Speed Bumps vs ground clearance

Ground Loop said:

Is there a published spec for the Fed Elise ground clearance? I'm seeing an alarming number of "SUV-sized" speedbumps going in at local business parking lots and even residential lotss. Some of these are higher than the curb, and visibly scraped on top already.

Exactly how many inches are we afforded from road to delicate chin? (without LSS) What's the first part to make contact? Most cars seem to have a sacrifical air dam that makes the first scraping noise, but I don't see anything expendable on the Elise.

Some lots have enormous concrete parking stops as well, usually with a few inches of rebar sticking out of the top for good measure.

It's a minefield out there.

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The ground clearance is 120mm (LSS) or 130mm (base). If the speed bump is more than that you will high-center on it. What that measurement doesn't tell us is whether the front or back will scrape on an incline, such as a driveway. That depends on the angle of attack. Unfortunately, even if you figure out the maximum angle of attack that the car will handle, most inclines don't have their angle posted.

Edit: The clearance numbers above were quoted, but I realized after posting that one of them has to be wrong. The LSS is 5mm lower than the base model.

Yeah, I'm worried about those speedbumps also. It seems that the more SUVs we have, the higher those get. (I have seen too many SUV drivers here in Huntington Beach who fly over speed bumps and curbs because "they can.") I think this is what prompts cities to put in larger speed bumps.

I know that my Audi A4 Quattro (lowered about 1") will scrape if I'm not extremely careful. And my Mustang SVO (on race springs - 1.5" lower) will scrape over every stinking speed bump in my townhome complex.

If the Elise (non-sport) has 130 mm of ground clearance (about 5.1 inches), then I think it will be close. I'm guessing there might be 1 - 1.5 inches of clearance on most "standard" speed bumps. Either way, get used to driving really slowly over them.

Bob

Maybe the hot accessory when pimping out an elise will be the little video camera that rather than letting you back up your SUV, lets you know if you are going to scrape a bump in the elise.

Evl said:

Maybe the hot accessory when pimping out an elise will be the little video camera that rather than letting you back up your SUV, lets you know if you are going to scrape a bump in the elise.

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I put a small camera under an MR2 Spyder at a race. With about 1/2" ground clearance. Worked well until I hit the brakes and transferred weight to the nose.

I've never had a problem with any speed bumps in my S1, however there are quite a few entrances to parking lots where I have to had to go very, very slowly to avoid scraping.

It's easier to scrape the front on an S2 than on an S1, especially the two 'ears' at the front.

120mm is usually OK on an S2 (I'm running that with my nitrons), while on an S1 you'd get away with 105/110..

Oh.. Ride height on the Elise is measured *with* ballast (75kg in each seat and 1/2 tank of fuel) and on the chassis beam right behind the front wheel and in front of the rear wheels (actually quite some way in front of the rear wheels where the visible beam ends..), so the bottom edge of the nose may be a little lower than the ride height especially if it has been set up 'raked' (rear higher than front)

Take speed bumps at an angle, so one wheel goes up before the other and do the same on the other side.

Try to avoid taking bumps and ramps 'head on' or with speed as the compression in the suspension will slam the front on the ramp/bump and fibreglass damage is not cheap..

Bye, Arno.

I test drove a cooper s years ago, looking over the car there were pieces of 2x6 in the trunk, thought nothing off it - so we are blasting out of this guys neighborhood, he stops, jumps out, grabs the wood and puts its on a speed bump, over we go, jumps back out, and says "ok you drive now" collects the wood and hops in the passanger seat.. i was sold right then and there! ..unfortunatly at the time my bank wasn't. but what a wicked quick little car!

Arno,

Thanks for the heads up. I really have to be careful with my S1 so I can't believe the S2 has more problems.

More than a few driveways into parking lots are so short and steep I can barely get in even at an angle. For some reason gas stations seem to be the worst around here.