Giant Defy Headset Bearings

This post is also a follow up to this post: Focus Cayo Bike Weights

Back in February I got the Giant of the rack in the garage:

only to find that the steering was stuck in the straight ahead positions. Clearly after 4 years and 4 winters the headset had given up the ghost, got rusty and siezed. Fortunately a little gentle twisting action loosened it again but it was clearly time to replace the bearings. A couple of days later I got the bike in the workstand and dropped the fork out to get to the bearings. I was hoping that they'd be marked up and I could read the part numbers of and source replacements easily, but unfortunately they were completely unmarked. I measured them up as best as I could, cleaned and applied some grease and re-assembled. I got the following data:

Upper Bearing - ID = 30mm, OD = 42mm, Height = 6mm
Lower Bearing - ID = 34mm, OD = 46mm, Height = 7mm
In both cases I estimated the taper at about 45° but had no way of measuring this. I used a standard steel ruler for the measurement - so within +/-1mm is the best I could do.

I also looked on the internet for information. The best I found was this Bikeradar Forum article: http://www.bikeradar.com/forums/viewtopic.php?t=12955189&p=18696395 where it identified the bearings as:

TOP BEARING 41.8mm x 6mm 45° X 45° MR136 (1 1/4")
LOWER BEARING 47mm x 7mm 45° X 45° MR137 (1 1/2")

This was close enough to my measurements to give me confidence that I had measured correctly:

Here's a few pictures of the bearings:

New Top

New Bottom

Old Bottom

Old Top

The bearings were OK again with the re-greasing, but this was obviously just a short term containment so as soon as I got the replacements I did change them. 

It was surprisingly hard to source some bearings. The best shot I found was here: Aire Bearings on EBay. I can't fault them for price, delivery and customer service - I would use again. The cost was £15.54 for a top and bottom bearing. Bearings seemed good quality and there was no issue with fit. Only time will tell for longevity but at that price I'd be OK with a couple of years given that the Giant is used all year round.

I took the opportunity to thoroughly clean and service the bike at the same time as I changed these bearings (new chain, new jockey wheels on the rear derailleur, replaced the short length  of gear outer cable at the rear derailleur etc and general tweaks). I also put the Cole Rollen Wheels back on after the Winter.

Because I had some of the bike apart I also weighed some of the components for comparison when I stripped the Focus/built the Scott.

Giant Defy Weights
Components	Detail	Actual Weight (kg)
Cole Rollen Wheel (Front) with skewer, inner tube and Continental 700cx23mm Gatorskin tyre		1.28
Cole Rollen Wheel (Rear) with skewer, inner tube and Continental 700cx23mm Gatorskin tyre, and 12-25 105 Cassette		1.77
	total	3.05
Giant Wheel (Front) with skewer, inner tube and Continental 700cx25mm Gatorskin tyre		1.92
Giant Wheel (Rear) with skewer, inner tube and Continental 700cx25mm Gatorskin tyre and 12-27 105 Cassette		2.27
	total	4.19
Weight saving due to Cole Rollen Wheels		1.14
Crank RH (drive)	FSA Gossamer (Scott)	0.55
Crank LH	FSA Gossamer (Scott)	0.25
Crank RH (drive)	FSA Vero (Giant)	0.64
Crank LH	FSA Vero (Giant)	0.42
Weight difference between Gossamer and Vero		0.36
Focus Weight		8.52
Giant Weight (Cole Wheels)		10.62