One Sunday afternoon in my late 30’s, I was bored out of my mind and wondering what I could do with myself that day. I took a quick stroll through memory lane and thought of all the coolest and most fun things I had ever done. I recalled learning how to drive as a kid on a race track with my dad and I wondered, “are there race tracks where you can rent cars around here?” So I searched for ‘race track near me’ and an indoor go kart track came up on the results. “Hmmm, Go karts? Aren’t they really fast? Like aren’t they like driving formula one race cars?” So I gave the track a call and they were open and ready for “walk ins”, I guess that was me so it was about 1pm and I drove down to the track.
A typical day at the indoor track. You might think it’s just for kids, but drivers of all ages test their skill and push the edge of the limits.
“Lets move out to the karting race track!”
When I got there I didn’t know what to expect, but the staff were really friendly and the karts were set up like a real little race track. They made me watch a video on flags and hand signals and got me into race gear with a helmet and overalls. When I went out to the track there were many karts and people ready to race and a bunch of us went out together. I didn’t know any of these people but it was cool to have someone to race against. As we sat in the pits, they started our engines and we sat there for a moment revving up and getting ready to go. I had adrenalin pumping as I looked around to see who else I was racing against. There was an older guy here, a dad and his son I think, and a few guys in their 20’s. It was ON!
“Get Ready… GO!”
They gave us the green flag, and for the first time in years I felt the joy of being allowed to drive a vehicle as fast as that vehicle would allow you to go. You know what I mean? I mean most times we have a car that we can’t speed in, we can’t floor it, we can’t really push the limits. But not on the race track, we can push it as hard as the machine will allow. Admittedly that’s not a great deal, these machines are not going to send you into a wall at 100Mph, but I found it impossible to not lose control. As I slid around and raced against everyone on the track I became addicted. Hopelessly addicted.
“So much fun, I’m addicted to indoor karting for life..”
During this first day at an indoor race track I raced 22 times. A total of 220 minutes on the track. I ran race after race until the track closed at 11pm. A total of 10 hours at the race track. Since that day I have clocked up thousands of more races. I also became involved in league racing tournaments, national and international racing events. Now would I say karting is fun?
“You betcha it’s fun! There’s almost nothing I would rather do.”
If you haven’t done so already, give karting a go. Search for ‘indoor kart track near me’ on Google.
Many years ago I had to coach a heavier driver with the goal of helping them qualify for the higher powered 9HP karts at Sykart. This would allow them to get out of the 6HP karts and drive the faster 9HP karts. As part of that mission I added weight to my own kart so we could both roll at around 350lbs. Now normally I roll around 200lbs so this was a great opportunity to see exactly what effect an extra 150lbs had on my lap times.
Well as expected, it totally killed my speed. What was unexpected was just HOW MUCH it killed my speed. We quickly realized that Sykarts qualification system that issues a handicap for lighter drivers was disproportionately biased towards lighter drivers. So on behalf of my student I had to go through the exercise of proving it, and had to try and convince Sykart to adjust their weight based ranking system.
Sykart did adjust their qualification system after this analysis.
So the rest of this document is basically the analysis and study as I looked into exactly how weight affects the speed of a go kart and lap times.
If you’ve ever raced at a go kart track, you’ll quickly realize there is something about weight that either helps you or hold you back. I’ve seen many debates about weight, some believe it’s an advantage to weigh more or that being light is a disadvantage. I must tell you, I’m not in that camp. Adding weight will kill your speed, and in this article we’re going to look at how I applied Newtons Kinetic Formulas to explore the effect of driver weight on lap times at Sykart Indoor Karting track during one winter season.
Newtons formulas tell us that any movement requires energy made up of the combination of weight and speed. If something weighs more then it needs more energy to travel at the same speed as something that weigh less.
You might want to apply some of these tricks yourself on your track because just going through the process will give you a better insight about your situation.
How to analyze exact sector times on your go kart track.
The first step was to find a Google Maps satellite image of the building that holds the track. Next was to use a track map and try to scale it exactly to the proportions of the building.
Next I created a scale image in photoshop then imported the image into Geogebra and scaled the image so that 1 unit = 1 meter in real life. This allows very precise measurements of arcs and line segments and you can start to get an idea of the total length of the track and each of its segments.
