Hi guys,sorry for the trouble but im new to karting.I have a Crg 2019 Heron kart with a Iame x30 engine.Im really enjoying karting and im around 1 second slower to the very front liners which have much more experience than me.
We race in very high grip condition as the tarmac is quite new.Currently i weigh around 83kg and im finding that the heron frame is quite ‘stiff’/grip biased at the rear which seems very difficult to have the wheel to lift.What normal settings can be done to try to bring more ‘balance’ and compensation for the rear grip bias?Thanks and sorry for the long post
The general things you can do to increase the amount of wheel lift you’re getting and help the kart turn in would be:
- widen front track width
- increase caster
- stiffen front bar
- move weight forward
This is an older guide, but the basic principles of the adjustments and their effects are still relevant:
2005 CRG_Kart_Tuning_Manual from SSC.pdf (1.2 MB)
Cheers for your reply:),Just to confirm if im heading to the right route,im running low ride height at the front and the rear.I beleive with the low ride height i will have less jacking effect but the kart seems more free and less tiring to drive.Is this contradictory to the supposely wheel lift i need?,i recently tried to run a softer axle as well which made the kart more free and easier to drive as well,but to get to the same lap
Times i just needed to add another seat strut to the ones i already had.
Unless you have a compelling reason to run the low ride height settings, I would run middle on both front and rear and tune from there.
Also, 1 second starting out is not bad at all! It may feel like a bit of mountain to climb at this point, but really for starting out that’s pretty impressive.
Out of curiosity, where do you race and what tires (Tyres ) do you use?
This is our track.We race in Malta(Europe).im a bit of a big driver(186cm and 83kg weight).To tell you the truth i saw some of the faster lighter/smaller drivers running the same kart/engine running the lower ride height and intried it and gained around .3 better lap times.also the 1 second off pace is per lap(40.6 vs 41.6) hehe not in a full
Race though lol,The faster drivers have a top
Speed of 4km better than me.
We are using the komet k2h tires.
More top speed is often times the result of better release off the corner preceding the straight, or more apex speed in that corner. Though it could be the result of gearing differences too.
What difference in feel did the ride height change give? How did the kart’s handling change?
Yes, lower ride height reduces weight jacking. “Easier to drive” doesn’t necessarily equal “faster”. When you say it freed the kart up, does that mean it made it turn-in better or slide more or what effect did it have specifically?
A kart must release the inside rear wheel to corner effectively. This is done either by sliding the tire (not the ideal method, but can work on lower grip situations) or getting the inside rear wheel off the ground or unloading it slightly. If your track surface is truly “high-grip” I would imagine sliding the kart isn’t going to be the way to go.
Sorry if the explanation may seem a bit lacking but i have very few experience in karting.I have some experience racing rc cars at modest national level and sometime i relate the kart with it but it seems with the higher ride height the kart was having the rear gripping a lot and ‘change of direction’ seemed slower,With the ride height lower the kart is not gripping/hopping that much(sometime it was making my head hurt) and seems to
Slide,A friend of mine stated that he is seeing the kart keep itself very flat with both ride heights(low and medium)
No problem, tuning the kart is a complicated process with a lot of variables and even for veterans it’s not easy, so as a newbie providing the feedback needed to tune the kart can be tough.
It would make sense that if you raise rear ride height, it will increase the “hopping” you’re feeling, because the kart is transferring more weight. Hopping occurs when the kart transfers too much weight to the outside tire, the tire slips briefly and then regains traction before overloading and slipping again. You can see this at work with you slide a pencil eraser across a table at the right angle and it skips along the table. And this would make sense with your size. A taller or heavier driver tends to overload the outside tire easier when the weight is transferred. So lowering the rear ride height will fix that, but it will also make the kart transfer the weight less effectively, potentially causing it to understeer since it isn’t lifting the inside rear wheel. It’s about finding the balance between the kart transferring enough weight to lift the wheel and turn properly, but not so much that it overloads the tire. Ride height changes in the rear are fairly large adjustments with big effects on the kart’s handling, so it’s possible with that adjustment you are going from one extreme to another when you change it.
