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Digirit Over Sized Pulley System
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I am really keen to try out a pulley system from Ceramic Speed, but cripes is it ever expensive! Does anybody have experience with Digirit Pulley System? Link is below. After searching the forum the only topic I could see is "Oversize Jockey Pulley at a reasonable price".

Digirit appears to be a Chinese company, so who knows about the quality!?

http://www.digirit.com/Products/PulleyWheelKit[/url]


Oversize Jockey Pulley at a reasonable price [/url]
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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I have one installed on my bike, on a DA-9070 di2 rear derailleur. Works great. No testing data on it, but assuming that the friction reduction is largely from pulley wheel size anyways - should be similar. Worst case scenario, it's not making me slower.

___________________________________
MS: Exercise Science
Your speed matters a lot, sometimes you need to be very fast, where sometimes you need to breakdown your speed.
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Re: Digirit Over Sized Pulley System [IKnowEverything] [ In reply to ]
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Except for that thing called aerodynamic drag from the larger pulleys and cage

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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I have some. They work fine. Double-check and loctite the screws that hold the pulley wheels in. Mine worked a little loose. Could be catastrophic to have one come out.

My latest book: "Out of the Melting Pot, Into the Fire" is on sale on Amazon and at other online and local booksellers
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Re: Digirit Over Sized Pulley System [jens] [ In reply to ]
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how much longer did your chain have to be?
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Re: Digirit Over Sized Pulley System [nbaffaro] [ In reply to ]
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2 links for me.

___________________________________
MS: Exercise Science
Your speed matters a lot, sometimes you need to be very fast, where sometimes you need to breakdown your speed.
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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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BryanD wrote:
Except for that thing called aerodynamic drag from the larger pulleys and cage

which might be an improvement at certain yaw angles..
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Re: Digirit Over Sized Pulley System [jkhayc] [ In reply to ]
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Science over marketing. Show me data.

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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BryanD wrote:
Science over marketing. Show me data.

Can you show me some data that it is worse, aerodynamically? While you're at it, can you also provide the testing context?
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Re: Digirit Over Sized Pulley System [jkhayc] [ In reply to ]
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Sorry, not my responsibility.

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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BryanD wrote:
Except for that thing called aerodynamic drag from the larger pulleys and cage


Can you provide data to back up this claim?

BryanD wrote:
Sorry, not my responsibility.


Ah, I understand. The burden of proof is never on you to back up your claims.
Last edited by: jkhayc: Jun 5, 17 11:28
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Re: Digirit Over Sized Pulley System [jkhayc] [ In reply to ]
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That's correct. If you have an issue, please call and get in line to complain.

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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Can someone explain the benefits of an oversize pulley?


--Chris
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Re: Digirit Over Sized Pulley System [chriselam] [ In reply to ]
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reduced friction and a lot of money lost from your bank account.

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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Thanks to all for the contribution to my question. I need to consider the cost advantage of going with Ceramic Speed over a less expensive copy. It's always R&D we pay for. I cant help but to laugh how often questions and comments turn into online scrums.
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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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Give me a break aerodynamics of a derailleur over drag reduction??? I have one and runs fine.
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Re: Digirit Over Sized Pulley System [Shambolic] [ In reply to ]
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You can call the complaint number and get behind James. All operators are busy and will get to you shortly.

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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Looks cool. Not sure what the data says, but here are some friendly, if slightly critical, thoughts:

If you're gonna completely replace the cage and pulley, why in the world would you design a system where only ONE pulley is oversized? For max benefit, you really do want TWO oversized pulleys, otherwise the chain friction reduction is going to be very, very small. (Most, if not all, of the other high dollar pulley cage upgrades include a system in which BOTH pulleys are oversized.) Then, if you're gonna go with the budget AL models, why in the world would you make the pulley wheels with cutouts? If the pulleys are AL, you're looking at a weight savings of just .0001 grams (don't quote me on that, I just made that number up) from the cutouts. For me, far more important is the way the cutouts attract dirt, grease, and grit (which, of course, adds drivetrain friction). Plus the fact that the pulleys are probably a lot more slippery (aero-wise) when they are solid. So those two things would be deal breakers for me ... But if they were to address these things and the cost is not too crazy, it might be a nice upgrade. Hope the designers are reading this ... ;^)

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Re: Digirit Over Sized Pulley System [DarkSpeedWorks] [ In reply to ]
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I have no stake in this outfit and didn't know anything about them until I saw this thread, but from looking at their offerings on ebay they also have offerings where both pulleys are oversized as well.
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Re: Digirit Over Sized Pulley System [Shambolic] [ In reply to ]
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Shambolic wrote:
Give me a break aerodynamics of a derailleur over drag reduction??? I have one and runs fine.

When you look at how much drag a drink straw adds in the tunnel, yes that big hanger could certainly hurt things.
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Re: Digirit Over Sized Pulley System [DarkSpeedWorks] [ In reply to ]
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DarkSpeedWorks wrote:
why in the world would you design a system where only ONE pulley is oversized?

Shifting performance?
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Re: Digirit Over Sized Pulley System [Shambolic] [ In reply to ]
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Shambolic wrote:
Give me a break aerodynamics of a derailleur over drag reduction??? I have one and runs fine.


Drag reduction resulting in a Watt or 2 savings at 250W or whatever. . Doesn't take a lot of aerodynamic drag to overshadow that.
Last edited by: trail: Jun 5, 17 21:21
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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user123 wrote:
Thanks to all for the contribution to my question. I need to consider the cost advantage of going with Ceramic Speed over a less expensive copy. It's always R&D we pay for. I cant help but to laugh how often questions and comments turn into online scrums.

CeramicSpeed has proven really good bearings. They're also smart on coatings. And they have a good reputation on quality and support

I'm not a CeramicSpeed fanboy by any stretch. But that's what you're getting for the extra cost if it's worth it to you.'
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Re: Digirit Over Sized Pulley System [trail] [ In reply to ]
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trail wrote:
Shambolic wrote:
Give me a break aerodynamics of a derailleur over drag reduction??? I have one and runs fine.


Drag reduction resulting in a Watt or 2 savings at 250W or whatever. . Doesn't take a lot of aerodynamic drag to overshadow that.

I'm not a CS or SLF fanboi either, but has anybody actually tested whether there are any drag penalties (or positives) from an over sized pulley system? I personally will never, ever buy one simply because the cost does not justify any "gains" but I'd still like to see data on this claim.
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