Go-Karting

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Discussion

julian64

Original Poster:

14,317 posts

256 months

Friday 6th September 2019
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Was down at Buckmore park yesterday for a half hour of go-karting

Was about a second off the pace of the fastest people there. When I tried to follow them I was getting oversteer problems. They were managing to hold a line through a corner and when I followed them, the back end of my kart would let go causing me to have to do some hilarious full lock antics.

I couldn't work out if moving my seat forward or backward would help in terms of my problem. So thrown out to the masses. Do I put my sea forward or back to make up that second

Purity14

1,919 posts

147 months

Friday 6th September 2019
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In my limited go-kart experience, I tend to find the following:

Light weight people = faster on the straights, slower on the corners
Heavier people = slower on the straights, faster on the corners

As such, moving the seat backward would increase the weight over the rear axle providing more grip.

I am happy to be corrected though.

motco

16,020 posts

248 months

Friday 6th September 2019
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If throwing a dart flights-first is any guide, you need marginally more mass ahead of the centre of gravity. Early Porsche 911s with heavy rear-mounted engines were notorious for losing the back end. It's a complex matter I suspect.

if in doubt

96 posts

125 months

Friday 6th September 2019
quotequote all
I think I read a while ago that there is an unintuitive technique in karts as they use very aggressive caster to help with the fact they have a solid rear axle. If you look when you apply lock the car will unload the inside rear wheel. So to get your cornering speed up you need to put additional load on the outside rear wheel, otherwise that solid rear axle will push you towards oversteer.

So the trick is not lean in to the corner like a motorbike would, but to lean out.


johnwilliams77

8,308 posts

105 months

Friday 6th September 2019
quotequote all
if in doubt said:
I think I read a while ago that there is an unintuitive technique in karts as they use very aggressive caster to help with the fact they have a solid rear axle. If you look when you apply lock the car will unload the inside rear wheel. So to get your cornering speed up you need to put additional load on the outside rear wheel, otherwise that solid rear axle will push you towards oversteer.

So the trick is not lean in to the corner like a motorbike would, but to lean out.
This is correct

RobM77

35,349 posts

236 months

Friday 6th September 2019
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Are you sure they weren't just making small corrections earlier than you? I've done a bit of track instruction and it's very common (if not almost universal!) for drivers to react far too late to oversteer, when they see it, rather than earlier when they should be feeling it. If you react early, just a small movement of steering to reduce lock is all that's needed (plus, especially with a car, the appropriate control with throttle and brakes; or as you get better, often just these two controls and leave the steering alone); whereas if you react too late, you'll need a much bigger movement, the downside of which is that being sideways scrubs off speed, plus at high slip angles tyres generate less grip - all tyres have an optimum slip angle for grip, and I suspect that's where the second difference is. Watch anyone good at karting and you'll notice lots of fine control in the corners, holding the kart at the optimum slip angle. Put simply, if you're putting in actual opposite lock, rather than just backing off the steering a bit, then you're usually reacting to the change in balance too late.

Edited by RobM77 on Friday 6th September 09:37

james_gt3rs

4,816 posts

193 months

Friday 6th September 2019
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All things not equal in Karting either... everyone could have different age tyres, different driver weights, healthier engines etc

Miserablegit

4,061 posts

111 months

Friday 6th September 2019
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I was at Buckmore many years ago on a corporate jolly. Was doing ok until I sat in one cart in the heats and couldn’t corner (similar to how you’ve suggested) . The only visible difference we established was the seat was further forward than the others

Plate spinner

17,788 posts

202 months

Friday 6th September 2019
quotequote all
if in doubt said:
I think I read a while ago that there is an unintuitive technique in karts as they use very aggressive caster to help with the fact they have a solid rear axle. If you look when you apply lock the car will unload the inside rear wheel. So to get your cornering speed up you need to put additional load on the outside rear wheel, otherwise that solid rear axle will push you towards oversteer.

So the trick is not lean in to the corner like a motorbike would, but to lean out.
That’s what I was also told, it’s all about putting weight where the forces are most impacting the contact patches.

I was also told that on karts where the rear wheels are brakes, use your arms to resist dive on braking. Keeping your arse pressed down into the back of the seat keeps more force over the braking wheels, reducing potential lock up especially when putting some steering angle on.

kiseca

9,339 posts

221 months

Friday 6th September 2019
quotequote all
james_gt3rs said:
All things not equal in Karting either... everyone could have different age tyres, different driver weights, healthier engines etc
This is the biggest factor in my experience. Even on tracks with lap times under 20 seconds, I can often make or lose a second a lap simply by swapping karts.


Edited by kiseca on Friday 6th September 10:14

nobrakes

3,031 posts

200 months

Friday 6th September 2019
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When my kart was changed out at a team event I told the next driver that this one was much faster.

He came back in and said, “No wonder it’s faster, there are effectively no brakes on it!”

Leon R

3,236 posts

98 months

Friday 6th September 2019
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nobrakes said:
When my kart was changed out at a team event I told the next driver that this one was much faster.

He came back in and said, “No wonder it’s faster, there are effectively no brakes on it!”
People use the brakes on go karts?