You probably need smaller changes to adjust the balance more finely.
The easiest things to try would be playing with front and rear track widths. Those adjustments are quick and easy and have very little side effects.
Also keep in mind that your driving can completely change the kart’s handling characteristics as well. Over or under driving the kart can have big effects on how it feels. With newer drivers it’s common to not be on the limit of the kart, not being smooth enough in their inputs, and causing handling issues that way.
Cheers thanks for the very detailed explanation it makes much sense with how the kart is behaving.Its possible im overdriving the kart as well.I wrote down the tips you gave me earlier(wider front,more caster etc),Just to get in some maybe not so important information for my level,in your experience if a kart has a bit more stiffer rear section and the front is ‘softer’ will a harder front bar bring the balance back?(as i was told the kt2 frame is better suited to the x30 as the heron is more oriented for a shifter or more powerful engines)
A stiffer front torsion bar will help the front turn-in, but any time you add a torsion bar you are increasing overall chassis stiffness as well. So yes, it will turn in better but the inside rear wheel will snap back down quick as well, because the whole kart is sprung tighter.
Other adjustments like increasing caster can help the front turn in and jack weight without the side effect of stiffening the the whole kart.
Cheers thanks for all the helpful replies:),I tried to run a session without any seat struts(i was using 2 struts on the brake side and 1 on the engine side),and the kart seemed to be gliding through the corners but if you overdrive a bit the kart was obviosly having less grip than before so afterwards i just used 1 seat brace each side
As i really liked the feel of the kart without the seat struts i was thinking to use the rear height in the middle(to bring some grip up as currently im using a low rear ride height) and try the kart without the struts.Is it something that is usually tried or it goes against the normallity of the setup?sorry for the long post
Seat struts do stiffen the chassis up, if the heron is stiff already I’d say maybe you don’t need them.
Just to add the team chief mechanic who spends winters with us (CRG Middle East) did tell me CRG chassis always you need to put even seat struts I.e. none, one each side or two each side, never one and two two and one or one and none etc. Certainly I know that to be true on the KT2 I tried 0/1 just for laughs. 1/1 was WAY more balanced
For the CRG KT2 and X30, we used to run with the black nylon front torsion bar.
In low grip 1 seat strut on each side, in medium or high grip no seat struts. In high grip a softer axle, possible cut down to 100cm.
Rear width 139cm (did never work with full width).
But most important a Tillett T11VG, 13cm from the rear axle.
I never tried with the front bar in. What does it do? I’m typically running low grip dusty conditions except race day itself when the track grips up.
My seat is T11t
I would say the front torsion bar gives a slightly better turn-in. We tried the metal ones, but it became to stiff.
T11t is slightly stiffer than T11VG. We tested both, and felt that T11VG was better. The driver was about 180cm and 70kg.
The CRG can be frustrating to tune, and hard to find the sweet spot.
Thanks, excellent info. I’m similar height 185, 90kg so I reckon 11t is ok for me. I’ve only seen the steel torsion bars, I’ll look for a nylon one n give it a go
Im running a greyhound silver seat(which is a replica of the 11vg seat) and i think compared with the original crg it had before it reduced some
Grip but its only a beginer feeling(i changed the seat as the previous owner was more lean)
As you mentioned the front torsion bar today i tried to drive without it but made the front ride height 3mm higher,it seemed to gain around .3 just by removing it and go to test immediately
Hi again,I tried a set of new komet k2H tires and was impressed how much better grip/laptimes the car had for around 5 sessions.Then obviously the tires started to have a drop off.I know that new tires most probably almost work better but what can be done setup wise to have the kart ‘handle’ similar to the new tires?will higher ride height front and rear bring maybe similar effect?Thanks