How fast is a Brompton?

[@Quetzacoatl85]

Wow, what have I stumbled upon here? Expecting a cozy Brompton bike channel made by a friendly elderly couple, proceeds to be an absolutely STELLAR explanation of advanced bicycle riding physics. The friendly and clear narration, the positive yet calm music, the consistent and considerate use of standard units (and their translation), the absolutely mindblowing animation (so clear, so detailed!), all of that in one great package. Rarely have I been this impressed by content on KZbin; thank you so much.

[@2Bikes4Adventure]

If you like this video, feel free to watch our Technical Video Playlist kzbin.info/aero/PLY2cxn6D6SpviTXWZVZiIOiDCgHwEOFgU&si=XBsBd0xS6Hben8X4 PS We are indeed a friendly elderly couple.

[@esesoysho]

super +1 on this, I was incredibly surprised by the quality of this content!

[@shotyaface]

Seriously professional-grade videos. Well done.

[@Chris-xz2il]

As a rider of both, I found this very informative. Thanks! You forgot scenario 3 where the Brompton rider decides they don't feel up to the 60km ride, spends a very efficient 30 seconds folding up their bike and hopping on a train to the destination, and having several celebratory beers and a full course meal before the road cyclist reaches the destination. This is one reason why, although loving my road bike, I'll never get tired of my Brompton!

[@Boub65]

Hahahaha excellent!

[@handsonbrompton7875]

I love this 3rd scenario… 😂🍻

[@whazzat8015]

True appreciation of the speed they are capable of.

[@geraldshields9035]

@クリス Yeah Chris: The thing with a Brompton is it's foldability.

[@MartijnVos]

Yeah, comparing a folding bike to any road or even racing bike, is never going to make the folding bike look good. The big advantage of a folding bike is that you can fold it and take it with you on a train. Bike to the station, hop on a train, and then bike the last mile to your destination. I bet that's going to be a lot faster than any road bike.

[@EverydayCycling]

How can anyone condense so much information in such a pleasant and engaging video, with a perfectly written script and beautiful animations... I am stunned! There's no one else on the face of this planet even attempting to make such informative videos on YT, I'm glad we have the two of you!

[@2Bikes4Adventure]

Funny, my mother was saying the same thing 😀

[@tim2015]

The videos produced by Brilliantbikes are also very informative, with a slightly different but very helpful perspective.

[@JBBell]

Wow, this is a Sheldon Brown level of both very detailed physics information and a presentation that makes it very accessible. Great job!

[@alxie]

^ so much this. Sheldon Brown must be smiling from the unknown place in the universe he inhabits nowadays. Cycle heaven?

[@bmp12]

Wow made me miss Sheldon Brown all of a sudden. He would have had a flourishing KZbin channel transferring all the written articles he wrote to videos.

[@ivanjednobiegowiec7656]

Such a shame Captain Bike is not with us anymore...

[@redstwok1123]

Holy cow, this is the best explanation of bikes on youtube

[@TheAnimejosh]

This was totally not what I expected when I clicked on this video. This was a very well made and very informative video. Hope to see more these kind of videos fro his channel. 👍

[@bisiklettin]

I'm pleaseantly disappointed as well 😊

[@jimmymacdad8194]

I am so absolutely stunned at how amazingly marvelous, informative and just absolutely brilliant your videos are... Someone should be nominating you for an award 🏆🏆 Many many thanks ❤️

[@whazzat8015]

It's the sound track.

[@zaharyaacob]

.

[@user-ot1dv6ri4f]

me too!

[@reptoJane]

I am so going to use this in my Physics class this year! I teach about rolling resistance and aerodynamics, but always in relation to cars. The info graphics and info here are absolutely fantastic. Thank you!

[@2Bikes4Adventure]

Stay tuned, a new “physics lesson” video coming up shortly.

[@alb.2021]

This is how math teachers make learning come alive and relatable to real life.

