated. Once you are resting on that 6 deg slope, at what point could the car could take on another 6 degrees? Tricky question huh?


PeteK said:
I've tried this before with other cars, doesn't work well. There are too many variables, including the ride height of your car and the tires you have on it. Short of creating a 3D CAD rendition of that driveway and road, and the underside of your car, the only way to see if it will go is to try it. Usually, you can get over obstacles or driveway aprons by approaching at an angle, instead of straight on. I'd go with Empty Pockets suggestion to ask your friend to have an assortment of planks to fill in the dips or lay down as short ramps.
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Take another car...

Here in LA there are alot of 45 degree inclines (Hollywood Hills, Beverly Hills, Canyons) and you will find yourself not just dealing with driveways, but all manner of side roads, ramps, etc that are just not good for GTs. Crawling in traffic up a 45 degree incline for 30 min is no fun.

You will be stuck parking on a night out, dinner or a visit...and your clutch and emergency break will feel it.
 
dtomaso1 said:
Agree, the old plywood and 2x4 shim trick! ...for kicks though, I'd like to understand more about the geometry from you engineering types... I measured 6 degrees between center of front tire patch and tip of spoiler. So a continuous 6% slope could be accommodated. Once you are resting on that 6 deg slope, at what point could the car could take on another 6 degrees? Tricky question huh?
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I don't know if six degrees is correct, but I would be more concerned about the slope going down after going up. That is how you get high centered. It's called ramp breakover angle. You typically see it as a spec for 4wd vehicles with off road capability. The calculation for that is not difficult to approximate.

http://en.wikipedia.org/wiki/Breakover_angle

You can take much more than the six degrees of approach angle if you can approach at an acute angle rather than at 90 degrees. One wheel up on the slope before the other wheel.

And, the chin spoiler is very tough. Nobody wants to scrape it intentionally, but scraping it is inevitable. I have plenty of marks on the bottom of mine. No big deal.
 
Xcentric said:
I have plenty of marks on the bottom of mine. No big deal.
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...a little sanding with, say, 300-400 grit or so followed by a 'spritz' of Krylon semi-gloss black (maybe it was "flat black"?) and no one will ever know.

'Dead serious. There's no way anyone will be able to tell (as long as we're not talkin' removin' GOUGES here).

'Looks 'factory' when you're done.
 
Empty Pockets said:
...a little sanding with, say, 300-400 grit or so followed by a 'spritz' of Krylon semi-gloss black (maybe it was "flat black"?) and no one will ever know.

'Dead serious. There's no way anyone will be able to tell (as long as we're not talkin' removin' GOUGES here).

'Looks 'factory' when you're done.
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Didn't earl schieb make a living fixing bodywork that way'?
 
dtomaso1 said:
Didn't earl schieb make a living fixing bodywork that way'?
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'Pretty much!

But, trust me, what I suggested really works as described...
 
If I'm not mistaken the front spoiler is one of the cheaper parts to obtain.
 
I have teh same problem, it is the Delta angle from road to driveway. I had to have trailer ramps made of aluminum so I can span the driveway and get the car on to the street. I can make a measurement later today and give you the angle that my GT will scrape. Best short term option is to get multiple 2x4 to fill in the delta gap. Obviously custom ramps are not possible. You can stack the 2x4s at the delta maximum point and should be able to get the car up driveway. Other option is to take anouther car for the tirp.
 
Try these on the curb:

http://www.bridjit.com/

I've seen several different manufacturers but this is the one that came to the top of the google search. One of the people on our street in CO has a set.
 
twobjshelbys said:
Try these on the curb:

http://www.bridjit.com/

I've seen several different manufacturers but this is the one that came to the top of the google search. One of the people on our street in CO has a set.
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That would fill the 'drainage gully' between the street and a driveway alright, but 'wouldn't seem to address the, say, 5-10-20-30(?!) degree diffs created where the street and the driveway surfaces meet, would it? :shrug

(Edit) E.g.: In my own case (before I regraded my driveway) I had to build a wooden 'bridge' that started at a point 8 feet or so up the driveway on the driveway end to the center of the road on the other end! We be talkin' major league surface angle diffs here!
 
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They have a channel for water. Maybe not this one but I've seen one that does
 
twobjshelbys said:
They have a channel for water. Maybe not this one but I've seen one that does
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'Not what I was saying, Tony. I was just referring to the fact the "bridjits" would remove the dip issue in between the driveway and the street.
 
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