DavidCH
In thought; expanding the paradigm of traversity
Holy crap. Not for the faint hearted. I'm pleased you didn't roll up with disc front and back. Ken ... I have to give you kudos. You did ever so well.
Bike Sebring 2018
- Thread starter Jim Parker
- Start date
Cool photo of the lead pack fighting the headwind on the second half of the 100-mile race.
That's Jesse Groves pulling at the front, Kyle Larsen, and Larry Oslund on Cruzbike V20s. Jean-Luc Perez is tucked in the group on his standard bike and will go on to win the 24-hour drafting race with 463.9 miles. Great photo shows just how much of the standard rider is sheltered from the wind when they are tucked. I'd estimate about 66%.
Awesome photo. 66% is right on the money for my 6'3'' frame. 0.290 CdA on road bike (bars, good kit, good wheels) vs 0.195 CdA and 145 watts vs 210 watts to go 22 mph. 66% less flipped around is 50% more.
telephd
Guru
Interesting profile pic. Three blazingly fast riders, each with a slightly different frontal exposure. Unless there is an optical illusion, it looks like 1st Larry's body position is the most horizontal and I assume most aero, 2nd Jesse's position looks to be the most vertical with the most frontal area exposed (less aero?) and 3rd Barefoot's looks intermediate between the two. If you could share - what seats and approximate angles do each of you ride?
And brilliant showing by all the Cruzbike racers!!
LarryOz
Cruzeum Curator & Sigma Wrangler
I am just riding the stock V20 seat. I have a lumbar piece in it but that should not affect my seat angle.
I think Kyle is also riding stock seat, but because he is taller, his head is up higher due to headrest going higher. Although it does look like his chest is at a steeper angle than mine.
I am pretty sure Jesse has a Thor seat mounted but not sure what the angle is. Steeper angle means ability to make more power, but your position is less areo. Probably ends up cancelling out to a greater extent.
Tigerpaw
Well-Known Member
Bottom line: three awesome motors running together right there. Kudos to you all!
The thing about that photo is a slight illusion created by the head-on perspective. The riders closest to the camera seem larger in relation to the riders further back and this makes the last rider (DF) look like he's lower to the ground than he might be in actuality, due to his distance and apparent relative size. A side pic would reveal more accurate frontal area differences, and it might be more than what is appears for the DF in spite of his lowered TT position.
Jesse Groves
Active Member
I have the Thor seat with ADEM headrest set up per the instructions Ratz wrote up, but I am not sure what angle of recline that gives. It basically follows the curve of the frame, but because the shoulder area curves up it pushes the upper body and head higher into the wind.
Cruzbike posted a side profile photo on Facebook of Larry, Kyle and I going through the last turn of the race; that photo has a fence in the background that gives a good horizon to compare our positions on the bike; in it, you can see that my head is about 6" higher than Larry and Kyle riding the stock configuration. It really shows the difference in setup better than the head-on photo.
The Vendetta with Thor seat is without a doubt less aero than stock, and for me, about .5 to 1 mph slower at 200w. I make the same power on the stock seat as with the Thor seat; which GASP...is the same power I made on the Schlitter (at 12 degree recline); basically, the angle of recline has little to no impact on my power-to-heart-rate ratio. It also appears that RWD vs FWD has no impact on MY ability to make power either; at least, that holds true for everything except sprinting...I have better max power on the RWD as opposed to FWD (that is not a typo); my max power on the Schlitter was close to 1000w and on the Vendetta is close to 800w. Hopefully, my max will improve on the Vendetta over time; I have had to DRASTICALLY change my pedal stroke as I was unable to keep traction on the V whenever I would sprint; I could break the wheel lose at will using the pedal stroke I developed on the RWD. It was apparently not a very even stroke and my torque would hit a huge spike in power in one particular phase of the stroke. If any of you ride with DF groups, you have probably heard the torque sound (WOOSH, WOOsh, Woosh, woosh, woo...) a tire makes when some riders start their sprint; I could make that sound on the Schlitter but not on the Vendetta; instead, the wheel spins out for that brief second.
