Climbing hills on a V20?

[ed72]

I wasn't wearing a skin suit, but to go 25 mph on my Specialized Venge took 350 watts. On my Trek Speed Concept 9, 25 mph required a steady output of 300 watts, which is exactly what another local TT racer's average speed/power was in a 40 K race. He and I are exactly the same size (6'-0" tall, 175 lbs).



It's a stock V20. It was Ben Tomblin's race bike, but he put the stock front wheel back on it, which aside from the Ventisit seat pad were the only non-stock items on the bike.

It was definitely that slow on the day in question, although I have only two runs on that particular road so far on the V20. We've been plagued by high winds, so it may be some time until I have enough sample runs to get a reliable average.

Nice looking bike.

I can't help you.

I am bigger than you and need less power on a DF for similar speeds. I don't understand. Sorry.

327 watts to go 24.7 mph on a flat windless road on a V20 means something very serious is off. Odd. Sorry, I can't help

 

[Osiris]

One thing I've stopped paying serious attention to is comparisons between different riders on differently modded bikes. I recall a conversation I once had with a retired pro-racer comparing his power/speed ratios to mine on what seemed like our very comparable TT bikes. The numbers he gave me were so different from mine that I thought he was delusional. I have on occasion compared my results to racers like Kent Polk, who is roughly my size and rides an M5 exactly like mine. His numbers matched mine except at 30 mph, where he was having to produce significantly more power than I did. He explained that differences in road surface alone could account for that amount of difference. Thom Ohlinger, who has been designing recumbents and racing them for decades, provided me with a list of variables that could account for as much as a 50 watt savings for the same rider on the same bent. I don't race, so I'm not about to go out and buy a speed suit, racing helmet, shoe covers, tubular wheels, etc. I do my tests on typical roads and trails, using conventional riding gear and equipment. Coast down tests have by far been the most reliable because they eliminate so many variables that could contaminate the results. Speed/power tests introduce a host of variables that are difficult to control for, so I place much less confidence in them. As Larry points out, the only way to get really accurate results is to do them on a close course like a circular track, which most of us don't have access to.

 

[ed72]

327 watts to go 24.7 mph on a flat windless road on a V20 means something very serious is off.

 

[Osiris]

Nice looking bike.

I can't help you.

I am bigger than you and need less power on a DF for similar speeds. I don't understand. Sorry.

What kind of power meter do you use? Larry and I use Garmin Vector pedals. If yours is a hub mounted meter, drive-train resistance and rolling resistance will factor into your readings.

 

[ed72]

What kind of power meter do you use? Larry and I use Garmin Vector pedals. If yours is a hub mounted meter, drive-train resistance and rolling resistance will factor into your readings.

I am not asking for help, I do not need any

327 watts to go 24.7 mph on a flat windless road on a V20 means something very serious is off.

If you need much more than 200 watts, there is low hanging fruit.

Did you really think a picture of your bike without you on it was what would help solve your problem?

 

[Osiris]

327 watts to go 24.7 mph on a flat windless road on a V20 means something very serious is off.

Possibly. We'll see after my sample size increases. For me it's purely academic anyway. I'll never race, so power/speed results are largely irrelevant. All I care about is my power output, because it's an indicator of my physical fitness.

 

[Osiris]

Do you Zwift by any chance?

No, I've never tried it. The closest I've come to a virtual race is on my CompuTrainer, but I much prefer real-world riding. Fortunately we get to do that year round here.

 

[ak-tux]

I wasn't wearing a skin suit, but to go 25 mph on my Specialized Venge took 350 watts. On my Trek Speed Concept 9, 25 mph required a steady output of 300 watts, which is exactly what another local TT racer's average speed/power was in a 40 K race. He and I are exactly the same size (6'-0" tall, 175 lbs).



It's a stock V20. It was Ben Tomblin's race bike, but he put the stock front wheel back on it, which aside from the Ventisit seat pad were the only non-stock items on the bike.

It was definitely that slow on the day in question, although I have only two runs on that particular road so far on the V20. We've been plagued by high winds, so it may be some time until I have enough sample runs to get a reliable average.

Probably some mechanical problem? Like BB cups clamped too tightly by the chainstay?

 

[Osiris]

You might consider giving it a go sometime. Since your main focus is power it is a really good fit. Lots of people don't consider the virtual racing really racing and they do have a point. It is more like a group powerfest event and is proven extremely effective in increasing ones power/fitness.

Larry and I talked about it some time ago, but it doesn't sound like something that would appeal to me. I plan to follow a training regimen created for me by Thom Ohlinger, which involves 30 second, high power intervals. That will enable to me to maximize results while spending only half an hour or so on the trainer. Though it doesn't involve speed, one thing I'm really eager to see is whether the V20 will allow me to climb the really steep hills I've been avoiding. My tests on short hills have been really encouraging. It's not that I'm able to put out more power than I can on my other bents, but it feels much easier to do it. A much longer climb will tell me whether that's an illusion or not. Unfortunately, the skewer I need to attach it to my CompuTrainer doesn't fit the V20, so I haven't been able to do any tests under the most controlled conditions.

 

[Osiris]

Probably some mechanical problem? Like BB cups clamped too tightly by the chainstay?

I've had it up on the bike stand to check for any unusual signs of resistance when pedaling, but it seems to be running very smoothly in every gear. No sign of drag on the rear wheel either. It may be that there was a headwind that day that I just didn't detect.

