Is it time for a new headset?
 

I am starting to notice that the bike is pulling to the right when I ride without hands. Enough so that I can only do it for 5 seconds or so without correcting it. There is no play with the stem. After reading some posts, it sounds like this could be due to a headset bearing wearing out. Before I took this one, I wanted to check with this group to see if it sounds like time for new bearings. In addition, I wanted to check the validity of turning bearings 120 degrees or 180 for that matter to extend their life by 2x or 3x.

09 Madone - Integrated headset
About 5,000 miles on this set of headset bearings.
At 1,500 miles ago, LBS turned them 120 degrees during final free maintenance check to extend their life. Was not having any issues at time.

CT

Take the weight off of the front wheel and turn the handlebars side to side slowly. See if there is any feel of "catching" or "indexing" as you turn them. If there is, your bearings are due for replacement. If not the headset is probably ok assuming it isn't adjusted too tight.

Pulling to one side is not a sign of a worn headset. The "indexing" that Hillrider describes is, but it doesn't cause pulling.

The headset is likely fine, and may or may not be due for some service, but you need to look elsewhere for the pulling.

Before looking, consider how long ago this started and what changes, if any, were made between when it was fine and when it started pulling. That will help focus your attention of the more likely culprits, but in geneal you're looking for something related to the wheel tracking and alignment of the tire contact points on the road. It could b as simple as a poorly mounted wheel, or as complicated as an alignment issue resulting from a crash.

By example, it you recently replaced a wheel, you might have mounted it poorly, or it might not be dished properly.

HillRider - That was it. Never did that test before. Pulled the bearings and the bottom one has two areas were it sticks. Feeling is almost like there is a grove on the inside of the sealed bearings. I appreciate the help!

FBinNY - As soon as I swap them will test ride and see if that did it or something else. Nothing has changed on the bike in a few months, so I will have to dig a bit more.

CT

Often wonder if the drainage crowning done in the road engineering is causing the perceived Pull to the right.. the road is not flat all the way across.. :innocent:

That actually crossed my mind when I first started noticing it. As a runner, I pay attention to crowned roads and often run in the middle of the road or switch sides of the road to even out the stress on my legs; traffic depending. While it was not as bad going on the wrong way of the road it was still pulling to the right.

What I am surmising based on HillRider's input was there was an index just to the right of center on the bearing. As I let the weight off of the front wheel, it naturally wanted to sit in that indent which pulled the bike to the right.

So I wrongly figured that the LBS would have a list of the correct bearing size or replacement headset for my headset. Not if you ride a 08-09 Madone. Turns out they used a non-standard tapered headset; IS 41\53

The mechanic at my LBS dug through the parts bin and found one left in the package. If anyone cares the correct bottom headset bearing is a MH-P20 or Enduro S68808 SP.

Specs:
ID: 40mm
OD: 53mm
Thickness: 7mm
Internal & External Angle: 45 deg

It is a bit unusual for an indexed headset to be off center because it is usually the result of cumulative trauma, which is pretty statistically biased to be dead center. Maybe it is because your mechanic had rotated it previously, and so an old worn spot was just off to one side, skewing the result.

Never a bad idea to check first what is easy to check, even when less likely to be the cause.