We tested my speed on mountain bike jumps, and here's what we found out

[@Titanius1066]

Not going to lie. I was always skeptical of an older friend of mine saying he was doing 40+mph down the trails around Bent Creek.

[@BermPeakExpress]

It would be really funny to ask people what they think their speed is, and then whip out a radar gun

[@flashfive23]

@@BermPeakExpresshaha yes

[@jason.bernier]

​@@BermPeakExpress next video idea

[@mrupholsteryman]

I remember my early 20's when there was an officer running radar in our neighborhood...I had my Robinson BMX 20" and was asking if he could tell me how fast I was. With a 44/16 gear and 175mm cranks and a 145lb body with a 30 inch inseam... 34. Speed limit was 25. I thanked him for letting me see...he didn't wanna give me a ticket and be ridiculed in court for pulling over a kid on a bike. Fastest I've ever been on a road bike was 54mph also around same time period on a Specialized Allez 54 cm. Down a very steep short hill where it was hard to keep up with pedaling... So yeah.. on a dirt trail with less ability to just mash the pedals and not die with rocks/roots/wildlife etc.... I'd also be skeptical... Trying to get my funds right so I can put some bikes back together... I'm 51 now and still have that kid in me that wants to ride bikes and jump stuff. I just never got beyond the no handers and my feet were never wanting to leave the pedals...still love riding. I am no R Williams with those bike flips! Crazy stuff to watch!

[@explorenaked]

According to my Garmin watch, so who knows if it was correct, the fastest speed I've ever achieved was 39mph. Not on a trail but a very steep dirt road in the mountain neighborhood I use to live in. Very straight and very long. Needless to say, my butt was puckered the whole time. On a trail, the fastest my watch recorded me was 25mph. Again, very long steep straight section of trail. I don't do that much anymore...but I'd like to. Going up the trail? I'm thinking if I achieved 5mph it would be a milestone.

[@theRozman88]

Those metric conversions wen't out the window pretty soon. Seth making me do math in my head while watching his videos... 😄

[@megatryn]

Yeah, thumbing down for that.

[@Mike-oz4cv]

I just multiply mph by 2 and divide feet by 3.

[@megatryn]

@@Mike-oz4cv mph to km/h is about 1,6, so multiplying by 1,5 is way closer than 2.

[@tbread1128]

@@megatryn better leave a comment like this, since downvoting doesn’t show up anymore, just influences the algorithm for you mostly, and only a bit for others

[@schwuzi]

@@tbread1128 It doesn't matter. The algorithm counts it as interaction anyway. Thumbs up or down don't matter.

[@matthewcacace6804]

I agree 💯 that going 24mph feels like 500 mph!

[@ginnipig]

805 km/h!

[@brokenrecord3523]

I road bike and 24 on a flat open road is not slow - can't imagine in the woods.

[@sapperROSS]

I'm in the mid 30s on some downhill sections on my mountian bike, its sketchy but fun. And yes I track my speeds

[@theGiver3]

​@@sapperROSS that's gotta be absolutely terrifying

[@sapperROSS]

@@theGiver3 haha depends on the trail.

[@bmmtb37]

The great thing is that you don’t need to have a degree in physics to MTB. Seth you inspired me to start my own channel and record MTB footage. Keep up the good work!

[@ff00005]

the bad side of the equation is that a physics degree won't make you a good MTBer either.

[@averytameduck8725]

Even worse, it won’t even make you good at physics.

[@sepg5084]

​@@ff00005 you don't need to have a degree in physics, nor be an MTBer, to be do a lot of things in life. So there's that 😂

[@ragomtb]

Same! It’s exactly why I made my channel

[@megatryn]

Banana: 18 mph = 29 km/h Double: 17 ft = 5,2 m, 18 mph = 29 km/h Snake pit skinny gap: 7 ft = 2,1 m, 14 mph = 22,5 km/h Rock garden: 20 mph = 32 km/h, 24 mph = 38,5 km/h Doing Seth's job for him

[@GrafRamolo]

Where is oscar?

