Climbing hills on a V20?

[Osiris]

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

Thanks for the heads up. I just PM's the seller to see if it's still available.

 

[Osiris]

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.

Yep, that boom is almost horizontal. I'm going to see if I can head up to the shop today to get some pictures taken of me on my V20. I'm virtually certain now that the BB is too low for me.

 

[Osiris]

Some other things to consider. A low BB isn't causing more drag as its already in the dirty air. My understanding is the problem is when the knees get above the shoulders and into the clean flow where the drag increases. In other words the higher the BB the higher the knees go. The trick is to get the leg reach correct and the arm reach and height comfortable without the knees going too high. Then use the crank length to get the knees in that perfect spot. Despite what I have commonly heard I don't think there is a "better" the BB position for power. NASA has done studies showing you can be in almost any position including upside down and still generate the same power. It is a case of training the body in that said position which you will do over time ;whichever, Vendetta position you go with. Yes, initially there may be that position you are stronger in but its because you are already acclimated to it. Six months in another more aero position and it will change but you will be in that more aero position. If the fit is good don't lust for a higher bb. There is no advantage. If you like that flatter boom position as most of us do you have room to flatten it by removing some of those spacers on the fork and cutting the fork. As most of us do. This will also bring the hands down.

I've instructed the shop to go ahead and install the Di2 system using the existing chainstay. They say it shouldn't be a problem switching to a longer chainstay if I decide to go that route, and this will allow me to do some coast down comparisons to see if a higher BB actually does result in better aerodynamics. Just for reference, I measured the height of the BB on my M5, and it's 31.5" above the ground. My V20's BB is only 26" above the ground. Considering that both bents have roughly the same seat height, that's a big difference in body position. A while back, I had a couple of pictures taken of me on the M5 to check my body position. It will be interesting to see how it looks on my V20.
https://photos.smugmug.com/Sports/Bicycling/i-rM5tJ8s/0/e788fbe2/X3/DSCN0113-X3.jpg
https://photos.smugmug.com/Sports/Bicycling/i-bqWDCxN/0/ef38fbaa/X3/DSCN0116-X3.jpg

 

[ElyDave]

That's about normal on an M5CHR, I have the M5 M-Racer and it's the same. I had to go for a 26" front wheel to allow me to see along the boom as I have proportionally longer legs than body for my height

I'm interested in how you get on with that chain line? I'm assuming two idlers down there? I've gone with one low idler and another at the top of the forks - requires some length of chain tube to prevent snagging the leg, but lessens the problem of low speed handling and wheel/chain issues.

 

[murmur]

... NASA has done studies showing you can be in almost any position including upside down and still generate the same power...

Can you point me to that NASA analysis? So far I've only seen studies that say there IS a measurable dependence of power capability on hip angle.

 

[Osiris]

Did you mention the seat to ground height? Mine is: seat 21" BB 31". I would love to have mine at 26" as the stability at low speeds would be easier. Seat measurement is the lowest point of seat. BTW In my unimportant opinion your the knees look way too high on the M%. Hard to tell with the angle though.

The lowest point of the seat to the ground on my M5 measures 21.5", so not much difference there between it and the V20. I think the angle of recline on the M5 is greater, but I'm not sure. The knee to shoulder height on my M5 is the same as on the M1, which was built solely for speed.

I just made a deal with another forum member to buy his size Large chainstay, so I'll have lots of testing to do when it arrives.

 

[Osiris]

That's about normal on an M5CHR, I have the M5 M-Racer and it's the same. I had to go for a 26" front wheel to allow me to see along the boom as I have proportionally longer legs than body for my height

No such sight line issues for me, fortunately. Did you see the special track racer M5 built? That one has the rider lying flat on his back!

I'm interested in how you get on with that chain line? I'm assuming two idlers down there? I've gone with one low idler and another at the top of the forks - requires some length of chain tube to prevent snagging the leg, but lessens the problem of low speed handling and wheel/chain issues.

I added a second idler to lift the chain above the front tire, and swapped out the stock idler under the seat for a pair of independent idlers so that they could rotate in opposite directions. https://photos.smugmug.com/Sports/Bicycling/i-fBm7zvb/0/f6d3e6c3/X3/DSCN0125-X3.jpg

I thought this was a huge improvement to the bike, but I got some nasty e-mail from M5 purists, saying that I shouldn't be implying that the M5 needed any improvements! LOL

 

[ElyDave]

that's the same raised idler I have, lengthens the chain a bit but has handling advantages. That track bike - crazy, apparently the guy had real problems getting used to the position, it was very aero but not easy to get the power down.

 

[Osiris]

that's the same raised idler I have, lengthens the chain a bit but has handling advantages. That track bike - crazy, apparently the guy had real problems getting used to the position, it was very aero but not easy to get the power down.

Did you have any problem getting used to the M5? I made the mistake of buying one as my first recumbent, and I thought it was the worst mistake I ever made. It took me three weeks of practice just to be able to ride around the parking lot without falling over. Judging by the reports I read on Bentrider, my experience was not unique.

 

[Osiris]

If it was custom made for your specific leg- knee fit then its undoubtedly the photo angle but they still had to include the crank size. Its unlikely they can make a one size fits all for leg/ knee size. We all fit differently on the same bikes. Just saying.

My M1 was custom built for Phil Plath, who went on to set three speed records on it. It was sheer luck that Phil's dimensions exactly match my own, because it has zero adjustability. The cranks are 165's, just like the ones on my M5. Not sure what the ones that came on my V20 are.

 

[ElyDave]

Did you have any problem getting used to the M5? I made the mistake of buying one as my first recumbent, and I thought it was the worst mistake I ever made. It took me three weeks of practice just to be able to ride around the parking lot without falling over. Judging by the reports I read on Bentrider, my experience was not unique.

