CrazyEngineers Archive

Old, but evergreen and popular discussions on CrazyEngineers, presented to you in read-only mode.

@vvishwaskumar • 19 Nov, 2009

hi

i have a bicycle having a load of 100 kg acting on it. I have to calculate the starting torque, to propell the bicycle, either on the wheel or on to the pedal(crank) considering the rolling friction....please give some numerical explaination...please

i have a bicycle having a load of 100 kg acting on it. I have to calculate the starting torque, to propell the bicycle, either on the wheel or on to the pedal(crank) considering the rolling friction....please give some numerical explaination...please

@gohm • 19 Nov, 2009
You are missing information. gear ratio? wheel diameter? length of crank arm? With your info you can only deduce the load is 50kg per wheel if two wheeled. You will take this 50kg weight at the drive wheel and multiply by the ratio of drive wheel size vrs. crank arm. Then multiply by the ratio of the front vrs. rear sprockets.

@vvishwaskumar • 20 Nov, 2009

gear ratio = front sprocket/rear sprocket =2

length of crank arm= 0.17 metres

wheel radius= 0.33 metres

so effort required = 50*2*(0.33\0.17) =

torque on pedal = 194.14*0.17*9.81 =

also

hello gohm..gohmYou are missing information. gear ratio? wheel diameter? length of crank arm? With your info you can only deduce the load is 50kg per wheel if two wheeled. You will take this 50kg weight at the drive wheel and multiply by the ratio of drive wheel size vrs. crank arm. Then multiply by the ratio of the front vrs. rear sprockets.

gear ratio = front sprocket/rear sprocket =2

length of crank arm= 0.17 metres

wheel radius= 0.33 metres

so effort required = 50*2*(0.33\0.17) =

**194.14 kg**torque on pedal = 194.14*0.17*9.81 =

**323.76 N-m****is it possible to have this much of torque..?**also

**a 150 cc bike is normally have 14 to 16 N-m torque, can it compare with bicycle calculation..? give me detailed explaination please**
@BigOhm • 20 Nov, 2009
100 kg? Gohm, tell your little brother to quit riding on the handlebars?:roll:😁

vvishwaskumar,

There are a bunch of ways of looking at this, but one you might consider is just in terms of work. Think of the 100 kg bike. It's weight is 980 N and you might guess the rolling friction to be 0.05 with good tires and a good level surface. So, every meter the bike goes, you have 49 Nm of work. So work backwards and see how many radians your pedal crank has to go through to move the bike one meter. Throw in a 0.70 efficiency factor for the chain, bearings, etc etc. Then just set (Torque)(radians)(0.70) = 49 Nm.

Sorry for not using math symbols. I'm a newbie and can't find them.

vvishwaskumar,

There are a bunch of ways of looking at this, but one you might consider is just in terms of work. Think of the 100 kg bike. It's weight is 980 N and you might guess the rolling friction to be 0.05 with good tires and a good level surface. So, every meter the bike goes, you have 49 Nm of work. So work backwards and see how many radians your pedal crank has to go through to move the bike one meter. Throw in a 0.70 efficiency factor for the chain, bearings, etc etc. Then just set (Torque)(radians)(0.70) = 49 Nm.

Sorry for not using math symbols. I'm a newbie and can't find them.

@Rohan_sK • 20 Nov, 2009
Gohm, dont you think that the Total Weight of the bike ie 100 kg must be considered while calcualting the Work done or hte Effort needed.

The bike weighs 100 kg, so each wheel takes up 50 kg. But the force required to drive will be the total Inertia force ie 100 kg plus the frictional resistance ( here 0.05).

So, Total Effort ( without the sporcket ratios, etc) = (W+f)9.81 = (100 + 0.05(100))(9.81). You can then multiply the sprocket wheels, crank arm ratios and get the Final Effort and Torque required.

Correct me if I am wrong.

The bike weighs 100 kg, so each wheel takes up 50 kg. But the force required to drive will be the total Inertia force ie 100 kg plus the frictional resistance ( here 0.05).