[@dawnjohnson8739]

No kidding :-). I iNSTANTLY fell asleep :-)

[@sepg5084]

Doesn't matter, some people hate math regardless. And liking math is regarded as being a nerd: pop culture hates needs and celebrates anti-intellectualism

[@notundermywatch3163]

It's called physics

[@keaixiaomeinv]

I did not expect this when clicking on the video thumbnail. Needless to say, the video completely blew me away, too!

[@Thinkrock]

This video is absolutely incredible! Thank you so much for producing this kind of content.

[@graemehill]

Holy moly! I'm really into this stuff inside the competitive cycling world and I watch all the youtube channels that are for "serious" or more racing oriented people and this content is 1000 times better presented, more useful, and more scientific than what I normally come across. I also learned a few new things. Amazing video!

[@georgemellen6922]

I've been a lifelong road bike rider, primarily on bikes with 700c tires. I bought a Brompton about 6 months ago due to 1) desire to travel by air and bring my bike with me, and 2) many years of arthritis in my hands has finally convinced me to move to a less painful riding position of the Brompton, which requires less weight on my hands. I love my Brompton more each time I ride it, due in part to so much less hand pain but also because I just find it quirky and also find that I'm riding a bit slower and just enjoying the slower more deliberate pace and the curious looks of the people I pass. I've wondered what the actual differences were in speed and performance compared to my very fast carbon road bikes, and this video has answered those questions with remarkable accuracy. Thanks so much for making these great videos.

[@2Bikes4Adventure]

Hopefully you will soon have the chance to travel by air as well. Being able to cycle to/from airports is an added bonus over full size bikes.

[@zatoichi-e4r]

fast riding missed a lot of interesting and beautiful things on the path wev'e past...

[@paulfaulkner6299]

What an educational video. I don't ride a Brompton or any other fold away bike but I do ride a flat handle-barred so called hy-brid. I have 3 cranks and 7 speeds at the back being 28, 38 & 48 over 34, 24, 21, 18, 15, 13 & 11. I know intuitively that I will always lose out to "racers" because of their aerodynamics - but i just wanted to say that even though I don't have either of the 2 bike types mentioned in the video, I learned something. The most important thing is to get a bike you like and enjoy riding it. My friends keep bugging me to buy a racer - but I just prefer "sit up and beg" over bending forwards for hours looking through my eyebrows! The main thing is that cycling is healthy and good for the environment. Happy safe cycling everyone. Have a great Xmas & 2022!

[@2Bikes4Adventure]

Hi Paul. The important is to enjoy the freedom it provides, what ever shape or form it has.

[@pokie0622]

This was the most detailed video on this subject i have seen. Well done

[@jeffyen]

My goodness, this is absolutely stunning stuff. Production value!

[@terryc8164]

What a brilliant piece of work. There has long been the "Bromptons are dead slow " type comments, but your calculations stack up with what I have found in practice. My P6R and old 1980s 5 speed "racer" show differences in average speed in the 1.5 to 2.0 mph range. Pretty close to your calculations. I must add though it depends greatly on the rider, when commuting on my Brompton I used to enjoy passing the lycra clad fancy road bike riders and wishing them good morning etc 😁 Can't do that anymore sadly!!!

[@2Bikes4Adventure]

Hi Terry. Older roadies are probably slower too by now.

[@paullevy-adophy9198]

Wiw! 😮 I think I have just arrived at "explanation heaven"! ❤️ That has got to be the most wonderfully presented explaination on this topic that I have ever seen (and I have seen LOTS!). The slow pace of transition from one frame to the next, and the moderate pace and the very clear diction of the narrator meant that I understood everything without having rewind or replay numerous time. Added to that was the calming backing track and the dulcet tones of the narrator. A joy! ❤️ I really do think the narrator would make a great living doing voice-overs or making instructional videos for a variety of clients. Awesome. Thanks. This video was so good that I have now subscribed to this channel just so I can watch more videos (no matter what the topic is! 🙂👍)

[@2Bikes4Adventure]

Thank you, the same voice narrates our complete video library, for your listening pleasure.

[@r.d.7094]

I never comment videos, but this such a good video. As an mechanical engineer it was pure fun to watch. Thanks for this high quality, superb video which is so on point. Never boring, no bla bla and perfectly reseachered and explained.

