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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.
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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.
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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.
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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?

Accelerate3 Coaching https://accelerate3.com/
Moxie Multisport https://www.themoxiemultisport.com/
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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.

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Moxie Multisport https://www.themoxiemultisport.com/
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.

Accelerate3 Coaching https://accelerate3.com/
Moxie Multisport https://www.themoxiemultisport.com/
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Re: Digirit Over Sized Pulley System [jkhayc] [ In reply to ]
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I haven't seen much data as far as aerodynamics on the OSWP but if it is good enough for Starky to have their BB, chain, OSWP and ceramic wheel bearing then the OSWP is good enough for me!

Speed kills unless you have speed skills!!!
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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I installed one for a friend a few weeks ago, the quality seemed good to me.

He hasn't magically gained any power, we're still about the same speed. It looks cool though.
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Re: Digirit Over Sized Pulley System [jkhayc] [ In reply to ]
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jkhayc wrote:

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.

CeramicSpeed claims that the theirs was tested and the result was "net zero drag over a range of yaws" (or something like that, I'm paraphrasing). But say they can't release the data. And no one knows if that means there's increased drag at zero yaw or not.
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Re: Digirit Over Sized Pulley System [jkhayc] [ In reply to ]
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My educated guess is that it makes no real difference with a rider on board. I heard of tests where they couldn't pick it up, but I've not done one personally. What I have seen is that going with a single ring is faster bike only and no difference with rider on. The feet and legs cause a lot of churn so anything near or behind them is in dirty air. I know I'm preaching to the choir a bit here.

To the other poster who compared a drink straw to a long cage, there is no comparison. The drink straw is basically on the leading edge which sees mostly clean air.


jkhayc wrote:
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.



Heath Dotson
HD Coaching:Website |Twitter: 140 Characters or Less|Facebook:Follow us on Facebook
AeroCamp February 25-26, 2020 A2 Wind Tunnel
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Re: Digirit Over Sized Pulley System [playero] [ In reply to ]
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playero wrote:
I haven't seen much data as far as aerodynamics on the OSWP but if it is good enough for Starky to have their BB, chain, OSWP and ceramic wheel bearing then the OSWP is good enough for me!

Sponsorship paychecks are a great thing for marketing

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:
Sponsorship paychecks are a great thing for marketing
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If this thesis is used to base anything being sold, then there would nothing but #fakenews cmon, simply because you may not believe that the gains are there doesn't mean they arent there! Could you tell 2.5watts at any given moment? Prolly not but if you had a PM you could easily measure it!

I have it on both of my bikesand i wouldn't have it any other way! Sure no longer a possibility for me to measure the difference since i just now got a PM but i don't disbelief their claim simply becaue you have unsustansiated claim that they aren't saving you anything! You gotta at least prove something that shows theae are wrongly measured and not doing what ceramicspeed says it does... can you prove that?

Speed kills unless you have speed skills!!!
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Re: Digirit Over Sized Pulley System [playero] [ In reply to ]
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I'll revert back to what I have said before on here.

The burden of proof should be on Ceramic Speed, not me. I didn't create oversized pulley wheels and claim they didn't cause drag.

They won't release the data because they don't own it. That's understandable.

Why should I have to spend money to try and debunk them?

If you don't like that answer, I don't care.

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
Last edited by: BryanD: Jun 6, 17 10:59
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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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Dude, did you have a really bad race or something? You are way to young to be this bitter. Leave that shit for the old guys like me.


BryanD wrote:
That's correct. If you have an issue, please call and get in line to complain.



Heath Dotson
HD Coaching:Website |Twitter: 140 Characters or Less|Facebook:Follow us on Facebook
AeroCamp February 25-26, 2020 A2 Wind Tunnel
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Re: Digirit Over Sized Pulley System [Ex-cyclist] [ In reply to ]
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I had a great race. I just don't care for people's sarcastic replies. Go find someone else to mess with.

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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Oh, so what you are saying is that you are off your meds?


BryanD wrote:
I had a great race. I just don't care for people's sarcastic replies. Go find someone else to mess with.



