The human-powered vehicles thread. (Bicycles, etc.)

[opendro]

Originally Posted by rippergeo

@zenx- asr245 is right.
on an incline, the geared bike will be easier and faster to propel than an ungeared one.it will not help much even if you slow down(unless its a very slight incline)

In both cases, the total energy spent on climbing the same incline will be the same. Lets say- 200kcal/ or joules or whatever.

but you can spread out that energy demand over more pedal strokes in a geared bike. so instead of expending 200/20 kcal per pedal stroke i.e-10kcal,
you can spend 200/40 or 200/100 and so forth per pedal stroke in a geared bike(depending on the gears available)

what that translates into, for your muscles is that
you can use your aerobic system to provide the energy in a geared bike up a slope. that system lasts longer, is more efficient and will cause less toxic by-products that cause fatigue.

in an ungeared bike, you are forced to come up with all that energy in a very short time, which will push your muscles into anaerobic metabolism.

simple rules for gear usage
1. if you legs are hurting, downshift
2. if you're panting- upshift.
3. if both your lungs and legs are on fire- slow down.

EDIT- I agree zenx- bangy inclines are not worth using lower gears on.

On the energy spending part, I have a little different opinion. The amount of energy required to run a kilometer is not same as amount of energy to walk a kilometer. The way how a gear vehicle helps is like this: assuming I spend 2 KCal to pedal a cycle for 10 kilometers in half an hour, it does not mean that I can spend 2 KCal in one minute to run the same 10 kilometers. The point is that there is a range of force we can exert from our weight through our legs. A rolling wheel needs a certain amount of torque to roll for a given mass of the vehicle/rider at a given surface. At lower gear, you exert more torque (free-wheel radius is larger) for the same force and thus make you feel at ease to move. But it will not move that fast as in higher gear.

It is as simple as comparing between opening a heavy door by pushing near the hinge or near lock/handle. If you try pushing near hinge, the door may not even open if it is a little tight fit or heavy.

[rippergeo]

Originally Posted by opendro

On the energy spending part, I have a little different opinion. The amount of energy required to run a kilometer is not same as amount of energy to walk a kilometer. The way how a gear vehicle helps is like this: assuming I spend 2 KCal to pedal a cycle for 10 kilometers in half an hour, it does not mean that I can spend 2 KCal in one minute to run the same 10 kilometers. The point is that there is a range of force we can exert from our weight through our legs. A rolling wheel needs a certain amount of torque to roll for a given mass of the vehicle/rider at a given surface. At lower gear, you exert more torque (free-wheel radius is larger) for the same force and thus make you feel at ease to move. But it will not move that fast as in higher gear.

It is as simple as comparing between opening a heavy door by pushing near the hinge or near lock/handle. If you try pushing near hinge, the door may not even open if it is a little tight fit or heavy.

I agree with that.
did not want to complicate things, thats all. in theory, the energy used should be the same for displacing the same amount of mass. adding variables like higher wind resistance at higher speeds, less friction for rolling vs walking,the extra effort required to just stay upright while walking, the extra effort for moving more parts of the body while running etc, the list of variables is endless.

I just wanted to illustrate the fact that geared vehicles are easier to use on inclines. The example I used was crude, but I hoped it would get my point across.

[zenx]

Yep, this is essentially what I was saying - mostly from recent experience. Geared cycles make life easier up slopes and those are hardly an issue - so go ahead and get that bike, and ride!

[opendro]

Originally Posted by rippergeo

I agree with that.
did not want to complicate things, thats all. in theory, the energy used should be the same for displacing the same amount of mass. adding variables like higher wind resistance at higher speeds, less friction for rolling vs walking,the extra effort required to just stay upright while walking, the extra effort for moving more parts of the body while running etc, the list of variables is endless.

I just wanted to illustrate the fact that geared vehicles are easier to use on inclines. The example I used was crude, but I hoped it would get my point across.

Coming back to the same again I meant to say that energy spent are not same. In theory, energy or work-done is a product of force and displacement. That means, even if you are carrying a 30Kg brief case for 10 kilometers, there is no work done, because there is no displacement of the brief case against the force (gravitational pull). But in reality, we end up burning calories to lift that brief case.

Strolling, brisk walk or running will all spend different energy even for the same distance and it is not because of friction or wind resistance or something. Our body ends up spending more energy to finish the same work faster, that is all. Or should we say, a car consumes more fuel when driven hard to run the same distance... something along the same line, somewhere our internal body engine burnt extra.

[rippergeo]

Originally Posted by opendro

Coming back to the same again

opendro!
chill! lets just enjoy the cycles. enough with the physics.
I said , in theory.
I know what you mean.
our bodies do not work in a theoretical lab situation. like you said , moving faster will consume more energy in pratice

[sammyboy]

Hey wanderlust we are eagerly waiting for the pics of the roadpro and a review too would be great

[wanderlustindia]

Originally Posted by sammyboy

Hey wanderlust we are eagerly waiting for the pics of the roadpro and a review too would be great

Sammy, have clicked a few pictures the day I got it home, but have not yet riden it. Went for a trek over the weekend, hence could not get my hands on it yet.