[@2Bikes4Adventure]

The following two videos may appeal to your MechEng background: Brompton Acceleration - Myth or Reality? kzbin.info/www/bejne/qaWkY518q5p6oc0 Downhill with a Brompton [safely] kzbin.info/www/bejne/gne9hWyElt1_rqM

[@dysfunctionalisme]

I clicked on this video hoping to learn something yes...but I wasn't expecting was a whole ass maths lecture lol. In all honesty, thank you for this insightful video. Safe ride everyone!

[@hackdaniels7253]

Fascinating. I recently did the London to Brighton (80km roughty) on a Brompton (M6L superlight - I removed the mudguards!) and did it in 5 hours, including about an hour's aggregated rest stops. I hadn't trained particularly - I was cycling to work a few times a week (20km round trip). I found I easily beat many people on road bikes - but was beaten by many people riding mountain bikes. What I'm saying is - it's all about the engine. And, yes - I hope to do the ride next year, and set a much better time.

[@hackdaniels7253]

Should just add: The fact that I have watched this brilliant video and *still* have no clue how a Sturmey Archer hub really works proves to me that I never ever will!

[@2Bikes4Adventure]

@hackdaniels7253 We did Newhaven-Brighton-London on our Bromptons a few years back (with an overnight in Crawley). Needless to say, we were slower than roadies (all about engines!) As for the SA hub, just need to remember gear 2 is the most efficient.

[@mlee6050]

Yeah I had a few mountain bikes over take me but in Brighton they ignore red lights that we was told to listen to, 56 miles in 2018 or 2019 and I only cycle 3 miles about 4 times a week and did 3 hours 40 minutes on my 6.8kg road bike, I have made it 6.7kg now, note that it not counting water weight and I pushed as hard as can I struggled on ditching beacon but no stops, a guy said I had a flat but I thought was someone else, anyway what could I of done? No pump so went down the hill at like 43mph with a flat front tyre, joy of tubular as glue on

[@mlee6050]

@@hackdaniels7253 don't worry me too! I also can do everything to build a bike and can't do those internal hub gears So know I call what I do bike builds and most KZbin I view as fake or nearly a bike build since unlike them I build the wheels for my bikes too

[@stevethecat9194]

Brilliantly explained. Both the bicycle enthusiast and physics teacher were completely engaged. Thanks.

[@guycharron11]

I've seen dozens of videos explaining all of this in one form or another, but this was the best and clearest explanation I have ever seen. Thank you for putting this together. Your teaching and illustrating skills are amazing.

[@rasmus9311]

Wow this is the most detailed and well explained video I have seen on bicycle power efficiency, very impressed and unexpected. Honestly speechless.

[@2Bikes4Adventure]

Stay tuned for more (and/or watch some of our previous Brompton-related technical videos)

[@ABDLLHSDDQI]

Exceptionally informative. One of my favorite videos on KZbin ever, saying that as an engineer who's been watching a lot of informative engineering videos since years.

[@2Bikes4Adventure]

Stay tuned, more technical videos to come.

[@Gromcan]

The way author expresses with infographics is amazing! Bravo. I wish my teachers did the same for students in my uni

[@boatman222345]

Easily one of the best explanations of the factors affecting bicycle performance I've ever seen! Five thumbs up! And thanks!

[@2Bikes4Adventure]

Stay tuned, more to come shortly

[@maievshinoda9442]

The best tire review for 16 349 . Thanks !

[@peterforde9513]

Wow, love this video. Now I know why I prefer to tour on my Brompton; more time to smell the roses.

[@winngh]

Presentation is beyond words. I owned a Brompton years ago (i loved hiw u was abe to get on and off easily), I currently own a mountain and roadbike ...this is really informative.

[@2Bikes4Adventure]

Time for a Brompton ride once again?

[@relativityboy]

I wish there was a "super thumbs up" button! Very informative. Thank you!

[@JeanPierre-980]

Wouahhhh !!!! Superbe vidéo très enrichissante et impécablement présentée. un grand MERCI !!!

