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joe9tea · Joined: 13 Jan 2010 Posts: 8 Location: essex

hi ,
im getting a little bit of bounce / hopping mid corner/exit , im running no torsion bars on a hard axle using sl8 vegas at 12 psi on a zanardi chassis. can anyone help

DBaldwin · Posted: Sun Feb 07, 2010 4:01 pm Post subject:

a softer axle should help.
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DanB93 · Posted: Sun Feb 07, 2010 5:48 pm Post subject:

from what i know and have heard, that's caused by having too much grip at one end. obviously, the easiest way is too loosen/free-up the rear end to loose a bit of grip. it can also be achieved by dropping the tyre pressures. try going down to 11.5 and if it doesn't work, 11 etc...
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mlc motorsport · Joined: 06 Dec 2009 Posts: 69 Location: Hertfordshire

also try runninga little wider on the rear.
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Terence Dove · Joined: 26 Sep 2006 Posts: 100

More stuff to try:-

Lower or recline seat position
Remove Seat stays
Reduce castor angle
try the front bar back in

use less steering input
heel stops to help keep your right foot still if it starts going

Sometimes hopping can be a bent chassis too

If I were you I'd take the kart to Msport and have Keiran set it up for you and check it on the flat bed - zanardikart.co.uk
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vizard · Joined: 28 Nov 2007 Posts: 50

OR do the exact opposite, go stiffer!

think about it, when the rear is hopping what is happening?
rear picks up, slams down, picks up, slams down.

9/10 times the cause is the driver, try to be as smooth as possible, and use just one steering input.

As well as going "stiffer" (ie harder axle, rear torsion bar) consider going thinner on the front. The effect of using softer axles or wider on the back is to decrease rear grip, so instead of gripping,sliding,gripping,sliding (bouncing) it will simply not grip at all! by giving it more grip, it will simply grip full stop!!
When it happens next time, try both methods, go full width on the back, then much thinner, and make your own conclusion!
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Traxtar · Joined: 19 Sep 2008 Posts: 6 Location: LONDON SOUTH EAST

have to agree with vizard

the cause is too much grip BUT you can never have too much grip if its there USE IT. Hopping is caused by the tyre bouncing up and down & can 9-10 be cured by the driver using throttle earlier to break the grip
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