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Losses in watts from worn drivetrain?

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Losses in watts from worn drivetrain?

Old 07-12-19, 11:00 AM
  #26  
Wilmingtech
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Originally Posted by Wileyrat View Post
You'll lose more money than watts from a worn drivetrain.
This is funny. Although if you keep the worn drivetrain it won't cost you a penny.

Originally Posted by subgrade View Post
This is'nt exactly true with cheap drivetrain components. For example, a chain and casette for $15 each will last for about 4000km before starting to skip, if the chain isn't replaced when recommended. If by timely replacement (say, after 2000km) of the chain you get 3 chains with one casette, you do 6000 km for 3x15+15=$60. That averages out $30/4000 = $0.0075/km in the former case, vs $60/6000 = $0.01/km in the latter.
Cheap crankset for $30 will outlive no less than 2 casettes, more likely 4.

Worrying about the drivetrain wear makes sense only if your cogs and chainwheels are significantly more expensive than the chain.
This is Hillarious.
1. Just a shot in the dark here but someone concerned about saving watts on a worn drivetrain is probably not running 15$ cassettes.

2. .01/km for a cheap drivetrain. I'd assume anyone counting watts is on a Dura Ace or Record Casstte. But let's say they got an Ultegra cassette on sale for 75$. 15 x 5 = 75, So .01 x 5 = .05/km

3. Wattage to Dollar amount conversion. I cant say everyone here but 100% of the people I know don't make a penny in thier lifetime from watts. If they replace their worn drivetrain it'll cost them more money than watts using that conversion method.

4. Now let's look at the cost of Watts per mile for someone who does make money. This would probably be directly related to income per revolution of the crankset. For someone like Peter Sagan 100 watts could be the difference between the Green Jersey and a million dollar contract or retirement. So 100/100,000.00 = 10,000. So about 10k per watt. In that case you would lose way more money than watts from a worn drivetrain.

Just sayin.
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Old 07-12-19, 11:21 AM
  #27  
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Originally Posted by JeffOYB View Post
How much do I lose in watts when I let my chain and cassette get worn. I'm not sure how stretched mine are right now but when I'm going really hard I'm starting to hear more sound even when the chain is lubed. Yes, I could measure the stretch. But I'm wondering about how much are the losses as a system gets worn, as measured in watts. I'm not talking about the maximum of badness of a ruined system. Just as a drivetrain wears, what happens to its efficiency? Thanks.
I'd think the efficiency loss would be so minimal it might not be measurable (specifically a worn drivechain, not a dirty one). With a worn drivetrain, I'd be more concerned about the chain skip when you put the power down for a sprint or climb.

-Sean
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Old 07-12-19, 11:51 AM
  #28  
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How many watts lost from a worn Rolhoff?

I think it's funny, but my Rolhoff got better & smoother as I rode it. For the whole drivetrain (according to those that have done the testing) it only takes 20 watts in it's lossiest gears & that is still comperable to a dirty/cross chained/worn conventional drivetrain. Easy enough to get back with decent tires, IMO...or (as noted earlier) shaved legs.

20 watts is what? About a half mile per hour? I think for the most part, no conventional utility cyclist is concerned with the fraction of a minute in travel times. For those that are concerned they won't be using an IGH anyway, & drive train cleanliness or cross chaining probably isn't the reason they didn't podium. So much more could be gained by a quality aero tuck, for example.
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Old 07-12-19, 12:02 PM
  #29  
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I bet you lose 50 watts from a worn drive train - a drive train worn to the point where the chain slips under heavy load. Maybe 51 watts.
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Old 07-12-19, 01:05 PM
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Originally Posted by tyrion View Post
I bet you lose 50 watts from a worn drive train - a drive train worn to the point where the chain slips under heavy load. Maybe 51 watts.
Close. 50.732 watts.
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Old 07-12-19, 01:23 PM
  #31  
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Originally Posted by livedarklions View Post
Close. 50.732 watts.
Depends on the lube. Perhaps we should start a thread discussing chain lube.
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Old 07-12-19, 01:42 PM
  #32  
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The OP's question brings up an interesting question.

How fast can a Wood Pecker pedal if a Wood Pecker can pedal?

Please show the math is your response.
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Old 07-12-19, 02:05 PM
  #33  
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Originally Posted by JeffOYB View Post
Whoa! I didn't know. I haven't shaved in decades. Free speed! Ha! ...Might do it! Hmmm....
Face/head matters too. Think El Pirate.
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Old 07-14-19, 07:32 AM
  #34  
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Originally Posted by JeffOYB View Post
Whoa! I didn't know. I haven't shaved in decades. Free speed! Ha! ...Might do it! Hmmm....
Hi, Jeff! Go back to your project on devices to improve aero! Lots more watts to be saved in the aero term of the bike power equation than in the rolling resistance term. But, lube your chain, take the 15 free watts or whatever, and prevent trashing your drivetrain.
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Old 07-14-19, 08:04 AM
  #35  
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Originally Posted by Wilmingtech View Post
This is funny. Although if you keep the worn drivetrain it won't cost you a penny.
It's a few dollars more if you don't replace the chains. Assuming $8-$9 chains and $15 cassettes and my usual wear and tear.

