Who enjoyed this karting series!? Massive thanks to Jack Aitken for helping us out. What would you like to see next?

“I’ve got my new timing system ready” shows calendar on his phone 😂 Jack is savage and I love it 😂

This irritates me because I met Jack in Montréal last year and I talked about karting and how being 90kg made me too slow but obviously now I realize I'm just terrible. The worst part is the experiment was done with the guy I discussed this with...

I'd typically agree with Jacks guess that 20kg would add 0.6 seconds. Usually I've seen that 10kg adds roughly 3 tenths. There are so many other variables though so it makes it hard to measure with complete accuracy.

Jack showing a calendar to record Matt's lap times... Pure Savage!

I work at a kart track with laptimes around 1.08, and after alot of testing we concluded that 10kg is around 5 tenths. It also depends on how much you start with 60 to 70kg makes more difference than 80 to 90kg. So i guess the type of track is also important.

Am I the only one who really loves the camerawork at 1:25?

20 kg is like 5 AR-15 (For Americans ) Edit : thx for 900 likes and the funny replies

12:15 skip to the results

So your telling me I can be fat AND enjoy karting! 😁😁

This karting series has been brilliant, I’m just back from Dubai and last year my best time around their outdoor track was a 1:17:3, this year its a 1:15:7 and the tips from this series helped a lot because I know I can still get that time down even more

I know these karts are available to the public and a bit different in terms of handling. But I worked at Ocala Grand Prix as a race mechanic for a little while . Working with the Tony Karts and Rotax. And you’d be so surprised how much weight makes a difference in the pro karts. For example the smaller drivers generally had a advantage as they could place lead weight in different areas of the kart to get better stability in the front or rear. And generally 1 pound can equal 1 tenth a lap . Which is massive . However with the public karts it’s different. It’s really luck of the draw on who gets the best kart. Especially when we switched our old public karts that were 4 strokes to the new rotax 2 stroke karts. It was essentially who had the best carb haha. Interesting to see this test though non the less !! Great content as always ! Keep it up guys !!

We have testet a lot on different indoor tracks. The results are all between 0.1 - 0.2s slower for 10kg extra weight on lap times of about 30s.

Really enjoying this series! So entertaining! Keep up Matt! P.s: Keep Jack, he's such a likable guy! :D

Great series, great video! Obviously there are many more "outside influences" that will change your pace, but it was still nice to see an example of how weight can affect your times. That affect will be different from Kart to Kart and from track to track, but it's still a good indicator. What I feel is also a downside in karting is being tall, but you can't really recreate that. Being tall gives you more drag first of all and second of all you can't adjust your position in the kart to help your driving style. You're basically forced to sit as far back as you can to have room for your legs. That weight distribution can affect the times quite a bit as well I think. I would be intersted in you trying out different positions with the seat of the kart and see how much it changes your times, because the position can change the kart from understeer to oversteer really quick. But overall thank you for the great content with this series!

Being lighter allows later braking and earlier on the throttle on exit which beats that bit of extra grip. Also, the sluggish start puts you back in the gird. A few kgs does not really make much of a difference but being a natural 110kg I am slower than I was at 90kg in a race.

I'm very surprised to see this. The track I go to actually have a weight equalization system, and I've used it a couple of times to compare my laptimes with different weights, and I've concluded that weight has a huge impact on laptimes.

Regardless of weight differences all things being equal otherwise, if you're only running 0.10 seconds off of Jack's best lap, I doubt you're losing many races to your buds. Solid driving from both of you guys.

Loved this series :D Hope you guys will do other cool stuff in the future.

@WTF1 We did this at our local E-karting track here in the states. We set tire pressures, alignments and had one of our fastest drivers compete against myself and the results of him at 120 vs me at 150 was split by a 23.5 and my own 23.7. Once we added weights just like these I ended up running a 23.7 and he ran a 23.8. Our top guys are all very consistent and the battles are close. We are talking about adding weights to the U.S.A. E-karting championship to balast the weights and also have weight classes since it does make a slight difference, and that slight difference at the top of competition makes a significant difference. Glad you guys covered this!!

