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The pedaling technique thread

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Re: Re:

30 Dec 2017 20:58

veganrob wrote:[quote="[

If you are so sure of your methods, why don't you just supply some data as everybody asks. You can't. You sound like a badly broken record


What type of data, you can either apply additional maximal torque through TDC and 1 o'c or you can't, it's as simple as that.
backdoor
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Re: Re:

30 Dec 2017 23:44

backdoor wrote:
veganrob wrote:[quote="[

If you are so sure of your methods, why don't you just supply some data as everybody asks. You can't. You sound like a badly broken record


What type of data, you can either apply additional maximal torque through TDC and 1 o'c or you can't, it's as simple as that.

There are ways to measure maximal torque with your pedalling style to see if it is better. Why don't you use those methods along with a video to prove your point. Should be easy.
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Re: Re:

31 Dec 2017 03:42

backdoor wrote:
Alex Simmons/RST wrote:It's also completely irrelevant wrt pedalling "technique".


But pedalling technique can be very relevant where wearing and stretching of the chain is concerned,

In Noel’s super special fantasy land it might be :lol:

Got any solid data explaining how?
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Re: Re:

31 Dec 2017 14:57

backdoor wrote:... But pedalling technique can be very relevant where wearing and stretching of the chain is concerned,

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Pedalling technique might affect the wear pattern on the CHAINRING.
Increased wear in the ring sectors (relative to the crank arm) at 3 and 9 oc would indicate increased torque being applied at 3 and 9 (relative to standard clockface). If identical ring wear occured at 6 and 12, that would indicate that similar torqued was being applied at 6 and 12. I don't know if anyone has done a good analysis of chainring wear patterns. You can examine YOUR chainring by using the round shank of drill bits to measure the size of the valleys between ring teeth to determine the size and location of wear. Probaby 3 drill sizes would be adequate - largest would indicate location of greatest torque, medium, and smallest. Relative to chankarm, check at 12&6, 3&9, 4:30&10:30, and 1:30&7:30.

Chain wear/stretch is NOT relevant because which chain links bear against the ring is constantly changing, and ALL links will wear at the same rate.

Jay Kosta
Endwell NY USA
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31 Dec 2017 17:28

I did try measuring the chainring on my bike, but results were inconclusive. The 3/8inch bit wouldn't fit in any of the valleys, and the 23/64 fit in all - but it seems like some were 'looser' than others. This was done on the large chainring, I changed the inner ring several years ago and do not recall if I changed the orientation of the outer ring at that time ???

I also inspected the old inner ring and it is also difficult to measure. But there seems to be a noticeable visual difference in the 'shark tooth' wear pattern around the ring - And I don't know what the orientation of that ring was on the crank.

Perhaps with an 'inspection magnifier' and a measuring grid, a more exact determination of the wear could be established. I am confident that the teeth around the ring do NOT wear evenly, so the amount of wear could be a meaningful indicator of what sections of the ring contribute most to the crank torque.

Jay Kosta
Endwell NY USA
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Re:

08 Jan 2018 05:28

JayKosta wrote:I did try measuring the chainring on my bike, but results were inconclusive. The 3/8inch bit wouldn't fit in any of the valleys, and the 23/64 fit in all - but it seems like some were 'looser' than others. This was done on the large chainring, I changed the inner ring several years ago and do not recall if I changed the orientation of the outer ring at that time ???

I also inspected the old inner ring and it is also difficult to measure. But there seems to be a noticeable visual difference in the 'shark tooth' wear pattern around the ring - And I don't know what the orientation of that ring was on the crank.

Perhaps with an 'inspection magnifier' and a measuring grid, a more exact determination of the wear could be established. I am confident that the teeth around the ring do NOT wear evenly, so the amount of wear could be a meaningful indicator of what sections of the ring contribute most to the crank torque.

Jay Kosta
Endwell NY USA


You should first measure a new ring, to see if they're even. If a new ring isn't even, measuring a used ring isn't meaningful.

You should also skip the teeth that are ramped for changing gears. They'll wear differently because the chain will be askew on those teeth when changing gears, and the links might not line up in length 100%.

The ramps can be slotted or pinned in the ring, and can be assisted by teeth of varied height and thickness. Inspect your ring closely to mark the teeth that are expected to wear differently.

When changing gears, half the chain is on the inner ring (say 39 tooth), and half on the outer (say 53 tooth), so the inner ring will experience 53:39 more torque per tooth than the outer when changing.

Also note that on a 10 tooth ring, 5 teeth are always engaged. On a 50 tooth ring, 25. You cannot wear just one tooth.
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08 Jan 2018 14:37

The chainrings that I inspected are 'old style' aluminum rings of 1970's vintage, so they are different from modern rings. I don't know what the expected wear pattern on modern rings would be, but I expect that the sectors of greatest wear would be where most torque was being produced.

If you hold the bike stationary and apply pressure to a pedal, you'll find that very few links are actually being held tightly against the chainring. At any instant, only a few links are being 'worked', the others are just being moved around with little contact pressure.