[@philip5463]

thank you

[@silvajay6443]

Why is it an American's job to translate our system of measurement for you to understand? I mean there's plenty of better ways to seek attention then to wine about someone not calculating things for you.

[@Taytay-wn4ik]

@@silvajay6443he converted the fastball. But couldn’t convert the other shit? Lazy af

[@megatryn]

@@silvajay6443 because he set it up in the start of the video and didn’t follow through. Also imperial measurements are stupid to begin with, get up to date americans!

[@hypasteve]

Since getting into ebikes, I have a speedometer on my bars. I'm not often able to look away from the trail at speed, but your speeds are pretty close to mine. Except a-line, where you add 8mph to clear the big jumps 😄

[@stanmustard7292]

That was my first thought...how fast was something like A line? Thanks for answering.

[@PeterKornum]

Thanks for the promised km/h conversion on screen THAT ONE SINGLE TIME YOU ACTUALLY DID IT!

[@koraykahraman2379]

Thanks so much for providing the metric information too😁

[@sawdustadikt979]

That story about what people think mtb is, reminds me of when I started taking my son with me on trails with a trail a bike. He was maybe 4. When told non riders that I took him with me they lost the color in their face and had a far off stair like I had just pimp slapped them. I know they must have had every old Mountain Dew add or whatever going through their minds, that’s on them. Same continues as he got older. What people don’t realize is that this is all learnable, individual skills. When he first started to ride on his own bike, he walked a lot. But we kept on the same trail loop for years, he kept getting braver, and I’d praise him for riding through something he had been walking through for years. He is 12 now, and we start every ride with a new skill, we run drills till he is ready to ride and he chooses to use or not use what he has learned. Sometimes it’s weeks later when he does use it, sometimes instinctively. Teaching kiddos and having them light up when they get the technique mid trail, is one of the best things ever.

[@dastoast5273]

Its the best thing of the week when Seth posts a video

[@tennesseemusicworks]

Great job, Seth. It’s always fun watching your videos. You have inspired me to build my own Berm Peak in my backyard, and keep up the great work!!

[@mateidji]

Best MTB videos! Keep it up Seth!

[@unlikehybrid8268]

Hi Seth, I just ran some calculations: On the Banana Cannon, the theoretical speed (assumption of ideal conditions) required to clear the 17ft (5.18 metres) gap would be 24.1 mph (38.79 km/h), which is 7.1 mph (11.43 km/h) off of the measured 17mph (27.36 km/h) and 10.1 mph (16.25 km/h) off of your prediction of 14 mph (22.53 km/h). The accuracy error of this calculation is therefore 41.74%. On the double after the Banana Cannon, the theoretical speed would be 16.07 mph (25.86 km/h), which is only 0.93 mph (1.5 kilometres per hour) off of your prediction of 18mph - the error would only be 5.5%. In theory you should have gone at least 3.3 ft (1.01 metres) into the air. In order to clear the snake pit gap of 7 ft (2.13 metres), in theory you would need a velocity of 11.7 mph (18.83 km/h), 1.3 mph (2.09 km/h) less than the measured speed of 13 mph - error rate 10%. On average, your guesses were on average 88.24 % accurate.

[@zmfb]

Does this include preloading and the 'pop' when you jump?

[@unlikehybrid8268]

@@zmfb No these calculations only account for a passive jump, so basically just rolling over the lip in order to get air. More advanced physical models of jumps incorporate complex systems of differential equations, for which I am probably underqualified. However, due to the difference between the measured and the theoretical velocity, it can clearly be seen that preloading the suspension and the rider actually performing jumping motion lowers the required speed by quite a bit.

[@CamrenHunsicker]

Hey Seth I've been with you since the very beginning. I remember when u were Seth's bike hacks and you had been creek. It's so cool to see how much you've grown as a KZbinr. Keep up the good work

[@ThisIsGoogle]

I was there before the beginning.

