Q ring upgrade - Ahhhhhhhhhhhhh......

ratz

Wielder of the Rubber Mallet
Ok so I understand the whole dead spot and #1 thing and I'm going with the middle cog for now unless told otherwise. Here's the problem I just ran into, I can't put the #1 mark at the first chain roller fully engaged because it would land on the unusable section between my 2 hole and 3 holes pattern found on only the 110BCD rings.

Correct some times you have to use a different bolt that will be perfectly in phase with a Hole set that isn't actually factory labeled. That will alway be 1 set of holes that lines up correctly with 1 of the bolt. The first and best is to see if the factory marks work on any of the five bolts. Because that's just easier. IF they don't they you find the unlabeled hole sets that match a bolt; and then just mark 1-5 on those holes with a sharpie.
 

RojoRacing

Donut Powered Wise-guy
Ok I did what you asked with the yellow and red box suggestion but I'm not totally clear with what your looking for as about 60-65% through the power stroke seems quite vague. I went ahead and mark both my tallest teeth with a silver line and set it at just at the first roller.
6279A195-AAC2-4311-80BB-B702AF09F056_zpshb1c9dgg.jpg
 

RojoRacing

Donut Powered Wise-guy
Correct some times you have to use a different bolt that will be perfectly in phase with a Hole set that isn't actually factory labeled. That will alway be 1 set of holes that lines up correctly with 1 of the bolt. The first and best is to see if the factory marks work on any of the five bolts. Because that's just easier. IF they don't they you find the unlabeled hole sets that match a bolt; and then just mark 1-5 on those holes with a sharpie.

I understand that but according to the idea for optimal setup I can't set #1 in a hole. What I can do is mark the tooth #1 would have landed on then continue marking the others. I just wont be able to choose #1 as an option.
 

ratz

Wielder of the Rubber Mallet
You said, "short crank arms reduce the time and size of the dead spot by virtue of the smaller diameter". My understanding of this claim is that the knee angle does not go below (approximately) 90 degrees. Therefore, the "dead spot" is consequently reduced by allowing the leg to extend from a more powerful (more advantageous) position. For example, the leg extension may start at 90 degrees instead of 75 degrees, resulting in more time spent in a powerful extension. This is because the "downtime" of the quads and related muscles would be reduced. Which means that less time would be spent in the "dead spot". It appears we agree on this point.

We agree. Optimal leg power as the muscles never have to full disengage as they bend beyond 90degrees. This is a gravy gain if you can get it; strive for minimization of the extreme angle; and rejoice if you can get complete elimination. I come up about 2 degrees short of null for my leg geometry but it's way better than the almost 12 degree of over flex I get on 170mm. As foot speed increase this gain is minimized as momentum will carry the leg throw this point with and you give velocity and reduce the force require and thus the muscle are spared the weakness.

This is where a non-round ring should help out by leveling out the mechanical advantage of the first half of the leg extension. A non-round ring would do this by changing the diameter of the chain ring, as if it were a continuously variable transmission. It appears that we agree on this point also.

Yes we agree; the diameter drop; an mechanical leverage helps the weak muscles get past that phase; There should be a micro acceleration of the foot that really can't be measure, or so the math says; and a micro deceleration give some rest on top of the leverage increase. This works similar to doing higher velocity. At the weakest point the foot moves faster... on the flat this is inconsequential

Which means we can get the same amount of driving power for a longer time. So maybe non-round rings allow us to be more efficient in a physiological sense, which translates to a given power output for a longer time
Rotor makes that claim; but provides no math or tests that are repeatable. I think they are following the thought process you are.


But what about hills?
Hills are Low Inertia Pedaling. This is where the micro acceleration comes in; when you go up step hill under heavy load any "weak" moment in the stroke will cause a "pulse" in the pedal stroke. An oval ring or a short crank allows you to compensate for that. Either use super high rpms which minimize the duration of the weak moment; Or use ovals to allow you to micro-accelerate in that dead spot and gain leverage. When you blast down a flat you don't notice this as inertia keeps you rolling if your pedal pressure is uneven. When you climb steeps inertia vanishes much faster making it suddenly a problem when pedal pressure wavers.

