V20 - S40 comparison overlay

[Vulcanelli]

I didn't know where to post this so I threw a dart and it landed here.

In comparing the V20 to the S40 I found it helpful to see the profiles on top of each other. I don't see that Cruzbike publishes any technical drawings for its bikes so I had to find similar sized photos and draw on top of them. S40 in blue, V20 in red.

 

[LarryOz]

Very cool - Now add this Cruzbike Prototype into the mix: Magic Profile

 

[Vulcanelli]

As it is written, so shall it be done.

I notice that some of these custom low riders have the crank set much lower to the wheel than the V20. If the idea is to lessen wind resistance by keeping everything as low as possible it seems like the V20 crank could be lowered something like on the magic. I am sure there are other factors I am unaware of, just curious.

 

[paco1961]

The main thing I notice when I occasionally switch back to the S from the V is how much higher off the ground I sit on the S. From the brifter scuff marks on my front hallway wall, the brifters also sit about 5” higher than on the V. And while the V is certainly more aero, the S is a better socializing bike.

 

[Rampa]

The Magic has a higher crank to seat. So even though the crank is lower to the wheel, the seat is much lower to the wheel. So you are correct in aero assessment, but it is also for greater efficiency that the crank is relatively higher. It gives the rider more power.

 

[Rob Lloyd]

How do you do those overlays? I (admittedly selfishly) would like to see my MBB overlaid with those 2 benchmarks also. Not sure you can do it from a drawing.

I don't have any good profile pics, but I can try to get one later.

 

[Randyc3]

Hi,
Vulcanelli, would it be possible for you to add the V20c since it has been released?

 

[Vulcanelli]

Rob,
I did these in photohop where I redraw on top of whatever image I am working with and then hide the original image layer. If you have a larger image it would be better, but I can probably make this work. I am having some computer problems at the moment so stay tuned. Good things come to those who are patient. This is an interesting design, not that I know much about bike geometry and I would like to see how it compares in an overlay.

Randy,
Yes I would like to put the V20c as an overlay, although I thought the shape of the bike was essentially the same as the previous V20, but then I have not kept up on all the changes. I would need a good side view photo or drawing to do it. I wish Cruzbike would provide dimensioned CAD drawings of all the bikes.

Cheers,

Jeff

 

[LarryOz]

Yes I would like to put the V20c as an overlay, although I thought the shape of the bike was essentially the same as the previous V20, but then I have not kept up on all the changes. I would need a good side view photo or drawing to do it. I wish Cruzbike would provide dimensioned CAD drawings of all the bikes.

Of course the V20 and and V20C can all have multiple (virtually unlimited) profiles when different chainstay lengths are used and the BB is adjusted by sliding the boom in and out on the slider therefore moving the BB in relation to the fixed point of the seat

 

[Randyc3]

Hi, Thanks Jeff. Attached a screen capture of the prototype. Maybe this will work.

Rob, did you finish the bike? Would you be comfortable sharing your model? I use Rhino, so STP or DXF work.

Larry, read your post for the Sebring race. Wow and hats off to you! Curious, how much faster is a V20 on flat roads compared to the S40(delta mph)?
Thanks to all.

 

[LarryOz]

Larry, read your post for the Sebring race. Wow and hats off to you! Curious, how much faster is a V20 on flat roads compared to the S40(delta mph)?

Thanks - it is tough to have a race like that, but it felt good to me to be able to catch that lead group over and over even though it ultimately would ruin the 12-hour race for me.
As your question on base speed between S40 and V20 - my "gut" feeling is about 2mph from my time on the S40 (however it is quite limited compared to time on the V20. It also still depends on the person riding those 2 bikes and how they are setup. It would be safe to say however that the taller a person is (or more correctly - the height of their upper body) - the greater chance their is going to be a greater difference in speed. This is because the S40 will tend to stick their shoulders and head up higher than it will on the V20. When I get some time, I 'll do a controlled test between the 2 and post them to the Forum

 

[Randyc3]

Hi Larry
Thanks for the response. Ok, I'm 6'1" so this might make a difference for me. I promised to ride the S40 for 1 year. The goal for this season is to do the Seattle to Portland ride in 1 day{contingent on back and neck cooperation } After this, not sure what I will do. I do have interest in a new or used V20 or maybe even build a composite or Ti variant. I am succumbing to my need for speed affliction. Still have a lot to learn about recumbents and MBB. Looking forward to the S40 and V20 comparison when you have time. Thanks again and safe riding.