[@jacobpoucher]

I was here before you were born you look 10 years old

[@MichaelRei99]

I was there before both of you put together!

[@theGiver3]

Congratulations. Do you want a cookie for your achievement?

[@CamrenHunsicker]

@@theGiver3 yeah sure

[@AlexanderBallot]

I think it’d be kind of interesting if you made a video all about filming techniques you use! Like different GoPro mountings, settings, different angles, filming the same shot from different locations, etc.

[@thomasafine]

It is totally physics, and your high school physics teacher can trivially calculate it to a very high degree of accuracy. Wind resistance for the brief time you are airborne has little effect, and the rest is just a parabola. Easy to calculate from speed, angle, distance. It's very straightforward and there's a definite, easy to calculate, right answer. The fudge factor that lets MTBers think that it is intuition is how much extra control they have on top of the basic physics. A pop from the lip basically adds kinetic energy (speed) and you go farther. Tucking the bike up under you doesn't change your trajectory at all, but it means you can go "farther" because your wheels are magically higher than they were, so you can save yourself from a case if your speed was too low. Conversely with too much speed you can extend your body and push your wheels lower to get them to contact sooner, or even angle the bike to force one or the other wheels to get on the ground and give you some control before it's too late. Or change your position to be able to handle the larger than expected shock you're about to experience because you went too far. So in other words the intuition (the knowledge of experience) has less to do with approach speed (thought that is still an important factor) and more to do with how much control you have when you are about to go into the air and you realize from that vast experience that you botched it, and have to make an adjustment to land it. A good followup video would be to find someone who knows the physics and can do the trivial calculations, and then experimentally see how much control you have to save the landing when you don't hit the magic number. It would probably be at least +/- 10%, and it might be more. And it almost certainly depends on the skill and experience of the cyclist. It would also be fun to see what happens if you could force yourself to make zero adjustments during the jump, and let speed and physics 100% dictate how and where you land.

[@EtniesMatt]

Be interesting if you had a racer and a freestyler hitting the same jump just to see the difference between speed and pull up power!

[@wchangose]

Excellent vid, thank you!

[@tomsouthworth8343]

Seth's Visor @0:23... My POC visor is ALWAYS crooked. THX for keeping it real, Seth!

[@AndreRicoyDias]

Metrics on screen (at least in your PC screen) @ 2:30: 16 mph - 25,6 kph 18 mph - 28,8 kph @ 2:37: 14 mph - 22,4kph @3:10 19 mph - 30.58 kph @4:43 7 ft - 2,13m @5:06 14 mph - 22,4kph @5:11 12 mph - 19.31 kph @5:55 22 mph - 35.40 kph @6:10 0,0 mph - 0,0 kph @6:33 24 mph - 38.62 kph

[@Shawn-wt4kh]

Even jumping is only practiced by a small subset of mountain bikers. A majority of us are just ambling along doing cross-country type riding, or a combination of XC and enduro like BKXC.

[@kennybicar528]

Never have I ever seen anyone with this content and bring up a speed gun to make a point. Kudos

[@southsoundrider5428]

Thank you for making this video. it's a big question I've had for so many years. I now understand how speed works when it comes to jumps.

[@Blue-X]

Big thanks for putting the conversions❤️❤️

[@Sebbern108]

Love the vids seth!

[@buickman70]

Love this video Seth. I've been watching the channel for years now and have never owned a mountain bike or been on one since I was a kid. Just love your creativity and genuineness. You're the best.

[@dr07828]

Wish I had a big that was that smooth over the rock gardens.