It should happen this week as early as tomorrow morning. The pictures would follow soon. Sorry for the delay.

[V-16]

Anybody heard of FireFox cycles. They look cool but i dont know how good they are. Will someone recommend a good bike for me to use. I intend to take up cycling as a hobby and to keep fit. This bug has caught me from the time I took up spinning as an exercise (and my school days when i used to have a bike).
I want a sleek looking, comfortable bike which i can carry on my outings.
Also can someone please explain the Funda of gears in a bike.
I dont understand how they work all i know is they do not operate like in a car.

[motorheadinc]

Originally Posted by V-16

Anybody heard of FireFox cycles. They look cool but i dont know how good they are. Will someone recommend a good bike for me to use. I intend to take up cycling as a hobby and to keep fit. This bug has caught me from the time I took up spinning as an exercise (and my school days when i used to have a bike).
I want a sleek looking, comfortable bike which i can carry on my outings.
Also can someone please explain the Funda of gears in a bike.
I dont understand how they work all i know is they do not operate like in a car.

You are right to an extent that they dont work like in a car i.e. where we have a clutch too.
The gears in a cycle are simpler, you simply need to twist the shifter and thats it.

Also just like in a car or a bike you can't take off from a standstill in the highest gears. you need to start from lower gears same is true for a cycle gear.

Again like you encounter a steep climb you need to shift down to lower gears so that you have least stress on the engine.

Well in a bike your legs are the engine.

So its more or less like any vehicle powered or unpowered.

Also in a bike you can have as much as 24 gears.

You can virtually climb up 45 degree slopes, though you may go very slow but your legs wont be feeling like lifting a lot of weight.
It would be distributed evenly across the greater number of pedal strokes

[nemo]

Originally Posted by nemo

@zenx, thanks for the link and the piece of advice that i have now decided to purchase a bike. I would want to start small, I've budgeted about 5-7k and if i really see myself cycling more I'll upgrade after a year or so and buy one of the fancy bikes - Trek seems to be a popular choice but for now it appears Hero Thuder MTB is the bike i should go far.

Does anyone a have a comment or feedback on my choice of bike? Also please let me know the shops that you can recommend based on your experience. I've few names from the bikezone forum but i wanted to check here aswell.

anyone? thanks much for any help

[asr245]

Originally Posted by V-16

Anybody heard of FireFox cycles. They look cool but i dont know how good they are. Will someone recommend a good bike for me to use. I intend to take up cycling as a hobby and to keep fit. This bug has caught me from the time I took up spinning as an exercise (and my school days when i used to have a bike).
I want a sleek looking, comfortable bike which i can carry on my outings.
Also can someone please explain the Funda of gears in a bike.
I dont understand how they work all i know is they do not operate like in a car.

My brother recently bought a firefox bike (ATB) from there store in Gurgaon for 12.5K inclusive of helment, stand & mud guards. Got 21 gears (Shimano) front & rear shockers among other things. As for comfort, the seats in these bikes are small & hard (?). So if the butt hurts for the 1st few days it is normal.

[wanderlustindia]

Originally Posted by asr245

My brother recently bought a firefox bike (ATB) from there store in Gurgaon for 12.5K inclusive of helment, stand & mud guards. Got 21 gears (Shimano) front & rear shockers among other things. As for comfort, the seats in these bikes are small & hard (?). So if the butt hurts for the 1st few days it is normal.

It is advisable to use cycling shorts (padded-ones). Very helpful in the long run.

[asr245]

Originally Posted by wanderlustindia

It is advisable to use cycling shorts (padded-ones). Very helpful in the long run.

Hmm. Never considered those. How do they help?

[wanderlustindia]

Originally Posted by asr245

Hmm. Never considered those. How do they help?

Most racer/ATB/MTB cycles have seats which have very less butt support (small and narrow seats). The crotch area is subject to a lot of friction due to the constant butt movement on a cycle. Paddings in cycling shorts can protect your crotch in such cases. Ofcourse if you are running only a few kms on a daily basis, you may think this is not necessary, but for long distance commutes they help a lot. Couple this with a gel seat cover (I got one along with my RoadPro).

[asr245]

Originally Posted by wanderlustindia

Most racer/ATB/MTB cycles have seats which have very less butt support (small and narrow seats). The crotch area is subject to a lot of friction due to the constant butt movement on a cycle. Paddings in cycling shorts can protect your crotch in such cases. Ofcourse if you are running only a few kms on a daily basis, you may think this is not necessary, but for long distance commutes they help a lot. Couple this with a gel seat cover (I got one along with my RoadPro).

Hmm... that's an important area to protect . Will keep it in mind. BTW how does the RoadPro feel? Pics anytime soon?