Here are estimated measurements of the approximate fast line, superimposed over a scale model of the building, taken from Google Earth satellite picture of Sykart
Next I took Go Pro videos of the track, and stepped through the videos one frame at a time. This allowed me to count the number of frames through each section and gave a measurement of the speed in meters per second. One frame of a 60 frame per second video is 1/60th of a second. By observing the wheels next to marks on the track and by noting hand and foot movements you can get fairly accurate estimates of the time spent in corners and on straights. As you know what the lengths of these sections are you can estimate your speed using time/distance.
By mapping the speeds of each section onto a spreadsheet, I was able to create these charts.
The following charts take into account an analysis of the driving line, using GoPro Video to find the distances and speeds through each section, and then measuring the total amount of acceleration and deceleration per lap. (see Chart 1). The calculations use a driver weight baseline of 160lbs and show how +/- 10lbs affect lap times.
Chart 1: Speeds and G forces of the turns were calculated, and adjusted for driver weight.
This chart shows the range of velocity in m/s, from an average Sykart lap where there are 3 deceleration / acceleration zones, two sharp brake zones and a two phased brake zone at around 18 seconds into the lap.
Creating Time / Weight Charts Using Newtons kinetic formulas, based upon the energy required to move the mass of driver and kart, we can calculate the amount of time it takes the power of your engine to reach maximum velocity. This allows us to build a chart of expected lap times given the weight of the driver.
Given Kart weight = 119 kilos (taken from scales) 6.5 hp = 4847.049168 Joules per second Power Capacity of Engine 9.0 hp = 6711.298848 Joules per second Power Capacity of Engine (Sykart has 2 different kart types, a 6.5hp and a 9hp model)
Formula
k = mv²/2 Where k= kinetic energy in joules, m=mass in kg, v= velocity in m/s
1 hp = 745.699872 Joules/second
Whats a good time?
Driver lbs
6Hp
9 Hp
Above Avg 6.5
Good 6.5
Expert
Godly
Expert 9 Hp
80
-0.844
-0.609
28.956
28.456
27.956
27.456
26.791
90
-0.739
-0.533
29.061
28.561
28.061
27.561
26.867
100
-0.633
-0.457
29.167
28.667
28.167
27.667
26.943
110
-0.528
-0.381
29.272
28.772
28.272
27.772
27.019
120
-0.422
-0.305
29.378
28.878
28.378
27.878
27.095
130
-0.317
-0.229
29.483
28.983
28.483
27.983
27.171
140
-0.211
-0.152
29.589
29.089
28.589
28.089
27.248
150
-0.106
-0.076
29.694
29.194
28.694
28.194
27.324
160
0.000
0.000
29.800
29.300
28.800
28.300
27.400
170
0.105
0.076
29.905
29.405
28.905
28.405
27.476
180
0.211
0.152
30.011
29.511
29.011
28.511
27.552
190
0.317
0.229
30.117
29.617
29.117
28.617
27.629
200
0.422
0.305
30.222
29.722
29.222
28.722
27.705
210
0.528
0.381
30.328
29.828
29.328
28.828
27.781
220
0.633
0.457
30.433
29.933
29.433
28.933
27.857
230
0.739
0.533
30.539
30.039
29.539
29.039
27.933
240
0.844
0.609
30.644
30.144
29.644
29.144
28.009
250
0.950
0.686
30.750
30.250
29.750
29.250
28.086
260
1.055
0.762
30.855
30.355
29.855
29.355
28.162
270
1.160
0.838
30.960
30.460
29.960
29.460
28.238
280
1.266
0.914
31.066
30.566
30.066
29.566
28.314
290
1.371
0.991
31.171
30.671
30.171
29.671
28.391
300
1.477
1.067
31.277
30.777
30.277
29.777
28.467
310
1.582
1.143
31.382
30.882
30.382
29.882
28.543
Becoming 9HP Qualified.
At the time of writing, the Sykart qualification times (given weight) to drive the higher powered karts are. They have created this system of weight brackets to simplify the qualification process. Its actually a very cool setup that lets newer drivers develop their skills in the pursuit of the higher powered club karts. It also makes some allowance for the speed handicap that extra weight creates.
