Max RPM's

bikeguy

Veloflash, hi there, yes I realised I made a mistake regarding the running turnover, indeed 300 rpm on an ergo is 'equivalent' to 12 steps per second in running. They aren't equivalent of course because in sprinting say at 45 kph the foot velocity may well exceed 100 km/hr (27.7 m/s) with a far longer range of motion while foot velocity in cycle sprinting is not significant, at 170 rpm and a crank diameter of 175 mm, is a mere 3.1 meters/sec.

As for overspeed training I am aware of it, but as you can see my ability to hit 275 rpm on an ergo didn't help me in sprinting. I'm simply a stiff person and a lot of eccentric work needs to be done on my hamstrings in particular before they will lengthen (wasted energy). This is why I abandoned sprinting, I feel that my ability to generate quite high power (my coach always told me I had a lot of power) when I'm not in a stretched position is well suited for cycling, where the ROM of the foot is so small compared to sprinting and my leg never gets stretched.

I'm still playing around with gearing (I've been pedaling too slowly, at 115 rpm max), and I haven't had the opportunity yet to do a real max sprint in a safe area. I will post my progress. I still haven't maxxed out my abilities with clipless pedals and really am still learning to use them after getting them one year ago.

I do have some questions though, in a track 200 m sprint, typically how long is the acceleration zone before peak velocity is reached?

Another, how much does frame and wheel flex effect maximum achievable speed ? Is an aluminum framed bicycle (I'm riding a Specialized Sirrus pro) sufficient to show my true sprinting ability (if I even have any). How would acceleration and top end speed on an aluminum road racing hybrid bike compare to a track sprinting bike ? I've looked on the internet for info on this, but I think only track cyclists who have actually ridden track bikes and know how they compare to road racing bikes would know.

Thanks for any info you might have.

VeloFlash

I take it you mean an individual 200m TT. It depends on the track and your gearing. You can only hold maximum speed for about 6-8 seconds.

So you have to know thyself how you fade after those 6-8 seconds. If you are a serious fader then you would want your 6-8 seconds to cover the last part of the 200m.

It is a balance between the speed of acceleration to max speed within the 200m and the speed of deceleration when you start fading.

The object is to use the high banking on the velodrome (250m) in the half lap before the 200m start strip so as to economically get up to a speed at the mark that allows you to hit top speed by the middle to end of the back straight. Try to carry that speed through the bend to the finish.

In a match sprint, tactics and positioning (and the lack of opportunity to use the high banking) can cancel out raw speed. That is why those 200m times are usually significantly less.

I would not know what amount of flex would lead to a deterioration in speed. Several years ago Bontrager, the bike and component builder, conducted tests on bottom bracket movement on several bikes and concluded the measured movement was so minuscule to affect power delivery. His tests brought to account that it is more likely to be flex movement in the crank arm that would affect performance.

If you have a stiff frame, stiff wheels and a stiff crankset you cover all bases and should not go wrong.

A track bike has a feeling of being one with you and more responsive to power input. It feels much faster. On a track it would be faster than a road bike. My computer readout of max speeds would suggest this to be so.

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VF

"Remember, even if you win the rat race, you are still a rat"

bikeguy

Veloflash, thanks for your reply. I'm kinda limited on funds right now, so I might be able to spring for a new stiff wheel, or a crank but definitely not a new frame. I busted two spokes on the rear wheel (aero spokes were replaced with normal round ones) and it wobbles a bit, so I figure a new wheel is probably better overall. What would you recommend as a good stiff, aerodynamic wheel?

I'm not clear on how many meters the individual 200 mm TT'ers have to accelerate before they reach the timed 200 zone?

Thanks for any advice you may have.

VeloFlash

I would not to be too concerned about frame and wheel stiffness. Unless you are putting out more than 2000 watts. If you were that powerful you would be sponsored or part of a national program and all your equipment would be supplied.

On a 250m track you are given 3 laps (or 3.5) which includes the 200m run.

The build up to the 200m TT is track dependent. On a 250m track you would be building speed high along the top of the opposite banking and just before the banking commences to flatten out to become the front straight start your acceleration to use the benefit of the descent. It would be about 125m plus the width of the track from where you commence your major acceleration.

You should have time to practice on the track before the event so I would not be too concerned about nailing the acceleration timing.

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VF

"Remember, even if you win the rat race, you are still a rat"

drewjc

I agree that acceleration usually takes about 125-150m during a flying 200m TT. The trouble is if you are measuring acceleration a 200m fly isnt ideal as the riders generally dont kick into the sprint as this saps valuable energy. It is more of a fast wind-up, usually starting at about 25-30km/h up to a max of 65-70 depending on the rider and conditions. Now if u want a real test of acceleration a team sprint start would be an ideal test. the top speed of the first rider from a standing start usually occurs entering turn 3 as the rider sits down (although they can accelerate in the seat it is usually a miniscule change). This i would estimate to be around 170m.