[@2Bikes4Adventure]

Nous vous invitons à jeter un coup d’oeil à nos autres vidéos (ex.: kzbin.info/www/bejne/jKi1g2aLl9Vjercsi=8VsZYBMPUBztC4uN )

[@joshb7415]

People like you are why we have come so far as humanity, thanks

[@cmchenth]

Even a road bike rider could be benefitted by this video,awesome job!

[@AndrewTiedeplus]

This is shockingly well put together

[@cwartcam]

Marvellous work, thank you! In practice I find my Brompton pretty similar to my road bike in terms of speed, maybe because I normally have the aerodynamic load of panniers on the latter, as opposed to a rucksack in my slipstream on the Brompton. I proudly remember one occasion when riding my Brompton, I found myself with a couple of club road bike riders slipstreaming me :-). I was fortunate enough to compete in the Brompton World Championship once, too -- and that felt like pretty scary full-on bike racing, with welcome straw bales on the corner obstacles. Thank goodness the tarmac was dry at least, as cornering traction is not a Brompton forte...

[@ganeshs5508]

Wow, wonderful explanation Keep up the Good work 🎉🎉 Subscribed 👍

[@RobWhittlestone]

What an EXCELLENT video! EXCELLENT graphics, EXCELLENT physics, beautifully illustrated and narrated. And about 500% better than I was expecting! Thank you so much! And a special bonus someone who can actually pronounce derailleur in French! Now that Brompton has a 4-speed derailleur we lose the friendly Sturmey-Archer 2nd gear, I think. All the best, Rob in Switzerland

[@2Bikes4Adventure]

Hi Rob. The 4speed derailleur (insert french pronunciation here) will be more efficient and lighter than the Sturmey-Archer (for a similar gear range), but at a substantial increase in cost. We will keep our 6 speed for now.

[@pixfirewall]

This is the best explanation and with a very good use of graphics to make understanding easy.

[@lilelbee423]

Wow I clicked this video out of curiosity and came away genuinely surprised and pleased by how informative it is! Thank you! Learned a good deal about bicycle mechanics

[@2Bikes4Adventure]

Stay tuned for more to come.

[@fender1000100]

The most informative and enjoyable bike channel I've ever found on youtube. This upload is simply amazing. Subbed...

[@frannelk]

Wow, some serious topic, should be called : The science of cycling. KUDOS to you for that beautiful video edition.

[@NoZenith]

I love how informative and yet accessible you make your videos with the visuals and the thorough explanations. Are you an engineer? Thank you Pam, you're amazing!

[@2Bikes4Adventure]

Pam is a technical writer and Gilbert is an engineer, a great team since 1993.

[@NoZenith]

@@2Bikes4Adventure amazing, phenomenal, Immaculate team! Thank you both very much for your efforts in making this information accessible to others.

[@delhoghond]

I love my road bike and am considering buying a Brompton to keep in the boot of my car for shorter journeys when I'm away. I'm surprised by quite how efficient the Brompton is. Fanastic video, really professional.

[@2Bikes4Adventure]

A Brompton is like a quality pocket knife. It may not be as ergonomic or cut as well as a chef kitchen knife, but you are more likely to have it next to you when the need arise.

[@Ontheroadtourism]

My son who rides a SL6 S works goes out for a cycle and comes back looking like he needs to go to The ICU. I go out on my Brompton and do the same miles all be it slower, but when I get home I carry on cooking dinner feeling energised and most importantly with a smile on my face. As he gets older he will understand the pleasure of the journey and and sometimes slower is better.

[@fuwafuwadance]

this is the most educational video about bicycle that i found on the internet, thanks for producing this kind of content

[@stf0146]

The best video on the topic I've seen so far. Thank you!

[@ottorocket03]

Amazing video and explanation! More than what i expected for sure! Thanks for the effort and beautiful illustrations

[@gam1471]

A very interesting presentation, thank you. I've been cycling for over 60 years, and have never got on with straight handlebars, particularly on hills. I've noticed that casual cyclists are unwilling to embrace the idea of drop-type handlebars - I've never made a convert!

