Textbook CdA for Tall Riders - Aero Testing Diaries ep. 13

[@justinlane5862]

Thanks for giving the speed Watt savings were normalised too 👌🏾

[@ronykuba]

Cheers 👋

[@jonathanzappala]

You should talk about the testing loop next time. It looks like my preferred one these days, which is a long stretch of rail trail lined with trees on each side, but more importantly no traffic.

[@ronykuba]

It’s a cycle path

[@rubendelrio6120]

Ronald, what would it be the proper width for an aerodinamic wheel front & rear? I have seen 25-21 , 24-24, 25-25. If you could make your own election, how would they be? Thanks

[@ronykuba]

What do you mean, the width of what exactly?

[@rubendelrio6120]

Internal and external Width of the rim in mm

[@maxwollendorfer7196]

Hi, I just got myself a Cube Aerium C68 SL 2022 with Profile design handlebars. I ride the aerobars at a maximum angle of 15 degrees but would like to try a steeper arm position. Do you guys know any possibility to increase the angle, like additional angle wedges or something like this? All that I have found so far only angles the armrest, or has me swapping out the aerobars, which tbh is quite expensive for me to only give it a try.

[@ronykuba]

Aerocoach tilt blocks will probably do the trick

[@atakdd]

I have this bike, if you flip the basebar you will gain an additional 10mm of stack. the mounting positions for each of the stack risers are not flat with the top tube, with this basebar you are either -5mm stack in the low position (currently in) and then +5mm in the high position (flipping the basebar upside down) compared to the height of the top tube. If he needs an additional cm of stack, it will require re-bleeding the brakes but just flip the basebar and problem solved.

[@rotreklhypoteky]

That is good tip. Thanks. I think that I would rather opt for longer bolts and aditional spacer since I like lower placement of handlebars, but this is not something that would occur to me. It might be of help in future. Thanks.

[@ronykuba]

Good tip!

[@benoitst-hilaire6276]

Hi Ronald, being a category 3 rider my self, it is possible to have a ball park of his CdA just to compare ? Thanks !

[@zieluch]

How much of stack more you need? I just changed from V to Flat and will be making custom solution to the spacers, how much you need ? Swiss side will have around February, March full shoe covers.

[@rotreklhypoteky]

its a great news with swiss side overshoes. At this point it is 130mm height including the bridge excluding Aerocoach angled adapter.

[@zieluch]

@@rotreklhypoteky I will let you know I am will make it for myself and will be happy with results

[@rotreklhypoteky]

​@@zieluchit is just the case I didn't have longer bolts. I has 160mm longest. I already bought longer for next time. I can ad more spacer which I have. I still have some 25mm to go with current set. I don't think I will need more. There is no need for custom solution IMHO. Just buy longer bolts and extra set of spacers. It will be out of BMC spec anyways, so do it at your own risk.

[@tdswedish]

Smooth transition between talking, him arriving and carrying on. What cda did you arrive at end of optimization?

[@ronykuba]

It wasn’t planned at all 😅 We don’t disclose that unless the client explicitly agrees. Sorry

[@tdswedish]

All good thanks for all the videos, learning a lot.

[@Lulu-h4q]

What do you think of the Aeox disc wheel (aerodynamically / engineering)? Is there much of an aero difference between disc wheels?

[@ronykuba]

We will have data on it soon. Team UAE is using it outside of sponsorship, so I would expect that they must have a good reason for it.

[@Lulu-h4q]

@@ronykubais there much of an aero difference between different disc wheels?

[@ronykuba]

@@Lulu-h4q that’s relative… within 2-4W@45km/h between the good ones

[@robertgreiner4703]

which size did you test the MET drone ?

[@rotreklhypoteky]

Large

[@alexaxel3653]

What is the maximum length of the bolts you have? M5 or M6? What length do you need?

[@rotreklhypoteky]

On day of test I had 160mm longest. I now have selection of bolts going to crazy 220mm, which I will not need for sure. They are M6

[@DanielWalker-l8q]

Thompson Kimberly Rodriguez William Perez Gary

[@Karan19880]

Hey Ronald Just a small question: my height is between 179 and 182 cm, and currently I am using 172.5L crank arm length on a TT bike, so do you think it is okay or I should get more low?? And just another question is about saddle height, so normally we test saddle height by putting the crank in line with the seatpost, the pedal straight down, then putting your heel on the pedal with the knee fully straight, and trying to touch the pedal, which means your saddle height is correct. And for me, my heel was touching the pedal, and I was having a slight bend in my knees, which means good, but even after that I was just feeling little pressure in my quads because of the low saddle feeling, so I increased a bit more, but than I can barely touch my heel on the pedal, so is it okay if my heel is a little lifted up, and does it cause any problem if our heel doesn't touch the bottom pedal strock while testing the saddle height? Now I know it will be very difficult for you to tell, but I am from India, and since the day you started making bike fit videos on KZbin, I have seen all of them and have been a fan of yours because of so much knowledge you have. So please, if you could answer my questions, it will make my day, and I will gain knowledge from it.