Possibly that your lap times improved as you were getting accustomed to the track. You should have backed it up by removing the weight again

I regularly race @ Teamsport (Harlow) and there is a group of around 10 of us that vary in weight and age (55-80 kg/14-50) and we are all with 0.4 of a second of each other week in week out. The main issue with their tracks is: once you know the line its very difficult to overtake. Still great fun though, the leaderboard is very competetive but it does put off the newer racers. We often see people turn up for a race, get annihilated and then never come back. It took us months and a lot of £££ to get up the leaderboard. Good vids, would love to see you visit some other tracks (or at least Harlow!).

great series! I really enjoyed it. Maybe outdoor karts with higher speeds next time?

Cheers, I don't have to feel too bad about being 57kg now! Was nice to see how weight affects the flow & style of driving, been to teamsport docklands once with a friend who's something like twice my weight, best times were 49.7 vs 51.4. I did put this down to the weight difference & more so the lack of power because we've always been quite closely matched otherwise in cars & sim racing (where he's quicker a lot of the time). We would likely be closer with two strokes on a quicker track, IIRC there wasn't such a large difference when driving the more powerful club karts at another outdoor venue.

I refuse to accept this reality.

I think it would be more realistic if you had tied the weights to Jack's belly

Jack Aitken is very good on these videos and in general explaining F2 and F1

excellent video!! You need to get one of those Jr kart racing champions in here and race them.

Excellent series. Enjoyed thoroughly but no longer do I have an excuse for coming last.

So you're saying that I can still be an f1 driver at 102kg. Lovely 😂

Worth mentioning what I have noticed. On some slippery tracks with not to much accelaration needed out of corners -> more open corners I have noticed that you can be to light weight -> les grip in corners. I was for a long time wondering why my brother 85 kg could go trought that open long corner so much faster without sliping like me with 68 kg After some research and talking with the track ceeper he stated that he noticed that every track has an somewhat ideal weight, I added 10 kg and have improved my times on that track, because I now can take that long open corner way faster without slipping.

Really depends on the track. I also tried it with 10 kilo's extra on a track without elevation change. I was 3 thenths slower. And I have 6 years of rental kart experience so im not a complete fool.

I don’t care what you bring up next as long as jack is still in it 👍🏻 You guys are great anyways but jack brings the extra sparkle :D

"It is not as fun if you weigh 110 kg" Me: *weighs 110kg on my own*

My guess is that there are a couple of different factors at play some an an advantage some disadvantage. For example at turn in the extra weight will give more grip against the extra inertia. Which is more affected probably depending on the steering angle. Then there is the polar moment of inertia which affects how quickly the kart pivots around its centre and how responsive it is, how stable or twitchy it is. Then there is the centrifugal force once into the bend versus extra grip afforded by the weight. I believe centrifugal is exponential with regard to speed whereas weight is linear. Each factor will vary in significance at different parts of the track.

Great video guys, very interesting :)

Cool, but.... With no added weight you would have improved on the second set vs the first due to practice. You should have alternated a few times.

Added grip from extra mass never exceeds the required grip to overcome the increased inertia! Quite surprising results anyway!

We have a track nearby, on a 50s laptime, it hat 7 hairpins and a hill directly before and after a double hairpin... out of the hairpins and up the hill i felt that i lost so damn much time (very tight track as well)... was kinda frustrating, when you do a cutback kinda ting out of the Hairpin before the hill and catch him up so quick untill you hit that darn hill and then hes just gone... Very cool video though! I think that a test on different corners would be awesome (like, how much time do you loose through a Hairpin, how much do you gain through fast corners etc.)

Awesome series, always funny 😂 please do something with a serious kart in an outdoor track!