0 – 150lbs = 30.200 lap times or lower 151 – 200lbs = 30.500 lap times or lower 201 – 250lbs = 30.750 lap times or lower 251 – 300lbs = 31.000 lap times or lower 300 + = 31.250 lap times or lower
What the calculations tell us is that if Qualification Times @ 160lbs = 30.500 then the weight adjusted equivalent time for a driver at 250lbs should be 30.500 + 0.950 = 31.45, but because of the Sykart Bracketed Weight Class System, the 250lb driver is actually required to beat 30.750. So there is a relative handicap to the heavier driver of 0.700 seconds. That is, for the 250lb driver it is like being 160lbs and having to hit a 29.8 in order to qualify instead of a 30.5. While this is a little bit biased and possibly unfair, it should also be noted that beating these times are incredibly easy even if you have average skills.
For a 300lb driver an equivalent weight adjusted time would be 30.500 + 1.477 = 31.977 seconds, etc. But they are expected to hit under 31.000, more than a .9 second handicap difference. This is like being 160lbs and having to beat a 29.300.
The driver at 140lbs would have an equivalent adjusted time of 30.500 – 0.211 = 30.289, so they also are at a little disadvantage to the 160lb driver, but only by about 0.200 so they are not hurt as badly as the heavy driver but they are still like a 160lb driver who has to hit 30.300 instead of 30.500, so there is some handicap.
And a 210lb driver would be 30.500 + 0.528 = 31.028, so they are a little closer to the asked time of 30.750. A difference of 0.278. So it is like being 160lbs and having to beat a 30.200.
The current qual times favour the driver between 150 to 170lbs, and become increasingly more difficult for the drivers above and below this range, particularly those above this range.
While these times are achievable, it must skew the skill levels of the 9hp qualified drivers and the volume of drivers who become qualified must disproportionately skew into the 150lb to 180lb range.
Personally I have found that running 30.3’s at 200lbs is easily achievable in all karts, where you are reasonably on line, under most track conditions and under race conditions I would expect to run in the low 29’s.
30.3@200 is a weight adjusted time of 29.878 @160
Currently we are asking a 200lb driver to run 30.5 – 4.22 = 30.078 weight adjusted times.
But what is the equivalent time to a 330lb driver?
30.078 + 1.700 = 31.778
But currently they are expected to run below a 31.250
The following chart raises the bar slightly to 30.3 for a 160lb driver, then shows a relative qual time for all weights on the blue line. This is the suggestion of where Sykarts Qual times should actually be.
The red line is an Elite driving time, for the 6.5HP karts which is in line with best times of drivers winning league races.
The orange line is an Elite Driving time for 9HP karts, given top league finishes.
Isn’t interesting how differences in weight create a linear handicap?
Here is a Table for Qualification, and Elite 6.5HP and 9HP Times. If you can hit the elite times here then you are in a very special class and could compete nationally. The Qualification times are where you would want to be if you are shooting to be amongst the top drivers.
29.200
28.450
27.250
Weight (lbs)
Qualified 6.5
Elite 6.5 Times
Elite 9 Times
80
28.356
27.606
26.640
85
28.409
27.659
26.679
90
28.461
27.711
26.717
95
28.514
27.764
26.755
