MTB chain weights

This post is about the weight differences (or rather the lack of a difference!) I've found in some 9-speed MTB chains.

The original chain on my 2010 Boardman FS Team was a Shimano HG-73. This chain is fitted to many new bikes as it is cheap basic chain. At the length I use, it weighs in at 266g. The current CRC price for this chain is £15.99.

Shimano HG-73 weighs 266g.  RRP £26.99

I later replaced this for a SRAM PC991 Cross Step chain. The Cross Step version is a stronger chain than the standard PC991 chain. The chain weighs in at 261g, about the same as the cheap Shimano, which is expected. The RRP of this chain is £45, but today's online price is £27 (in the Jan sales).

SRAM PC991 Cross Step weighs 261g.  RRP £44.99

This Christmas I received a Wiggle voucher, so I treated myself to a new chain as the SRAM above was rusting too readily and getting stiff, even after a good clean. It was getting too hard to keep this chain in good order. So I purchased a KMC X9SL Gold, probably the most expensive 9-speed chain on the market. This is KMC's "Super Light" chain that has hollow pins and slotted links.  The RRP for this chain is £59.99, but is reduced in the January sales and today's price is £39.89 at Wiggle and £46.99 at CRC, which is the typical normal retail price.

I was going to get the X9L (Light) as it is reported as possibly being stronger, but there were plenty of good reports of the SL, so I opted for the top model for that bit of extra weight saving.

However, the big surprise came when I weighed it. I first shortened it to the correct size (same as two chains above) and then I weighed it (and my old chains above) to see how much lighter it was and to my surprise it was only 11g lighter than the SRAM!

KMC X9SL Gold weighs 250g.  RRP £59.99

To be fair, KMC do state that this chain is "Super Light - weighs only 255g", so they are not lying there. But I was assuming that 255g (at it's full new length) would be considerably lighter than other cheaper chains. I was very surprised to see that there was such a minimal difference.

For a MTB'er there is not enough of a weight saving to justify buying this model for the weight saving credentials alone. However, maybe different for a road biker who's looking for trim off a few grams.

I'm in no way criticising this KMC chain. It says 255g on the box and that's what it was (before I shortened it) so they are correct, which is something that many other bike manufacturers aren't with their stated weights on other products. I've only just received this KMC chain so it is too early for me to comment on the quality and reliability. I'm sure it's a mighty fine chain and I'm happy with my purchase, particularly as it was a gift, so it's cost me nothing!

SRAM rear derailleur model changes

Following recent investigations in to replacement jockey wheels for my SRAM X9 rear derailleur, I found that there was lot of confusion as to what jockey wheels fit which SRAM derailleurs.  For example, some suppliers might say "not X9", but there 4 different X9 model changes and also the short cage versions can have different jockey wheels to the long and medium cage models.
This SRAM parts list will help.
Basically, this is when the model year changes on SRAM rear derailleurs...

9 speed
X0 2006-2011
X9/X7 2010-2011
X9 2007-2009
X7 2007-2009
X9/X7 2005-2006
X9/X7 >2004
X5 2008-2011

10 speed
XX 2010-2011
X0/X9/X7 2011

So based on this, the KCNC jockey wheels should fit the following 9-speed derailleurs (pictured below): X0 2006-2011, X9 2010-2011, X7 2010-2011, but possibly not the short cage versions.

2010-2011 X7 9-speed

2010-2011 X9 9-speed

2006-2011 X0 9-speed
(although colour/materials shown here may be only on later models)

Replacement jockey wheels for SRAM X9 rear derailleur

When looking for replacement jockey wheels for SRAM derailleurs, there is a lot of conflicting compatibility details, particularly for SRAM X9.  I've written this to help X9 owners.

SRAM X9 (2009/2010) jockey wheels

My X9 (2009 model) jockey wheels were seizing up after every winter ride.  I had to remove the wheels, clean them (where I noticed that that rust would come from the bearing), and grease them after every ride.  I found the bearings on the X9 wheels would give problems after just a few weeks from new.  I only ride at weekends, so I found that after just 2 or 3 rides, the bearings went stiff.  I tried greasing them or just using TF2 spray and neither helped.  Some people recommend not greasing as this can attract dirt and make it worse.   I had to buy a new derailleur (for another reason)  and  got another X9, but a 2010 model.  This was exactly the same and again the jockey wheels then went stiff and were seizing after just two rides.