Try this at Buckmore Park and then share the results

"Weight is not such a bad thing... you've got the rear to play around with." My mate, around the curves.

Good video dude.😃👍

Love the videos

I actually went to that exact track when I weighed 140kg and my best time was 59s!

8:40 it doesn't keep you more planted, there is more force going into the ground but there is also more force pointing outward from the direction you're turning, countering any benefit you could have from the extra mass.

It would be interesting to try this on other tracks like Buckmore Park which have long stretches of uphill and downhill which might give different results.

At my local indoor karting track, there is a mix of high speed corners and straights, with some hairpins. Being 140 lbs I have to lift through the high speed sections to maintain grip, whereas my 180 lbs friends can take them flat. Its about a 21 second lap so about a 1/3 of this circuit with (importantly) no elevation changes which is where the weight was most felt. Thus, the excess weight is negligible.

its because of the floor, its greesy and there is no grip. So more weight helps with that. but obviously the accel is effected

0,2s is massive difference. Thanks for this informative video. :D

As a rule of thumb, for traction limited racecars, 10kg adds 1/10th of a second every 750 metres. So, for a 3km track, if you somehow find a way to make the car/driver combination 10kg lighter, you should see a 0.4s improvement in lap time, all other things being equal. Likewise, 10kg of success ballast should slow a car/driver down by 0.4s/lap. In indoor karting, funny things can occur. 10kg is a lot of extra weight for a 9hp engine, but it's also a fair amount of weight with regard to the total weight. More weight pressing down on the tyres also equals more grip. This track is quite slick, so if there were places where Jack couldn't quite carry the speed he wanted, that situation could be improved, allowing him to negate the hit in accelleration he'll undoubtedly take. Let's watch the video and see what transpired on the day.

hard to believe. maybe on the slow speed tight circuit it, it helped making the times a bit closer at our home circuit here, we race Tag 125 and difference between a light driver (Kart & Driver weight 162kg) & Medium (Kart & Driver weight 182) There is approx 4-5 tenths a lap each lap.some drivers do overlap but talking about the top 3 - 5 in each of the classes. you tend to see 3 tenths trend in both classes. most of the speed loss is coming out of the corner and down the long straight.

Can you please make a BTS video? I want to see those guys running with the camera rigs... to get those awesome shots!

I went karting a few Sundays back, I actually thought my 17st+ was holding me back, but I suspect I'm just a bit shit at it instead. Oh well. 🤷‍♂️

Pretty much as expected. The difference is smaller in rental carting than real racing due to the hard hockey puck tyres. The increased weight get them up to higher temps(with some increased grip) , which ofsets the extra weight quite a bit.

I enjoyed the Bojack reference at the start there Matty

DO THE SAME TEST IN AN MORE OPEN OUTDOOR TRACK WITH LONGER STRAIGTHS , SURE THE GAP IS ALOT MORE

Great test! But could you try to do the same type of test on a real (outdoor) kart circuit? These indoor circuits usually have a quite slippery surface and short acceleration distances. I think the difference would be much more noticeable on an asphalt track where the light guy has decent grip anyway and where you do need top speed and acceleration through long bends...

Such an interesting video. I used to race shifter karts AT 240lbs, which is a biscuit from 110kg. I thought that these might be the results, and they made some great observations regarding the handling of the kart. With my weight, I could jack the inside wheel off the ground 6 inches and the turns would be so brutal that they would pull your eyeballs out sideways. My racing partner weighed 60 pounds less than me when we raced we bolted 60 pounds of scuba diving weight to his seat and frame so he could race in the same class as me. I was always competitive with him for the first half of the race, but come the second half, he would drive away from me. It didn't come down to anything other than what our bodies could physically handle. A 240 pound body going around corners and a 180 pound body with 60 pounds of weight strapped to it are two different rides!!!