[@ThisTimeTheWorld]

I like dutch style bars. Like drops but higher up. They look great and make cornering at speed a lot more fun

[@itsame1277]

Very comprehensive explanation of which I only understood a small amount of the mechanics and maths!

[@2Bikes4Adventure]

Luckily, there are no exam at the end.

[@Ellipsis115]

I did not expect such a scientific video, THANK YOU! I learnt a lot The references given have earned you a fan in me as I look forward to looking at all these sources in your various videos, however I couldnt find things like 8:37 whether this was all about frontal area which I could probably work out with a friend taking pictures on a camera and maybe a measuring tape or if it was about drag from air tunnels based off of olympians or such.

[@2Bikes4Adventure]

Both the drag coefficient (Cd) and the frontal area (A) will affect the cyclist aerodynamic drag. While it could be relatively easy to evaluate the difference in frontal area between a Brompton and a road bike (using picture pixel-count or even a measuring tape), evaluating the respective Cd would likely require a more controlled environment (like the wind tunnel you suggested). After measurement and research (especially as related to the wheel size effect on drag, ref link.springer.com/article/10.1007/s12283-021-00341-6 ), and applying those corrections to the following generally accepted CdA: Tops: ..408 (100%) Hoods: .324 (79.4%) Drops: .307 (75%) Aero: .2914 (71.4%), we arrived at the results presented in the video.

[@JurisKankalis]

What a great piece of graphical explanation! THanks! Been riding MTBs for decades - and in the recent years advocating against the recently popular 1x12 systems, mainly because shifting upwards under heavy load (when experiencing sudden steep uphill) is nearly impossible, while dropping a cog or two by the front derailluer is almost instant and effortless... Another point being - if I have the biggest sprocket in front at 44 and smallest at rear at 11 (golden standard in MTB for decades up to recently), I'm still limited at max speed slightly - while in my 29 inch MTB I have 3x10 with 48 and 11, which means I can overtake almost anyone on the road... Which is perfect, but bikes (especially frames) like that are being phased out, esp. in higher end stuff. The problem is new bikes don't even allow to have several sprockets in front, relying solely on smth. like a 36 or 39 max at front and going down to 10 in the back... Which kinda seems all kinds of messed up. IN addition to that, as I see now in the video, there's more friction, also, in smaller sprockets, which proves my point - don't change what's been working since Gary Fisher. So they better watch out, those big manufacturers - I got the facts now! Nah but seriously - not being able to buy the sprocket combination I want for my own money bums me out. Greetings from Latvia - you've got yourself a new subscriber.

[@jacek5894]

I can nothing but agree with you. I have 2 bikes - a Specialized hardtail with a 3x9 and a full sus Scott with 1x12. On the hardtail, I can pedal untill around 60 kph, on the full sus I can barely pedal above 40. I know, full sus bikes aren't made for going fast on a road, but my point about the drivetrain still stands. 1x systems are useful for riding the trails as they are simpler, however they make no sense on bikes made for easier terrain. To add on top of that, they are much more costly, both to buy and to maintain. By the way, could you recommend an affordable 29" tire to put on my hardtail? I have a Schwalbe Thunder Burt on my rear - it works great, I gained a couple extra kph just by upgrading the tire. Now my front tire is pretty worn so I'm going to need to get a new one but would like something cheaper (the Thunder Burt was like 45€) - do you have any ideas?

[@Natuh21]

In a good portuguese " Esse canal é muito FODA! Its amazing how I cannot stop finding great subject videos here, OMG! Plz tell me both of you where like teachers of a journalism university cos the quality of the information is absurd above the level of the rest of the youtube videos. Hope I could get my self understood as not an english speaker, Love from Brazil

[@2Bikes4Adventure]

Obrigado! Engineer is the right answer (in aerospace industry).

[@supeinjinsan]

So much effort behind this video, thank you for your hard work!! Still the comfort and the convenience of the Brompton seems like a fair trade-off.

[@alxie]

This video is a gem. Very well researched and a master class on what influences speed on whichever bicycle. Very well done!

[@sven_ftw]

What a delightful instruction and diagram set. Kudos!

