Enter I just turned 60 and even though my joints are stiffer than when I was 20, I am not going any faster😜

300w is really not the best wattage to test this. The reason us sprinters and elite riders need stiff carbon shoes is because at high wattage, we lose a lot of power out of those nylon shoes. Then, they actually feel like crap too. The flex in them feels horrible at decent power. Then consider that we hit 2000+ watts in our sprints.... those nylon shoes would actually hurt our feet tendons and muscles at that wattage. That is why the number one shoe in track cycling is BONT, I have 4 pairs of them for that reason and I’m not even a fan of the company. I just need them.

I've had tons of road shoes. From unreal stiffness (Bont carbi) to flexy (shimano low end) to midrange specialized. I track what shoes I wear on my PRs/KOMs in Strava and notice no correlation between shoes and performance. My favorite are my specialized carbon which have the least stiff carbon soles in specializes lineup. Apparently these are 8.5 on their stiffness index vs a max of 12. I find the slight give helps greatly with comfort. Bont's are so stiff I have no sense of the pedal and the flexy shimano's are so flexy that I can feel the pedal through the sole.

14:31 the stiffer it is, the easier it is to enter

"ENTER" Wow, surprising information. Most interesting. I've found that the lighter the shoe the more I like it. I don't think my performance is improved, but having super light shoes, pedals, and crank set helps me get to the top of a challenging climb feeling strong and ready for the next one.

Enter! Yes, stiffer shoe makes walking less comfortable. But when deciding before my ride on what shoes to wear (i.e. how much I will be walking, is it workout or tourism) is not deliberation on “more or less stiff” but “SPD or Look cleats”. Very good vid‼️

ENTER: You and Hambini are bad news for marketing teams around the cycling world, I just hope I knew half of the information before I spent my hard earned money on sudo science

Thanks coach Alex, I've been eagerly awaiting this video. You've covered a lot, I think there's a few factors that can't be measured ie: clumsiness without a cleat, psychological boost from top notch gear, obviously comfort that also aids in the former. I rode almost 2 years on a giro rumble touring shoe, walkable, stiff rear but the front flexes at the ball of the foot and rubber is heavier than carbon. Recently I purchased the giro empire acc. carbon road shoe. Personally I think when you factor in the above plus what you've measured it's probably more like 7-10 watts, or maybe it's less but you can sustain them a few minutes longer (fresher post ride) Point is I think it's the real world randoms that factor a lot of the gains that can't be measured. P. S. the proper arch supports and insoles made the world of difference in foot / ankle alignment and eliminated all knee pain, something to note for sure.

Enter. Thanks. My reason for stiffer soles has been comfort on long rides and especially racing when I'm putting down higher wattage. For me this has been especially true for MTB with the smaller pressure area at the cleat. With some painful experiences I now only buy carbon soles for MTB.

Enter Got to admit, my last pair of cycling shoes were a carbon sole, but I didn't pick them due to "stiffness", but due to the fact they were on a sale, and looked pretty nice (in my eyes anyway).

Enter You're the researcher we need, not the one we deserve.

Enter Interesting piece. I’d like to see a video looking at power transfer through different fore and aft clear position. 😊

This video has really helped me decide between a $170 and a $350 pair of shoes.

Me: All i need is a pair that is comfort Also me: That looks stiffer Also me2: That looks beautiful

Finally some common sense. Enter

Ok this may be a little late, but here is my comment. Having a soft sole is somewhat analogous to having rubber bands attached to your feet. If you are a sprinter and you need that power transfer you do not want to be working on a trampoline. Inevitably power in equals power out but there is a connection between you and the bike that is necessary for confidence. I would suggest choosing the right pedal with the right stiffness that works for you.

Enter Wear what’s comfortable and not bow to peer pressure, or hype

3:33 i had that brown shoes, it was comfort and good for low temperatures because was wide and i could put 2-3 socks on foot

I have an older S-Works carbon shoe I picked up when the new model came out. Super stiff. I just love it.

ENTER: The most important thing is fit in shoes and placement of the cleat on clipless shoes. If you have a super stupid expensive shoe and it hurts your damn feet and not setup properly then what is the point, Right? If you are not a professional, or competitive rider I would say go with comfort over stiffness any day.