R8Steve

4,150 posts

177 months

Friday 6th September 2019
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Plate spinner said:
That’s what I was also told, it’s all about putting weight where the forces are most impacting the contact patches.

I was also told that on karts where the rear wheels are brakes, use your arms to resist dive on braking. Keeping your arse pressed down into the back of the seat keeps more force over the braking wheels, reducing potential lock up especially when putting some steering angle on.
I've never experienced dive on braking in a kart.

You'd struggle to move your weight at all in a kart TBH.

OP, try the following -
Check tyre pressures and raise rear tyre pressure by 1 PSI and reduce front pressure by 1 PSI
Move the seat back and raise it if possible
Raise the rear ride height
Add seat support stays or use a stiffer seat
Increase rear track
Reduce front track

Unfortunately it's trial and error with setup sometimes, too much rear grip can bring problems of it's own.

fido

16,884 posts

257 months

Friday 6th September 2019
quotequote all
Leon R said:
People use the brakes on go karts?
Buckmore Park has a few hairpins, not to mention it's on the side of a hill.

OP what was your time .. 50s, 51s, 52s .. and how much do you weigh? The RT8 Sodi karts at BP seem very evenly matched - always get new tyres when i go.

Edited by fido on Friday 6th September 09:53

R8Steve

4,150 posts

177 months

Friday 6th September 2019
quotequote all
nobrakes said:
When my kart was changed out at a team event I told the next driver that this one was much faster.

He came back in and said, “No wonder it’s faster, there are effectively no brakes on it!”
With your username was he surprised? hehe

Krikkit

26,672 posts

183 months

Friday 6th September 2019
quotequote all
R8Steve said:
I've never experienced dive on braking in a kart.

You'd struggle to move your weight at all in a kart TBH.

OP, try the following -
Check tyre pressures and raise rear tyre pressure by 1 PSI and reduce front pressure by 1 PSI
Move the seat back and raise it if possible
Raise the rear ride height
Add seat support stays or use a stiffer seat
Increase rear track
Reduce front track

Unfortunately it's trial and error with setup sometimes, too much rear grip can bring problems of it's own.
Most of which are impossible in a rental...

Frustrating but I believe that tyres are often a key factor in rentals - get a good set and it's easy to dominate, a bad set and you're nowhere.

joema

2,659 posts

181 months

Friday 6th September 2019
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Could be something with Kart.

Most likely it's technique. you're trying to keep up/make time through corners and whatever you're doing is unsettling it. Could be line choice. Braking late and too much speed at turn in etc.

james_gt3rs

4,816 posts

193 months

Friday 6th September 2019
quotequote all
kiseca said:
This is the biggest factor in my experience. Even on tracks with lap times under 20 seconds, I can often make or lose a second a lap simply by swapping karts.
Racing driver excuses 101 biggrin

kiseca

9,339 posts

221 months

Friday 6th September 2019
quotequote all
james_gt3rs said:
kiseca said:
This is the biggest factor in my experience. Even on tracks with lap times under 20 seconds, I can often make or lose a second a lap simply by swapping karts.
Racing driver excuses 101 biggrin
hehe

Also wanted to add as a suggestion, be very gentle with the steering. At Buckmore, there's one particular downhill right hand corner which, in the kart I was in when I was there, could be taken flat out, but only if very gentle with steering. If I turned in a little too aggressively, the back would slide out which caused two immediate problems. One was that I was now facing right and avoiding braking like my life depended on it, at a point when I should be braking for a tight left hander, and the second problem was an immediate need for new underwear. That section also happened to be the fastest part on the circuit, if I recall.

julian64

Original Poster:

14,317 posts

256 months

Friday 6th September 2019
quotequote all
fido said:
Buckmore Park has a few hairpins, not to mention it's on the side of a hill.

OP what was your time .. 50s, 51s, 52s .. and how much do you weigh? The RT8 Sodi karts at BP seem very evenly matched - always get new tyres when i go.

Edited by fido on Friday 6th September 09:53
Sorry didn't spot this . best time was 51.4, averaging 52.0, but at least three were lapping in the 50's. They were all young and I an 87Kg so not exactly a lightweight.

They were making ground on the straights which I think was due either to their light weight or better corner exiting speed than me. I was having to do a bit of correction coming out the curve, they weren't.

The Karts were a limiting factor because every lap the two corners at the end of the straight were taken without taking my foot off the throttle. The Karts weren't powerful enough to make the weight less relevant.

The seats were easily adjustable on the go. simply pull up the yellow cord when no on looking and let go to click it in. Not immediate feedback on laptimes when you are on the move so I wasn't sure what I was doing.

My thoughts were if I move the seat back I'm putting more weight over the rear wheels but also as the Kart cornered the rear wheels were having to hold my weight from moving sideways. More downward pressure but much more sideways force applied to the wheels.

If I moved the seat forward less weight on the rears. Less downforce on the rear tyres, but also load better spread between front and rear so less for the rear wheel grip to have to do.

I still can't work it out. What I do know is that there was a great deal more grip on the front to the rear. Not enough power to steer on the throttle, and not really enough power in the Kart for the circuit