100
28.567
27.817
26.793
105
28.620
27.870
26.831
110
28.672
27.922
26.869
115
28.725
27.975
26.907
120
28.778
28.028
26.945
125
28.831
28.081
26.983
130
28.883
28.133
27.021
135
28.936
28.186
27.060
140
28.989
28.239
27.098
145
29.042
28.292
27.136
150
29.094
28.344
27.174
155
29.147
28.397
27.212
160
29.200
28.450
27.250
165
29.253
28.503
27.288
170
29.306
28.556
27.326
175
29.358
28.608
27.364
180
29.411
28.661
27.402
185
29.464
28.714
27.440
190
29.517
28.767
27.479
195
29.569
28.819
27.517
200
29.622
28.872
27.555
205
29.675
28.925
27.593
210
29.728
28.978
27.631
215
29.780
29.030
27.669
220
29.833
29.083
27.707
225
29.886
29.136
27.745
230
29.939
29.189
27.783
235
29.991
29.241
27.821
240
30.044
29.294
27.860
245
30.097
29.347
27.898
250
30.150
29.400
27.936
255
30.202
29.452
27.974
260
30.255
29.505
28.012
265
30.308
29.558
28.050
270
30.361
29.611
28.088
275
30.413
29.663
28.126
280
30.466
29.716
28.164
285
30.519
29.769
28.202
290
30.572
29.822
28.241
295
30.624
29.874
28.279
300
30.677
29.927
28.317
305
30.730
29.980
28.355
310
30.783
30.033
28.393
315
30.835
30.085
28.431
320
30.888
30.138
28.469
325
30.941
30.191
28.507
330
30.994
30.244
28.545
335
31.047
30.297
28.583
340
31.100
30.350
28.621
345
31.153
30.403
28.659
350
31.206
30.456
28.697
355
31.259
30.509
28.735
360
31.312
30.562
28.773
365
31.365
30.615
28.811
370
31.418
30.668
28.849
375
31.471
30.721
28.887
380
31.524
30.774
28.925
385
31.577
30.827
28.963
390
31.630
30.880
29.001
395
31.683
30.933
29.039
400
31.736
30.986
29.077
405
31.789
31.039
29.115
410
31.842
31.092
29.153
Time Lost to Weight
Driver lbs
Low 5m/s
High 10 m/s
Joules to climb
6.5Hp
9Hp
6Hp
9 Hp
80
1,932
7,728
5,796
1.196
0.864
-0.844
-0.609
90
1,989
7,955
5,966
1.231
0.889
-0.739
-0.533
100
2,046
8,182
6,137
1.266
0.914
-0.633
-0.457
110
2,102
8,409
6,307
1.301
0.940
-0.528
-0.381
120
2,159
8,637
6,477
1.336
0.965
-0.422
-0.305
130
2,216
8,864
6,648
1.371
0.991
-0.317
-0.229
140
2,273
9,091
6,818
1.407
1.016
-0.211
-0.152
150
2,330
9,318
6,989
1.442
1.041
-0.106
-0.076
160
2,386
9,546
7,159
1.477
1.067
0.000
0.000
170
2,443
9,773
7,329
1.512
1.092
0.105
0.076
180
2,500
10,000
7,500
1.547
1.118
0.211
0.152
190
2,557
10,228
7,671
1.583
1.143
0.317
0.229
200
2,614
10,455
7,841
1.618
1.168
0.422
0.305
210
2,671
10,682
8,012
1.653
1.194
0.528
0.381
220
2,727
10,909
8,182
1.688
1.219
0.633
0.457
230
2,784
11,137
8,352
1.723
1.245
0.739
0.533
240
2,841
11,364
8,523
1.758
1.270
0.844
0.609
250
2,898
11,591
8,693
1.794
1.295
0.950
0.686
260
2,955
11,818
8,864
1.829
1.321
1.055
0.762
270
3,011
12,046
9,034
1.864
1.346
1.160
0.838
280
3,068
12,273
9,204
1.899
1.371
1.266
0.914
290
3,125
12,500
9,375
1.934
1.397
1.371
0.991
300
3,182
12,728
9,546
1.969
1.422
1.477
1.067
310
3,239
12,955
9,716
2.004
1.448
1.582
1.143699
The chart above basically confirms the old theory that for every 10lbs you lose 0.100 seconds per lap.
Possible errors: It doesn’t take into account things like clutch slippage and extra binding in slow corners to heavier drivers, so heavier drivers might actually have even more of a penalty, consider this best case scenario..
If you know driver weights then you can adjust their lap times into a baseline time. If a driver is 230lbs in a 9hp kart, then you subtract 0.533 from their time and you get the 160lb driver time. If a driver is 140lbs in the same kart then you add 0.152 to their lap time.