Jay Kosta
Endwell NY USA
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Re:

08 Jan 2018 22:12

JayKosta wrote:The chainrings that I inspected are 'old style' aluminum rings of 1970's vintage, so they are different from modern rings. I don't know what the expected wear pattern on modern rings would be, but I expect that the sectors of greatest wear would be where most torque was being produced.

If you hold the bike stationary and apply pressure to a pedal, you'll find that very few links are actually being held tightly against the chainring. At any instant, only a few links are being 'worked', the others are just being moved around with little contact pressure.

Jay Kosta
Endwell NY USA


Answer from a question and answer type of forum;

"Depends how well the chain and chainring mesh. Assuming perfect alignment, exactly half the teeth are engaged.

In the real world, the chain will be somewhat elongated. So your worst case is one single tooth is taking all the strain. At this point, wear is accelerated."

Do you know where exactly in the 360 deg. chainring circle this one tooth would be positioned when taking the strain.
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Re: Re:

08 Jan 2018 23:33

backdoor wrote:... Do you know where exactly in the 360 deg. chainring circle this one tooth would be positioned when taking the strain.

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I don't KNOW exactly where, but my view is that it would be at the position where the chainline is tangent to the chainring - slightly before TDC because of the angle of the chainline from the rear sprocket to the ring.

Jay Kosta
Endwell NY USA
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Re: Re:

09 Jan 2018 10:34

JayKosta wrote:
backdoor wrote:... Do you know where exactly in the 360 deg. chainring circle this one tooth would be positioned when taking the strain.

---------------------
I don't KNOW exactly where, but my view is that it would be at the position where the chainline is tangent to the chainring - slightly before TDC because of the angle of the chainline from the rear sprocket to the ring.

Jay Kosta
Endwell NY USA



That would mean another marginal efficiency gain for Anquetil's special TT technique.
backdoor
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Re: Re:

10 Jan 2018 01:16

backdoor wrote:
JayKosta wrote:
backdoor wrote:... Do you know where exactly in the 360 deg. chainring circle this one tooth would be positioned when taking the strain.

---------------------
I don't KNOW exactly where, but my view is that it would be at the position where the chainline is tangent to the chainring - slightly before TDC because of the angle of the chainline from the rear sprocket to the ring.

Jay Kosta
Endwell NY USA



That would mean another marginal efficiency gain for Anquetil's special TT technique.


Not so , using chain tension testing there are at least 19 teeth engaged on my used chainring and chain but it's hard to get the answer.
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Re: Re:

10 Jan 2018 01:52

backdoor wrote:... Not so , using chain tension testing there are at least 19 teeth engaged on my used chainring.

-------------------------
What was the position of the crankarm for your testing?

Jay Kosta
Endwell NY USA
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Re: Re:

10 Jan 2018 12:08

JayKosta wrote:
backdoor wrote:... Not so , using chain tension testing there are at least 19 teeth engaged on my used chainring.

-------------------------
What was the position of the crankarm for your testing?

Jay Kosta
Endwell NY USA


2 and 3 o'c
backdoor
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10 Jan 2018 21:05

Yawn, more bullsniz to hide the fact you haven't actually tested your theory, coached someone to do this and reported the results, and taken up the offer to prove your claims in a biomechanics lab. We have tried your theory within the constraints of the current allowed time trial technology and there is reduced power and greatly reduced efficiency!

Provide the evidence Noel, waffle about chain wear and tug of war proves nothing.
Hamish Ferguson
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10 Jan 2018 21:49

I checked the chain on the 52T ring, and the chain seemed tight against the ring about the same as you mentioned. The ring is old and probably quite worn, the chain is relatively new (so no telling how it fits the worn teeth). On the tight section, I couldn't determine where the chain rollers were pressing firmly against the ring's teeth - or just being pulled tight between the teeth.

I think the question of 'which teeth do the most pulling?' is determined by the wear of the teeth and chain. Detailed inspection of the wear on a new ring and chain, would give the best information.

Jay Kosta
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Re:

13 Jan 2018 19:07

JayKosta wrote:I checked the chain on the 52T ring, and the chain seemed tight against the ring about the same as you mentioned. The ring is old and probably quite worn, the chain is relatively new (so no telling how it fits the worn teeth). On the tight section, I couldn't determine where the chain rollers were pressing firmly against the ring's teeth - or just being pulled tight between the teeth.

I think the question of 'which teeth do the most pulling?' is determined by the wear of the teeth and chain. Detailed inspection of the wear on a new ring and chain, would give the best information.

Jay Kosta
Endwell NY USA


That question arose as I was trying to figure out if applying max torque at 12 o'c had the same effect on friction at BB ball bearings as when applying it at 3 o'c.
backdoor
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Re: Re:

13 Jan 2018 21:03

backdoor wrote:... That question arose as I was trying to figure out if applying max torque at 12 o'c had the same effect on friction at BB ball bearings as when applying it at 3 o'c.

------------------
I don't think that pedalling techique has any perceivable affect on BB ball bearing wear. The balls and contact surfaces are hard steel, and as long as the BB is lubricated and isn't contaminated with abrasive particles the actual 'wear' would be extremely small. The bearings in wheels and headset do experience a lot of 'impact shock', so it's common to find damage from that.

Jay Kosta
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