Also, i have found that my track bike has significantly better acceleration possibly due to the fixed gear or lighter weight (while still being stiffer) but most likely due to the age of the bikes. Track is 1yr old and road is about 10yrs (carbon Cadex) one of the flimsiest frames known to man!! I still think that regardless of gearing etc. track bikes are faster in a drag race than a road bike. the direct drive is much more efficient and track bikes are lighter (although not significantly so) and stiffer.

bikeguy

Since my rear wheel is acting up, I've ordered a Mavic Elite to replace it. I'm getting noticeable flexing and a strange vibration from the rear wheel particularly when accelerating hard but even at a steady 40 kph.

Thinking about wheel flexion, it's not so much the energy going into flexing the wheel as the fact that the front wheel and rear aren't tracking in the same direction that I imagine costs a lot, as this is like having a brake applied to the bike (the rear wheel would be sliding at an angle to it's direction of rotation increasing rolling friction enormously).

As for being on a track, not for a while I think as the nearest is 250 km away and I have no car. I don't want to cycle 250 km and then do a track run and then cycle back 250 km in one day. I do my training on the road, and I've found a suitable long straight road with barely any cars and no intersections where I can sprint.It's a bit bumpy but what the heck. I'll be looking for a maximum velocity reached as my guide, I won't be able to get a stopwatch time over a distance or anything like that. I figure if I hit 68 kph with barely a tailwind I will head to the track.

For weight training I do deep back squats, power cleans and deadlifts. I've deadlifted 240 kg at my current 80 kg bodyweight, though my squat is only 160 kg or so, deep, OL style. My vertical jump is maybe 28 inches and broad jump about 9 feet, I can power clean 110 kg (caught on straight legs) As for power output, I don't know, but I seem to have some fair amount of blast capacity.

Another sprint question. Is it better to remain standing when reaching close to max speed, or better to go into a deep aero tuck while remaining off the seat blasting away? I know the acceleration is best done standing up, but should you go into a aero position just as you approach max speed as air resistance and drag becomes enormous at 65 kph+.

VeloFlash

You are in the land of Nokia, Polar & Santa Claus, aren't you? Finland or Suomi.

I have seen pics of a velodrome in Finland. If that is the one you mean, it was in need of major surgery. So you can save your 500km round trip ride

If you are relating to accelerating on a velodrome, out of seat accelerating would only occur from low speeds. It is not efficient to be out of the seat pedalling wise with high cadence.

One of the rule of thumb guides to weight training is that you can be satisfied you have a sprinter's high proportion of FT muscle if you can back squat a minimum of 2.5 times your body weight.

If you can achieve 65kph + on a level road by yourself without a lead out then you are definitely sprinter class.

In Sydney we have a group ride known as the Bar Coluzzi ride (I may be corrected on that name). It is frequented by many top elite riders on a Saturday morning. One participating rider informed me his computer readout on quick changeover bunch sprints is 75-85kph. I would have to experience this to believe.

But it does show how a leadout improves speed.

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VF

"Remember, even if you win the rat race, you are still a rat"

bikeguy

Yeah, that's the Tampere track. I'll avoid that one. There's a track in Helsinki and I think that one's pretty good. Right now I've been training for a short TT so that's what I'll be doing next. As for 65 kph without a leadout, I'm at 60 km/h (on a hybrid with regular 32 blade spoked wheels and non-aero aluminum frame with no aero-bars) right now but I haven't got down the mechanics of sprint cycling down and I think I'm wasting quite a bit of energy. The rear wheel is also sucking something, I'll have the Mavic elite installed on Tuesday.

Thanks for informing me about how a 200 meter TT goes.

drewjc

sounds to me mr bikeguy, that you have some excellent speed and power capabilities. Hitting 60km/h on a hybrid by yourself is awesome. I have hit 61km/h on my mtb with a one man leadout and slick tyres, but i was fast running out of gears. Good luck with the training.

ecstomesm

velo flash...does the same towing technique oyu mentioned work for other events such as pursuit?? and would this be along the lines of motorpacing?

closesupport

The most i have done is 173rpm at a speed of 46.3mph generating using (53x13) on 0%??? slope thats my boast.

my max speed on the flat is 46.8mph (75.32Kph) (53x12) on 0%??? slope, 144rpm, my max power output is 661watts and i could probably squat about 160lbs but i haven't done them in a long long time my max was around 300lbs but that was some years ago, the most i have ever lifted and carried is 1 Ford Orion 1.6l Ghia engine and gearbox but again that was some years ago when i used to do weight training.

closesupport

its called echelon riding and yes they do do motorpacing for pursuit rides

velomanct

I don't know where you got that power output, but it is way off. 660watts would probally get you 33mph IF you held it till you stopped accelerating. most road sprinters(cat 3 to pro) will peak between 1400 and 1800 watts.

46mph on a flat road is world class track sprinter zone.

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closesupport

my error! well spotted velomanc i missed that, anyway - not on 0% but on a -4% slope leading, onto is where i got that, 661watts would give me 35.9mph on a flat 0% with a cadence of 109Rpm was my error with the 0% slope.

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