No "route X" near me at all that I am aware of

The nearest thing I have to a flat, straight bit of tarmac lacking cars is the Bournemouth promenade.

its good apart from the pedestrians - they probably dont like me much, and I dont like having to dodge them or their dogs either. Tend to go there later rather than earlier, so theres less people during June it was nice, as its too cold for 90% of people to be standing around but its just fine for 20+ mph blatting along there

One other cool place nearby (around 6 miles from me) is in Poole Park:
view here - Google Earth

its a nice little circular lap and you can do it in the mid to high 50s before collapsing on the grass at the end - its crazy as theres always a headwind for at least one part of it which kills you

I think a Recumbent will be best for this sort of thing, seems they are built for high-speed flat-land stuff really, because of their aerodynamics. Theres plenty of dead-quiet B roads near me, which most of my loops are composed of most involve hills, but the 15mile loop we have has a 2 mile stretch of flat lovelyness where much slipstreaming ensues!

The one pictured is 9kgs - not bad really, my plastic as Max calls it, bike is only 1 / 1.5 kg less So hills wont be too bad all in all.

what google earth do you have. I want to plan a route decently I think.. need something other than the 10mile commute to work as its getting boring. Its lovely landscape but you take it for granted after youve seen it about 9 times in a week.

Google Earth, Beta 4.

Does that not worky?

theres a way of pointing google maps at a kml file, and itll go there too but I cant remember how to do it.

Quote from: M3ta7h3adFC9K im sure will kinda understand my gibberings!

Your maths is wonky.

Quotesame amount of force will be applied via the muscles in any situation upright vs recumbent... why? because the pedals move. Your maximum force applied via muscles = the maximum resistive force of the pedals.

^ Wrong in all cases except for where youre travelling at constant speed.

QuoteExcept on an upright its as follows:
Weight + Muscular Force = Maximum resistive force of pedal.

Hmmsk.  I know what youre getting at, but youve got to remember that "Muscular force" will be different for each bike; youre in a far more efficient position on a bent so youll be able to deliver a hell of a lot more power.  On an upright, the role of your arms is purely to try to keep your body in a fixed position so you can pedal with your leg muscles.  Youll evidently have more luck pushing against a solid surface since you wont dissipate as much energy in flex etc, and the chair will hold you in the right position with much more stability than your arms would.

All in all I reckon youd have an easier time of it on a recumbant, purely due to the line of action of the force youre supplying going roughly through your back into the chair.  On an upright, youre applying force sort of at an angle, so you can kinda picture you getting less "useful force" out of it.  Maybe.

You could prove this experimentally, but I cba.

[edit] YARR, cracked the badger.

You cant get any usefulness out of your weight on an upright.  Think of an energy argument; over half a crank rotation you can put energy into the cycle purely by letting your weight turn it, thus your COG drops.  Next half rotation though, youre shafted.  Your COG cant keep getting lower and lower, so you have to actually *pull yourself back up* with your leg muscles.  Since over the course of a ride your COG stays at the same vertical position relative to the bike, YOUR BODY WEIGHT HAS DONE NO NET WORK.  (nb this is dependent on whether you treat work as a vector quantity, but it should be obvious what I mean).

Oh and COG = centre of gravity.

except surely for the other half of the cycle your other leg (weight) is pushing down as well, which brings up the other leg naturally. In fact on an upright its possible to solely use the muscles in your back to facilitate a shift in weight position (rather than applying a direct force) and maintain a pedalling motion.

Quote from: M3ta7h3adexcept surely for the other half of the cycle your other leg (weight) is pushing down as well, which brings up the other leg naturally. In fact on an upright its possible to solely use the muscles in your back to facilitate a shift in weight position (rather than applying a direct force) and maintain a pedalling motion.

M3 invents a perpetual motion machine  

Get out on your bike and try it.  I guarantee you you will have to lift your own weight on the pedal to complete a full revolution of the pedals.  The only way you can avoid using your leg muscles to drive the pedals is if you wait until both cranks are horizontal before switching your weight over.  And the cranks will obviously only ever reach that position with you standing on them if a) youre going downhill in which case its irrelevent or b) total rolling and drivetrain resistances = 0, which is clearly not possible.

Not really considering you have to input energy into it.

The mere act of pushing down means your pushing the other leg up.

Anyhows physics of no physics, Ive spent the last few days reading posts in a recumbants thread on a biking forum. Appears recumbants are indeed slower up hill.