 

[LarryOz]

Thanks for the response. Ok, I'm 6'1" so this might make a difference for me. I promised to ride the S40 for 1 year. The goal for this season is to do the Seattle to Portland ride in 1 day{contingent on back and neck cooperation } After this, not sure what I will do. I do have interest in a new or used V20 or maybe even build a composite or Ti variant. I am succumbing to my need for speed affliction. Still have a lot to learn about recumbents and MBB. Looking forward to the S40 and V20 comparison when you have time. Thanks again and safe riding.

Randy, My gut says you will notice more speed difference between the S40 and the V20. As I said earlier this will most likely due to getting you head and shoulders out of the wind. This will depend on how much you work to get it that way. You seat selection will mater. If you want to be as fast and aero as possible the stock seat is probably the best although. There are pros and cons to all setups. You will probably find that the higher seat angle of the S40 will allow you to make more power than the V20 but the better aero of the V20 will still yield vastly faster times. I had a similar experience when first moving from a Silvio 2.0 to a Vendetta during my first year on Cruzbike back in 2014 (wow - has it been that long!) Here is a link to my original benchmarking between the 2. This was done when I was pretty fit (which I could have this fitness back at 62!) - and I had both frames. I had found someone with a Vendetta that wanted a Silvio, so he sent me his complete Vendetta. I swapped out all my components with his and send him the Silvio back. But right before that I did this test. I ran this test at a local track 1/3 mile in similar conditions. What I did was start riding at 100 watts for 5 min and kept increasing the wattage by 25 watts for each each succeeding interval until I could not go any harder. It was almost like an extended ramp test. I would start each interval at the same location on the track and stop it after 5 min were over. For each lap I would make sure I was up to the next wattage before I started the next lap. As you can see I was able to hold 361 watts for 5 minutes at the end of the Silvio test - and had an average speed of 25.4mph with that effort. 3 days later (so I had plenty of rest) on the Vendetta I was only able to hold 265 watts at the end of the nearly hour long test. (At this time my ftp was probably in the 275 watt range for 150lbs.) That wattage gave me 25.9 mph. So 100 watts less and 0.5 mph more. If you look at the spreadsheet you can see that at 200 watts the Silvio Speed was 19.6 mph and the Vendetta speed was 23.2 mph.
https://docs.google.com/spreadsheets/d/1rF0wEX2WpNRJ42GzFw70Zk5nfN_H28AP0c8nLisuCxM/edit?usp=sharing

Also interesting for me to note that a year later I was able to average 25.1 on 200 watts when I set a WUCA 100-mile road record at 3:59:31. In that year I had learned to be much more aero when compared to needing 250 watts to average 24.9 mph during that benchmark testing a year earlier. Better wheels, curved slider, case on the back, better BB placement, narrower handlebars, better helmet and visor, etc. This was also on a V20 (red one) - which had the newer front setup that was probably more aero too.
https://cruzbike.com/blogs/blog/rec...ile-record-on-v20?_pos=1&_sid=4b0057d18&_ss=r

 

[Randyc3]

Thanks for the spreadsheet and checking out the data. Wow, October 11, 2015 was an exciting day. Very cool and congrats.

 

[Vulcanelli]

Here is what I came up with for overlaying the V20c (blue) on the V20 (orange).

 

[Randyc3]

Very cool! Settle differences as I thought. Thank you!

 

[Vulcanelli]

And here is the V15 in red over the V20 in blue. I was thinking that the low 15 deg angle would mean less visibility over the handlebars, but it actually looks about the same.