Now do this at an outdoor circuit and see the difference. Indoor tracks aren’t too dissimilar to wet conditions where weight does help

Woefully unscientific. Do a drag run over a certain distance with one kart, and then add 20 kg to that kart and time it over the same distance interval, it will be slower. This would actually be a great test in rental karts because there's no manually operated clutch and they aren't powerful enough for wheelspin, so you'd just floor it and go. This is true in any vehicle, look at all of the cars, motorcycles, etc. that have the same engine with the same tune and the heavier one is always proportionately slower. F=ma, it's physics guys. On a track like this, how you drive it, how warmed up the kart and tires are, etc. matter a great deal. Also the kart setup matters as having weight in certain areas can fix over or understeer, and tire pressures will favor lighter or heavier drivers as well as a tire with too much pressure may have a smaller contact patch with a lighter driver, but might buckle and hop with too heavy of a driver on a lower pressure tire. On a cold track with a cold kart, a driver 100 lbs lighter than me might not run faster than my typical lap time, but then once the track and tires are at ideal temps (which takes lots of people running the track for at least about 30 minutes on rental karts), I will no doubt beat his cold time, but he will have run even faster in the warm conditions all else being the same in ideal conditions. I've seen times vary as much 2-3 seconds on a ~35 second-per-lap indoor kart track between first session on a cold track and a warm session at the end of the day with consistent drivers that can lap within a tenth of a second every lap. If you're 5 seconds off it's your driving (or a dud kart), but on equal karts a 20kg lighter driver is going to run 0.5-1 second faster depending on track length and complexity, I've observed this at literally every league race I've ever been to that had different weight classes. And don't tell me "oh, it's because the light drivers are just better", not only are the heavier guys usually older with many years of racing school, track days, and even wheel to wheel racing under their belt (compared to many light drivers who are teenagers and haven't done any of that and barely have a basic driver's license), but when the track does a special configuration that nobody has seen before just for a league night, the heavy guys are usually faster at first because the light drivers don't have the real skills and knowledge, and only after they've put in a ton of laps (or followed a heavy driver to learn the line) do they start running faster. This video is nonsense. To reiterate and conclude: weight matters. More than a second on most tracks is likely the fault of a driver, but a substantial weight difference will matter all else being equal and the 2 tenths shown here probably has more to do with warming up the kart/track before running the heavier lap. Gather all of the fastest laps for the year in each weight group and you will ALWAYS see a gap between weight segments unless there simply aren't any good drivers in one of the segments.

Add 200kg and see if it adds 2 seconds.

I'd imagine it's track dependant. TS tower bridge has a long straight after the ramp, that's easily 5 tenths.... Well that's what im telling myself anyway. Great video though!

6:15 "he's probably going to be sliding around a lot more" *screeching intensifies*

there may still be a bias as when you have been timing the benchmark, you usually improve the more you drive. you could have warmed up the karts and got used to the kart before starting the test, so it would be a fair test

*Hello I have a very serious&personal question: Im really tall. About 203 centimeters. (And bit more than 90kg) I feel like being tall also really affect your laptime. Because you have to put your seat and pedals really far from the steering wheel, so you have a worse weight balance in turns (I mean "I lost the rear" more than my friends who are smaller). Also being tall, you have much more of your body parts "outside" of the kart, I also feel like it is affecting your weight balance (and maybe your aerodynamic..?)* *So being tall and by the way being heavier adds a lot of tenths at your laptime, isn't it? So how to compare yourself to your friends?!!* Really big issue here. I hope someone could say if some of the things I said are true or false. Thanks. Great video!

I’d be interested to see the same result on a flat tarmac track where your extra weight won’t push you so far past the limiter when you come down those hills. Also I’d expect that inability to hold in lines as much as the next guy to come in to play instead of that slick surface you were on. I’d expect that 2/3rd second differential out there

Baring from tire overheating, weight doesn't affect cornering speed. You get extra grip from the extra weight, but you also need the same extra grip to pull the same lateral g force. The same goes for braking. Weight doesn't affect your performance when mechanical grip is the limiting factor (cornering, braking, and accelerating out of corners where you can't give full throttle). It gets more complicated when you consider weight transfer but that's negligible on a rigid-frame go kart.

