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 @ 16:47

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itproJoined: August 2001
Total Posts: 6
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I don't beleive in 'axle whip' at all..... but those of us who feel like that are in a minority..... but we tend to be the most experienced....!

Tall and heavy...? If you are getting 'hopping'.... go for lowering the CofG. That was alsways my problem.... too tall and fat!

Widening the rear is the easiest.... however, try soemthing for yourself. Disconnect the chain (or remove the engine) and push the kart with ONE finger. If you have oiled and set it up properly and the track is flat and smooth, it'll roll EASILY. Now, turn the steering and try and push it with as many fingers as you like........ it will hardly MOVE!.....so..... why IS that?

It's becasue we have a solid rear axle. If you remember athletics tracks, you'll remember the inside lane is SHORTER than the outer lanes. That's like the 'tracks' your rear tyres try to travel in a corner. The inner wheel has a shorter distance. With a 'diferential' in the axle (like in a car) the two rear wheels can rotate at different speeds...... but they CANNOT in a kart because of the solid axle....that fight between the two rear wheels effectively JAMS the axle!

Now, think about the effects of that 'impossible to push' action on the track.... the moment you ask the kart to turn, it's like applying the BRAKES! (another reason why I'd say move the steering as LITTLE as possible: all corners MUST be taken with steering DEAD AHEAD!)

The wider the rear, the MORE that 'pushing resistence' increases. So..... I would argue that you are better off keeping the rear as NARROW as you can get away with as possible.

However, narrower will increase the chance of hopping..... hence..... try to kep the rear narrow if you can by lowering your CofG as much as you can, then set the rear width so you don't hop.

The above is a GROSS simplification.... it ignores how karts 'pretend' to have a 'diff' (our HUGE caster angle), the fact that we ENCOURAGE the rear of the kart to 'slip' in corners, etc., etc., etc..

So... get the weight LOW and then set the axle.

BUT..... ideally, time yourself, change ONE thing, re-time yourself. Not much else works better!

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' (21 Jan 2011 @ 1:03)

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' << You are here!

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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