Heath Dotson
HD Coaching:Website |Twitter: 140 Characters or Less|Facebook:Follow us on Facebook
AeroCamp February 25-26, 2020 A2 Wind Tunnel
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Re: Digirit Over Sized Pulley System [Ex-cyclist] [ In reply to ]
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Ex-cyclist wrote:
Oh, so what you are saying is that you are off your meds?


BryanD wrote:
I had a great race. I just don't care for people's sarcastic replies. Go find someone else to mess with.

For public knowledge, I don't take any meds. Good try though. You have my number if you also want 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 [BryanD] [ In reply to ]
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BryanD wrote:
I'll revert back to what I have said before on here.

The burden of proof should be on Ceramic Speed, not me. I didn't create oversized pulley wheels and claim they didn't cause drag.

They won't release the data because they don't own it. That's understandable.

Why should I have to spend money to try and debunk them?

If you don't like that answer, I don't care.

So the only problem i see is that they haven't released any data... is that why you're trying to strip the brand from everything they're worth???

Obviously if you dont like ceramicspeed then dont buy it, read threads of it and most importantly just leave! This will save you alot of watts i promise! Ha ha ha

Speed kills unless you have speed skills!!!
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Re: Digirit Over Sized Pulley System [playero] [ In reply to ]
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playero wrote:
BryanD wrote:
I'll revert back to what I have said before on here.

The burden of proof should be on Ceramic Speed, not me. I didn't create oversized pulley wheels and claim they didn't cause drag.

They won't release the data because they don't own it. That's understandable.

Why should I have to spend money to try and debunk them?

If you don't like that answer, I don't care.


So the only problem i see is that they haven't released any data... is that why you're trying to strip the brand from everything they're worth???

Obviously if you dont like ceramicspeed then dont buy it, read threads of it and most importantly just leave! This will save you alot of watts i promise! Ha ha ha


I don't have to go anywhere. I just asked for data. Pretty simple concept.

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
Last edited by: BryanD: Jun 6, 17 12:14
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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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BryanD wrote:
playero wrote:
BryanD wrote:
I'll revert back to what I have said before on here.

The burden of proof should be on Ceramic Speed, not me. I didn't create oversized pulley wheels and claim they didn't cause drag.

They won't release the data because they don't own it. That's understandable.

Why should I have to spend money to try and debunk them?

If you don't like that answer, I don't care.


So the only problem i see is that they haven't released any data... is that why you're trying to strip the brand from everything they're worth???

Obviously if you dont like ceramicspeed then dont buy it, read threads of it and most importantly just leave! This will save you alot of watts i promise! Ha ha ha


I don't have to go anywhere. I just asked for data. Pretty simple concept.

Then don't go anywhere, call ceramicspeed and ask them for it! I sure as hell dont have it and dont care!!! Have you even tried to contact their customer service? Emailed them?

Speed kills unless you have speed skills!!!
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Re: Digirit Over Sized Pulley System [playero] [ In reply to ]
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Dude...go read the other threads on these pulleys.

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:
Dude...go read the other threads on these pulleys.

Wow you're taking whats on said thread as true & factual?! Something said by a hillbilly has more weight than what ceramicspeed has to say about their own products??? Yup, that makes sense to me!

Speed kills unless you have speed skills!!!
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Re: Digirit Over Sized Pulley System [playero] [ In reply to ]
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You have no idea what you are talking about.

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:
You have no idea what you are talking about.

First you discredited their lack of data then discredited their equipment, discredit others of knowledge... 🤔🤔🤔 are you a trump follower??? If not, surely using his tactics to make your point!

Speed kills unless you have speed skills!!!
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Re: Digirit Over Sized Pulley System [playero] [ In reply to ]
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playero wrote:
BryanD wrote:
You have no idea what you are talking about.


First you discredited their lack of data then discredited their equipment, discredit others of knowledge... 🤔🤔🤔 are you a trump follower??? If not, surely using his tactics to make your point!


Sigh...you are exhausting. I said go search the forums and read the other threads discussing this.

