Friday, January 13, 2012

Removing some Gold Bling from my Ultegra RD

Sometimes, adding 3rd party parts to your bike can be detrimental to the performance! This is what I found out for my Ultegra RD. Previously, I had added some gold bling to my Ultegra RD, which looks really cool. Performance wise, it worked pretty OK, just that I couldn't seem to tune the RD perfectly. I couldn't really pinpoint the cause, but since it worked OK, I left it at that.

Ultegra with lots of gold bling!

As mounted on my bike 
It looks very good, as the gold bolts and stuff matches very well with my overall colour scheme. However, one day when I was doing some routine maintenance, I realised that the RD is not securely fixed to the bike. Usually, there is a B-axle bolt that you screw into into the frame dropout. For this Ultegra RD with the gold B-axle bolt, even with the bolt tightened, the RD can still wobble quite a bit from side to size.

Gold B-axle bolt as previously upgraded, and the silver coloured bolt that comes stock with the RD

I had changed the B-axle bolt previously, from the stock one to the gold coloured one. You can read about it here. Based on the wobbling, I suspected that the B-axle bolt may not have been a good fit for the RD, since there is a gap between the RD and the frame.

To find out what is wrong, I had to remove the B-axle bolt again! I had previously said that I wouldn't take it out again, because it was so hard to fix it back. But since it now concerns shifting performance, I had no choice but to take it apart again to find out what is wrong.

As you can see from the picture above, the two B-axle bolts are not quite similar! Note the location of the groove in the middle of the bolt. The gold bolt has a groove that is about 1mm higher than the original bolt. Just because of this 1mm difference, it prevents the RD from being fixed properly to the bike. It is likely that because of this, the shifting performance is not ideal as the RD will flex and wobble when under high cable tension. In bike component engineering terms, a 1mm difference in the RD movement is totally not acceptable as it means that the chain is probably already 1/3 of the way to the next gear sprocket.

Reinstalling the B-axle bolt this time was not too difficult, as I managed to find a suitable tool to help me reinstall the bolt.

Lesson learned: Check your 3rd party part before you install it on your bike, make sure it has the same dimensions as the original part! Or it may affect the performance or safety of your bike.

Another part which I changed from the gold bling back to the stock one is the gold jockey wheels, or pulleys.

I had previously changed from the original plastic pulleys to gold Token pulleys with sealed bearings. These sealed bearing pulleys are really smooth, much smoother than the original pulleys. However, because these gold pulleys are actually made of aluminium, when you pedal, the steel chain will contact and rotate these pulleys. Due to the metal to metal contact, these gold aluminium pulleys are significantly noisier than the original plastic pulleys. I prefer a quiet bike when I pedal, thus I decided to change back to the original plastic pulleys.

Ultegra RD with original B-axle bolt and original pulleys

Once again, a part may look good, but it may have an adverse effect on the bike that you will not realise immediately. For the sake of better bike performance, I decided to sacrifice a bit of gold bling!

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