Also of importance is the length of the chainstay because it effects how high your feet and knees go. If you look at the photo of the last turn, you will see that Larry has the shortest chainstay (even speaking relatively) and I think increases his aerodynamics a little bit. I have the 23" chainstay and am in discussions with Robert Holler about whether I should switch to the 21" or 19.5" chainstay. The last I heard from him was that it is best if the knees do not go higher than the shoulder; however, I believe I have seen Ratz post that the knees should not go higher than the head. Any input on head vs shoulder height in that regard would be appreciated.
Cruzbike posted a side profile photo on Facebook of Larry, Kyle and I going through the last turn of the race; that photo has a fence in the background that gives a good horizon to compare our positions on the bike; in it, you can see that my head is about 6" higher than Larry and Kyle riding the stock configuration. It really shows the difference in setup better than the head-on photo.
The Vendetta with Thor seat is without a doubt less aero than stock, and for me, about .5 to 1 mph slower at 200w. I make the same power on the stock seat as with the Thor seat; which GASP...is the same power I made on the Schlitter (at 12 degree recline); basically, the angle of recline has little to no impact on my power-to-heart-rate ratio. It also appears that RWD vs FWD has no impact on MY ability to make power either; at least, that holds true for everything except sprinting...I have better max power on the RWD as opposed to FWD (that is not a typo); my max power on the Schlitter was close to 1000w and on the Vendetta is close to 800w. Hopefully, my max will improve on the Vendetta over time; I have had to DRASTICALLY change my pedal stroke as I was unable to keep traction on the V whenever I would sprint; I could break the wheel lose at will using the pedal stroke I developed on the RWD. It was apparently not a very even stroke and my torque would hit a huge spike in power in one particular phase of the stroke. If any of you ride with DF groups, you have probably heard the torque sound (WOOSH, WOOsh, Woosh, woosh, woo...) a tire makes when some riders start their sprint; I could make that sound on the Schlitter but not on the Vendetta; instead, the wheel spins out for that brief second.
Also of importance is the length of the chainstay because it effects how high your feet and knees go. If you look at the photo of the last turn, you will see that Larry has the shortest chainstay (even speaking relatively) and I think increases his aerodynamics a little bit. I have the 23" chainstay and am in discussions with Robert Holler about whether I should switch to the 21" or 19.5" chainstay. The last I heard from him was that it is best if the knees do not go higher than the shoulder; however, I believe I have seen Ratz post that the knees should not go higher than the head. Any input on head vs shoulder height in that regard would be appreciated.
LarryOz
Cruzeum Curator & Sigma Wrangler
I think you will be more aero if you adjust your chainstay to keep your knees at their top no higher than your shoulders. Putting a 650 wheel on the back may also help you some.
Jesse Groves
Active Member
I hadn't thought of putting a smaller wheel on the back, but I guess that would effectively increase my angle of recline. Good advice Larry, now for the tough question: How do I convince my wife that I need another carbon wheel?I think you will be more aero if you adjust your chainstay to keep your knees at their top no higher than your shoulders. Putting a 650 wheel on the back may also help you some.
DavidCH
In thought; expanding the paradigm of traversity
Hey @LarryOz ... that was a pretty small gap at 40kph and it looked like you didn't brake. I enjoyed the video... it appears you can save 30 watts when drafting another Vendetta. If there is fog... I think it's important for a front light. It looks like the other vendetta riders following some DFs were saving at least 50watts. Good to save watts and sprint at the end. Fine race... anyone who took part in that race was a winner. It's true, when you put your name down to race Sebring it means a hell of a lot of training and over xmas and to get race fit like that is awesome.
