Would you recommend Q rings

[FanieFiets]

You are making me crazy with all your mubo jumbo!!!!!!!

I read the conclusion in the Scientific study, looked at all the pretty pictures and will now ignore you all while enjoying my funny looking new cranks.

 

[Willehond]

wat dink julle manne van ovaal wiele?

 

 

FanieFiets,  I think it is a great idea and will definitly improve your pedaling efficiency as long as the flat spot on the wheel matches up with the flat spot on the rotor, this way you will get a multiplied force efficiency that will reduce your downward friction and reduce muscle fatigue in about 59.72% of recreational riders (in the pro's this figure might be less, 55.99% is my best guess, depending on their crank length and shoe colour of course).

For the uphill sections you have to make sure that the reverse is applicable of course, i.e. flat spot on wheels line up to top position on the rotors, this effect is however severly impairder on dual suspension bikes where the natural frequency of the intelligent shock might cause suspension bridges to collapse, which will probably lead to them being banned by the UCI fun spoilers...

[mdk555]

All this is way above my head but I promise that when I get my Q-rings I will give a full report if my boet and I, all 200kg of us, climbed Hellshoogte any better, or lost the wheel sucking half bikers sooner or instead of spinning out at 78km/h on the downhill, we loose contact at 85km/h. The proof will be on the speedo.

[Johan Bornman]

Ivan writes:

 

Johan I must correct your comment they are not expensive. Expensive is in the eye of the beholder. In fact they are less expensive than some of the standard 'high'end chain rings available at present. But Q Rings have definite advatage no matter what you say.

 

Johan: They are more expensive than the stuff I use - BBB.

 

 

Ivan: May I ask if you have tried or fitted any or even seen them. If you have you will be impressed at the quality of the workmanship, engineering and style. 

 

Johan: I have seen them and ridden a distance with them. They feel like oval rings. Style is irrelevant in our discussion. Workmanship also, unless it affects the function. Engineering...kinda the same things as workmanship. There is no real engineering genius there, standard CNC stuff with some anodising which is superflous and adds to the cost.

 

Ivan: If you are skeptical about Rotor systems are you open to any other advances in bicycling technology?

 

Johan: I am open to advances. Unfortunately I have seen very, very few in the last 20 years. More gears is not an advance, just in case you ask.

 

Ivan: It seems with cyclists weght , power, carbon fibre are okay to advances but where the real problems are i.e.  in the pedalling action everyone is closed to the fact that this can be improved 

 

Johan: This is the thing. Q-rings are a solution to a problem that does not exist.

 

 

[FanieFiets]

Johan - mens kan nie oor jouself in die derde persoon praat nie. Dis weird!

[bruce]

Efficiency in my eyes would be : normal power output at less kilojoules usage per minute??<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

 

Yes, or put another way, greater power output (or work performed over a period of time) for the same kilojoules used.

 

At the end of the day, there is a difference between the power put into the pedals, and the power that reaches the road - if the same power reached the road as was put into the pedals, the drivetrain would be 100% efficient.

[Willehond]

All this is way above my head but I promise that when I get my Q-rings I will give a full report if my boet and I' date=' all 200kg of us, climbed Hellshoogte any better, or lost the wheel sucking half bikers sooner or instead of spinning out at 78km/h on the downhill, we loose contact at 85km/h. The proof will be on the speedo.

[/quote']

 

I got a pair of really cool Pearl Izumi 8-ball socks for fathers day and I wore them the first time on the Knysna road race and had an absolute screamer!  I rode a lot better due to the weave pattern and brilliant wicking power of socks, much better than my cheap ol' cotton ones.  I have therefore scientifically proven that Pearl Izumi socks make you go quicker!

 

Placebo...

[FanieFiets]

Willehond - Waar kan ek koop. Ek het dit NOU nodig! of dalk moet ek wag vir die groot races......

[pcarrasco]

 

Pablo' date=' I have to disagree with your assessment of energy returned when that chain is dropped the 30mm. It is not returned to the system, but actually lost. Unlike an elastic system such as a tyre or wheel that gives when you're pedalling, this is an inelastic loss.

 

We're talking minute quanties of energy lost here, but it's the principle that's being argued here, not the quantity.

 

Your example of spinning the crank is totally bogus. Since the energy lost is so small, friction in the system (bearings, seals, chain efficiency, freewheel etc) is far, far larger than the energy lost due to the chain being dropped and picked up each revolution. You cannot prove it by your method.

 

Johan Bornman

[/quote']

 

I disagree again. You don't need am elastic system to have an energy return: throw a ball vertically up, and will go back in some seconds.

If you put the bike pointing up, the chain movements will go side to side instead vertically, but the energy lost is the same than when the bike is flat. It is nothing to do with the 100gr of chain moving up and down.

 

Anyway, if this energy lost is too small that can be covered by the bearings, seals, chain efficiency, freewheel etc, why to lose time in it?