[@donaldoconnor7689]

Nifty, I am a die hard roadie but i respect the small bike world even if I choose something more suited to my strength.

[@All4Grogg]

Very, very well presented! It's hard to convey the differences in a way that is understandable, realistically that brompton rider could arrive with their road bike friend just by staying on their wheel, thus spending significantly less effort entirely.

[@2Bikes4Adventure]

Yes, a reasonably fit rider with a properly geared Brompton would most likely be able to “draft” a road bike of similar price.

[@AethericEchoes]

I've pondered this question for years. Incredibly informative. Thank you. But there's one variable you overlooked. Since the Brompton folds, you will sometimes be able to ride when you would otherwise have to walk. In such a case, the Brompton will be much faster!

[@johnwight6041]

This is the most awesome video I’ve seen on this

[@grahamatsea3575]

What an excellent and very understandable explanation on the different efficiencies of both bikes. Well presented, thank you.

[@2musiclover534]

Thanks. Very informative. The difference is less than I anticipated. There are other high performance folders such as the Canadian made Helix. It has 24" tires but folds remarkably compact and is much closer to a full sized bike in performance.

[@make.and.believe]

Wow this was wonderfully informative. Way beyond what I expected when clicking on the vid. I ride a Mountain Bike primarily for cardio calorie burn, it's better for my purposes than a road bike because about 1/4 of my daily circuit is off of the paved roads. I have a salvaged BMX that I use for my backup bike (when the primary bike is down with a flat, etc. and I don't have time to fix it before my riding window) - and I'm planning to replace my BMX with a Brompton style folding ebike, so was doing some research on how they ride. This was a great vid, thanks for diving deep in your analysis. Have an awesome weekend!

[@JohnUyArts]

i know nothing aboutthe channel, just watched first time, SOOO VERY INFROMATIVE AND VERY GEEKY NERDY I DUNNO!!! SUBSCRIBED INSTANTLY :D

[@ClanMacqueen]

Very educational - beautifully explained physics! I rode my Brompton in the 100 mile RideLondon sportive last month with 20,000 other cyclists. The ability to draft other riders mostly negated the wind resistance penalty of the Brompton and I managed to keep pace with the road bikes, much to their surprise! Great little bikes.

[@2Bikes4Adventure]

The Brompton lower profile helps when drafting full size road bikes. With proper gearing, you can indeed surprise them, but stay in the middle of the pack (i.e, resist the urge to take the lead :-)

[@batlin]

Excellent and unexpectedly detailed but comprehensible explanation!

[@remote3652]

wow VERY well done! I'm picking up my first Brompton in few days and I'm very excited!

[@2Bikes4Adventure]

Congratulations and enjoy your first Brompton (you can even have a celebratory beer).

[@remote3652]

@@2Bikes4Adventure thanks will do!

[@madiantin]

I'm always so happy to see your videos! They're so detailed, well researched, and your graphics are excellent. I was watching your video and my husband overheard and was immediately fascinated. He's an engineer so it totally appealed to him. =)

[@2Bikes4Adventure]

Graphs and equations: basic food group for engineers

[@Gregorydyesmith]

Excellent work. Thanks for a great explanation of why I prefer my road bike with panniers over my Brompton in even short commutes to work- except for the cool factor in riding the Brompton, which is worth several km per hour!

[@harrisonswyter4601]

This is everything I want in a bicycle video.

[@linusloo]

Learned so much from this video. Thanks for putting this together.

[@jonathanabelheim5932]

This is an amazingly well structured and informative video. My mind is blown - thank you!

[@IbraHimself]

I stumbled upon this video after viewing GCN's Brompton vs road bike video. Thank you very much for this well montaged explanatory video.

[@2Bikes4Adventure]

Too bad GCN’s video wasn’t on a flat road (could have been used to confirm (or disprove) our calculation).

[@SingaporeUntold]

@@2Bikes4Adventure I think no challenge as the road bike will obtain a faster top speed

[@888SpinR]

Incredibly well done video, even my half-asleep brain can understand it! I've noticed barely any difference to my commute time or tiredness so I'm glad to know why! Of course what my hybrid lacks in foldability, it more than makes up for it in comfort and stopping power (not to mention it costs less than a third of the price!).

