Building a 100mpg consumer vehicle

[drmiller100]

Are you psychic?

How do you know my car will flip "given the right tires?"

I changed the RC height in front and back. I changed the spring attachment points. I did not use the stock suspension upper attachment points.

How the hell should I know the rest? The car isn't done yet.

So we agree you haven't driven a similar car. You have never built any car. You don't have a clue as to what I am doing.

But you offer your opinion.



I don't want your opinion.

[ProDarwin]

1) Physics. Rollover is basically just a calculation of CG, cornering force, and track width. Given enough tire to generate enough cornering force, any car will roll. That said, it may be an incorrect statement. Even though this will be very prone to lifting the inside tire off the ground, the single rear wheel may not have enough grip to generate that kind of force anyway.

2) How did you change the RC in the rear? With a single rear wheel, the roll center is where the tire contacts the ground.

You really need to lighten up. This is a public forum. Myself and others have only offered constructive criticism. There no need to act so offended and childish.

[Frank Lee]

The simple fact that it's a trike and has bodywork gives it a tremendous leg up on safety vs a motorcycle or bicycle, which most of us will ride without giving it a second thought. All this isht about cornering, rolling, and getting smacked- good God, the cure for most of that is to not drive like an idiot.

[Bicycle Bob]

Reading through this thread, I begin to understand why New Jersey paid Paul Van Valkenburgh actual money to run experiments on trike stability. On 4-wheelers, we commonly tune cars for understeer or oversteer by fairly small changes in the anti-roll bars, to increase weight transfer at the stickier end and get neutral handling. A trike eliminates all weight transfer at one end, so the other end always slides first, unless everything else has been radically compromised. Camber is a relatively minor issue in this debate, although it can be very important with some tires.

[some_other_dave]

Originally Posted by ProDarwin

Negative. The car does lean the opposite way, however it would still be sitting right on grippy tread, as opposed to the sidewall of a square car tire.

Good point, it will still be on a treaded section of tire that is intended to be driven on. The rear will still want to "step out", I think, because of the camber thrust toward the outside of the corner.

It could very well be a non-issue, or not enough of an issue to matter. Real world results trump theory. But keep in mind the possibility that the handling could be really wicked. Perhaps testing at an autoX would be in order?

Good luck with the build, it looks very cool! I hope you hit your MPG target, as well. It'll be great to see what you get out of it when it is on the road.

-soD

[drmiller100]

Originally Posted by ProDarwin

1) Physics. Rollover is basically just a calculation of CG, cornering force, and track width. Given enough tire to generate enough cornering force, any car will roll. That said, it may be an incorrect statement. Even though this will be very prone to lifting the inside tire off the ground, the single rear wheel may not have enough grip to generate that kind of force anyway.

2) How did you change the RC in the rear? With a single rear wheel, the roll center is where the tire contacts the ground.

You really need to lighten up. This is a public forum. Myself and others have only offered constructive criticism. There no need to act so offended and childish.

You are an idiot. I bet you are an engineer.

[drmiller100]

Originally Posted by Bicycle Bob

A trike eliminates all weight transfer at one end, so the other end always slides first, .

This statement is patently untrue.

If you want to ask questions, I'm more likely to help you.

[ProDarwin]

Originally Posted by drmiller100

I bet you are an engineer.

Yes.

Perhaps you should go back to your first post in this thread and correct your statement...

Originally Posted by drmiller100

I invite discussion, argument, and ideas

Or perhaps you could have a civil discussion?

Originally Posted by drmiller100

If you want to ask questions, I'm more likely to help you.

Why not answer my question?
How did you change the rear roll center on a single wheel?
How are you achieving weight transfer with only one wheel?

Originally Posted by some_other_dave

Perhaps testing at an autoX would be in order?

This would be my approach... but given the rollover guidelines in section 3.1 of the SCCA rules, I find it very unlikely it would be allowed on course - it would be at the extreme rollover end of the "SSF" chart. Actually its off the chart. (http://scca.cdn.racersites.com/prod/...lo%20Rules.pdf) You'd have to make your own private test course.

[drmiller100]

How did you change the rear roll center on a single wheel?

the donor car had an RC higher then it has now. The front suspension of the donor car had an RC different then it does now. Hence, it has changed.


How are you achieving weight transfer with only one wheel?

When you go around a corner, weight transfers from the inside front tire to the outside front tire and the back tire.
You do know what a tire is?

[drmiller100]

>>>Perhaps you should go back to your first post in this thread and correct your statement...

Done.