I will use a great example from Portland. I had the pleasure to ride the 100miles in the hills with Tom. He was on his Silvio and he's a a flat lander from Texas. Beautiful pedal rhythm; I'd follow behind him and it was like watching a metronome on the flats; truly fun to watch. Elliot for that matter too. But when the road turned up; I would watch as Tom would hit this "hitch" in his pedal stroke; right at the dead spot his rhytm would be disrupted; and you could see him loose forward momentum each time he hit that; it was like clock work and he'd have to slow way down and spin up the hill. To go faster up the hill he needs some more mechanical advantage to smooth that out. He's going to try an QXL and report back.... I have a ton of gun camera footage from that day from PluckyBlonds bike. I'm going to try and find some footage of him climbing that with his permission we can clip out to show the effect... It's really easy to see on someone else but not so easy to see on ourselves when we ride.

The force to the pedals over time and the distance traveled (by the drive wheel on a roller) vs. the oxygen use and carbon dioxide production should tell us how efficient the non-round chain ring system is compared with a round chain ring system.
Yes; it would total a v02max stress test system to do that. Low Inertia; high resistance to failure with full O2 exchange measurement to really tell how it all comes together. I agree with that very expensive


Small non-round chain ring? I remember that you suspected the small non-round chain ring would have a lesser effect than the large non-round chain ring. I think the effect would be identical as long as the shape and ratio of the two non-round rings are exactly the same.
Ah I was un clear. The Small Oval rings are Less Oval because of the Limits of the 110 BCD diameter. A 34T Q ring is less Oval than a 36TQ ring The 36 is has the same ratio of the big ones the 34 does not. So for 110BCD a 36T QXL with has the same 15% oval as the Big QXL and it's actually smaller than the 34Tq on it's minimum axis and bigger than the 36Tq on it's major access. So on a 110BCD the 36QXL is the better product even though the "number on it's label 36" is bigger than that on the 34Tq. Does that clear that up?

The trick is to determine the specific ring shape for a given person through math, and then prove it through measurement.

Good, fast, cheap pick 2 :) We do not disagree;

My only remaining point is that there are dimensioning gains. If you get a gain of "2" from ovals; and a gain of "2" from short cranks; at some point in the combinations 2+2 = 3 instead of 4. But that's still better than only get a gain of 2. And that is what I believe made Larry's test some what hard to review in a vaccum and why the discussion is so useful.

Note: also really good therapy as I wait for my sprained ankle to finish healing.
Note2: Your line of thought is very much in sync with Mark Stonich's opinions
 
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ratz

Wielder of the Rubber Mallet
Ok I did what you asked with the yellow and red box suggestion but I'm not totally clear with what your looking for as about 60-65% through the power stroke seems quite vague. I went ahead and mark both my tallest teeth with a silver line and set it at just at the first roller.
6279A195-AAC2-4311-80BB-B702AF09F056_zpshb1c9dgg.jpg

that crank position is something John T computed a long time ago and it's an alternative to Rotors tricks; it yields the same result and it's very handy in these cases. At that crank position you have reach the ½ way point in the max diameter and are now getting easier. In theory that crank position should be the strongest point in your push; it builds to that point and then gets weaker; therefore at the peak you want the max leverage from the max tooth to be occurring. There's actually an entire thread about this in the archives.

So that actually looks very good. I would say you should test pedal that.

My Guesses are as follows: Placing #2, #4 on that bolt should feel pretty good; #2 should feel stronger; #4 should spin smoother and accelerate better.
This is based on what I recall from your photos of you on the bike.
#1 should also feel super strong but constantly a hard to pedal force. Larry likes that; I don't

If that's all true.... #3 and #5 will liking feel out of phase or Jerky.
IF #2 and #4 feel out of phase then #3 and #5 should be smooth work and #1 will be complete crap.

You just need to test now and see.

Very curious to see what you think.
 

RojoRacing

Donut Powered Wise-guy
Ok so here is the ring with new positions marked. It seems I'm about 1.5 teeth off the original but I'm going to just call it 1 tooth because I can't offset 1.5. So I can't choose #1 or #2 positions but I can pick #s 3, 4 & 5 which are more like 3.5, 4.5 & 5.5 but now were splitting hairs. Another thing I'll note is the advancement between each hole or numbered position is greatly different between the 110 rings and the 130 rings. Advancing 1 position on the larger 130 ring is comparable 1.5 on the smaller 110 ring. I'll just start with my sharpy marked position 4 as it's my middle option available and then I'll try 3 & 5 later.