[@ronykuba]

Hi. Crank length isn’t really correlated with height at all. Also, none of the ways you described are very helpful when adjusting your saddle height.

[@Karan19880]

@@ronykuba so it doesn't matter if your heel touch bottom of the pedal stroke??

[@ronykuba]

@@Karan19880 no

[@Karan19880]

@@ronykuba so can you please tell me that is there any way to know our saddle height or just go by feeling?

[@ronykuba]

@@Karan19880 there’s no equation for it, as there are many variables. Your best bet is a skilled bikefitter.

[@drjanswiercz1616]

How tall is the rider and how high is the saddle?

[@rotreklhypoteky]

I am 196cm and saddle is center to saddle top 87.5cm. 175mm cranks.

[@chrispyy606060606]

@@rotreklhypotekyWhat’s your power for 40km and best 40km TT time? Nice setup and good luck!

[@rotreklhypoteky]

@@chrispyy606060606 Thanks. Year 2024 was my first year racing after more than 20years and I did not race anything longer than 25k TT, so I dont accually know. My power for distances I did was around 370w best. Hope there is room for improvement for next year.

[@Dramboli]

So are the nopinz overshoes normally one of the faster ones or are there no big differences (for uci legal stuff)?

[@ronykuba]

It’s not something we test regularly, so I don’t have much data on that yet.

[@rotreklhypoteky]

I think the main cauuse of Nopinz not performing very well is that Nopinz has visibly more bulk around shoe. I had size M with shoe size of 48 and it still dont hug shoe very well. Thicker material that dont stretch that well. Assos is much more delicate and tightly hugging shoe with no velcro strap. There is danger of riping Assos one apart when putting them on, but when on, its visibly smaller than Nopinz in shoe area. The knee high lenght of Nopinz is offset by somewhat worse design of shoecover itself in my opinion. If Swisside would make shoecover with their calf fabric and Assos shoe cover, that would be top for me I think. It is also worth noting, that fabric is more efective on slimer parts of leg according to research.

[@Dramboli]

@@rotreklhypotekythanks for your answer. I have the rule 28 and old assos ones. The old assos overshoes don‘t really have a structured material, so they are probably not very fast, but they dont bulk the shoe. You could try the Swisside aero socks with the short velotoze shoe cover. I often saw this combination of aero socks and the velotoze in timetrialing. But its hard to tell, since the shoe itself will probaby play a big part - maybe a shoe with laces and only aerosocks could be faster, but since the pros wear overshoes I don‘t want to try it 😅

[@rotreklhypoteky]

@@Dramboli I actually plan to test DMT laced shoes with aerosocks only. Pogacar can sometimes be seen in this combination. For example this year Tour TT. I think laced shoes without boa is way to go even with overshoes on. I will have rule 28 for test as well.

[@bdyer4606]

What kind of saddle to armrest drop did this rider finish up at ? 100mm ?

[@ronykuba]

I don’t know, we never really measure that.

[@bdyer4606]

@@ronykuba Did you measure arm pad stack ?

[@ronykuba]

@@bdyer4606 no. We don’t really care about absolute values during testing

[@rotreklhypoteky]

its aproximately 12cm

[@bdyer4606]

@@rotreklhypoteky Thank you. That's interesting to know.

[@voidsofold]

Song name?

[@robertgreiner4703]

cda below 0.2 ?

[@rotreklhypoteky]

Yes

[@robertgreiner4703]

@@rotreklhypoteky my size is like you. I could not get below 0.215. i am really wondering what else i could try

[@rotreklhypoteky]

@@robertgreiner4703 I don't think I can be sure with absolute number. I am looking for relative improvement. On the other hand I know rider of my height with wind tunnel measured sub 0.2 cda, so it's doable. So many details needs to be considered.

[@robertgreiner4703]

@@rotreklhypoteky If i upload a gpx file from a TT into windsock i get quite good cda values. Tried already?

[@rotreklhypoteky]

@@robertgreiner4703 yes, many times, but If you go part after part of ride you see such a wild swings. It's only as good as recorded weather(wind). And it only needs some nearby forest to be completely off. I don't think it can serve as good tool for absolute measurement of CDA. Not to mention braking on technical course.

[@hallockstuart7899]

What was his CdA? .18?

[@ronykuba]

We don’t disclose the values of customers, unless they explicitly agree.

[@poernerg1]

​@@ronykubaSo, asked a bit differently, do you think it's possible at all to go to a CdA below .200 or even .190 for this type of rider/height?

[@ronykuba]

@@poernerg1 sub 0.200 surely. Sub 0.190 we have yet to see, but I would say yes.

[@drjanswiercz1616]

Is it bmc m/l size ?

[@zieluch]

Looks like L

[@rotreklhypoteky]

its L

[@세상사-n3m]

@@rotreklhypoteky why didnt you choose XL?

[@rotreklhypoteky]

@@세상사-n3m there isnt any. L is largest size