For big watts, for example on TT or uphills standing, helps moving the cleats towards the heel and then the stiff carbon sole really helps - just imagine that nobody is making squats with heels not touching the ground. Not to mention that with top shoes and top cleats (eg Sh sphyre with Sh Dura ace cleats) the stack hight is the smallest and the aero advantages are worth as well.

i recall when carbon first came into shoes and it did take the muscles in the foot some time to adapt to, but for certain they beat your feet up over long distance, which is why sidis have cork next to the carbon and so soften the impact and also they don't make their shoes over stiff....you definately can't put out as much power with fatigued and aching feet so readily. For real long distance I prefer nylon soles (enter)

Enter Well that's going to change my outlook when buying shoes next, cheers buddy 👍

Enter I come from a science background. Couldn't agree with you more on this one!

Enter I'm still in the 'better power transfer' camp on this one. The argument that the flex doesn't matter because all of the cyclists' power is on one point is like imagining that we have pegs for feet. Our feet compress, flex, and bend outside of that power point and flexing the shoe consumes energy that is better directed onto the pedal. The energy that goes into that flex doesn't simply 'bounce back' into the pedal. I know because I've cracked 2 specialized soles this year alongside the cleat. I upgraded to a stiffness level 9 and I'm no longer wasting energy on the destruction of my shoes.

Definitely comfort is the priority, but I'm always wondering what about the aerodinamics of the upper part of the shoes?! Like your chanal Alex!

Another great video shoe manufacturers don't want us to watch. I've been wearing a Mavic with a full carbon sole for a couple of years and now it's time to replace it I will definitely not go just for the most expensive full carbon anymore, thanks to you! Thanks for saving me at least 100 Euros. Enter

I would confirm that. Because i did mainly alpine single trails i uses kind of traking shoes over years. I never had the feelings of power loses. With spikes almost a 3/4 stroke is possible as well. Changet to to road set up last season and was a bit of a challence at the beginning. I gues it comes down to what you are used to.

I wear hiking sandals on my hybrid and carbon soled shoes on my road bike. There is a huge difference in think.

It's not necessarily the sole, but high-end shoes have also better fitting designs and material choices elsewhere in the shoe. Less shaking or foot movement within the shoe = better power transfer?

sole is important only over pedal, rest of sole is waste, just to protect foot, i remember when carbon sole appeared in1995/6, only benefit was from shoe mass reduction

Very interesting. Comfort maybe y best reason. Summer of 2018 I finally switched to clipless peddles. I have a real issue with a bunion on my right foot and fallen arches. So it sounds like a better shoe and arch supports may be worthwhile for me, may not too. The goal would be to improve the pressure distribution. Thank You. Enter.

Alex, Thanks for your well made videos and trying to bring some science into cycling! I have some questions for you about this video: 1. Wouldn't any energy coming back from the shoe actually be released in the pedal upstroke and therefore be of little to no use? 2. I looked at the paper you cited for the energy loss data and couldn't find anything about energy loss, only about the distribution of pressure. Could you in the future maybe post a screenshot of where exactly you get the data from? 3. The last study you cite compares TORSIONALLY flexible shoes to stiff shoes. I don't think that the results of this study can be applied to the question we're actually looking at. What do you think? Caspar

Enter into the enjoyment of not spending big bucks on cycling shoes. I'm a cheap Charlie and normally buy what's on sale, so I feel relieved that I haven't been cheating myself power wise by my thriftiness. 😉

ENTER. Very interesting. Bought into the stiffest shoe give better power transfer idea. Have S-Works 7’s. They are the most comfortable shoe I have to be fair though.

Enter love these videos! It's like an oasis to have some science backed advice in cycling.

Enter: a compelling argument. Think this summarises the whole bike market with mid tier items being perfectly adequate. And yet I still find myself trying to justify the price tags on top end kit.

When a sole goes up to 11, it just means it's 1 louder.

Your power goes through the ball of your foot where there should be zero flex.

Enter so I can avoid nightmares on wax 😂😂 I also agree with the point below that doing the test on the shoes upside down doesn’t make sense. It’s well known that carbon can be laid up to resist flex in one way and not another so you can’t really say that flex would be resisted equally both ways without doing the actual test and showing it here. For example imagine you had the sole made up of equilateral triangles all laid with a flat edge parallel. This would mean in one direction, flex would be essentially limitless, whilst in the other as soon as the triangles met, they would not flex anymore. This would allow you to make that part lighter, flex in one way a lot, and flex in the other a little allowing comfort, stiffness and light weight all in one. This is done at the molecular level in carbon and could be done here so you’d need to do and show the test to know

Enter I noticed a huge difference in stiffness going from cheap carbon soled DHB Aeron shoes to my super expensive carbon soled Bontrager XXX shoes. Maybe because I can tell they are stiffer, I trick myself into riding harder... thus, going faster lol.