 

[LarryOz]

200W gets me around 21 mph, you are light years ahead of me. I have a lower BB and am 6'2 with big feet. I also like the wide bars on the V so would not go to something thinner. I am thinking of going to midsole cleat position to raise the feet higher and shorten the boom a bit which would also raise the BB a little. My body tells me midsole is the way to go.

If I could get 4W/KG I would be pretty happy. To get there I would need to raise FTP by 10W (currently 290) and lose around 4KG (currently 79). It is my target and I'm getting there! As an aside I always wonder why people never add the bike weight to the W/KG figure, that would make it easier to compare riders, no? It's a little bit arbitrary if we're riding bikes with different weights.

I think climbing on the V is helped by not lifting the BB too high, so I'm quite happy where it is on my build (standard chainstay). It's probably around 3 or 4 inches lower than what a lot of you guys have.

Nobrakes,
You are correct about total bike weight, and the more climbing the more the total weight makes a difference.

You are also correct about a lower BB is better for climbing. A high BB is better for aero because it cuts a hole in the air where you shoulders are. Chances are, because you have 7" on me, you shoulders are also probably a lot higher in the air then mine, so you are less aero on the flat. You can probably out-climb me though.

Mid-sole cleat position is also a good idea and will get your feet another 1" higher while keeping the BB the same. It also helps with hot foot.

 

[LarryOz]

Larry is incredibly slippery on the V20.....maybe 0.140 plus or minus. It is obvious he put in the work to find these aero gains. They aren't free.

Thanks Ed. You are right. I am a small guy and not really very powerful. I have spent most of my time testing and refining my Vendetta and me to be aero together. That is why 200watts can get me 25mph. My lowest calculated CdA using the Chung method was about 0.154.

 

[bladderhead]

I ride on my insteps on both my bikes. I am not fast or powerful, I just prefer it. Mike Burrows says that the conventional foot-placement is a myth that evolved because people on DF were getting toe-strike.

When I got a 'bent I gave up riding on my balls (of my feet).

 

[ed72]

Thanks Ed. You are right. I am a small guy and not really very powerful. I have spent most of my time testing and refining my Vendetta and me to be aero together. That is why 200watts can get me 25mph. My lowest calculated CdA using the Chung method was about 0.154.

Surprising at 0.154. I was quite sure you got it lower.

I have read how you test and it makes sense (relatively quick setup or equipment comparisons) but have one question, a bit OT sorry. How do you get precision and accuracy on speed measurement? Or do you do multiple replicates and average speeds? I am going to be "optimizing" my setup hoping to break 200 miles in 12H. The Chung method works fine but I am slow at it and have to bring the laptop out to the country when doing the half pipe runs.

 

[murmur]

I ride on my insteps on both my bikes. I am not fast or powerful, I just prefer it. Mike Burrows says that the conventional foot-placement is a myth that evolved because people on DF were getting toe-strike.

When I got a 'bent I gave up riding on my balls (of my feet).

Me too, I've even made some "adapters" for my Magnalock pedals so I can move the pedal backward on my foot and still have some positive position control. Right now I'm about an inch aft of the "conventional" position but I plan to go further back before long.

 

[Osiris]

A high BB is better for aero because it cuts a hole in the air where you shoulders are.

Hmmmm. I've been wondering about this since you mentioned it. At the moment, I only have the pictures that Ben sent me of my V20, but it does appear even from this angle that the BB is too low for optimum aerodynamics. When I compare it to pictures of other V20's on the net, I can't help but notice how much closer to horizontal their booms are. What do you think, Larry? Do I need to get a longer chainstay? For reference, I just had the tech at the shop measure it, and the chainstay is 19.5" long.

 

[LarryOz]

Hmmmm. I've been wondering about this since you mentioned it. At the moment, I only have the pictures that Ben sent me of my V20, but it does appear even from this angle that the BB is too low for optimum aerodynamics. When I compare it to pictures of other V20's on the net, I can't help but notice how much closer to horizontal their booms are. What do you think, Larry? Do I need to get a longer chainstay? For reference, I just had the tech at the shop measure it, and the chainstay is 19.5" long.

Osiris -= Yes, it almost looks like the center of the BB is aligned with the bottom of the seat. For reference, mine is around 7" above. My boom is nowhere horizontal either but definitely more than this picture. Get the BB at the right height is a dance between crank length, chainstay length, and your inseam - which will determine how much the boom and slider will pivot back toward you in the seat. I would suggest trying a 21.5" chainstay for starters.

 

[Osiris]

Osiris -= Yes, it almost looks like the center of the BB is aligned with the bottom of the seat. For reference, mine is around 7" above. My boom is nowhere horizontal either but definitely more than this picture. Get the BB at the right height is a dance between crank length, chainstay length, and your inseam - which will determine how much the boom and slider will pivot back toward you in the seat. I would suggest trying a 21.5" chainstay for starters.

I just had the guy at the shop measure the distance from the floor to the center of the BB, which turned out to be 26". With an inseam of 32", I'm not sure what the optimum height would be for me.

How can I order just a chainstay?

 

[telephd]

Osiris, IIRC there is a L for sale in the forum

 

[jond]

I just had the guy at the shop measure the distance from the floor to the center of the BB, which turned out to be 26". With an inseam of 32", I'm not sure what the optimum height would be for me.

How can I order just a chainstay?

Osiris take a look at cruzbike blog archive from feb. here you will find the a2 wind tunnel testing of the vendetta with three bodies . Note the pics showing boom position of each bike.