[@halfgeek1394]

It's hard to gauge speed on a bike. In the woods, the trails are so narrow and rough that you feel more movement and have the blur affect from your peripheral vision. This will make you feel faster than you are. My fastest speed on a trail was probably 30mph, if my phone was accurate, and that was at a bike park going full tuck and well beyond spun out in my fastest gear. I hit 50mph on my hardtail last year on a dirt road using the same phone as reference, and on a road bike I reached 51 or maybe a little more given GPS. Those times I felt fast only because of the wind, and I was thankful to be wearing glasses. Those speeds, though I know I only hit for maybe 5 seconds at the very bottom of a hill, are a lot harder to reach than you may think. 30-40mph on a road bike is common for most fast descents. 18-22 is common for most singletrack descents. Though of course these numbers change depending on the trail and conditions.

[@E_Mrgan]

Seth it would be great if you could do more crawler videos I love them

[@gbririmi897]

Thank you for the mph to km/h conversion

[@TheTothtamas]

For the rock . What matters did not get a conversion.

[@griffinmontfortbalfour5388]

friends that dont understand mtb always make you feel like such a badass.

[@matevzsluga563]

Great video! However, the uneven helmet visor is killing my soul😂

[@PJSinohin]

the friction-less plane reference got me ;)

[@imabigfanbro]

How my friends imagine mountain biking, is riding in a gravel path.

[@jonasbekaert2889]

"I'll put up some conversions" proceeds to not put up any conversions lol

[@jipasd]

Any speed through the rocks is bizarre to most people. Then again, riding down hill it feel like 500. So this was kinda educational. Wish you also added the numbers from the phone/watch/what ever.

[@TAndz256]

Glad people see me hurling myself off a lip aimlessly as me being a super smart physicist

This is an interesting video, and I like how you put in the conversions in the intro. However, right at the first jump and every jump after that, you forgot to put them on the screen for us non-imperialists. :D

[@creepingjesus5106]

I use the local 'your speed is...' traps on the roads. They're probably no more accurate than an Amazon special radar gun, but it's handy to gauge how much push in which gear results in what speed. Also, my phone freaks out when GPS signal drops, and I've seen 2,550mph indicated. If only! Pretty sure I could clear anything at over Mach 3.

[@andyheilmann1656]

I have a physics degree among others. There's lots of fun things you can calculate. The trajectory off of the airbag jump would be fun to analyze. Distance, height, and airtime would fun to calculate

[@BikesAndHills]

3d print idea! replacement for zip ties in your cockpit!

[@marktechsci]

Garmin with MTB dynamics. Gives score, hangtime, distance and speed. Best coupled with a speed sensor for most accurate speed and distance. The 830 has an MTB kit which includes the remote, speed sensor and barmount.

[@wickedmountainfilms]

It’s a parabolic function that includes friction and atmospheric drag. Speed isn’t constant which makes acceleration one of the most important functions of hitting jumps, not speed. You need to be marginally speeding up taking off the lip! Which is why pumping is important (centrifugal force). What’s beautiful is you’re right, our brains do make this intuitive and you don’t need a degree to figure it out, but it’s a very simple dynamics problem here on earth that a physics teacher would take 5 mins solving. 5:46 great video

[@KevinLindstromMedia]

As a physics/engineering graduate student who TA's intro phys courses, yes that comment was justified, BUT its really only reflective of the introductory coursework. Modelling a bike is really not trivial and is part of why they are dummy expensive/why our bodily intuition is more relevant when riding. We are so much better at estimating environmental factors and compensating, because math would require a complete knowledge of everything to be able to effectively model, which is just not practical in many situations. Either way, good video, appreciate the jab at physicists, cheers! :)

[@qwqwqwq2401]

Thank you for including the metric System!

[@kiwi.fisho.luca.]

Seth we need the old intro back “today we’re doing something a little different but kinda the same”

[@one234569and10]

love your videos Seth !

[@darojos]

Funny subject. Reminds me that Douglas Adams referred to "playing catch" as "performing amazing feats of differential calculus".