Increased comfort with stiffer shoes. I had mid level fiberglass soles, and after 4 hours, the bottoms of my feet were on fire. I would have to back off. The shoes I wear now, are much much stiffer carbon sole S Works , and so far so good have ridden 6-7 hours without foot pain. So, yes, added foot stiffness and lightness can increase your overal power if you feet are more comfortable. That is what I am finding. However, my ass and neck tell a different story.

ENTER: GREAT VIDEO, WILL DEF. CHANGE HOW I PURCHASE MY NEXT PAIR OF SHOES.

Yes obviously ultra-stiff soles don't allow feeling thru the sole but, if you want out&out performance: you need them.. When I rode competitively I'd have lost out big time, that said, fit of the shoe is the major factor and theirs still development that can be done in this area as manufacturers are still making very narrow shoes and they're only good for 50% of people!

For me Carbon soles are the reson I'm still cycling. I can ride all day, thats if the shoes have a proper arch suport. My CX shoes are stiff and I have no problem walking with them

Enter. I got my expensive carbon sole shoes for the weight reduction. I didn't think that power transfer would be that significant as I'm generally putting my power through the ball of my foot where the pedal is anyway.

Enter Now I'm disappointed knowing this. Just bought a stiff cycling shoes expecting it will make a lot of improvement compare to my previous shoes

ENTER So glad I have never coughed up more than 100 sheets on Carlos Fandango super shoes. Bont sell a decent pair for triathlon for around £50 that have carbon soles and can be heated and shaped to your foot. Works for me!

I would like to see you apply a "sprinting load" to the shoe, eg. 300kg, mainly to see how bad the rubber soles would be. Good to know to science though. Enter !

I had basic sidi with nylon soles. Hate the noodly feeling. And then i bought s works sub 6. Never looked back. You need to consider weight also.

Enter. My feet get less tired if I cycle with stiffer soles. Muscles, tendons, blood stream and nerves get less impact.

Enter. Thanks for making me realize to not to buy a carbon sole. The comparation of the wattgain/€ is very usefull too. Congrats

Enter! I knew that stiffer does not know more power. I have tried different shoes and I think comfortability is key in most situations - except for instance track racing :-) But what do you think about carbon insoles that are supposed to stabilize the footposition? Also just marketing?

Great video as usual, Alex, cheers 👍

Really interesting Alex, I’ve got two pairs of Shimano shoes, one with carbon soles and one with plastic, I found that once I started using the carbon soles on the road I didn’t want to go back to the plastic ones as they felt really flexy. I use the plastic soles indoors on a Wattbike though and don’t seem to feel the same effect, probably I’m thinking due to pedalling being smoother? Either way I really prefer the feel of the carbon soles outside on the bike.

Enter Size 15 feet hard to find a carbon shoe so good nylon has worked well glad to hear I have not lost watts. Lol

my biggest issue with the Nylon is the sole thickness (away from clip) = higher from saddle

Enter, why not!

Cheers for the video, mate!

Thanks Alex. Enter Always thought top end carbon shoes were way over priced. I wear a lightweight carbon sole for racing and a heavier nylon sole for training. 🚴‍♂️👍 Regards Mark Gibbens

enter - another great video that helps us to understand the hype versus reality! Find shoes that really fit your foot in ALL dimensions, then pay for the additional bells and whistles you can afford (or spend your money on the things that really made a difference).

I love it when I enter a competition for chain wax.

Enter. Like the analysis, I'll stick with my cheaper Nylon sole shoes then!!

Enter ! By the way really interesting as I am looking for my next cycling shoes !

For me I buy carbon sole shoes for comfort more than anything else

Nylon soles over time begin to soften, carbon fibre over time has no change on the stiffness, the increased stiffness will improve comfort, power transfer and overall stability of the foot

Cycling shoes for my exceeding wide feet is $400. Consequently, I use clips and running shoes and the harder I ride, the more my feet fall asleep. Any solutions come to mind?

Enter ... love the video, but must admit I’m a sucker for sidi shoes, just for the looks alone. 🙈🙈🙈

Enter! Good video! I wonder what would happen if you could somehow attach a trainer shoe to the pedal, so that it cannot move around. I think that is what makes a difference: relative motion drives me crazy

Enter if shoe stiffness is so important why do we stick a foam rubber insole inside our shoes?

Enter That looks like a potato on your left chain stay...