Genuine SRAM jockey wheels are £23 from CRC.  I started looking for alternatives, as I'd proved that the SRAM bearings were hopeless, but soon found that none seemed to be compatible with the X9 derailleur.

Then a fellow BikeRader forum user (thanks 'glennpro09') confirmed that the KCNC wheels fitted his 2010 X9 long cage derailleur, even though sites list the KCNC's for only SRAM X0 and some specifically say "not X9".

The KCNC jockey wheels get excellent reviews, but are quite expensive.  They do 10,11,12 & 13 teeth versions and all available with either a stainless steal bearing or a ceramic bearing.  I opted for the ceramic version of the 11T at £37.99 (delivered) from Ready to Ride Cycles via eBay.   The benefits of a ceramic bearing may be wasted in a jockey wheel, but for the £11 premium I decided it was worth buying the 'best'.

They are a perfect fit for the 2009/2010 X9, as you can see from these photos...

They've now been fitted on my bike for last four rides and so far are still running as smooth as they were when new (and the ceramic bearing is soooo much smoother than the SRAM wheels were when new) and not needed cleaning, apart from the normal hose down I give my bike after each muddy ride.  My new SRAM wheels were stiff by this time, so so far they've proved to be superior.  Only time will tell, but build quality and the way the bearings are sealed, these look like they will work and prove to be far better than buying genuine SRAM jockey wheels.  By fitting these, the time I need to spend cleaning the bike has certainly reduced considerably.  Although these KCNC wheels were expensive, it was money well spent.  Just wish SRAM could make their bearings cope with the UK conditions.

Update: My 2009 X9 rear derailleur is stamped 'DEC2009', is actually a 2010 model.  After referring to the SRAM parts lists, it seems that these KCNC jockey wheels will fit the following SRAM 3x9 models:

• X0 2006-2011
• X9 2010-2011
• X7 2010-2011

Check first though.  See the SRAM parts list here before you buy.

Differences between SRAM X7 & X9 shifters

SRAM state model years on their products and it is probably just a big marketing racket to make people upgrade.  Also there is some confusion about technologies shifting down the range when a new higher range is introduced.  i.e. is this year's X7 kit the same as the previous year's X9 kit?  Chat on the forums suggest this is the case sometimes.


I don't have any answers, but I do have a selection of SRAM 9-speed shifters, so I thought I'd post these comparison photos as this might help someone in the future. 


My bike (a 2010 Boardman Team FS) had SRAM X7 shifters with an X9 rear derailleur and X7 up front.   Over the last few weeks there seems to be loads of new SRAM kit on eBay.  I assume all the shops are selling off the 2010 kit to stock up on the 2011 kit.  Some of it is quite cheap, so I decided to upgrade my rear shifter to match the X9 derailleur.


So I purchased a new X9 9-speed shifter, only to find that when it arrived it was a 2009 model.  After asking on the forums, I was advised this was probably not an upgrade to my 2010 X7 shifter!  So I hunted out another new X9 shifter and this time purchased a 2011 model.


The differences between the two X9 shifters can been seen in these photos.  One is a 2010/2011 model (stamped Aug 2010) and the other is a 2009 model (stamped Jan 2009).

They both weigh the same at 130g.

My previous X7 shifter is stamped Aug 2009.  I'm not sure if this is a 2009 or 2010 model.  However, it is almost identical to the 2011 X9 shifter above.

The only visible difference is that the casing is all plastic rather than half metal of the X9.  The X7 shifter weighs 128g.  I've not opened them to see if there is any internal differences, but the shifting action feels the same when in your hand.

Obviously the case design has changed recently and is now slightly slimmer, but my conclusion is that the difference between an X7 and X9 model is just the metal case and obviously no point in spending the extra money for the X9 unless you really like the little bit of bling!