The dreaded hop .

flattop1

Dawg 89
Triton 35 kart runs good most times . When it starts hopping it can not go any faster .
Situation is , we have changed set up and tires till the cows come home .
Heavy and super heavy weight , maxxis .
Changed to a std and never hopped again .
Is the chassis too stiff ?
I want too modify it . Seat bar change or slip joint . Maybe cut the conection at the right waist joint .
What chassis mods do ya'll think would effect a change for the better ?
 

flattop1

Dawg 89
Thanks XXX40.
Chassis % changes don't do it . Last time ran we had both chassis 2 classes . Finally gave up on it , mid event and never ran it since .
 

flattop1

Dawg 89
Also thought change the left side rail out too 1 1/4 inch .
The thing was fast on the big tracks , soft and short not its design parameter .
 
Triton 35 kart runs good most times . When it starts hopping it can not go any faster .
Situation is , we have changed set up and tires till the cows come home .
Heavy and super heavy weight , maxxis .
Changed to a std and never hopped again .
Is the chassis too stiff ?
I want too modify it . Seat bar change or slip joint . Maybe cut the conection at the right waist joint .
What chassis mods do ya'll think would effect a change for the better ?
I had same problem, tried everything . Then someone said do something real crazy like going to 8 9 lbs of air.
Worked. then after a while went to 61 left side and 68 cross. That worked better. went back down to 7 and 6 on air.
That was on a Seraph. Hard dry clay.
 

flattop1

Dawg 89
I'm not gonna say any of that won't help .
Phenom , icon ,seraph , the 35 then a std .
Same driver , same tracks . Tires. Tire guy . The std never once hopped .
 

XXX#40

2A supporter
I'm not gonna say any of that won't help .
Phenom , icon ,seraph , the 35 then a std .
Same driver , same tracks . Tires. Tire guy . The std never once hopped .
yeah 35 is for super duper heavy on the high bite calcium tracks in the south
 

msquared

Member
You can try and free float the RR bearing, meaning run no axle collars, no key stock, and no set screws. Just let the axle free float in the bearing. Be sure to lube the axle. On the LR bearing, put axle collars on both sides of the bearing and remove one of the set screws, drill a hole into the axle and use a screw to "pin" the axle. That will soften the RR and put more weight transfer to the RF and less at the RR. This should free the kart up.

What happens with a hop is that there is extreme grip, things flex and "snap" free, thus the hop. It means something is too stiff somewhere.

Other things to try is more air in the RR and shaving the lip off the seat. Another huge mistake I see is super heavys way over prep the tires and run way too little air pressure. With super heavies you need less prep and more air pressure. On Maxxis 8 psi or more.

Mike McCarty
Understanding Chassis Theory and Dynamics
 

95 shaw

Site Supporter
Hop always gets me thinking about harmonics.
We have several undampened springs in the system.
If the resonant frequency of the tire matches the resonant frequency of the chassis, strange things can happen. Including absorbing a lot of power.

Have you tried preloading the bumper, or seat bar, or even the turnbuckle at the left rear?
 

flattop1

Dawg 89
Ran with left rear pinned rr free to move .

Have not tried preload on bumper , torqued it to some spec .
No turnbukle on kart , easy too add .

Cutting the rear bar would change the harmonics.
That seems like a simple easy fix . Make it a slip joint .
 
What are you torqueing the rear bumpers too? We are a floating cage green plate most the time and have always just snugged them up.
 

flattop1

Dawg 89
Can't say 100% it was in inch lbs . Nothing outrageous.
Always had zip ties on as well so it would not get knocked off .
The thing might make a good cage or wing type kart .
The thing is just too stiff .
Per Mr McCarty: What happens with a hop is that there is extreme grip, things flex and "snap" free, thus the hop. It means something is too stiff somewhere.
 
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