28-07-08

2 x 9 set up

The Yeti ASRc I have on order uses a press fit bottom bracket bearing to work with X-type or Hollowtech cranks (24mm axle for external bearings on 'traditional' bikes).

I planned to use some Race Face Deus XC cranks that I had some where in my parts box. It was once on my Dean hardtail, but the RF bearings are crap and soon stopped spinning. I then ditched the cranks for traditional square taper BBs with eiter a RF Turbine or Middleburn RS8 cranks.

The Yeti has Shimano press fit bearings which schould be of a better quality then RF bearings.

Having used a 2x9 set up on my Dean (for everything but the steepest, longest, hardest big mountain races) I wanted to use a 2x9 set up on the Yeti as well.

One option would be to use an Extralite 30T ring in the middle position combined with a normal outer ring (42 or 44T). Having used this set up on the dean I found out that the chainline is no good.

Then I saw pictures of people running 26T or 28T chainrings in the granny position. This triggered me to go for a similar set up. The 28T is perfect (just a bit better gearing then the 29T I have on the middleburns). Specialites TA has a very comprehensive range of chainrings, including a 28T with a 64mm BCD that would fit the granny position. I also ordered one of their 42T middle rings. It would be possible to use a regular outer ring as well. BUT the middle ring has machined shifting ramps, combined with shifting pins. The outer ring only has shifting pins. The middle ring will thus offer better shifting performance.

TA outer vs middle ring

In the proces some weight was saved versus a set up with the traditional 22 (RF) - 32 (RF) - 44 (TA) rings.

2x9 vs 3x9

deus 2x9

With this 2x9 set up the chain line schould be better, I will use some very thin washers to optimise the chainline. The set up will be complemented by a SRAM Force road derailleur.

 

 

 

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