By extension, is it safe to assume that given a reasonably and equivalently stiff sole that power transfer will be the same with either SPD or road cleats? But comfort might be different after a certain number of hours?

What about the stack height difference? Could be a cm difference between carbon and nylon sole thicknesses, this could change effective crank length no?

ENTER - I just so happen to be in the market for new shoes. This video potentially saved me a lot of $$. Thanks

Enter, I don't know if you did already but I would like to see the difference between klit positions. Is it any benefits. Thanks

I completely disagree with your conclusion and the method used to estimate shoe stiffness. The flexion of the sole at length (or at a sagittal axis) has nothing to do with the overall stiffness of it. Besides the deformation of a sole in a longitudinal axis there is another deformation in a vertical axis. I used to wear Giro Rumble VR MTB shoes personally and I felt that the sole was bending up and down beneath my cleats for about half a centimeter when I applied significant force/torque (e.g. sprints, low cadence intervals during workouts) both pushing and pulling. And there's no way it returns any power - it's like stretching and pressing a spring all the time. I switched to Giro Empire VR90 with carbon soles and the difference was like day and night. They don't bend at all (at least I am not able to notice it) under my quite modest power output while the first pair bends even under 250+W on 60-70RPM. And that way you waste some amount of energy EVERY pedal stroke just to deform your rubber sole. It doesn't mean that Rumble shoes are rubbish - they are decent quality shoes and a great value for money - I am happy with them and still use for commuting. But if you feel that your power transfer is compromised by the stiffness of your shoes, then a carbon sole pair could be a game changer indeed.

Enter I've been thinking about doing the shorter triathlons in trainers to save time in transition. 20km is 30 minutes.

Enter Very interesting. Now you just need to bust the myth about road cleats giving the best performance over MTB cleats, unless you have done that already.

Enter. Good to know I don't need to spend 200 pounds or so for good shoes. It would be interesting if you could make a video about insole too. I wonder if it is true that the insole that is not flat but the shape of the bottom of your feet would really help power transmition. These insoles are very expensive.

Enter I have wondered if that stuff actually works since it only stays on outside and not into the links inner. Looks cool at least.

Great video really going to research the next shoe purchase! Enter

*ENTER.....the 'draggin'* (foot; ride; u name it) 😎 +FastFitnessTips Am damn glad u are not "bought out/for sale" touting major brands like some guys on ytube doing reviews of all sorts. You give an honest appraisal & admit what u are not sure of, etc. You went all out, as usual, trying to ascertain on the makeshift sole-flex experiment. Tks! 🤔 Curious though, why did u choose 5kg vs. any other wgt total? @FastFitnessTips 🤔

Enter Good information. Now we need a video on laces vs velcro vs boa shoe closures.

Please make a comparison with the watt gain by the weight difference between a cheap shoe and pedal and high-end products. ENTER

I think nylon is the best. I think it is necessary to build in a little flex. The human body doesn't generally like being forced in to narrow range of movement. We learn this in orthotics/Prosthetics. I was trying to convince a guy that £6.00 plimsoles could be more efficient than Vaporfly running shoes. He wouldn't have it. The thing is they have never been tested against each other as far as i'm aware. I sense a tinge of hostility in some people when you throw something like this at them. Ah well! maybe the earth is flat and a bit of glitter on my shoes will make me faster lol

ENTER Thanks for convincing me to get the next cheap carbon road shoe on clearance haha

Enter : I love this kind of video, especially for me who can't afford those high end part and love to destroy those super rich who buy anything expensive because of " bling factor" but justify it by saying " this could improve 23% this and that " in the group...

Yip a little bit of flex is always better 😁

Yeah, but more expensive shoes look cooler. Enter

My Sworks7 road shoes are uber comfotable.

What’s with the “Enter” ??

Thanks for the information and scientific fitness tips, as always!! ENTER

Without even watching this.... I am going to say Carbon shoes are far far better. No doubt about it.

Enter.

A 5 kg weight? Really? The reason this claim is refuted is that it is demonstrably difficult to test, but a 5kg weight with a scissor gauge is pretty poor by your standards. I couldn't put only 5kg down if I tried.

Guessing you didn’t check the science from Zero friction cycling before purchasing the Wend Wax?

I miss the diffrenses of the material-fatigue...it means how stiffis a shoe with nylon after maybe 30.000km and how stiff is a carbon shoe after 30.000km ?

Eyeopener video! Please "ENTER" me for some wax on, wax off Sensie.

enter thanks for the video!! It was definitely helpful information.

Enter. Thanks for the data and findings