2BB03DDE-0D79-475E-AE1F-484116A3F2A5_zpsywfevhws.jpg
 

RojoRacing

Donut Powered Wise-guy
that crank position is something John T computed a long time ago and it's an alternative to Rotors tricks; it yields the same result and it's very handy in these cases. At that crank position you have reach the ½ way point in the max diameter and are now getting easier. In theory that crank position should be the strongest point in your push; it builds to that point and then gets weaker; therefore at the peak you want the max leverage from the max tooth to be occurring. There's actually an entire thread about this in the archives.

So that actually looks very good. I would say you should test pedal that.

My Guesses are as follows: Placing #2, #4 on that bolt should feel pretty good; #2 should feel stronger; #4 should spin smoother and accelerate better.
This is based on what I recall from your photos of you on the bike.
#1 should also feel super strong but constantly a hard to pedal force. Larry likes that; I don't

If that's all true.... #3 and #5 will liking feel out of phase or Jerky.
IF #2 and #4 feel out of phase then #3 and #5 should be smooth work and #1 will be complete crap.

You just need to test now and see.

Very curious to see what you think.

So after all of that hoping over one another as I tried stuff waiting for you responses I kind of ended up at what you suggested. I'm starting with my marked #4(the originally mark #2 you suggested) at your suggested bolt hole.
 

ratz

Wielder of the Rubber Mallet
Ok so here is the ring with new positions marked. It seems I'm about 1.5 teeth off the original but I'm going to just call it 1 tooth because I can't offset 1.5. So I can't choose #1 or #2 positions but I can pick #s 3, 4 & 5 which are more like 3.5, 4.5 & 5.5 but now were splitting hairs. Another thing I'll note is the advancement between each hole or numbered position is greatly different between the 110 rings and the 130 rings. Advancing 1 position on the larger 130 ring is comparable 1.5 on the smaller 110 ring. I'll just start with my sharpy marked position 4 as it's my middle option available and then I'll try 3 & 5 later.

2BB03DDE-0D79-475E-AE1F-484116A3F2A5_zpsywfevhws.jpg

Ok see what you see now.

Your plan seems workable.

The other question would be:
Do any any of the other 3hole 2hole pairs line up on other bolts? It doesn't to be that cluster you marked;
usually one of the other blocks of three or block of two will line up on one of the 5 bolts. but we haven't had many people try those new hidden bolt cranks yet so you are blazing a trail.
 

ratz

Wielder of the Rubber Mallet
So after all of that hoping over one another as I tried stuff waiting for you responses I kind of ended up at what you suggested. I'm starting with my marked #4(the originally mark #2 you suggested) at your suggested bolt hole.
Yup. I'd say great minds think alike but at this time of the night I'm squarely in the simple minds have obvious thoughts camp. but you make me feel smart so go with it.
 

RojoRacing

Donut Powered Wise-guy
Ok see what you see now.

Your plan seems workable.

The other question would be:
Do any any of the other 3hole 2hole pairs line up on other bolts? It doesn't to be that cluster you marked;
usually one of the other blocks of three or block of two will line up on one of the 5 bolts. but we haven't had many people try those new hidden bolt cranks yet so you are blazing a trail.

It looks like if I count from the tallest tooth around to the original #1 it 15.5 teeth to the bolt hole. Now if I do the same from the tallest tooth on the opposite side 15.5 teeth nearly lands in one of the 2 hole pairs. SOOOO theoretically if I go that route I should gain my #1 and 2 back but loose my 4 and 5. You may be 3hrs ahead of me in time zones but I'll bet I go to bed 3 hrs earlier so we are both not in the prime of mind to dissect this.
 

ratz

Wielder of the Rubber Mallet
It looks like if I count from the tallest tooth around to the original #1 it 15.5 teeth to the bolt hole. Now if I do the same from the tallest tooth on the opposite side 15.5 teeth nearly lands in one of the 2 hole pairs. SOOOO theoretically if I go that route I should gain my #1 and 2 back but loose my 4 and 5. You may be 3hrs ahead of me in time zones but I'll bet I go to bed 3 hrs earlier so we are both not in the prime of mind to dissect this.
Ah that would be cool if you can keep it straight in your head you would have almost all of the positions; just not linearly adjacent. But then I think you'll like #4 most of use do that report RPMs equal to what you have stated. And yes I'm about ready to call it a night; gotta get this leg healed so can pedal
 

super slim

Zen MBB Master
We agree. Optimal leg power as the muscles never have to full disengage as they bend beyond 90degrees. This is a gravy gain if you can get it; strive for minimization of the extreme angle; and rejoice if you can get complete elimination. I come up about 2 degrees short of null for my leg geometry but it's way better than the almost 12 degree of over flex I get on 170mm. As foot speed increase this gain is minimized as momentum will carry the leg throw this point with and you give velocity and reduce the force require and thus the muscle are spared the weakness.



