Test riding a true racing recumbent
- Thread starter Osiris
- Start date
I am still curious why you make more power on the V20 than these two machines.
I don't know if others have the same observation as I. The positioning on a bent seems far more critical than on an upright in terms of properly engaging the quads. On an upright, one can slide back on the saddle and rotate the hips in 3D. On a bent, one is more fixed in position. If I get my boom wrong (say after disassembly when traveling), I get soreness in places on my quads. A mere 3-5 mm shift is all I need to fix it.
That was the nature of my question about comfort on the M1. I'd love to be on that thing at Sebring this weekend, it looks fast as all get out.
I don't know if others have the same observation as I. The positioning on a bent seems far more critical than on an upright in terms of properly engaging the quads. On an upright, one can slide back on the saddle and rotate the hips in 3D. On a bent, one is more fixed in position. If I get my boom wrong (say after disassembly when traveling), I get soreness in places on my quads. A mere 3-5 mm shift is all I need to fix it.
That was the nature of my question about comfort on the M1. I'd love to be on that thing at Sebring this weekend, it looks fast as all get out.
bladderhead
Zen MBB Master
Old tyres - been there, done that. Both mine blew up at once at 27mph. I lost some skin. Lesson learned.
Olecranon - been there, done that. I broke my right one. My fault entirely. I ran my Grasshopper into the side of a car at 30mph. Her wing-mirror was destroyed. Chainwheel snapped in two. Bike was otherwise undamaged. These Germans build stuff properly. I cannot straighten my arm. They are not going to want me bowling.
Olecranon - been there, done that. I broke my right one. My fault entirely. I ran my Grasshopper into the side of a car at 30mph. Her wing-mirror was destroyed. Chainwheel snapped in two. Bike was otherwise undamaged. These Germans build stuff properly. I cannot straighten my arm. They are not going to want me bowling.
Balor
Zen MBB Master
The fact the over-extending hurts your power seems very plausible. On DF, you 'brace' against gravity that is always there for you, pointing downward from your CG so to speak.
I think that, due to 'flesh flex' and seat flex (I plan on making a much tougher seat on my DIY carbon REV with 'Baloresque twist', ehehe), just 'heel on pedal, stright leg' is not enough. It should be done while 'firmly braced' at the very least.
BTW, intergrated (and hence rock-solid) seat on both Vendetta and M1 might further contribute to efficiency.
bladderhead
Zen MBB Master
And your knees.Balor said:
Osiris
Zen MBB Master
It's probably just that my quads have gone to pot due to lack of use. Basically, the more open the hip angle, the more the workload shifts to the quads when straightening the legs against resistance. The V20 isn't as reclined as either the M1 or M5, so I've been using much more glutes and hamstring muscles when riding it. The same thing happened when I swapped the M5's stock seat for the much more reclined Railgun seat: max power dropped significantly, but after a few months it came back as my quads gained in strength.
I can't really say that I've noticed that, but a 3-5mm change in position will definitely determine whether I end up with knee soreness. It's for that reason that I have to be very careful to position myself properly when I first sit down on a bent.
I removed the M5 seat pad and went back to using the 1/8" thick mat Phil used. It provides almost no bump absorption and becomes very uncomfortable after about an hour, but Phil insisted that it soaks up less energy for better power transfer. It will also mean that I can scoot about 1/2" further back on the seat, so it will be interesting to see how that affects my pedaling. Unfortunately I haven't been able to source a replacement 20" tire locally, so I'll have to risk using one of the old spares Phil sent me if I want to do any power/speed testing this weekend.
I was warned by Bram about certain pads absorbing power. I am using a ventist pad on the Thor seat right now and I had not thought of it, but that coincides with an 8-10 watt drop in my FTP. It just didn't make sense to buy a pad to fit it as I await the railgun seat. The new Railgun GT is a lot faster than the one you have (per Kent's measurements).
Balor
Zen MBB Master
I wish I could perform a similar experiment: quickly dropping like 10 points in BMI and comparing power output "before and after'. Unfortunately, 'quickly' part gets tricky.
When you think about, 'slabs of meat on taped to soles' is not exactly a convincing experiment, but it did register about 15% drop in power.
When you think about, 'slabs of meat on taped to soles' is not exactly a convincing experiment, but it did register about 15% drop in power.
Osiris
Zen MBB Master
The M1's seat is probably the most efficient design I've seen yet. The top curves up over the rider's shoulders, holding him firmly in place, and the seat is part of the one piece frame, making it extremely rigid. The downside of course is that it's designed to fit one specific rider. If your physical dimensions are different, there is no way to adjust the seat or change the boom length.
