Oversized Pulley System Questions
04-17-19, 07:43 AM
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Oversized Pulley System Questions
Hi Guys,
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 180, speed will be 30kmph?
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 180, speed will be 30kmph?
04-17-19, 08:32 AM
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I don't have, nor have I ever used, over-sized pulleys, but I think that even the marketing departments of manufacturers like Ceramicspeed would dismiss your power savings numbers as being 2-4x too optimistic.
I think, and it's very possible that I'm wrong, that the claimed benefit has to do with the frictional losses as chains wrap around a smaller radius - the more the chain has to bend, the more friction it'll see (much like track cyclists avoid really small cogs on the rear and would rather achieve their desired gearing ratio by going with chainrings larger than typically used in road riding scenarios). Going to over-sized pulleys helps to flatten out the (relatively) tight S-turn that the chain has to pass through, so it should help, but I would be shocked by anything on the order of 10% (I think that an ordinary, well-maintained drivetrain transfers well more than 90% of your effort, so 10% should be a non-starter).
I think, and it's very possible that I'm wrong, that the claimed benefit has to do with the frictional losses as chains wrap around a smaller radius - the more the chain has to bend, the more friction it'll see (much like track cyclists avoid really small cogs on the rear and would rather achieve their desired gearing ratio by going with chainrings larger than typically used in road riding scenarios). Going to over-sized pulleys helps to flatten out the (relatively) tight S-turn that the chain has to pass through, so it should help, but I would be shocked by anything on the order of 10% (I think that an ordinary, well-maintained drivetrain transfers well more than 90% of your effort, so 10% should be a non-starter).
04-17-19, 05:23 PM
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Hi Guys,
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 199, speed will be 30kmph?
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 199, speed will be 30kmph?
04-17-19, 05:52 PM
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04-17-19, 06:14 PM
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04-17-19, 09:41 PM
#8
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Hi Guys,
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 180, speed will be 30kmph?
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 180, speed will be 30kmph?
04-18-19, 04:18 AM
#10
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Ceramic Speed claims 2w savings for the pulleys, and more power savings if you use their other ceramic bearings and chain products - up to a total of 16w. You can see their claims here, with time savings claims on flat and hilly (2% anyway) courses.
The time savings come because you would either increase cadence or shift to a higher gear and apply the power that used to go to drive-train friction to moving the bike forward faster. Think of it like a reduced headwind, or a more aero position - albeit, a really expensive one...
The time savings come because you would either increase cadence or shift to a higher gear and apply the power that used to go to drive-train friction to moving the bike forward faster. Think of it like a reduced headwind, or a more aero position - albeit, a really expensive one...
04-18-19, 05:31 AM
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Hi Guys,
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 180, speed will be 30kmph?
I am not quite sure about ospw. As I know, ospw suppose to be helping on the climbing but my question is how it helps? Some saying giving extra gear ratio, some saying pedalling at lower power needed at the same gear ratio comparing to normal pulley.
Am I understand ospw correctly:
Example
1. Normal pulley: gear at 53x11, cadence 90, power is 200, speed will be 30kmp.
2. Ospw pulley: gear 53x11, cadence 90, power is 180, speed will be 30kmph?
They may reduce friction in the drivetrain by a watt or so, or fractions of that, but then you're probably losing that back in aerodynamic drag because they're so gigantic.
04-18-19, 06:30 AM
#12
Senior Member
Its only when you compare the worst to the best jockey wheels you see any real difference. Just get a par of ultegra or DA wheels and you are fine. Even DA is Much cheaper than ceramic speed or the like, and only lags a fraction of a watt behind.
04-18-19, 10:35 AM
#14
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If you have the disposable income, go for it!! 1-3 w isnt noticeable, but it all adds up over time and in conjunction with other watt saving, aerodynamic adding, toys to buy. Nothing wrong w/ spending on the things you enjoy. I've wasted a lot more over the years on other stuff that'd probably be considered just as wasteful.
04-18-19, 12:42 PM
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I got some Ceramic Speed jockey wheels to put on my road bike, not the oversize set up but just the jockey wheels with bearings. they were a gift and they are red so of course I am going faster 
Anyway they are much much quieter and they look really nice I think against my matte black bike but other than that they do nothing the stock factory ones ever did.
they do look nice and seem of really nice quality though, makes good conversation at the coffee stops but has no speed/performance value. I would not spend the money on them if otherwise. Better spent money on more noticeable upgrades.
Anyway they are much much quieter and they look really nice I think against my matte black bike but other than that they do nothing the stock factory ones ever did.
they do look nice and seem of really nice quality though, makes good conversation at the coffee stops but has no speed/performance value. I would not spend the money on them if otherwise. Better spent money on more noticeable upgrades.
04-18-19, 09:08 PM
#16
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I recently got some (Digirit 11/16). Not to save a watt or two but to increase my (etap) RD capacity since the cage is longer. That worked and I’ll have to say the pulleys are really silent and just seem to make the drivetrain so smooth. I was pleasantly surprised and I think OSPW will become more and more common.
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