Would you recommend Q rings

[Marius]

NEE, HULLE GEBRUIK EPO, DUS GOEDKOOPER EN WERK REGTIG

[FanieFiets]

 

Op hierdie oomblik nie' date=' want daar is altyd probleme met shimano en campag. Team Discovery en Astana het toetse gedoen (ek dink) en ek weet Rotor is besig om te praat met 'n span. Die koste is omtrent ?500 000.00 om 'n span to kry sonder stock.

 

Daar was a paar van die nuwe stem gebruik in die toer maar ons wag om te se wie dit gebruik het.

 

As one eitse se dan soek die ryer en span compensation en so aan en soo aan

[/quote']

 

So al ry hulle met iets kan mens nie na hulle luister nie want hulle is basies gebribe of hoog op EPO?

 

[Ivanb]

Exactly Thats why we get opinions from others.Look at product reviews on the hub and you will see what the q ring riders have to say.

 

And they look cool

[Newboy]

Ivanb. Can you try to explain the difference between position 1 to 4?

[FanieFiets]

 

Exactly Thats why we get opinions from others.Look at product reviews on the hub and you will see what the q ring riders have to say.

 

And they look cool

 

Lyk koddig, dis hoekom ek hulle laaik!

 

[Ivanb]

The positions allow to find optimum pedal positon. If you like to sit and need more power then pos 1 if you like to stand need more power position 4 etc. TT rider use pos 4 or 5 because of where they sit.

 

see www.rotorbike.com for more info

[Barend de Arend]

With oval or eleptical rings the accelerations are not uniform ,

the mass  of chain lifted varies continously etc, and at times during a

revolution of the cranks it is not lifting at all

 

The acceleration isn't uniform when pedalling with round rings.  It's faster at 3/9 o'clock and slower at 12/6 o'clock.  That's because your legs work like that.

 

Q rings are intended to make that acceleration more uniform -- not less uniform.

 

[Ivanb]

Yes Thats kinda true. But becuase with q rings the bigger gear or portion of the blade is in your power stroke between 3-6 on theclock and the smallest gear or blade size in the dead spot you do have an increase in acceleration through the dead spot which makes it easier to pedal through, making the stroke more uniform and the pedal pattern more consistent.

[peloton]

I've read around a bit, and found this to be the web's general take on :

 

 

Elliptical & non-round Chainrings.

There has been development into shaft driven bicycles, but the ?cog & chain? drive remains the most effective transmission system to date. With a chain-driven bicycle the possibility exists to vary the mechanical advantage of pedalling according to the position of the cranks, by using elliptical and non-round chainwheels.

1) Elliptical Chainrings. The idea centres on the fact that the large radius of the elliptical chainwheel can 'drive' the chain when the cranks are horizontal, with the small radius 'pulling' the chain when the cranks are vertical. As a result you will be able to 'push a higher gear' when the cranks are vertical whilst you are reaping the benefit of a smaller radius of the chainwheel during the 'dead spot' in pedalling motion. Accordingly - so the argument goes - the pedalling stroke becomes (overall) more efficient.

It has always looked great in principle, but does not work in practice. The high gear (with the cranks being horizontal) encourages the rider to push too hard - a common cause of knee problems - and the low gear (cranks being vertical) means that the knees are moving extra fast when they are changing direction (from going up or down (a "whiplash" effect).

Over time elliptical chainwheels have been re-invented and abandoned - for the same reason - every ten or fifteen years.

2) Shimano's Biopace? was a patented, computer-aided 'non-round' chainwheel design. It looked like a traditional elliptical chainring, but wasn't. It worked diametrically opposed to the 'traditional' elliptical chainwheel, as the small radius of the chainring was engaged when the cranks were horizontal, the large radius when the cranks were vertical. The Biopace? design was different from the elliptivcal chainwheel/ring, based on analysis of the motion and momentum of moving cranks and legs, unlike the static, geometric analysis that produced the first elliptical chainrings.

The theory behind Biopace? was that during the power down-stroke - the cranks being horizontal - you would be using the power of your legs to accelerate your feet, and the momentum of your feet, legs and cranks can carry you through the "dead spot" (when the cranks are near vertical). Since the rider doesn't push as hard during the Biopace?'s power phase of the stroke, and motion is slower when the leg is changing direction, the design is substantially gentler on the knees than a normal chainwheel!