LarryOz
Cruzeum Curator & Sigma Wrangler
I actually tried the 650 myself, but it put me down so low that my visor and helmet were catching more air and the visibility was also a little worse. I appear to be in almost perfect location with everything stock. One of few times in my life that being short has a good benefit. I would look around for an inexpensive used 650 - maybe Zipp 404 and put some wheel covers on it. You still in Asheville?I hadn't thought of putting a smaller wheel on the back, but I guess that would effectively increase my angle of recline. Good advice Larry, now for the tough question: How do I convince my wife that I need another carbon wheel?
DavidCH
In thought; expanding the paradigm of traversity
So question for Kyle @Barefoot Biker : the flashing rear radar system you are using... why did you decide to ride with it? Does it tell you how fast another rider is coming up on you?
Wow. One slippery machine. Looking at speed vs power on the same segments, it looks like your CdA is around 0.135 or maybe 0.140 but not much more than that. Not that you don't have a ton of power but I was blown away how fast you are on 160-165 watts. Is there a crash at the turnaround all the time?
LarryOz
Cruzeum Curator & Sigma Wrangler
Thanks - one nice benefit of being 5'6'sh and 150 pounds. Plus - I lather up with Crisco before every race to be extra "slippery"!
Just kidding - do not try!Yes, I think someone almost always goes down at that turnaround every year. I did back in 2015. I rode off the edge and tried to turn in the sand - bang!. Luckily the speed is about 1mph - so mostly just embarrassing to the rider!
DavidCH
In thought; expanding the paradigm of traversity
How on earth does a velomobile turn? I noticed recently that my track bike has toe overlap and if you try and do a u turn on that clipped in, you fall.
I did notice that a rider behind me last year had a fall... it is quite a common occurrence. Perhaps the event organizer could do something for next year or someone could take a YouTube video of everyone falling. It's a little crazy.
If I was going to do it again I wouldn't take so much fluid with me and on the turn around have support load me up with fluid.
Just before donning the token I decided to unclip one foot for balance.
1happyreader
zen/child method
Donate to the Buy Larry a brighter headlight fund, every penny helps.
@ you did have a headlight,, right.org
Barefoot Biker
Active Member
My setup is stock seat and headrest. I did add lumbar support, but it's only a few millimeters (for me it was slightly less comfortable but better power). I think Larry has more padding there than I do, but I kept it minimal to feel more connected to the bike. I experimented with reclining my head further like Larry and I couldn't make as much power (there must be more than one stock headrest height because mine is taller than B Girls, though we switched her out to the adjustable one to make it perfect, and because I can see Larry's head is lower). It could be that my equilibrium was better with my head upright or that I'm pressing into my neck, not sure.
I agree with Jesse that Larry's lower feet, and probably also shorter cranks, make a difference. For me, I got the best draft off of Jean-Luc on the TT bike, then Jesse, then Jim, and Larry's draft was hardest to find. I have also ridden behind Dave Lewis in his velomobile, and I was unable to distinguish any draft at all though he claims there is a small one. I do have the medium chainstay, but I decided to stay with the large. The other difference is that Larry's hands and elbows are in tight. It took me about one year before I was comfortable riding that way and I did use it a few times. I also used the one hand folded into my neck position, but neither of these are as stable and I can make more power holding wide on the hoods or bar ends.
That's interesting about the 200w sprint loss with the FWD. I suspect you'll be able to gain most of that back. For me, I can compare only to my upright (S-Works Tarmac). I am usually about 100w less on the Vendetta than the Tarmac, but wheel spin is the limiter I think. I can spin the wheel on both bikes, but on the upright, it only spins if I adopt Caleb Ewans sprint position with my nose above the front wheel (this unweights the back wheel a bit, but it's ridiculously aerodynamic so, there is a sweet spot somewhere). On the upright there is a lot more flexibility to move your weight around so, you can theoretically always weight the drive wheel to 100% which is impossible on the Vendetta. One thing I did, on the advice of Alvin Maxwell, is practice a ton in the little ring to increase my maximum cadence. At first, the Vendetta felt completely out of control spinning fast, but over time, I was able to spin at 130 to 140 rpm and keep it smooth and in control. That's what helped me the most to smooth out the power. Of course, when the pace increases so much with still seven miles to go, the real limitation at the end was my aching legs!!