Yes we agree; the diameter drop; an mechanical leverage helps the weak muscles get past that phase; There should be a micro acceleration of the foot that really can't be measure, or so the math says; and a micro deceleration give some rest on top of the leverage increase. This works similar to doing higher velocity. At the weakest point the foot moves faster... on the flat this is inconsequential


Rotor makes that claim; but provides no math or tests that are repeatable. I think they are following the thought process you are.



Hills are Low Inertia Pedaling. This is where the micro acceleration comes in; when you go up step hill under heavy load any "weak" moment in the stroke will cause a "pulse" in the pedal stroke. An oval ring or a short crank allows you to compensate for that. Either use super high rpms which minimize the duration of the weak moment; Or use ovals to allow you to micro-accelerate in that dead spot and gain leverage. When you blast down a flat you don't notice this as inertia keeps you rolling if your pedal pressure is uneven. When you climb steeps inertia vanishes much faster making it suddenly a problem when pedal pressure wavers.

I will use a great example from Portland. I had the pleasure to ride the 100miles in the hills with Tom. He was on his Silvio and he's a a flat lander from Texas. Beautiful pedal rhythm; I'd follow behind him and it was like watching a metronome on the flats; truly fun to watch. Elliot for that matter too. But when the road turned up; I would watch as Tom would hit this "hitch" in his pedal stroke; right at the dead spot his rhytm would be disrupted; and you could see him loose forward momentum each time he hit that; it was like clock work and he'd have to slow way down and spin up the hill. To go faster up the hill he needs some more mechanical advantage to smooth that out. He's going to try an QXL and report back.... I have a ton of gun camera footage from that day from PluckyBlonds bike. I'm going to try and find some footage of him climbing that with his permission we can clip out to show the effect... It's really easy to see on someone else but not so easy to see on ourselves when we ride.


Yes; it would total a v02max stress test system to do that. Low Inertia; high resistance to failure with full O2 exchange measurement to really tell how it all comes together. I agree with that very expensive



Ah I was un clear. The Small Oval rings are Less Oval because of the Limits of the 110 BCD diameter. A 34T Q ring is less Oval than a 36TQ ring The 36 is has the same ratio of the big ones the 34 does not. So for 110BCD a 36T QXL with has the same 15% oval as the Big QXL and it's actually smaller than the 34Tq on it's minimum axis and bigger than the 36Tq on it's major access. So on a 110BCD the 36QXL is the better product even though the "number on it's label 36" is bigger than that on the 34Tq. Does that clear that up?



Good, fast, cheap pick 2 :) We do not disagree;

My only remaining point is that there are dimensioning gains. If you get a gain of "2" from ovals; and a gain of "2" from short cranks; at some point in the combinations 2+2 = 3 instead of 4. But that's still better than only get a gain of 2. And that is what I believe made Larry's test some what hard to review in a vaccum and why the discussion is so useful.

Note: also really good therapy as I wait for my sprained ankle to finish healing.
Note2: Your line of thought is very much in sync with Mark Stonich's opinions
Guys I wish you would stop discussing the virtues of Q rings for climbing, especially when watching Tom climbing, as it has FORCED me to go and buy a QX2 inner ring for my triple, to replace the circular, as I could only buy double Qrings in 2011?!!!
$112 AU from Velotech UK, OR $183 AU Backcountry USA.
 

JOSEPHWEISSERT

Zen MBB Master
Guys I wish you would stop discussing the virtues of Q rings for climbing, especially when watching Tom climbing, as it has FORCED me to go and buy a QX2 inner ring for my triple, to replace the circular, as I could only buy double Qrings in 2011?!!!
$112 AU from Velotech UK, OR $183 AU Backcountry USA.
Me too! Now I won't be able to rest until I get a new, small chain ring.
 

