UK Karting - Notice Board (2-Stroke Karting) : Re: chassis hopping 30mm, 50mm axle

Notice Board (2-Stroke Karting)

Re: chassis hopping 30mm, 50mm axle
Posted by 'itpro' on 21 Jan 2011 @ 01:03

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itproJoined: August 2001
Total Posts: 6
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Traxtar is correct but it's not ONE thing you need to consider.... effectively, it's THREE!

The reason the chassis 'hops' is because of the ratio between the track width, the centre of 'gravity' (not quite correct, it's actually the 'centre of force' but CofG will do for this discussion)..... and the cornering force.

Take an example: a double decker bus with a FULL top deck (and empty lower deck) is more likely to topple-over when cornering than an empty one or with the passengers only on the lower deck. That's becasue the cornering force is, effectively, applied 'sideways' at the 'CofG'. The higher the 'mass' of the passengers (in BOTH senses of 'higher') IN the bus, the more likely it is to topple over.

The thing that STOPS it toppling is the TRACK WIDTH (distance between the two wheels on the SAME axle). The rule is simple: the wider the track and the lower CoG, the LESS likely it is to topple over.

Now.... karts don't (usually) get as far as toppling over.... they just.... produce too much grip for the track-width/CofG and that FORCES kart to start to 'topple' by lifting the inside wheels. You then LOSE grip as they are now only on TWO wheels, then slide until the 4 wheels are back on the ground, then increase the grip until it's too high for the track/CofG, then lift the inside wheels..... and so on at a fast-rate.... that's what 'hop' really IS!

So..... to reduce 'hopping', you can either widen the track OR you can lower the CofG....

There are LOT'S of ways of lowering the CofG if you are already as wide-track as you can go.... Move the lead down the chassis, lower the SEAT in the chassis, rotate the seat so you are more 'laid-back', 'hunch down' in the seat, lower the kart's ride-height, get a lighter helmet and suit..... or the BIG one.....lose some fat..... (pot and kettle come to mind, here!)

Think of the track-width/CofG as a 'triangle' comprising the 'contact patch' of your two rear wheels and your belly button. Your CofG is surprisingly close to the hight of your belly button in a kart.... Lower that point (the CofG) and you may WELL find you can NARROW the track and STILL not hop!

Ian

Message Thread:

chassis hopping 30mm, 50mm axle by 'bayfordboy' (20 Jan 2011 @ 21:47)

Re: chassis hopping 30mm, 50mm axle by 'Traxtar' (20 Jan 2011 @ 22:04)

Re: chassis hopping 30mm, 50mm axle by 'Aquila' (20 Jan 2011 @ 22:05)

Re: chassis hopping 30mm, 50mm axle by 'philharrison' (20 Jan 2011 @ 23:23)

Re: chassis hopping 30mm, 50mm axle by 'buzzinrussell' (21 Jan 2011 @ 0:26)

Re: chassis hopping 30mm, 50mm axle by 'itpro' << You are here!

Re: chassis hopping 30mm, 50mm axle by 'tkm59' (21 Jan 2011 @ 10:08)

Re: chassis hopping 30mm, 50mm axle by 'philharrison' (21 Jan 2011 @ 12:28)

Re: chassis hopping 30mm, 50mm axle by 'itpro' (21 Jan 2011 @ 12:35)

Re: chassis hopping 30mm, 50mm axle itpro by 'KevinW' (21 Jan 2011 @ 13:03)

Re: chassis hopping 30mm, 50mm axle itpro by 'itpro' (21 Jan 2011 @ 14:19)

Re: chassis hopping 30mm, 50mm axle by 'tkm59' (21 Jan 2011 @ 13:47)

Re: chassis hopping 30mm, 50mm axle by 'itpro' (21 Jan 2011 @ 14:22)

Re: chassis hopping 30mm, 50mm axle by 'tkm59' (21 Jan 2011 @ 14:56)

Re: chassis hopping 30mm, 50mm axle by 'itpro' (21 Jan 2011 @ 16:47)

Re: chassis hopping 30mm, 50mm axle by 'tkm59' (21 Jan 2011 @ 18:11)

Re: chassis hopping 30mm, 50mm axle by 'chriskasch' (21 Jan 2011 @ 18:26)

Re: chassis hopping 30mm, 50mm axle by 'chriskasch' (21 Jan 2011 @ 18:38)

Re: chassis hopping 30mm, 50mm axle by 'itpro' (21 Jan 2011 @ 18:27)

Re: This is what itpro is on about by 'philharrison' (21 Jan 2011 @ 21:24)

Re: This is what itpro is on about by 'itpro' (21 Jan 2011 @ 23:28)

Re: This is what itpro is on about by 'tkm59' (22 Jan 2011 @ 21:42)

chassis hopping/ skipping and then bump by 'alex205' (09 Jun 2012 @ 12:28)

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