So, Total Effort ( without the sporcket ratios, etc) = (W+f)9.81 = (100 + 0.05(100))(9.81). You can then multiply the sprocket wheels, crank arm ratios and get the Final Effort and Torque required.

Correct me if I am wrong.

@vvishwaskumar • 21 Nov, 2009

also a 150 cc bike is normally have 14 to 16 N-m torque, can it compare with bicycle calculation..? 100kg=bicycle weight(15kg) + rider weight(85kg)

thanks rohan, but how this much torque is possible..think andRohan_sKGohm, dont you think that the Total Weight of the bike ie 100 kg must be considered while calcualting the Work done or hte Effort needed.

The bike weighs 100 kg, so each wheel takes up 50 kg. But the force required to drive will be the total Inertia force ie 100 kg plus the frictional resistance ( here 0.05).

So, Total Effort ( without the sporcket ratios, etc) = (W+f)9.81 = (100 + 0.05(100))(9.81). You can then multiply the sprocket wheels, crank arm ratios and get the Final Effort and Torque required.

Correct me if I am wrong.

also a 150 cc bike is normally have 14 to 16 N-m torque, can it compare with bicycle calculation..? 100kg=bicycle weight(15kg) + rider weight(85kg)

@vvishwaskumar • 21 Nov, 2009
hey guys help me for calculation......please

@rpower • 22 Nov, 2009
give the coefficient of friction.

You want to calculate starting torque that means the torque to overcome static friction bw wheel and ground.

static friction(forcew) = u(coeff of friction) x N (weight normal reaction)

torque at wheels=forcew x radius of wheel.

divide this by 2(gear ratio)

u'll get the torque applied by rider to accelerate the bike from 0.

You want to calculate starting torque that means the torque to overcome static friction bw wheel and ground.

static friction(forcew) = u(coeff of friction) x N (weight normal reaction)

torque at wheels=forcew x radius of wheel.

divide this by 2(gear ratio)

u'll get the torque applied by rider to accelerate the bike from 0.

@vvishwaskumar • 22 Nov, 2009
😁

i am getting from this .torque on pedal = 8 Nm and effort applied on pedal=5 kg..and it looks feasible because 150cc bike normally have 15 Nm of torque.

also can we compare the bicycle torque with that of bike..in terms of their mechanics....? reply please

thanx rpower...rpowergive the coefficient of friction.

You want to calculate starting torque that means the torque to overcome static friction bw wheel and ground.

static friction(forcew) = u(coeff of friction) x N (weight normal reaction)

torque at wheels=forcew x radius of wheel.

divide this by 2(gear ratio)

u'll get the torque applied by rider to accelerate the bike from 0.

i am getting from this .torque on pedal = 8 Nm and effort applied on pedal=5 kg..and it looks feasible because 150cc bike normally have 15 Nm of torque.

also can we compare the bicycle torque with that of bike..in terms of their mechanics....? reply please

@rpower • 22 Nov, 2009

I do not understand your question compare torque of bicycle with motorbike "in terms of mechanics" !!😒vvishwaskumar😁

thanx rpower...

i am getting from this .torque on pedal = 8 Nm and effort applied on pedal=5 kg..and it looks feasible because 150cc bike normally have 15 Nm of torque.

also can we compare the bicycle torque with that of bike..in terms of their mechanics....? reply please

@vvishwaskumar • 23 Nov, 2009

also we are using a chain drive for transmitting torque from wheel to pedal...so is there no any consideration for tension on sides and moment of inertia....?

a 150 cc bike is normally have 14 to 16 N-mrpowerI do not understand your question compare torque of bicycle with motorbike "in terms of mechanics" !!😒

**torque**, can it compare with bicycycle torque...?also we are using a chain drive for transmitting torque from wheel to pedal...so is there no any consideration for tension on sides and moment of inertia....?