[@jalapenohotcakes]

So cool. Good video of you going fast. Looks fun. 😁

[@RyanKinal]

I think the most valuable part of this for me was watching you jump. I'm still figuring it out and just seeing you do it over and over - full speed, no slow-mo - was really interesting.

[@zuck759]

good to know i have to be going the crusing speed i sit at while im on my road bike to hit a jump

[@tbread1128]

Really nice conversions on the screen man, love that invisible ink

[@seattlegrrlie]

Another thing people don't realize is not all of us like to go over sick jumps and drops. I'm more in the skinny line go anywhere faster than hiking part of it

[@winklertribe5268]

What I learned is to hone my intuition. Thanks Seth!

[@Clarky_AU]

Gotta unlearn what i learned now, however i did find it entertaining!

[@igori3532]

Well at this distance and speed you can neglect the air friction. Once you are in the air it's approximately parabolic trajectory. Now you can calculate the slowest speed and check whether jump will still work. You can also design jumps precisely for the certain speed. Not just guessing, but knowing pretty exactly "I have the slope angle at the takeoff X degrees. This means at the speed V it'll give me so much height". You can tweak you trail to be more fun knowing this facts.

[@jfaust97]

That visor has seen better days.... LOL

[@Durwood71]

I was running some errands on my bike once when a man spotted me, asked if I was on a mountain bike, and when I confirmed, he shook his head and said something to the effect of, "You mountain bikers are crazy." As I'm sitting here a week after my latest crash with a sore back and bruised knee, I can't entirely discount his opinion.

[@georgealexanderp]

"instantaneous speed". we're breaking the laws of physics here, man.

[@elephantrockfarm1447]

Love you work! Binge wt hung while work on my bikes in the garage… thanks!

[@purespeedmedia]

fun fact if you press the button on the radar gun once and hold it down for 3 seconds and let go it’ll switch to kph I think. Love you Seth 👍

[@domenfatur2018]

YES NEW VIDEO

[@kaitiller1117]

Seth is one of the most entertaining mtb youtubers

[@Dino-oj2pr]

Seth is definitely THE most entertaining MTB KZbinr. Bet he is top 3 of ALL KZbinrs

[@stone5770]

Change MPH to KPH: While ON press and hold the trigger then press the button under the LCD, and vice versa. I have one of these radar guns I use for dodgeball.

[@benboo6351]

proper Doug vibes at 4:34

[@Stellonier]

Love it, thank you that you do Meter and KMH for the European love it!

[@Jan-Cort]

Once....only once...

[@Stellonier]

@@Jan-Cort true but he tried

[@kshysztof9649]

Yeah! Nice video. Okay, check this out; Compare your climbing speeds, with someone who rides XC. Technical climbs, long but consistent climb. Flat - Comfortable pushing position. Would be nice to see that comprasion, as I don't ride trail, or MTB, or whatever you guys are riding, it's hard to put an etiquette on this. Would love to hear what you think!

[@Nobreakmedia]

Omg I love this, teacher Seth in the HOUSEEEE

[@mrphil2159]

4:34 got a Doug Demuro "This" going on for sure!

[@miniMEGA29]

Most of us have great sense of physics, it's not like we know speeds or angles of jumps but we can feel them and adjust accordingly.

[@comsheperd]

That awesome Industry Nine Hub🤩

[@TheGotoGeek]

As long as you’re converting units, you should list the angles in radians :-).

[@chrisfish5309]

I wish he would go back to Markham Park. We’ve done so much for the trails.

[@faiind]

Fun fact: The GPS system does not tell you the average speed during two points, it actually tells you the "instantaneous" velocity in each of those two points. The GPS uses doppler effect to give out such a precise and quick measurement. The "slow part" of GPS is just your phone that can communicate with the satellite only once per second :)

[@Motoadventurespr]

Very good video. Really like the way you explain things. Keep up

[@rony-g]

I don't know how accurate they are but you can try those magnet things that tell the speed on bicycles

[@Bwopro]

Great vid

[@CantWin4Losing]

I learned I will watch absolutely anything

[@Loepert_]

At first I was really happy as a non American for the conversions but then... they went out the window hahaha better luck next time, I guess that I got some homework for tonight. good video still

[@zp3721]

wow thanks so much for converting like you said you would...

