# 7 spd der pulleys - how many teeth?



## Smurf Hunter (Mar 13, 2008)

Hi,

After riding my bike with an old DX group, I've noticed the bottom pulley on my rear derailer is rounded a bit. In certain gear combos it skips. Really not a huge deal, but kind of annoying when I occasionally get into a higher gear.

I notice these pulleys have 10 teeth, as compared with 11 teeth on more modern pulleys.
I also am aware that modern chains are a bit narrower - so my question is, *can I put a modern 11 tooth derailer pulley on my 7spd derailer that was originally fitted with 10 tooth pulleys?*

Thanks
-Sean


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## DeeEight (Jan 13, 2004)

10T but 11T pulleys fit fine...


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## ssmike (Jan 21, 2004)

The reason Shimano went from an even number of teeth to an odd number of teeth was to even the wear of the pulley teeth. On an even tooth number, a particular tooth will always mesh with an outer or inner plate. An odd number of pulley teeth will alternate between inner and outer plates.


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## Smurf Hunter (Mar 13, 2008)

Well that certainly opens my shopping choices a great deal.

Also - any opinions on anodized CNC pulleys?
eBay has a handful at reasonable prices:
http://cgi.ebay.com/New-CNC-Seal-Be...ryZ27950QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

http://cgi.ebay.com/10T-Green-Anodi...VQQcmdZViewItemQQ_trksidZp1638Q2em118Q2el1247

I was kind of thinking anodized pulley wheels might add some vintage flair. just an idea... 
-Sean


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## CS2 (Jul 24, 2007)

The plastic pulleys last a long time and Shimano still makes them new. http://aebike.com/page.cfm?PageID=30&action=list&Category=512&Brand=367&type=T

If you have a lot of 7 sp bikes buy these: http://aebike.com/page.cfm?PageID=30&action=details&sku=DP8350 They're pennies for a set. Good luck

Tim


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## heeler (Feb 13, 2004)

Be careful, some of those fancy pulley sets don't come with a top jockey pulley, which means that if you RD adjustment comes out just a bit, chain will be-a-jumping.


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## ssmike (Jan 21, 2004)

On-One said:


> Be careful, some of those fancy pulley sets don't come with a top jockey pulley, which means that if you RD adjustment comes out just a bit, chain will be-a-jumping.


Not difficult to get non-floating guide pulleys to work in a Shimano system. Campy and SRAM seem to work fine without a floating guide pulley.


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## heeler (Feb 13, 2004)

One of the advantages of the jockey pulley is that they are less sensitive to RD posistion relative to the cog so cable stretch and/or housing tension changes are less noticable...

Im just saying you lose that when you lose the jockey pulley.

I do, however, run SRAM RD's on at least two bikes and they both work perfectly...which kinda destroys my argument on some level.

I am feeling very conflicted right now.


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## Smurf Hunter (Mar 13, 2008)

CS2 said:


> The plastic pulleys last a long time and Shimano still makes them new. http://aebike.com/page.cfm?PageID=30&action=list&Category=512&Brand=367&type=T
> 
> If you have a lot of 7 sp bikes buy these: http://aebike.com/page.cfm?PageID=30&action=details&sku=DP8350 They're pennies for a set. Good luck
> 
> Tim


CS2,

I've shopped at AEBike before and will do so again. Unfortunately for some bonehead reason, their pulleys are not eligible for shipping.

_"This item is not permitted to be shipped, however it can be purchased online and picked up at our Michigan-based retail store.	This item is not permitted to be shipped, however it can be purchased online and picked up at our Michigan-based retail store."
_

I could appreciate them not shipping heavy tools or maybe even frames, but pulleys would fit in a padded envelope. I may email them and inquire why these don't ship.


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## CS2 (Jul 24, 2007)

Smurf Hunter said:


> CS2,
> 
> I've shopped at AEBike before and will do so again. Unfortunately for some bonehead reason, their pulleys are not eligible for shipping.
> 
> ...


I'm sorry, I forgot. They are waiting for their official Shimano Internet sales status. They choose not to sell until Shimano certifies them. Try Harris Cyclery. They're all using the QBP online catalog.

This is the same QBP page only for Harris. http://harriscyclery.net/page.cfm?PageID=49&action=list&Category=512&Brand=367&type=T
There phone is 617-244-9772

Tim


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## CS2 (Jul 24, 2007)

Speaking of 6/7 sp pulleys, I've got some older XT 73* series with the gray pulleys. Are they really any better than the cheaper black versions? I've put lots of miles on my Deore black versions that aren't sealed. 

Tim


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## DeeEight (Jan 13, 2004)

The real reason shimano gave for going to 11T pulleys was they spun 10% slower than the 10T pulleys, so bushing wear was reduced and less energy was lost from friction in the chain (yeah we're talking tenths of a percent, but for shimano, EVERY little bit counts). Not to mention the increased diameter of the pulleys actually increased the total chain capacity of the derailleur for a given cage length. The short cage road models like Dura Ace went from 26T to 29T, the middle cage lengths went from 33T to 37T, and the long cages went from 38T to 43T.


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## CS2 (Jul 24, 2007)

DeeEight said:


> The real reason shimano gave for going to 11T pulleys was they spun 10% slower than the 10T pulleys, so bushing wear was reduced and less energy was lost from friction in the chain (yeah we're talking tenths of a percent, but for shimano, EVERY little bit counts). Not to mention the increased diameter of the pulleys actually increased the total chain capacity of the derailleur for a given cage length. The short cage road models like Dura Ace went from 26T to 29T, the middle cage lengths went from 33T to 37T, and the long cages went from 38T to 43T.


That's an interesting bit of info. So, can I replace my 10T pulleys with an 11T version? Does Shimano make a sealed bearing version in 11T or does it really not matter?

Tim


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## Smurf Hunter (Mar 13, 2008)

I wish pulley wheel drag was the biggest bottleneck in my drive train


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