I'd been riding an ICE B2 for a year, twin 26"/700c wheels, big and heavy and an ideal trainer.

By comparison the M5 out of the box was almost unrideable. Restricted seat positioning meant I had to cut the boom - still needs a bit more taken off it as I want to shift the seat by about 50mm to improve the vision further. With the very reclined angle, and that long tiller the steering took quite a bit of getting used to as is quite twitchy. Low speed handling was very challenging to start with, but at speed downhill and in a straight line it's like its on rails.

I'd say it took me a good year/1500km on it to feel really comfortable, and I had a "aha" moment in slow heavy traffic one day when I suddenly realised I was doing OK with it.

I'm finding the S40 much easier right now, perhaps 3 years of riding 'bents, perhaps the slightly more upright position. I think it may be a while before I'm comfortable with drinking from a bottle on the move though - I have a water bladder I'll rig up - good for audax and touring.

 

[LarryOz]

Did you mention the seat to ground height? Mine is: seat 21" BB 31". I would love to have mine at 26" as the stability at low speeds would be easier. Seat measurement is the lowest point of seat. BTW In my unimportant opinion your the knees look way too high on the M%. Hard to tell with the angle though.

MY BB is 27.5" from the ground, so yours is way higher than mine. Mine is set ideal for my shoulder height. Also with the M5 there is no adjustment in the BB height, the only thing you can do is build the seat up if the seat to get a more ideal seat to BB height differential if needed. There are so many possibilities and we are all so different. You just have to keep experimenting to find out what is best for you.

 

[Charles.Plager]

Can you point me to that NASA analysis? So far I've only seen studies that say there IS a measurable dependence of power capability on hip angle.

You two are arguing about different points.

You are saying that hip angle matters (and I think it's clear it does).

The NASA analysis is likely claiming that given a given hip angle, the body produces the same power regardless how you rotate the whole system. So if we strap you to your bike and turn it in random directions, you'll produce the same power (according to said study).

 

[Osiris]

You two are arguing about different points.

You are saying that hip angle matters (and I think it's clear it does).

The NASA analysis is likely claiming that given a given hip angle, the body produces the same power regardless how you rotate the whole system. So if we strap you to your bike and turn it in random directions, you'll produce the same power (according to said study).

I'm also rather curious about what the NASA analysis says. If they concluded that the hip angle (the angle between the torso and femur) doesn't influence power production, then their findings completely contradict my own. In my tests, a more open hip angle reduces power. Some of that loss will be mitigated by better aerodynamics, so that a rider with a flatter seat angle may still be able to go faster despite the power loss. This is a nuanced question though, because over time the body will adapt to the more open hip angle and regain some of the power that was lost initially. How much will be regained will no doubt differ from person to person. In my case I've never regained all of it. Even after years of riding bents exclusively, my peak power measurements are still well short of what they were on my diamond frames, but my sustained power has increased. So for example, back in 2013 my peak power on a road bike was roughly 1300 watts, and my FTP was roughly 210 watts. When I switched to the M5, my peak power dropped by a whopping 400 watts, but my FTP remained the same. Today my peak power on a recumbent is in the neighborhood of 1100 watts, but my FTP has jumped to 280 watts.

 

[nobrakes]

Interesting. I produce more power on an open hip angle. However I pedal in a completely different way from most, based on my 15 years of Alexander Technique. It definitely favours open hip angles.

 

[Gary123]

What in the heck is the Alexander technique. I haven't even figured out the hoochie coochie swivel.

 

[ElyDave]

What in the heck is the Alexander technique. I haven't even figured out the hoochie coochie swivel.

That's why nobrakes gets all the girls!

 

[nobrakes]

Lol. Don’t tell my wife

 

[LarryOz]

What in the heck is the Alexander Technique. (AT) I haven't even figured out the hoochie coochie swivel.

I did not know, but read up on it a little bit. It really looks like recumbent riding "almost" uses Alexander Technique because you hips are pretty fixed from going forward and back with the pedals like they do on an upright. The other part of the AT is appling power with the heals, or nearer the knees, and also spinning fast to lessen the load on your leg muscles and knees. So, it is my impression that if you ride a recumbent with mid-sole or lower cleats and spin fast while riding you are employing the AT. I guess that is what I do - my secret is out - at least part of it - the other part of the secret sauce is cinnamon! - yeah that has to be another thread.

 

[nobrakes]

AT is all about taking conscious control of the body and reducing tension and bad use through mental direction. One of the side effects over a long period of practice is you become hyper aware of your body and muscles.

When I rode uprights I started to become very aware of the tension they bring to the lower back, even on relatively upright bikes. I started imagining myself riding my bike but flipped 180 degrees over onto its back. Sounds familiar, no?

When I went to recumbents I discovered that they promote exactly the kind of shift in the back and neck that I was trying and failing to achieve on the upright. I have long term problems in my back, which I have been rehabilitating through AT over 15 years. The most amazing thing happened when I started riding recumbents - my speed of rehabilitation increased massively. I have improved my back more in the past 2 years than the previous 13. Amazing stuff. The bikes are a large part of that.

In terms of pedal technique, I focus on the mental image of lengthening the legs out without tension, and let the rest of the stroke take care of itself. It’s as much in the imagination as anything - mental directions subtly affect the way you organise the muscles for use, and telling the muscles to lengthen gives a very different pedal action. I tried kick and scrape and it felt really bad to my body, so I’ve stuck with what my body tells me and it’s kept me in pretty good stead.

One day I hope to write an article on it - there are not many AT practitioners cycling, and not many recumbent riders either. I imagine the union of those two sets is tiny. I feel there’s a lot that recumbent riders can gain from AT.