[@Ozz527]

Fantastic video packed full of great information. Thank you!

[@Swalkervf1s]

wow, this is a master degree essay, thanks a lot

[@kkaupapa5469]

Great, very professional information! I appreciate it! 👍👍👍 I own a Bromton and now I am taking a break while riding a road bike. Though it is slower, I find Bromton has its own merits and unique fun that road bikes cannot give. Speed is not the only purpose of riding, is it?

[@jamma246]

What an amazing video. No opinions, no conjecture. Just solid fact-based discussion, methods carefully explained and presented in a totally clear way with extremely helpful graphics. Just awesome. I love my Brompton and currently don't have a roadbike. This almost makes me feel like I don't need one. Between a 10-15% gain in speed isn't too relevant to me, I'm not competing in races (and it's so fun to overtake MAMILs on a Brompton, you sometimes get funny looks!).

[@LydellAaron]

This got surprisingly technical. Refreshing. I learned.

[@2Bikes4Adventure]

@LydellAaron, this one on Brompton Acceleration does contain some technical content as well.

[@natjes6017]

Wow, this was an unexpected pleasure. Great video!

[@Mr89Falcon]

This is just fantastic! Love how you break it down into straight physics. Thanks for this amazing analysis...has applications to a lot of types of riding!

[@ClownAl3n]

I love these detailed and informative videos. I wish school was taught like this in ALL Subjects and than maybe I would have gotten a "B" in some of my classes 🙄. Man school blows.

[@2Bikes4Adventure]

Stay tuned for more like it (no need to stay up until 3am however)

[@voilier3000]

I compared my speed when going to work and back with my Brompton and I had an average of around 2 km/h slower with my Brompton compared to my road bike. I would suspect it would be greater with a great wind since my position is more aerodynamic on my road bike. I will certainly follow your advice, and use the second gear of my internal hub more often. Nice technical analysis, well illustrated with excellent comments. Keep up the good work !

[@sophocles1198]

I do not understand your first sentence.

[@2Bikes4Adventure]

@sophocles1198: 2 km/h difference between both bike types we would assume?

[@philthewriter]

Lot of thought gone into this!! I just took my two bikes on a 10-mile loop making a similar effort for both rides. 14.5mph on the Brompton, 17.5mph on the road bike, about 8 minutes difference. Lot harder to get my road bike in the car afterwards though!

[@gclh22]

This some of the best analysis I have seen of cycling on KZbin regardless of the "expert" making the video or type of cycling. One other factor of a Brompton ride is the suspension system/ hinge, lots and lots of flex in that area of the bike meaning lots of effort lost also. But they are still unchallenged in the folding/ storing of a bicycle. There are other folding bikes availble that should not be dismissed by consumers. Dahon are very good, lighter and quicker but no where near as well marketed and not London made and don't fold as well. But would be nice to see their ride quality analysed like this

[@2Bikes4Adventure]

You are right about the frame flex (and the suspension in particular). Additional energy lost would be noticeable when high torque is applied to the bottom bracket (high speed in our video). We own a Dahon Mariner D8, it would be interesting to do some comparison against the Brompton. A subject for a future video.

[@barrydonaldson]

Fantastic graphics. Brilliantly researched and presented. Well done!

[@markovermeer1394]

I use the larger 54T crank wheel, because I like a bit more push: I hardly every use the lower gears except up-hill. Cruising about 21km/h for longer trips, 28km/h for 15 minutes in town. For in-town use, there is no measurable loss in speed when compared to city bikes. However: as advantage I usuall park my bike dry, under the coat rack in bars and restaurants.

[@andymonis5368]

Very informative and well put together

[@Rcck.7282]

this is comprehensive and technical analysis videos. Could you do wiht other type of bikes as well like MTB with road tires aero bar, MTB with knobby tires, gravel bike, road bike, etc?

