What ground clearance is a reasonable streetable height?

[LS1_78Bandit]

I'm working on my 78 t/a and I want to upgrade the suspension, in part because I have to (I'm switching to the LS1 which is lighter) and because 78 parts are so 1978. :)

Anyway, I was going to put 255/40/17's up front and either 285/40/17's or 315/35/17's in the back. With just the wheel change, this drops me down about 1.5".

I was thinking of using the Hotchkis TVS system, which I think will lower it a bit more. But now I'm getting worried about how streetable it will be. I want to be able to comfortably drive it around and here in CA it seems like they really like deep dips in the driveways and big speed bumps. And the front air dam doesn't help ....

So, do any of you have recommendations on minimum ground clearance before it starts getting too annoying to drive normally?

[6'9"Witha69]

Avoid low hanging headers! Other than that, if you don't go crazy low, you should be fine. Not like half the ricers running around here!

[LS1_78Bandit]

Avoid low hanging headers! Other than that, if you don't go crazy low, you should be fine.

OK. My big concern actually is just the front air dam. It's been so nicely restored/repainted and it has pin-striping going along the bottom, so if I whack that even a couple times it could get ugly fast.

[TLWiltman]

The DOT rules in Washington seem to be pretty common sense.

Basically, if you take all the tires off the wheels, put the bare wheels back on the car, and set the car back down, the only thing touching the ground should be the four wheels. This translates to a minimum ground clearance of around 3.5-4" for us "low profile folks"

[CAMAROBOY69]

I think the lowest part of my car has around 2" from the ground and I never bottom out even on Michigan roads. Unless I am turning into a really steep drive way. I just avoid speed bumps. My headers are my lowest point of the car.

[silver69camaro]

When I design a chassis, I try not to make the frame lower than 4" from the ground. With 2.5" of bump, that leaves only 1.5" of clearance. I would prefer 5".

[LS1_78Bandit]

Good info guys! Thanks! I'm less worried about the underside than I am the front air-dam. The underside can take some scraping, but as soon as I whack that air-dam it's going to be noticeable (if you're looking) and the front is the most prone to hitting when going up the steeper driveways that seem to be so common around here.

[CAMAROBOY69]

The best way to tackle a steep driveway or any other obstacle is to drive over it at an angle. Let your front driver side tire go over first. Then your front passenger side tire go over. Next the driver rear and finally the pass rear. Remember his tip. Very helpful. :look:

[CAMAROBOY69]

Just like this.
https://static1.pt-content.com/images/noimg.gif

[USAZR1]

Another nice thing about Air Ride. I can set my headers on the ground or push a button and have 6" of ground clearance in about 5 seconds. :smoke:

[GBodyGMachine]

I was always taught 3" from the lowest point to the ground. I think this is a pretty good rule. Have you ever seen a car 3" off the ground? Its low.

Jeff

[vanzuuk1]

Also, marry a light woman!

[Damn True]

Also, marry a light woman!

check

[syborg tt]

I've set my trucks ride height to 4.75" from the ground.

I think the question that hasn't been asked is how low is your front spoiler at this time.

[MuscleRodz]

I am building to 5" clearance at the rocker which should make the lowest point on my car 4 1/2".

Mike

[gonein67bird]

front spoiler 5" from the ground. 67 firebird

[protour_chevelle]

Best way to clear speedbumps, Line it up straight and launch like a SOAB! lol. My car hated speed bumps the last time it was out. The chicks liked hearing the *scrape* *ting* though. I think it was a decent trade off.

-Matt

[CAMAROBOY69]

Also, marry a light woman!
:lmao: My girlfirend is no more than 110# easily fits the light category. :yum:
The bad thing is a couple of my friends are 300# so I think my car would drag with them in there. I guess I will find out eventually.

[vanzuuk1]

Believe me , you never want to say "honey, get out of the car for a sec, we need to lighten up to clear this speed bump"

[Steve68]

Adam, alot like crawling HUH!!

[Jagarang]

I think your going to have the most trouble with your air-dam when parking. There is nothing you can do about parking stumps and curbs. Aside form an Air Ride setup you jack up every time you park. You could retrofit one of those parking assist units to the front of the car, which would be trick, so you will be able to get as close as possible without bashing it.

[Neil B]

My '69 Camaro has Hotchkis front springs and Hooker Super Comp headers and the driver's side collector flange is 2.75" off the ground. It does not scrape in normal driving, but it will not clear speed bumps.

My '87 Camaro has 2.0" of ground clearance with it's Hooker big block swap headers. I have to be very careful with this one.

IMO, 2.75" is livable, but 2.0" is not. I agree with others that if you're going to put serious street miles on it and expect to go over speed bumps and not stop traffic pulling into parking lots, you need 3.5"-4". The problem is that getting that kind of clearance usually requires chassis fab and/or custom headers.

https://static1.pt-content.com/images/noimg.gif

https://static1.pt-content.com/images/noimg.gif

[LS1_78Bandit]

I think your going to have the most trouble with your air-dam when parking. There is nothing you can do about parking stumps and curbs.
Yeah, I'm familiar with the parking stumps problem. Even at stock height that's been a problem, so I've been dealing with that for years. But I actually consider that a solveable problem. I can either make sure I don't pull up too far or I can back into the spot. As I mentioned my concern is more about the driveways and speedbumps.


The problem is that getting that kind of clearance usually requires chassis fab and/or custom headers.

Well, that may be a non-issue for me. I haven't decided yet whether I want to try being a scofflaw or not (I live in CA :( ).

[TLWiltman]

Also, marry a light woman!
Not gonna help when I weigh 280lbs.:pat: . Maybe... don't get married at all? (also helps with being able to afford our hobbies...hmmm?)

[High Plains Mopars]

When I was racing stock cars we were required to have 4 " to the stock rocker panel, so the sub frame was around 2", which is waaay low.

I'd tend to agree with the approach of nothing so low that a flat tire would cause it to drag on the ground. Speed bumps are always a good litmus test for that as some of those are pretty big.

With the air dam issue, that is going to be a tricky situation for the simple fact that you've got a fair amount of overhang on the nose of your T/A. Going to have ot e real careful and maybe carry a bottle of touch up paint...or go with an air suspension.

[68ls1wannabe]

I think the lowest part of my car has around 2" from the ground and I never bottom out even on Michigan roads. Unless I am turning into a really steep drive way. I just avoid speed bumps. My headers are my lowest point of the car. How much clearance do you have at the front frame crossmember? I'm planning on about 3in right there.