1 x 9 conversion

I was running a 2 x 9 setup on my daughter's bike with 36 and 24 front chainrings and a 7 speed 14-28 tooth rear cassette.

Getting a new rear wheel meant that I could run a 9 speed rear cassette. With an 11-34 tooth gear range it soon because apparent that by going to a single 28 tooth front chainring the gear range would be the same as the 36/24 14-28 range of the previous chainring/cassette combination.

What are the advantages of 1 x 9?

The key advantage is you can do away with having a front shifter, front derailleur and associated cabling. You also do away with a front chainring as well.

You do however need a few extras - without a front derailleur the chain can easily jump off the front chain ring. A chain keeper / guard is needed. Here's a picture of a prototype that I made. It works well. You'll have to excuse the dirty great bolt holding the clamp on, its was just temporary to make sure the concept worked. The picture also shows a 24t granny ring, but the chain keeper profile it optimised for a 28t chain ring.


DIY 28t optimised chain keeper

Here's the final chain keeper (bashring also shown):


A bash ring is also a good idea. It will stop the chain derailling to the outside and also it provides a little added safety by protecting young calves from chain ring 'bite'. I couldn't find a suitable bash ring (30t size just big enough to cover the 110mm spider on the Sugino cranks ) so I custom made one for a perfect fit .

How much weight can I lose going to 1x9?

Along with the reduced complexity comes a reduction in weight by going to 1x9. I was able to ditch an XT front shifter pod (120g), a LX front derailleur (145g), 36t middle ring (55g) and some shifter cable and housing (maybe 20g). Total weight of stuff removed - 340g.

But, there was some stuff we needed to add back on: 30t bash ring (30g) and chain keeper (32g).

So total weight saving was around 278g.

1x9 drivetrain


1x9 drivetrain picture with 11-34 cluster and tuned XT rear derailleur

Related articles:

BOR XMD 333 rim

This looks like a really nicely made rim with a combination of great features:

Read more »

Alex DC 19 rim

Quick facts:

Read more »

Rockshox SID SL 1999

Quickfacts:

Read more »

Shimano XT v-brakes

Almost as good as the XTR M952 v-brakes, but once the linkage developed wear (even on these M750 versions with the reinforced linkage plates) the pads would flop around. 190g.

Read more »

2012 HS1 Rotor

The braking surface design of these rotors is identical to the 2012 HSX rotors . The weight is very similar (98g each in 160mm) as well and quite consistent across the 4 rotors that I have.

Read more »

KCNC BE1 bar ends

Read more »