[@RedWingsninetyone]

You mentioned you estimated 14 MPH but actually were clocked at 18 MPH. An interesting note on that is there's a thing called the cosin effect with radars. Radars are most accurate when you're going directly at (or away from) them. That almost never happens and you get a little bit of an angle. It's only measuring how fast you're approaching the radar unit. In other words, you are actually going faster than the readout shows, and how much depends on how much angle you have toward the radar.

[@lucas_z_mtb7031]

Very interesting my g

[@hazelbaumgartner9706]

The physics teacher dig reminded me of one of my favorite jokes. A butcher, a rancher, and a physicist wash up on a desert island. After exploring, they find two cows and a bull are the only meat on the island at all. The butcher says "This is great news! Each of these animals will yield five hundred to eight hundred pounds of meat. At roughly 1,000 calories per pound, that should be enough food to keep us alive for months until we get rescued." "You're missing the bigger picture," the rancher says. "We can breed them and then we'll have an endless supply of veal, plus the milk the cows give. Supplemented with fish and fruit, we could live for years off these three animals." "This is true," the physicist says, "but I'll bet we can do better." The rancher and the butcher look at her and ask "how do we do better than veal and milk?" The physicist draws back, thinks long and hard, and says, "well, let's suppose three spherical cows in a vacuum..."

[@harmik98]

Thank you for straightening the visor

[@USAmtb]

I have speedometer mounted handlebar from cateye and when I was editing footage from thunder bike park, black jump trail and I was able to see the speed around 25mph at takeoff. So I guess my speedometer is pretty accurate.

[@RandysRides]

I'd like a same style vid on control while jumping. How to not loop or dive or freeze up in terror. All I've heard is heels down, stand tall, etc. Is a trampoline the only way to learn air control ?

[@latemhh5577]

That's exactly what i needed

[@Supersloth58]

Does anyone else want Seth to do some brainstorming and episodes with smartereveryday?

[@matt_m126]

At 4:49, did I spot a sticker from Seth from Backyard Trail Builds? Did they do a collab that I missed or is that foreshadowing? Or perhaps just an Easter egg?

[@fintancostello_ok]

It’s like the real life GoPro effect…

[@seanmcadams1216]

1:40 I think Seth accidentally gave us calculus in a nutshell

[@johnjohannesjuan]

5:40 Mechanical Engineer here. Kinda have to agree with that statement. This stuff is way too comlicated for school physics equations. You'd have to solve a multibody dynamic system and even that won't be enough as through pumping or pedalling, the rider is actively able to put energy into the system while at the same time actively changing the center of mass. Plus friction and air resistance and so on.

[@kainpwnsu]

FYI, the Android (and probably iPhone) phone calculator is able to perform conversions for you. Turn the phone sideways to show all the extra buttons and modes.

[@WorldwideDarts]

Once you case a jump and wreck your rear rim you know that you can only go full send mph after that

[@jacobpoucher]

True story

[@tylerdonald2034]

Mr bike hacks, I formally challenge you to a game of B.I.K.E

[@gregschramm8180]

Very cool

[@noahstraub7537]

You need to try ski biking

[@dtolios]

Fun playing with the radar gun, but I am willing to bet that a bike computer with a speed sensor will be at least as accurate, if not more. And you don't need a second person to work it. 🙄

[@johnjohannesjuan]

Well done video! More unit conversion to metric would have been nice though. I guess a large part of a flowy feeling comes from the ideal speed of a trail being somewhat constant.

[@ryan56976]

For reference, my average mtb’s top speed on flat land is about 18mph. Cruising speed is about 12mph.