[@fabiopunk1661]

excellent analysis - even if the actual numbers depend on the modeling/ simulation tools of which we have no insight and just have to trust. they question however is ill posed. If I use a foldable bike it is because I need to fold it - at some point during the trip. So, the comment made by Chris below where he suggests the foldable bike rider stops, takes a train, has a meal before the road bike rider arrives, is very realistic. If I do not need to fold my bike during the trip, there is no question I would hop on my road bike - which, thanks to its larger wheels and different geometry, offers better stability and smoother rides.

[@2Bikes4Adventure]

Hi Fabio, This is the model we used: www.researchgate.net/publication/279937184_Validation_of_a_Mathematical_Model_for_Road_Cycling_Power If you have experience with a better one, we will be happy to experiment with it.

[@viktor.tsonev]

wow, amazing presentation and analysis

[@bromptinowner763]

My brompton is as fast as i want to make it ! Interesting info as always x!

[@jonathanleach3914]

Excellent, thank you. On the flat, I can usually keep up with a casual road biker. It is up hills that I fall behind. I consider this to be due to the difference in wheel size offering different momentum, with the smaller wheels size having less....thanks

[@letsif]

Wheel size has less to do with speed - either up, down, or on flat. The only possible advantage is small size wheel weight advantage. The wheels just go around more often to achieve the same speed. The important factors are gearing and the rider. Weight and aerodynamics come in next. These are just general physical dynamics. It can get even more nuanced the more anal we are.

[@kamalhm-dev]

Superb video. I'll comment and like hoping for this to trending. Keep it up!

[@2Bikes4Adventure]

Thanks Kamal, it seems to be working.

[@danhoang6335]

Very informative and fairly accurate in real life. I thought that I could ride much faster on my road bike than my Brompton but on average I was gaining only 10-15% while riding a road bike compare to Brompton on the same courses.

[@whazzat8015]

Wind, tires, position. I use the big bikes more if distance is an issue, as gears , weight and tires make a big difference in fatigue. And of course if road conditions are harsh

[@davidhunternyc1]

This was awesome. I'll have to revisit this video over and over again. So much to learn. Brompton's seem fun but not efficient.

[@2Bikes4Adventure]

Folding bikes are indeed a compromise, efficiency is not their main attribute.

[@debruce]

wow, this is mindblowing analysis! amazing!

[@RakeshBalakrishnan]

could you do similar comparison for tilt 120?

[@2Bikes4Adventure]

We haven’t had the chance to try a Decathlon bicycle yet. If the occasion presents itself, we will certainly share our findings.

[@sbsb4995]

Fantastic video. You are a great teacher.

[@Shindinru]

This very well done and a clear explanation. Having said that the numbers used are under "lab" conditions. The chain line efficiency discussed is the maximum efficiency that you could expect. Actual efficiency drops quickly under real world conditions. The largest influence on drive line efficiency is chain tension followed by cog size. As the chain stretches, gets dirty and the cogs wear those numbers steadily drop usually ending in the low to mid 80's or even high 70's at the time of scheduled replacement. The tire rolling resistance is the same in that the numbers used are lab conditions and are only true for professional level indoor velodrome tracks where tire deformation is a non-issue. For real world surfaces, like asphalt, a wider tire (more air volume) with a lower pressure is more efficient.

[@2Bikes4Adventure]

Hi Shindinru, Yes, we assumed both bikes’ chaindrive were clean and in good condition. Would be unfair to have one bike with a dirty and stretched chain while the other had a new and clean one (The effect of dirt/stretch could make an interesting video). Lower pressure/wider tire can indeed provide improved rolling resistance in many situations (ref Frank Berto’s 15% deflection rule). This rule obviously applies to both bikes. Both being equipped with the same tire/pressure (35mm Schwalbe Racer) in this study, the main differentiator will be tire diameter. The relationship mentioned in the video was taken here: Bicycling Science, Chap 6 Rolling: Tires and bearings, MIT Press 2020, Figure 6-2. For more details, the book refers to this (German) study www.forschungsbuero.de/PV32_S15_19.pdf .The analysis was done at various pressure (3 to 7 bars/44 to 100 PSI) with various tire sizes and, no, not in a velodrome.