When you think about it 2 tenths is a lot faster because that means you lose 1 second every five laps

10:25 "I cannot WEIGHT to see the end results."

There are a few other factors at play. Due to the power/weight ratio reduction the kart is not capable of such high acceleration so you are approaching corners at a lesser speed, which might not require you to brake or raise your foot off the throttle. Also this effect would tend towards inside lines which shorten distance. Added weight is always going to be a disadvantage, but is negligible for driver weight differences under 20%.

Because is an indoor, in the karting of my city that is outdoor the time are 2 seconds slower than without the 20kg, only brake in two corners.

Matt instead of jack is also +20 kilos

This is why kart classes have weight classes, too many variables here

This is quite interesting and I suspect there may be some more dynamics at play than covered here... but equally now I feel slightly less guilty about being probably amongst the lighter of the adult members at my local track and that maybe my relatively respectable pace is as much due to capability as it to a weight advantage.

As i am pretty big guy i still can keep up with the small ones. I loose at the start or in slow climbs but noticed that i can go faster in high speed corners. Also my braking points and kart placement are different so i will carry as much speed i can through the slow corners. I can even beat my friend who is about 35kg lighter.

Our "local" Gokart track (Vandel Gokart bane) has holders beside the seat, that can hold UP to 30 kg, to exual out weight, so this excuse is taken away.

This has actually made my day, it means that weight adjusted I had the lap record at my local track since I was 7 stone heavier than the official record holder and I got within a tenth of his time !!

i weigh 100 kilos and when go karting with me friend that weighs 70 our lap times were two tenths away from each other i was slower so we decided to do a standing start together and we found that in the corners i kept up with him but on the straights i lost a lot of time both same hire karts.

good will buxton impression in the start

There's a massive difference between the 20 kg dead weight on the car and the extra 20 kg body mass that the driver is carrying around. Source: My stats 1 year ago: M26, 170 cm, 96 kg, fastest lap time then: 57.678 (Daytona Kartbahn, Essen, Germany) My stats now: M27, 170 cm, 82 kg, fastest lap time, few days ago on that same track: 52.35

Still feels wrong. Not sure about this analysis. Also, where to place extra weight does affect balance through corners. Extra weight does affect time to top speed as well as beating inertia. Shouldn't weight interfere, there'd be no need for drivers to weigh in before and after races. Do it again, only now make it outdoors with long straights.

When it comes to lap times, usually the difference is minor, but when it comes to acceleration and braking for overtaking and defending, that's when weight may be a problem.

Perhaps the better grip and more inertia that results from the added weight, if handled proficietly, compensates enough? I am sure though that there is a cut off point also for adding weight at which point the added grip and inertia, even when handled by a master, will not be sufficient to compensate for the slow down of the engine having to do too much work against gravity and friction.

Of course weight matters. If it didnt there wouldnt be ballasts in professional racing.

Now to prove this even further and get better differences..... go to another indoor track with lots of little corners and hair pins and do the WEIGHTED lap times FIRST and then take the weight off. Your weighted 2nd session lap times probably increased as you had already warmed up with the non weighted before hand. I reckon it would be 0.300-0.400 difference.

I think that with this kind of indoor surface the wheight helps a lot in the corners, in a tarmac track the difference would be certainly bigger. In my 20 years racing Karts experience 20 kgs will make you 7 to 8 tenths slower.

The local karting track karts mostly loose back tyre grip, almost never front wheel grip. Maybe rearmounted weights would actually make the kart faster around the corners.

Isn't added weight proportional to the mass of the car? So the lighter the car the more the 10kg will effect its time??