Quote from: M3ta7h3adThe mere act of pushing down means your pushing the other leg up.

...and then you have to straighten the leg.  Which means holding your weight on it.  Think about it!  If you keep it bent, then what happens?

aye I see what your getting at, and at TDC and BDC you will be applying 0 force or rather the horizontal component will be zero, itll take either weight movement or muscular force to get it to move from that point

But momentum often will be able of carrying the weight applied on a pedal around further than the TDC and BDC areas, at which point a slight shift of weight will mean that youll continue to pedal, without requiring any further exertion. (if on a frictionless flat plane, in the real world yes some exertion will be needed to recover from the losses in transmission, and friction however not as much exertion as a recumbant

I think were both saying the same things maybe

Quote from: M3ta7h3adaye I see what your getting at, and at TDC and BDC you will be applying 0 force or rather the horizontal component will be zero, itll take either weight movement or muscular force to get it to move from that point

But momentum often will be able of carrying the weight applied on a pedal around further than the TDC and BDC areas, at which point a slight shift of weight will mean that youll continue to pedal, without requiring any further exertion. (if on a frictionless flat plane, in the real world yes some exertion will be needed to recover from the losses in transmission, and friction however not as much exertion as a recumbant

I think were both saying the same things maybe

No.  Were not.  Because you seem to be conveniently forgetting the fact that at TDC, one leg is bent and the other isnt.  And like it or not, you cant just "shift your weight" to do another half-stroke.  You have to straighten the leg, and surprise surprise you have to lift your weight to do so.

No because your forgetting that when you straighten the bent leg, your straight leg will become unbent.

Apply force to raise leg out of BDC and get leg down out of TDC by a few degrees and voila... your weight and balance will take over. Your body weight is not distributed equally on both sides of the bike, the one leg (the one that is rising) will be carrying less weight than the one on the descending side.

damn physics nerds.





I dont mind if its not quite as quick up a hill.

its all about the amazing speed along the flats and the like

Quote from: M3ta7h3adApply force to raise leg out of BDC and get leg down out of TDC by a few degrees and voila... your weight and balance will take over. Your body weight is not distributed equally on both sides of the bike, the one leg (the one that is rising) will be carrying less weight than the one on the descending side.

I feel like Im banging my head against a brick wall here.  I say again, go and try it.  Youll find your error pretty quick even if the whole "conservation of energy" thing doesnt wash with you.

Quote from: funkychicken9000

Quote from: M3ta7h3adApply force to raise leg out of BDC and get leg down out of TDC by a few degrees and voila... your weight and balance will take over. Your body weight is not distributed equally on both sides of the bike, the one leg (the one that is rising) will be carrying less weight than the one on the descending side.

I feel like Im banging my head against a brick wall here.  I say again, go and try it.  Youll find your error pretty quick even if the whole "conservation of energy" thing doesnt wash with you.

I had the same problem with dave and space travel some time ago, people dont notice that when they straighten their leg from a sitting position is different from going up hill when you are going to be standing in order to maximise your weight on the pedals. In the first you dont move your body up visibly, even though that is what you are pushing against. in the second you straighten the bent leg at the top and there is a delay before the pedals turn, which is what we have been going on about, and in that case you do lift your body reducing efficiency.

I dont need to try it. Though even just pedalling a bike you will be doing this.

Conservation of energy applies to my case.

You convert potential energy in the one leg (starting just forward of TDC), to kinetic (as it moves) and potential (by lifting the other leg with the pedal).

There will be energy loss (Through friction on bearings and air resistance) but this is why you will need to use muscles to apply extra force to keep the motion going.

After the half motion (taking one leg from TDC to BDC, and the other vice versa) inertia carries the leg through the areas in which no force can be applied (if this wasnt true then youd come to a halt after pedalling one half revolution)

This brings you back to the beginning on the other leg/side.

Imagine viewing the motion from behind... youll see a pendulum motion, rocking back and forth across the top bar. That would be your center of mass. You will put the center of mass over the leg with the TDC position, and gradually swing it over to the other side as the positions of the legs swap places.

With the pedals horizontal your center of mass will be directly over the crossbar 50/50 each way.

this positioning of your mass is what I mean by using the weight of your body to power the bike.

Recumbants have no way of allowing you to use your weight to aid your pedalling. Sure they provide a solid support for you to apply force from, but all that force requires use of your muscles.

Uprights merely require muscles as supplemental input to a pedal motion.