@rpower • 23 Nov, 2009
in a bike or car there are several inertial loses. innertial loses in transmission , then in differential (in cars), in running engine components.

e.g Torque(clutch)=torque(engine)- Ia

where I is moment of inertia of engine cmponents and a angular acceleration

e.g Torque(clutch)=torque(engine)- Ia

where I is moment of inertia of engine cmponents and a angular acceleration

@vvishwaskumar • 23 Nov, 2009

sorry

but in calculating torque do u not think that, as the power is transmitted by chain drive from front to rear sprocket, there is also a consideration of tension in the chain...?

rpowerI do not understand your question compare torque of bicycle with motorbike "in terms of mechanics" !!😒

sorry

but in calculating torque do u not think that, as the power is transmitted by chain drive from front to rear sprocket, there is also a consideration of tension in the chain...?

@rpower • 24 Nov, 2009
Ofcourse, tensions on tight side (upper) and slack side (down) of the chain drive are to be taken into account.

[T(tight) - T(slack)] velocity = Power

[T(tight) - T(slack)] velocity = Power

@gohm • 24 Nov, 2009
As far as the weight issue, it totally depends on if you are only condsidering torque at the drive wheel. Energy loss would be used in the calculation to equate a procise calculation however this problem does not appear to need to factor that based on the info provided by the OP. Sounds like a class theory problem.

@sachin121 • 06 Sep, 2010
hi have vehical of four wheels having 150mm dimeter. i need to transport load of 50kg with velocity 3m/s then which motor should i select .please send me motor specification

@sophia9rev • 09 Sep, 2010
some great tip guys..😀 ....my dads a mechanical engineering but heslearning to use the forums

@beyonbala • 09 Jun, 2011

Also when searched for static friction co efficient between wheel and tyre, it is found to be 0.7-0.8.

what is that 0.05?

I don't understand how did u arrive at 15Nm ..vvishwaskumar😁

thanx rpower...

i am getting from this .torque on pedal = 8 Nm and effort applied on pedal=5 kg..and it looks feasible because 150cc bike normally have 15 Nm of torque.

also can we compare the bicycle torque with that of bike..in terms of their mechanics....? reply please

Also when searched for static friction co efficient between wheel and tyre, it is found to be 0.7-0.8.

what is that 0.05?

@techfresh • 14 Jun, 2011
with out specifying the force you are applying at the pedal/crank how can you calculate the torque ??? the weight is acting over the bicycle not on the pedal ,please be specific about your question

techfresh

techfresh

@Dev92 • 29 Mar, 2015
Hey fellas, i am working on a project where in which i have brought a few changes to pulsar 150 bike, my end result is increase in rpm which we have achived, now help me out about how to calculate the torque for the same??? plz reply

@wanderer2711 • 16 Sep, 2015
will the torque applied be reduced/increased when we use a shaft drive instead of a chain drive ?

@wanderer2711 • 16 Sep, 2015
will the torque applied be reduced/increased when we use a shaft drive instead of a chain drive ?

@Deepak Durgasrinivas • 25 Sep, 2015
Generally what is cycle weight which was commonly using in India and how much force is applying on pedal

@ImSj17 • 11 Mar, 2016
I am designing a electric bicycle... Load applied is 120 Kg so how can I calculate torque if I use 600 watt motor

17.5k views

## Related Posts

@Ankita Katdare · Feb 9, 2014

TeLEOS-1 is the first commercial remote sensing satellite being developed by Singapore Technologies Electronics Limited (ST Electronics) to be launched in 2015. It has come to light that for the...

10.8k views

@chiru2218 · Jul 16, 2009

I would plz like s/w & n/wng professionals to post their views on aspects like job stress,demand for their skills,compensation,security of job,working hrs etc.Your views will be most valuable to...

7k views

@Kaustubh Katdare · Feb 27, 2016

Idea cellular is sending texts announcing the launch of 4G services and I'm willing to give them a try (before the big daddy Reliance Jionet sets its foot). The latest...

66.1k views

@Ankita Katdare · Mar 27, 2014

Sony India has launched the first DTH Theatre in India with Sony HT-IV300 home entertainment system. Providing the viewers with great sound quality, the Sony DTH Theatre system features an...

18.7k views

@SHAIK NAFEEZA · Jan 13, 2016

i just want to know the oppurtunities of selinum testing tool.can you people guide me whether the selinium is best or not.

5.1k views