Re: the rear view radar. I used it because it enhances my safety on the road. There were plenty of cars passing by during the race. Several months before I got one, I was going for a KOM on a short segment. I went 100% and at the end, I was seeing stars, panting, and delirious. I weaved out of the bike lane at about 7mph and heard the honk of a large truck that I had no idea was there. I swerved back into the bike lane, but I just never saw him in my mirror. I was mad at myself for letting my guard down. With the radar, you get (if you can hear your garmin beep) an audio warning and a visual indication right on your screen. It's a game changer in terms of safety for me. That little beep and the color change on the screen is enough to get my attention with plenty of time to check my mirror and get out of the way. It works best riding alone, but it does work in the pace line too provided another rider is not shielding the entire view of the car. It can detect another rider bridging up, but only if the speed relative to yours is high enough which, at race pace, it probably never will be. And, it's a light!
I agree with Jesse that Larry's lower feet, and probably also shorter cranks, make a difference. For me, I got the best draft off of Jean-Luc on the TT bike, then Jesse, then Jim, and Larry's draft was hardest to find. I have also ridden behind Dave Lewis in his velomobile, and I was unable to distinguish any draft at all though he claims there is a small one. I do have the medium chainstay, but I decided to stay with the large. The other difference is that Larry's hands and elbows are in tight. It took me about one year before I was comfortable riding that way and I did use it a few times. I also used the one hand folded into my neck position, but neither of these are as stable and I can make more power holding wide on the hoods or bar ends.
That's interesting about the 200w sprint loss with the FWD. I suspect you'll be able to gain most of that back. For me, I can compare only to my upright (S-Works Tarmac). I am usually about 100w less on the Vendetta than the Tarmac, but wheel spin is the limiter I think. I can spin the wheel on both bikes, but on the upright, it only spins if I adopt Caleb Ewans sprint position with my nose above the front wheel (this unweights the back wheel a bit, but it's ridiculously aerodynamic so, there is a sweet spot somewhere). On the upright there is a lot more flexibility to move your weight around so, you can theoretically always weight the drive wheel to 100% which is impossible on the Vendetta. One thing I did, on the advice of Alvin Maxwell, is practice a ton in the little ring to increase my maximum cadence. At first, the Vendetta felt completely out of control spinning fast, but over time, I was able to spin at 130 to 140 rpm and keep it smooth and in control. That's what helped me the most to smooth out the power. Of course, when the pace increases so much with still seven miles to go, the real limitation at the end was my aching legs!!
Re: the rear view radar. I used it because it enhances my safety on the road. There were plenty of cars passing by during the race. Several months before I got one, I was going for a KOM on a short segment. I went 100% and at the end, I was seeing stars, panting, and delirious. I weaved out of the bike lane at about 7mph and heard the honk of a large truck that I had no idea was there. I swerved back into the bike lane, but I just never saw him in my mirror. I was mad at myself for letting my guard down. With the radar, you get (if you can hear your garmin beep) an audio warning and a visual indication right on your screen. It's a game changer in terms of safety for me. That little beep and the color change on the screen is enough to get my attention with plenty of time to check my mirror and get out of the way. It works best riding alone, but it does work in the pace line too provided another rider is not shielding the entire view of the car. It can detect another rider bridging up, but only if the speed relative to yours is high enough which, at race pace, it probably never will be. And, it's a light!
Maybe it was pointing backwards, a "catch me if you can" beacon (if so, it didn't work - they couldn't catch him!).
LarryOz
Cruzeum Curator & Sigma Wrangler
The real estate on the front of my Vendetta is pretty cramped. Light means no video. I just have to rely on my cat-like reflexes!
