Switching rear derailleur pulleys from 11t to 13t - is it possible?

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alcatraz
Posts: 4064
Joined: Mon Aug 29, 2016 11:19 am

by alcatraz

Hey

I wanted to ask if anyone has successfully gone from 11t stock to 13t without problems?

I'm currently on a sram red 10s derailleur (oldest version) and I've decided to change the pulleys to something better spinning (the stock ceramic is not that smooth). The question that arises is, can I at the same time go 13t instead of 11t?

It would be nice to increase the lowest radius a bit, get the chain running a bit more freely. The diameter difference between 13 and 11 cant be that great. Probably almost negligable but since I can choose either one, why not go with the sligtly larger.

The derailleur cage is short and the question arises, will they come too close together?

What do you think about this mod?

Edit: I forgot to add that running a 11-25 cassette leaves a fair amount of space between the upper pulley and cassette cogs. My "B-screw" is only screwed in to about half it's length. Trying this on a 12-30 might be impossible.

Edit2: I've taken some measurements. The outer diameter of 11t and 13t pulleys from the same manufacturer is 41 vs 50 mm. That means that the chain will run 4.5mm further away from the center.

Edit3: The upper pulley can not be 13t on this derailleur without removing the little flap to the lower right of the pulley, shown in the picture. The space is 4mm with 11t. The question remains, change the lower pulley to 13t?

/a

Image

PS. Don't make fun of my ugly cable end cap.

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Marin
Posts: 4035
Joined: Wed Jan 22, 2014 11:48 am
Location: Vienna Austria

by Marin

I once put a 10t in the upper position of a Red derailleur like yours to make it work with an 11-32 cassette, and had a 12 or 13t in the lower position to take up more chain so I wouldn't have to shorten it. Worked ok.

What do I think of your planned mods? Performance wise, they won't gain you anything, and shifting performance will stay the same or get slightly worse.

You'll get an order of magnitude higher performance gains by cleaning your chain and switching to a lower friction lube probably :D

Hexsense
Posts: 3270
Joined: Wed Dec 30, 2015 12:41 am
Location: USA

by Hexsense

I know 13t wouldn't work on top.
but can we put 12t on the top and 12 (or probably 14t) at the bottom of Wifli (mid cage) RD?

I don't know if 12t or 14t with Narrow-wide teeth pulley will do anything to 2x11 road bike vs normal 11t pulley.

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