Generally speaking, the slower motion at top and bottom means that as legs change direction from upward to downward/ vice versa, they will do so at a slightly slower speed. The increased leg speed near the middle of the stroke is the result of a more gradual acceleration / deceleration with the leg moving in the same direction. Thus, as Biopace? makes it easier on your knees, it may also help you 'spin' better without bouncing, as 'bouncing in the saddle' results from the changes in the legs' direction.

Biopace? chainwheels (and their derivatives) are particularly suitable for touring cyclists / any application that involves a steady, constant cadence, and they tend to allow more efficient pedalling at slower cadences than what is possible with round chainwheels. They are especially suitable for triathletes (the motion of 'transition' is a little bit closer to that of running, making it a bit easier) and mountain bikers (the design seems to somewhat smoothe out the delivery of power to the rear wheel) as traction can be increased.

Non-round chainwheels can be of real value to the majority of non-racing cyclists, but do not work well with high cadence application.

It is possible to mix Biopace? and round chainwheels on the same crankset - usually a small Biopace? chainwheel  coupled with a round bigblade - taking advantage of Biopace?s? superior (climbing) performance at low cadence, whilst having the ?big blade' available for flatland spinning.

Shimano has discontinued Biopace? chainwheels. It should also be noted that within the bicycle industry the term "biopace" has come to represent slang for any "new product" which revolutionizes a certain aspect of cycling, yet - on closer inspection - does not really perform as advertised.

 

[mdk555]

Well I can add to this that I have also ordered mine and soon the 555EXPRESS will be EXPRESSING even more. mdk5552007-08-02 04:13:36

[FanieFiets]

 

I've read around a bit' date=' and found this to be the web's general take on :

 

[/quote']

 

general take on biopace? Herhaal ager my: Biopace en Q-rings is nie dieselfde nie.

 

[Ivanb]

That is exactly why Q Rings are Q rings.They are not in any way the same as any previous elliptical rings.

 

There are studies showing reduced knee strain not increased . This is also comments of riders here with knee problems that can now ride again.

 

I have guys sending me their printouts from computrainer  tacx etc and they all have better times over the same route with increased power, reduced heart rate. 

 

You need to read on http://www.rotorbike.com/2006/q_previous.htm for more info.

[GoLefty!!]

I think the elliptical rings that the posted article mentions are the highly elliptical rings that were experimented with the early 80's.

Those were shyte.

 

I've been on Q-rings now for 6 months and they are still running well.

Knee strain is not as much as factor as it was previously  and on the MTB the Q-ring certainly helps at low cadence as mentioned for BioPace type rings in the article.

 

 

[Gumpole]

The power loss on lifting th chain is one thing' date=' but what about power spared when the chain drops off the back of the q-ring again. Thats when you have gravity working WITH you. If you factor that into yoru calculation you'll find a very small NETT difference...[/quote']

 

Hello everybody! This is Pablo form Rotor <?:namespace prefix = st1 ns = "urn:schemas-microsoft-com:office:smarttags" />SpainoN>, I am aeronautical engineer and I have personally developed all the Rotor's products.<?:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" />

Ivan invited me to response this physics? issue about energy losses being the chain every moment up & down. But in fact the answer is right here above (thanks Fand). All that energy in the chain is gained again when it comes down.

 

In physics, you can put everything in a black-box and see what in coming into and coming out. If they are different then you have not considered the heat (coming out). I can assure that the chain and Q-rings do not take more temperature than round rings do.

 

You can make a rude test: spin your cranks with round rings, turning back with the chain engaged and see how many turns the can spin until they stop due to the friction.

Then make the same with the Q-rings? and it seems just the same? friction in the BB, in the chain and in the hub.

 

Best regards,

Pablo CarrascooNNAME>

 

another chain question... doesn't the rear derailler move forward and back with each pedal stroke ( as the chain moves up and down it is also moving left and right - to keep the same shape without stretching) ???

Would this accelerate wear on this component?

[pcarrasco]

 

The rear derailleur should be moving forward and backwards twice per revolution.

 

You can calculate considering the aditional chain (to 40 cm) needed to raise its end about 1 cm. This is (40^2 + 1^2)^.5 (Pitagoras)=40.012498...less than 1 mm

 

Finally this is less than the real movements due to the terrain and also to the variations of the cyclist pedaling speed. So there is not any additional wear reported.

pcarrasco2007-08-02 11:26:05

[razlerblade]

alright alright, now educate me, wtf are Q rings