Balor
Zen MBB Master
In theory, if you use eccentric BB shell, you can add *some* adjustement while keeping boom and seat fixed. I'm pondering something like that because my x-seam tends to fluctuate from season to season
.By the way... is it me or BB is EXTREMELY high on this bent? Like, 12+ inches high? Do you get numb feet on it?
Osiris
Zen MBB Master
What kind of pad is Kent putting on the new Railguns? Mine just has the typical thick foam pad that most bents, including the V20 and CA2, come with. It's very squishy, which makes for a comfortable ride, but it's certainly not the most efficient for power transfer. Ideally I would prefer something like the 1/2" thick pad the M5's stock seat came with, but I have no idea where to obtain that material or how to cut it to fit the seat without making a mess of things.
By the way, when did Kent make the Railgun GT? It looks identical to the one I've got. If I remember right, there was an older version of the Railgun, but that's not the one I have.
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Osiris
Zen MBB Master
In theory, if you use eccentric BB shell, you can add *some* adjustement while keeping boom and seat fixed. I'm pondering something like that because my x-seam tends to fluctuate from season to season
By the way... is it me or BB is EXTREMELY high on this bent? Like, 12+ inches high? Do you get numb feet on it?
It looks that way in the picture above, but I think that's an illusion caused by the fact that it was parked on a slope. In the photo below, you can see that the BB isn't really that high. No numb feet, even after 2 hours of riding it.
It is like a very dense camping mat. Maybe 10 mm thick. My ventist is a bit squishy and it seems I slide around on it, I was thinking of making it sticky somehow
Don Smith, BBM Racing. He makes zotefoam pads and all reports on them are excellent. No personal experience with his pads but I bought my crankset from him and he was very easy and good communicator. The BB and rotor bearings were perfect. bbmracing@yahoo.com
Don Smith, BBM Racing. He makes zotefoam pads and all reports on them are excellent. No personal experience with his pads but I bought my crankset from him and he was very easy and good communicator. The BB and rotor bearings were perfect. bbmracing@yahoo.com
Osiris
Zen MBB Master
I've got a Ventisit on my V20. It's a big improvement over the stock foam pad in various ways, but you do slide around on it. Probably not ideal for racing.
Excellent. I'll send him an email and see what my options are.
bladderhead
Zen MBB Master
After 5 minutes on a DF the elbow starts to hurt, so no more UCI races, but Lords made a rule just for me.
Osiris
Zen MBB Master
Yesterday I took the M5 out to the West Orange trail and I did notice that when hard on the gas, my upper body moves up and down the seat a bit with every pedal stroke, so I'm definitely losing some efficiency there. I got a response from Don Smith, saying he's no longer making custom seat pads because he can't justify the cost of having to make the wood templates for them. I may just try making my own, providing I can get the proper cutting tools.
Overall though, my power numbers look better than expected. Comparing my recent performance to two PR's from a couple of years ago, I see that my average wattage has increased by about 22 watts. What's interesting about this is that when I make it a goal to get a KOM, I'll save my energy until I get to the segment in question. This time I didn't do that. I rode pretty hard the whole way, and despite that still managed higher power numbers on both segments. Comparing those results to my best performance on the same segments when riding my V20, I see that the Vendetta still has an advantage in terms of power output, but it's not as great as I thought (10-20 watts), and the V20 was still slower by about 2 mph on average.
Someone on another forum claimed that swapping my relatively un-aerodynamic aluminum front wheel on the M5 for a carbon three spoke wheel would increase my top speed by about 1 mph. Does that sound reasonable to you? It sounds a bit optimistic to me.
Osiris
Zen MBB Master
Just got back from another speed/power test on the M1. No flats this time, so I got some good data.
Changes to the M1 since last week's aborted run were a new 28mm Schwalbe Durano front tire, a tighter fitting jersey, and I trimmed 2" off each side of the handlebar. This moves my hands fully behind my thighs and out of the air stream.
From the trailhead to the first road crossing is roughly 4 miles East, at which point I turned around and headed in the opposite direction. Average grade according to Strava is zero.
Running West to East: 25.4 mph average speed @ 186W
Running East to West: 25.1 mph average speed @ 183W
Yep, it's definitely faster than the M5, even with the Railgun seat.
Changes to the M1 since last week's aborted run were a new 28mm Schwalbe Durano front tire, a tighter fitting jersey, and I trimmed 2" off each side of the handlebar. This moves my hands fully behind my thighs and out of the air stream.
From the trailhead to the first road crossing is roughly 4 miles East, at which point I turned around and headed in the opposite direction. Average grade according to Strava is zero.
Running West to East: 25.4 mph average speed @ 186W
Running East to West: 25.1 mph average speed @ 183W
Yep, it's definitely faster than the M5, even with the Railgun seat.
