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Re: Are you sure about this......?
Posted by 'itpro' on 26 Oct 2010 @ 20:25

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itproJoined: August 2001
Total Posts: 6
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Rafe...

The hopping is actually slightly different than you are thinking. Yes, it does go 'two wheels' but then (usually) drop back and then start the lift-drop-cycle agin. I believe the following occurs:-

1) The outer tyre has FULL grip on the track with the tread (contact patch) FIRMLY and SQUARELY planted on the track.
2) The CofG is too high for the amount of grip and they kart starts to 'topple over' and the chassis starts to lift.
3) This changes the ANGLE that the outer tyre is presenting to the track: it was flat on the ground, now it's lifting onto its outer edge.
4) as it does so, the grip is focused onto the outer (let's guess) inch of the 'tread' (contact patch) and the tyre LOSES its 'good grip' because the contact patch is SO small.
5) as the tyre slips away, the chassis falls back to the ground bringing the tyres back into FULL contact allowing the grip to build again.....
6) ....and the cycle starts again!

For a giggle, you need to try quite how LOW your CofG really is! You can test this with a friend:-

a) sit in the kart,
b) Get a freind (or TWO friends in our cases.....) to lift you AND the kart on ONE side (let's guess) the LEFT side of the kart. Get him to lift you until you are into that central balance-point where he needs almost ZERO force to have you balanced, neither falling back to the ground or onto your head.
c) Your CofG is now DIRECTLY over the point where your tyres are touching the ground...... and you'll be STAGGERED how nearly vertical you are beefore you fall over. That imaginary line runs (roughly) through your navel!

Strictly, we have found the Centre or Force..... but who cares.

Finally, you can check if your CofG is like other-people's. Measure (e.g., photograph the kart from behind) the angle that your kart 'balances (as above) and then find a smaller, lighter friend to sit in your kart and do the same...... you'll be depressed how MUCH further you need to tip the kart before you find his 'balance point'.

Also try this with other people in THEIR karts and you'll soon see if YOUR CofG is significanyly higher than theirs! I'll bet you it's quite a bit higher than those who are NOT suffering 'hopping'!

Ian

Message Thread:

Full Mag Wheels, Would they help? by 'RWR' (25 Oct 2010 @ 17:58)

Re: Full Mag Wheels, Would they help? by 'MattScott' (26 Oct 2010 @ 10:09)

Re: Full Mag Wheels, Would they help? by 'DarrenC' (26 Oct 2010 @ 10:28)

Re: Full Mag Wheels, Would they help? by 'RWR' (26 Oct 2010 @ 11:11)

Are you sure about this......? by 'itpro' (26 Oct 2010 @ 12:01)

Re: Are you sure about this......? by 'chriskasch' (26 Oct 2010 @ 12:42)

Re: Are you sure about this......? by 'Rafe005' (26 Oct 2010 @ 12:59)

Re: Are you sure about this......? by 'itpro' (26 Oct 2010 @ 13:27)

Re: Are you sure about this......? by 'Rafe005' (26 Oct 2010 @ 15:36)

Re: Are you sure about this......? by 'Rafe005' (26 Oct 2010 @ 15:40)

Re: Are you sure about this......? by 'itpro' (26 Oct 2010 @ 15:59)

Re: Are you sure about this......? by 'Rafe005' (26 Oct 2010 @ 16:16)

Re: Are you sure about this......? by 'itpro' (26 Oct 2010 @ 16:33)

Re: Are you sure about this......? by 'Rafe005' (26 Oct 2010 @ 16:55)

Re: Are you sure about this......? by 'RWR' (26 Oct 2010 @ 17:18)

Re: Are you sure about this......? by 'Rafe005' (26 Oct 2010 @ 17:21)

I was always a bit backwards by 'MattScott' (26 Oct 2010 @ 17:27)

Re: Are you sure about this......? by 'itpro' << You are here!

Re: Are you sure about this......? by 'Rafe005' (26 Oct 2010 @ 20:45)

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