Rear Derailleur Pulley Wheels / Jockey Wheels - 17t and oversized sizes - where?

Discuss light weight issues concerning road bikes & parts.
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prendrefeu
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by prendrefeu

Hello,

Does anyone know of a resource where I can purchase 17t or other oversized jockey wheels (pulley wheels) individually? I'm looking for carbon fiber or other low-mass options. The one 17t wheel I have in hand is alloy, it could be lighter.
It should be lighter.

No... it must be lighter. :twisted:
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addictR1
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by addictR1

Do those actually work as in help with climbing or things like that?


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by Weenie


2old4this
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by 2old4this

prendrefeu wrote:Hello,

Does anyone know of a resource where I can purchase 17t or other oversized jockey wheels (pulley wheels) individually? I'm looking for carbon fiber or other low-mass options. The one 17t wheel I have in hand is alloy, it could be lighter.
It should be lighter.

No... it must be lighter. :twisted:


Try http://berner-bikes.com/
I remember the full cage with pulleys being 78 grams. I think half the weight came from the pulleys. I can measure the pulleys individually this weekend, if you want to be sure...

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prendrefeu
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by prendrefeu

The larger jockey wheels do help with efficiency. It's the basic principles of a pulley...
"our own" Dan Connel wrote a great article about the efficiency:
http://djconnel.blogspot.com/2010/08/be ... grade.html

http://www.bikeradar.com/us/gear/articl ... ent-37615/

The full cage I have on hand is a 17/12 and weighs 61g... but the wheels are both alloy.

Does anyone know if DarkAlbert is still in business?

I may end up just making my own and 3d printing them in carbonfiber.
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prendrefeu
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by prendrefeu

Yes, thanks, that's not what I'm asking for. :)

I'm asking for the jockey wheels only. I'm not asking for the cage. As I wrote above, I already have one, and it's 61g complete. Not as light as the one you've just sent however, but slightly lower priced (and for SRAM).

I'd like to reduce the weight by going with a lighter-weight 17t wheel. I already have a carbon 12t wheel for the upper.
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Kayrehn
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by Kayrehn

Fiber lyte says they can make 15t without extra cost from their standard ones, if you don't mind 2 less teeth, fwiw.

(side question - do you think my Wifli mid cage can use 15t/17t without any problems?)

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prendrefeu
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by prendrefeu

Good side question! I'll measure the length of my cage when I get home and we can compare. It's going on a tuned derailleur that originally had a short-cage on it.
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addictR1
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by addictR1

Wait what? You can print in carbon fiber now? That would be so awesome if you printed your own.


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prendrefeu
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by prendrefeu

You can print in CF, but there are two issues:
there's a 4mm minimum wall thickness if you want a continual CF strand laid in by the printer. This is good for strength, but takes finessing on the print side to make sure the printer will lay it in the way you want it... and it is just one thin strand.
-Everything else is basically a resin mix + finely chopped CF mixed in, which does not do much for overall tension strength because the CF fibers are not continuous, just sort of 'random' but really dense.

The end result are parts that are 'strong' and 'stiff' in compression, better than comparables in tension (but not amazing), and not as light in weight as a hand-laid cf piece, but lighter than alloy.
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addictR1
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by addictR1

prendrefeu: that's awesome. always learning new things from you! :) i have an old RED 10sp short cage and a Red Wifli... so if i wanna get larger pulley.. how would i go about in know which one to get?

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Kayrehn
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by Kayrehn

prendrefeu wrote:Good side question! I'll measure the length of my cage when I get home and we can compare. It's going on a tuned derailleur that originally had a short-cage on it.
Suddenly reminded of this - any help @prendrefeu?

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dmp
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by dmp

Prendrefeu, your post piqued my curiosity, and I found a set of hollow printed titanium jockey wheels on line from CeramicSpeed for the bargain price of (for real!!) $1000. I wonder if they have actually sold any:) That's a weight reduction costing about $500/gram!
On that rideabikes site, if you click on the "integrating components" tab, scroll down about half way, and you can find jockey wheels without the cage-item code PXLY. No price, weight, or ordering information, however.

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prendrefeu
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by prendrefeu

Kayrehn wrote:
Mon Dec 25, 2017 12:10 am
prendrefeu wrote:Good side question! I'll measure the length of my cage when I get home and we can compare. It's going on a tuned derailleur that originally had a short-cage on it.
Suddenly reminded of this - any help @prendrefeu?

Thanks for the reminder! (and I just returned from a short holiday, sorry for the delay)

I measured 82.26mm from center of the top wheel (which is also the center of the axle) to the center of the lower wheel. The "oversized" cage I have runs a 17t lower, 12t upper.
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by Weenie


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naylor343
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by naylor343

[/quote]

I measured 82.26mm from center of the top wheel (which is also the center of the axle) to the center of the lower wheel. The "oversized" cage I have runs a 17t lower, 12t upper.
[/quote]


Hi, can you say what brand and model your oversized cage is? Thanks.

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