If you did...you would know Ceramic Speed commented and said they cannot release data. Many others have discussed the pros and cons to all of this.

So....please....go read the forum

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
Last edited by: BryanD: Jun 6, 17 12:51
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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user123 wrote:
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]

I have seen these pop up in the past few months from many manufacturers including RockBros 17t-17t and KCNC 14T-16t. Personally I am still rocking the Berner Cage (13T-15T). I would like to run a cage that at least some aero was put into the design. Airfoils aren't rocket science at this point in the game and at least CS attempts to make a cage that looks like it uses airfoils.


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Re: Digirit Over Sized Pulley System [BryanD] [ In reply to ]
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Well, this has escalated quickly...
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Re: Digirit Over Sized Pulley System [Thomas Gerlach] [ In reply to ]
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Airfoils aren't rocket science

Um
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Re: Digirit Over Sized Pulley System [user123] [ In reply to ]
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user123 wrote:
Well, this has escalated quickly...

I love the sarcastic comments though. Definitely keep them coming

Make Inside Out Sports your next online tri shop! http://www.insideoutsports.com/
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Re: Digirit Over Sized Pulley System [Thomas Gerlach] [ In reply to ]
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Whatever you do, don't buy the KCNC. I have one and it is a monumental bodge.

- you have to shim the cage at the lower pulley to make the two cage plates parallel
- stock grease in the bearings has an unnecessarily high viscosity. With CS TT grease the bearings actually start to work
- cylindrical interface with goes into the RD is too long (21.20 vs the shimano 19.45mm) so if you tighten the bolt, the mechanism will bind
- bores for the different spring settings have edges so sharp they will eat the bushing in the RD
- NW tooth design not optimal, the wide tooth will contact the chain plate not the roller. There is no step in the wide tooth to clear the plate
- inner plate is unnecessarily thick at the top pulley (clearance for disc wheels...)
- pulleys have quite a bit of lateral float, debatable if this is a good idea or not

So I would wait for the updated version...
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Re: Digirit Over Sized Pulley System [marcofoils] [ In reply to ]
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marcofoils wrote:
Whatever you do, don't buy the KCNC. I have one and it is a monumental bodge.

- you have to shim the cage at the lower pulley to make the two cage plates parallel
- stock grease in the bearings has an unnecessarily high viscosity. With CS TT grease the bearings actually start to work
- cylindrical interface with goes into the RD is too long (21.20 vs the shimano 19.45mm) so if you tighten the bolt, the mechanism will bind
- bores for the different spring settings have edges so sharp they will eat the bushing in the RD
- NW tooth design not optimal, the wide tooth will contact the chain plate not the roller. There is no step in the wide tooth to clear the plate
- inner plate is unnecessarily thick at the top pulley (clearance for disc wheels...)
- pulleys have quite a bit of lateral float, debatable if this is a good idea or not

So I would wait for the updated version...

You don't obviously want to flip it upside down if you can avoid it. It is an option though should you need it. Fwiw, I tested this is the wind tunnel, I don't have the data of the top of my head but will post sometime about it. It was slower, as expected. Please don't message about specifics though, I am traveling for a bit and won't have that data for a while as it is home.


Save: $50 on Speed Hound Recovery Boots | $20 on Air Relax| $100 on Normatec| 15% on Most Absorbable Magnesium

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Re: Digirit Over Sized Pulley System [IKnowEverything] [ In reply to ]
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Hi there,
Can I ask what size of the cassette do you have and if the b screw wad long enough? I can’t seem to figure out to gain enough clearance. I have 11-28 cassette atm. Thanks
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Re: Digirit Over Sized Pulley System [Davooc] [ In reply to ]
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I’ve run it with an 11-28 and an Ultegra 6700 di2 rear derailleur. Chain long enough?
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Re: Digirit Over Sized Pulley System [IKnowEverything] [ In reply to ]
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Thanks for fast reply. That was my thought too. I’ve just tried it with brand new chain. 118 links. I have di2 9070. Both pulleys large. Spring setting high. B screw on max.
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