JOSEPHWEISSERT

Zen MBB Master
For anyone who's interested, here is a super easy method of tuning an elliptical chain ring. I realized that I could tune mine this way after finding the holes too complicated for my taste. This is based on my mechanical advantage theory. I realized this last year and it has worked ever since. I also was able to correct the poor tuning that resulted from trying to follow the manufacturer's instructions, which made me feel as if I had been doing squats. With my brain. After tuning the big ring this way, it felt really smooth, which is very desirable. It makes a noticeable difference when fighting supervillains (such as bike shop owners who would like to wipe recumbents from the face of the earth. Or would like to make recumbents drink from different water fountains. Or make recumbents ride at the back of the pack with all the slowest C riders. Or treat recumbents as if they all have offensive body odor. Even though said bike shop owner puked out after a measly hundred and ninety miles, what a wuss. A poor excuse for a supervillain. Kind of a let down really. But I digress.)

First, find a friend to help if you can. If you have no friends (or if you're an IT guy - same thing), you can still do it yourself, but you might have a lower quality of life and might not live as long.

Put your bike on a trainer so you can pedal as if you were actually riding. You won't go anywhere, but if you have no friends, then why would you need to go anywhere anyway?

Shift your chain ring to the big ring. Shift your cog to one that is somewhere in the middle. For instance, if you have ten cogs, the largest is number one and the smallest is number ten. Pick a cog somewhere around six, seven, or eight. The difference is that different cog size will affect tuning. So there is a little compromise here. One cog will be optimal, but the others will only be close to optimal.

With both feet locked in to the pedals, turn the cranks a few times to get a feel for the maximum leg extension. This is the crank arm position where the right leg is fully extended, but only as much as the crank arms allow so the leg will still be a little bent at the knee. This is the end of the pedal stroke for the right leg. You don't need the chain or chain ring connected to find this position if you don't have them connected. Find a way to mark the angular position of the right crank arm. This is where a friend can help. If your "friend" makes this part exceptionally difficult, then you might have confused your friend for your future ex-wife.

Dismount from the bike. Pirouette with good form until facing the chain ring. Enjoy the applause. Find a way to lock your crank arm in the fully extended position that you just determined and marked. This is also the position where your left leg would be at its most disadvantaged position (at the beginning of the stroke) and would need the most help from the non-round ring. So at this position, the chain ring should provide the most leverage, which it will provide by having the least diameter.

Follow the chain in the direction of travel from the cog to the chain ring. The tooth on the chain ring where the chain first touches the ring is the point of tangency. Draw an imaginary line from this point of tangency to the center of the chain ring. Call this imaginary line the radius.

This is the critical tuning part. Adjust the anglar position of the chain ring so that the radius is the smallest when the crank arm is in the position where your leg would be fully extended.

Now your pedal stroke will get the most leverage where it needs it the most, which is at the beginning of the pedal stroke. And the leverage will gradually decrease as your leg extends to the halfway point of the stroke, where the ring's leverage will be at its minimum and the trigonometric effect of the force to the crank arm will be at its maximum. This is where the radius of the chain ring at the point of tangency will be at its maximum. For the second half of the stroke, the leverage will gradually increase from minimum to maximum as your leg's mechanical advantage continues to increase, but is effectively reduced by the trigonometric effect of the crank arm angle relative to the applied force.

Now, set the resistance on your trainer and feel the "smooth". You won't believe it's not butter.

If you've already tuned your chain ring some other way, you can double check it with this method. If you don't like this method, please don't beat me like a red headed step Balor.

Last step. Go out and fight for your right to paaaaaaaaaar-teeeeeee.
 
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super slim

Zen MBB Master
FSA Gossamer pro triple , cut down from 175 to 153 by Bikesmith Design, who is another Eskimo that lives in Ratz's town!

http://bikesmithdesign.com/Short_Cranks/index.html
He can not shorten Carbon cranks, only u shaped Aluminium, and SOME older Al hollow cranks.
He normally buys new cranks that he knows there is enough meat on them, and shortens them!
He does an excellent job, answers all silly questions, even after reading his very informative web site.

He even bought a set of Q rings (cheaper than I could) and set them up perfectly on a new shortened crankset, and sent them to Bellingham WA, where I installed them and then rode my Quest north to the Canada border, decided I did not like it and turned around and rode south until I hit the Mexican border!
 

Dave Arnold

Active Member
Does this look like OCP #4? Chain is not completely in Regulation #1, but very very close. Cranks are positioned in my dead zone. Q-Rings are 52/36 110 BCD if it matters.

IMG_0443.JPG
 

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