 

[Willehond]

Efficiency in my eyes would be : normal power output at less kilojoules usage per minute??<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

 

Yes' date=' or put another way, greater power output (or work performed over a period of time) for the same kilojoules used.

 

At the end of the day, there is a difference between the power put into the pedals, and the power that reaches the road - if the same power reached the road as was put into the pedals, the drivetrain would be 100% efficient.

[/quote']

 

Sorry guys, but the shape of your chainring cannot affect the efficiency of the power your foot affects on the chain. That power is almost a 100% transfer of the force you exert (minus crank/BB flex and lateral shoe movement maybe?).  Newton and his blerrie laws are pretty clear on that.  You loose power due to fiction and wind resistance (another form of friction) and the shape of your chainring does nada to change that.  What the chainring DOES do is vary your gear during the pedal stroke which aids riders who are inefficient pedallers (that means you lot!) to have smoother stroke and therefore maybe have a more even (i.e. smoother) power distribution, but the power output improvement is technical bs!

[bruce]

Efficiency in my eyes would be : normal power output at less kilojoules usage per minute??<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

 

Yes' date=' or put another way, greater power output (or work performed over a period of time) for the same kilojoules used.

 

At the end of the day, there is a difference between the power put into the pedals, and the power that reaches the road - if the same power reached the road as was put into the pedals, the drivetrain would be 100% efficient.

[/quote']

 

Sorry guys, but the shape of your chainring cannot affect the efficiency of the power your foot affects on the chain. That power is almost a 100% transfer of the force you exert (minus crank/BB flex and lateral shoe movement maybe?).  Newton and his blerrie laws are pretty clear on that.  You loose power due to fiction and wind resistance (another form of friction) and the shape of your chainring does nada to change that.  What the chainring DOES do is vary your gear during the pedal stroke which aids riders who are inefficient pedallers (that means you lot!) to have smoother stroke and therefore maybe have a more even (i.e. smoother) power distribution, but the power output improvement is technical bs!

 

Which is my point exactly.

[Ivanb]

 

I got a pair of really cool Pearl Izumi 8-ball socks for fathers day and I wore them the first time on the Knysna road race and had an absolute screamer!  I rode a lot better due to the weave pattern and brilliant wicking power of socks, much better than my cheap ol' cotton ones.  I have therefore scientifically proven that Pearl Izumi socks make you go quicker!

 

Placebo...

 

Hey hey don't mock socks Rotor socks will be here soon!!!

[Willehond]

.....You don't need am elastic system to have an energy return: throw a ball vertically up' date=' and will go back in some seconds.....

 

[/quote']

 

This must be the single most idiotic piece of technical mumbo jumbo that I have EVER read on the Hub.  What wonderful school of Engineering and wizardry did you go to where gravity gets related to elasticity?????!

 

I give up, this thread has turned into a complete farce.

[Willehond]

 

 

Hey hey don't mock socks Rotor socks will be here soon!!!

 

The really scary thing is that I can akshilly believe you would do that.  Keep going, don't let science get in your way...

Willehond2007-08-03 09:07:35

[Johan Bornman]

Pablo writes:

I disagree again. You don't need am elastic system to have an energy return: throw a ball vertically up, and will go back in some seconds.

 

Johan: Yes, but remember, the only way it can return energy is if that return energy can be converted into tension which is 90 degrees away from the directionof the ball (chain)'s travel. I.e. pressing down in the centre of a chainring does not put any energy into the chain.

 

The reason you are right is because your chainring is oval. Since the return cycle then finds the chain's downward force perpendicular to the chain's direction of travel but in a position offset from the centre, energy is in fact returned. It is like pressing down on the slope of a cam. You are not right because of the inelastic example but because the chainring is oval. The poster who then raised this issue originally is wrong. We both argued as if the chainring is round but still lifting the chain up and down. Therefore the net energy expended in lifting the chain up and down is zero.

 

 

Pablo writes: Anyway, if this energy lost is too small that can be covered by the bearings, seals, chain efficiency, freewheel etc, why to lose time in it?

 

Johan: I talk about it because you devised an experiment to compare energy losses. Your experiment wont work because frictional losses are larger than the measured losses and therefore obscured. Like I said, it is was an argument of principle, not quantity.

[GoLefty!!]

.....You don't need am elastic system to have an energy return: throw a ball vertically up' date=' and will go back in some seconds.....

 

[/quote']

 

This must be the single most idiotic piece of technical mumbo jumbo that I have EVER read on the Hub.  What wonderful school of Engineering and wizardry did you go to where gravity gets related to elasticity?????!

 

I give up, this thread has turned into a complete farce.

Ithink the guilty party in this case is Mr Bornman who called the rise and fall of the bicyce chain an elastic system..

 

As pablo points out it is infact a potential to kinetic energy system..

 

and now let the pedantry continue