How much time it takes to go from dead stop to vmax at 11m/s, given weight of driver
Driver lbs
Driver+kart lbs
Driver Kilos
Driver+kart Kilos
joules at 11m/s
6hp T to vMax
9hp T to vMax
80
340
36
155
9,350
1.929
1.393
90
350
41
159
9,625
1.986
1.434
100
360
45
164
9,900
2.043
1.475
110
370
50
168
10,175
2.099
1.516
120
380
55
173
10,450
2.156
1.557
130
390
59
177
10,725
2.213
1.598
140
400
64
182
11,000
2.269
1.639
150
410
68
186
11,275
2.326
1.680
160
420
73
191
11,550
2.383
1.721
170
430
77
195
11,825
2.440
1.762
180
440
82
200
12,100
2.496
1.803
190
450
86
205
12,375
2.553
1.844
200
460
91
209
12,650
2.610
1.885
210
470
95
214
12,925
2.667
1.926
220
480
100
218
13,200
2.723
1.967
230
490
105
223
13,475
2.780
2.008
240
500
109
227
13,750
2.837
2.049
250
510
114
232
14,025
2.894
2.090
260
520
118
236
14,300
2.950
2.131
270
530
123
241
14,575
3.007
2.172
280
540
127
245
14,850
3.064
2.213
290
550
132
250
15,125
3.120
2.254
300
560
136
255
15,400
3.177
2.295
310
570
141
259
15,675
3.234
2.336
Conclusion So at the end of the day Sykart Adjusted their timing requirements and made it easier for heavier drivers to get into the 9HP club up from the 6HP club.
On most tracks I have visited 10lbs will cost you about 0.100 seconds per lap, this is the result of the cumulative effect of the acceleration zones. This is the easy rule of thumb, but if you have more or less corners this could obviously vary quite a lot.
Weight handicaps are real, and for this reason most well run indoor karting leagues will have strict weight requirements and use ballast to equal things out.
This could be a good thing, because the easiest way you can improve your lap times is to lose some weight. Managing your weight becomes a very important part of the sport and hobby of indoor karting. If you are struggling with your weight, you might consider a keto diet and intermittent fasting (I’ll discuss this elsewhere). Keto is insane at stripping the weight off, you can easily strip 0.100 off your lap time every 2 weeks.
In this video I break down in detail several different types of passing in an indoor go kart. These methods will give you the advantage under almost any conditions. Note while some tracks are harder to pass than others, there is ALWAYS some way to get around the other drivers. Often it is just a case of having the right mind set about passing, because you can easily talk yourself out of being able to pass on a track.
I am fond of telling students, ‘Look if you can pass in 3 corners when your opponents can only pass in 2 corners you’re going to have a huge advantage in the racing leagues’. For this reason I make it a point to at least have a plan of how I would pass in every corner, given optimal conditions. This has enabled me to pass in many cases when otherwise I would have had no hope. Just think what a difference this makes in a 50 lap race when you don’t have to wait to make a pass, or when you are so threatening to the other drivers that they have to defend themselves in every position.
Now in this video I must admit we are dealing with drivers of lesser skill levels. But these are the kind of drivers that you will have to deal with when you are visiting an indoor go kart track, so these are the kind of passing conditions you’ll have to deal with.
Guide to passing
Passing And Overtaking Guide for Indoor Karting Drivers
As a regular at indoor karting tracks with more then 6000 races under my belt, I would love to say that Indoor Karting is not dangerous at all, but I can’t really in good conscience. Let me back up a bit though, it’s about as dangerous as crossing a busy street, with a helmet on your head.
By this I mean, ‘if you decide to walk in traffic without paying attention you’re going to get run over and killed’. Likewise, if you’re driving on a busy road you’d better look where you are going or you’ll either crash into someone or have someone crash into you. This is a real possibility, but are you going to blindly wander around a race track? Probably not, and I think this is why for most the risk is minimal.
However, it really depends on who you are on the track with. Over thousands of races I have totally seen people who are not paying any attention to where they are, or where they are going. I’ve seen all types.
While 9 out of 10 people are conscious of the fact that they could hurt someone, there’s always that 1 in 10 who has no clue at all. Facility workers can get pretty nasty with these types and can come on pretty strong. Now when someone honestly has no clue at all that they’re a menace, an angry track worker in your face can be a very confusing thing. Just look at the reviews of indoor tracks anywhere and you will see a common theme about the track worker who was mean to someone. Confrontations can even get physical as drivers react (especially drunk drivers). But try not to worry about the workers too much, in almost every case there is something dangerous going on and people who are not aware of it. Its the track workers job to make sure people don’t hurt each other.