Very cool and interesting test, but it could have been much more representative. You would need to shift a lot more weight higher up, as Jack mentioned. That drastically affects your Center Of Gravity, or CG (especially in a very low Go Kart) and decreases performance more than strictly adding weight low down near the existing CG. They put the weight on the seat, that is fine, but the rest should have been strapped to their body and upper chest to be honest. How much more weight are a fat persons feet and tibias, versus their ass, gut and chest? Trust me, Im an engineer. That may also be why I am so harsh on their overall great experiment. Honestly, probably more lilke 0.4 of a second. You need to also account for the fact that (especially Jack) will be doing on average faster laps on his 2nd stint as you grow more comfortable driving around the track.

Being more consistent to begin with and having a better sense of control, Jack suffered less with the added weight. Our esteemed host, being less consistent and theoretically having less control skills, does not reflect the true penalty of the extra weight. IOW, this is a really fun and entertaining video, but not a falsifiable, scientifically controlled test, if we're only comparing the two drivers to each other. But Jack's results are pretty credible. I'm 6' 3.5", 245 pounds, and for me, carts are so desperately slow that little children rip by me at the start, and pretty much anywhere, unless I'm protecting my line through a corner! It's so depressing, I don't go karting! I stick with my 700hp Viper! Anyway, big thumbs up for a really fun video!

As a bigger driver (I weigh 110 kg), I would say the impact on straight line acceleration is very obvious. I tend to run mid to high 29 second laps at my local track. I can get a good run off of a corner on someone who is doing 31 second laps and still have them pulling away at the end of the long straight. It means for passing I either have to go up and under right at the corner exit or dive bomb a bit at the end of a shorter straight.

try it on a more high speed track, i guess the diff will be bigger.

Weight doesn‘t impact your cornering. If your weight increases by 20% your grip increases by 20%. But also the centrifugal Force increases by 20%. It evens out. The only thing you will have is slower acceleration. Braking is the same. Again, 20% more grip while breaking, but also 20% more force pushing you forward. Evens out. I‘m shocked a f2 driver doesn‘t know this. Its one of the first things you learn in mechanics. Edit: Not entirely true, look into the Comments for more information. I didn‘t took tire load sensitivity into account. Thanks for correcting me.

The track also builds up grip. In 3h team races, the laptimes go down about 1sec.....

I think that there are a few things that have been missed here - The standing start, i race in multiple championships using corporate karts/hire drive. i currently weigh 56KG which is heavy for a 10 year old (i am 5ft2 and have size 9 feet). Every race i am in, i lose at least 4 - 10 places off the start as there are drivers that weigh as little as 25kg. These are adult karts used to carrying the weight of the kart and bigger drivers, In Bambino, Cadet or Junior series this is amplified. In virtually all forms of motorsport there are minimum weights, apart from corporate karts/junior racing - how many talented larger kids have been dismissed as not having talent, because they are not as quick as the kids that are half their weight... i have to battle constantly to recover places, be super smooth to maintain the momentum and work hard to win races. I feel so strongly about this as i have 2 friends who in the rain were untouchable, have given up racing as they can't compete with the small kids... this to me is fundamentally wrong and accepted by all. I hope the extra skills i have learnt will put me on a good footing when i step up into seniors and can race my Rotax (with minimum weight next year)

+0,2 sec.. How much power these karts have? I doubt that they have 5 hp, as usual karts... With them, the difference will be much greater.

Now i can figure out if i'm slow or just to big (i'm not fat, rly i'm not!)

There are always excuses abound in racing. Mine today was that the qualifiers were based on lap time and there were two older ladies in my heat running their karts at half throttle. In the tight corners, you just had to wait to overtake them. It landed me 10th in the Finals, but I muscled up to 5th by the end of 12, 20ish second laps. Not bad I'd say, but a better starting position would have given me the title.

In rental karts yh but I was 14 kg underweight on a race with my own kart and was getting high 39 second laps but when I added 14kg I got a 38.6 I'd say alot of this is due to me learning the track more but alot is also the added downforce so less sliding with own karts being alot lighter than rental karts