It's only a few dollars though, and I don't bother scrubbing my chains and fanatically replacing them at 1/16" stretch. But the noise, shifting and efficiency keep me doing a modicum of chain maintenance.

1. Just a shot in the dark here but someone concerned about saving watts on a worn drivetrain is probably not running 15$ cassettes.
Speak for yourself. A watt is a watt and the level of the drive train has basically nothing to do with it.
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Old 07-14-19, 08:11 AM
  #36  
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I know it's a little different scenario than the original question, but in long rides I've seen my "watts lost" from drivetrain/frame go from 2% up to 8% as the lubrication is lost on the chain. I have both P1 and powertap GS hub powermeters and in a recent ride I started with an 3w difference which about 6hrs in grew to 14w. And this was riding at a lower power around 170w. At higher wattages it is even higher. Seems to be a percentage loss rather than a fixed wattage.
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Old 07-14-19, 02:50 PM
  #37  
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Originally Posted by subgrade View Post
This is'nt exactly true with cheap drivetrain components. For example, a chain and casette for $15 each will last for about 4000km before starting to skip, if the chain isn't replaced when recommended. If by timely replacement (say, after 2000km) of the chain you get 3 chains with one casette, you do 6000 km for 3x15+15=$60. That averages out $30/4000 = $0.0075/km in the former case, vs $60/6000 = $0.01/km in the latter.
Cheap crankset for $30 will outlive no less than 2 casettes, more likely 4.

Worrying about the drivetrain wear makes sense only if your cogs and chainwheels are significantly more expensive than the chain.
The stuff on my bikes cost a few more bucks than that, but by all means run what you brung.
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Old 07-14-19, 03:20 PM
  #38  
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I found the GCN video on ceramic bearings and other watt savers interesting even I can't afford any of it.
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Old 07-14-19, 03:46 PM
  #39  
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My touring bicycle uses the Rohloff with the Gates Carbon Drive and I ride it with my Schmidt Son alternator hub always on. I also have a beard but the ceramic bearings are of internist.
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Old 07-14-19, 04:48 PM
  #40  
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Originally Posted by JeffOYB View Post
So when you're riding at 200 watts, say, 5% from worn drivetrain + 1% from badly lubed chain + 1% from stretched chain = 7% = 15 watts. Noticeable.

The old efficiency stats seem probably from WAY before the era of 10speed cassettes. I wonder what thinner chains and losses due to wear and bad lube?

Yeah, it's summer and as I struggle to keep up and hold the wheels I wonder about those stray watts here and there and if I should bother chasing them down and fixing them up.

The last time I rode easily w the fast bunch I had deep section carbon wheels. I now have bladed Ksyriums and suffer. But they seem like they'd be fast. Hmmm... Lots of screwy things to try to track down.

...Getting skinnier has always been my #1 go-to, though...
Factor in from 1% - 3% for dirty grease/wrong type.

I think ceramic bearings nullify this, only up to 2% though, as the return from ceramics less friction has to work harder with loss of lubricosity.

Spinay70
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Old 07-14-19, 06:11 PM
  #41  
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Originally Posted by BansheeTwin350 View Post
I know it's a little different scenario than the original question, but in long rides I've seen my "watts lost" from drivetrain/frame go from 2% up to 8% as the lubrication is lost on the chain. I have both P1 and powertap GS hub powermeters and in a recent ride I started with an 3w difference which about 6hrs in grew to 14w. And this was riding at a lower power around 170w. At higher wattages it is even higher. Seems to be a percentage loss rather than a fixed wattage.


Interesting! Do you lube the chain before each ride?

Fatigue could be a factor (pedaling squares).
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Old 07-14-19, 10:15 PM
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No, I haven't been lubing the chain before each ride. Probably do it every 100 miles. But I did clean and lube before that ride. I don't believe fatigue was a factor.
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Old 07-15-19, 05:17 PM
  #43  
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Originally Posted by BansheeTwin350 View Post
No, I haven't been lubing the chain before each ride. Probably do it every 100 miles. But I did clean and lube before that ride. I don't believe fatigue was a factor.
Different gears, start of the ride and later?
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Old 07-15-19, 08:14 PM
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Nope. The ride consisted of 5 HC hill climbs. My cadence and power was close on all climbs and was using the same gears.
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