There are idiots who show up every now and then (and who are not regulars themselves) who get a bit carried away by the fun and excitement of being able to race as fast as the pedal will allow them to. It is not uncommon for these types to use the kart as a ramming device. The facility will try to manage the situation but its not always possible until someone shows their colors. Unfortunately, not everyone realizes that they have a 1000lb weapon under their seat, or what a 1000lb weapon can do. And what they do is bruise and dislocate ribs and give you neck injuries.
Another common situation that can happen at peak hours is the pros and semi-pros will show up. When you get a situation where average drivers are on track with pros, its as if someone came along and grid locked a freeway and there’s a police chase going on in the middle of it all. As a faster driver, I must say, this is a blast.
Now a true pro is a graceful picture of elegance. They can weave through chaos like you would not believe. Flying through dozens of average drivers as if they are sitting still, without touching anyone. It’s really something quite amazing. But it takes a long time to get to that level.
The trouble usually comes with developing drivers who have developed their skill to be fast, but they have not yet the experience to deal with newer drivers in traffic. A lesser experienced driver can be very unpredictable, whereas a veteran will be totally predictable. For example a common problem is for a lesser experienced driver to spin out and lose control, coming to a dead stop in the middle of a turn. A pro who is at top speed can find themselves with less than 0.200 of a second to deal with a sudden stop right in front of them. Collisions happen right there. Now a top pro is going to predict the accident, and compensate, you’ll see it coming from a mile away if you’re paying attention to the other drivers on track with you. But it takes some time to develop that sensitivity.
So you’re at some risk when you’re on track with pros, but only if you can’t drive yourself and you have a habit of losing control, spinning out and parking yourself in front of others who are much faster than you.
So here’s how you can keep things safe for yourself.
#1 Teach your kids (and yourself) how to LET BY safely. That means how to let faster drivers pass you without being a danger to yourself and others. The trick is fairly easy, you use corners, and just go as wide as possible through a turn, and just point your finger to the inside to let the driver know you are letting them pass. DO NOT try to let the driver pass you on the OUTSIDE! I should repeat that. DO TRY to let the driver pass you on the INSIDE of the corner. YOU take the outside. If you do this properly you will lose very little speed, and you’ll have very little chance of having an accident. By properly you should leave a gap of about a kart width between you and the apex. You just basically travel a kart length further before you turn into the turn and take the whole turn later.
#2. If you are new, as a general rule, get off the gas as you come into a turn, coast to the middle and WAIT until you get to the middle of the turn to get back on the gas. I REPEAT.. coast and WAIT to get on the gas until you are clearly PAST the middle point of the turn. This will stop you from sliding and losing control in front of other drivers. It is VERY IMPORTANT that you get this right. It is a very common problem with newer drivers who want to race and who rush to speed out of turns and get on the gas too much too early. They slide out of control.
Believe it or not, this one trick is usually the only thing you need to be the fastest person on the track. Wait until you are PAST the middle of a turn before you get back on the gas.
#3 If you are not going to let someone pass you, be prepared to get nailed in the next turn. There is really no way to stop someone who is determined to smash into you, from catching you in the next turn. And when they do, they can give you quite the neck injury. You should keep that in mind and err on the side of courtesy. Let faster drivers by, politely.
On the other hand, if you MUST block, then you should probably also know that a pro is going to take advantage of you, no matter what you do. That’s because any deviation from the best line will cause a cascading side effect that will make you a slow target down the track. But even the optimal line has holes in it, and a pro will target this. Let me say, there IS a way to block skillfully, but trying to explain all the 100’s of different situations is a bit beyond this article. Let me tell you, it’s really funny when you have a driver in front of you who is more interested in looking behind himself (to block you) than where he is going and you still pass them like they’re sitting still. I’ve even seen pros who wait for the really aggressive drivers to catch up, and then deliberately pinched them off into the wall. Stuck.
Conclusion: Is indoor karting dangerous? For experienced drivers or newer drivers with a little humility (and don’t mind letting faster drivers pass them) there’s very little risk. But what is dangerous are people and their intentions. The chance of being killed is pretty much zero, but if you have others on the track who are going to be maniacs, yeah you can get hurt. Really bad drivers (and there are LOTS of those) go out and hurt themselves because they basically race themselves into accidents. These are not your weekend warriors and pros but drivers who are intent to push the limits, but have not yet earned the skill to do so. Those guys are scary.
