Madone bottom bracket issue resolved!
I am happy to report that the issue with my Madone (see yesterday’s blog) is resolved! As it turns out, the problem was not the known Madone bottom bracket issue mentioned in yesterday’s blog.
When the mechanic put the bike on the stand and started looking at the problem, the first thing he said was, “Did you or someone else already take a look at this?” I truthfully replied “No”, as I was aware that this could wind up being be a frame issue and I did not want to void the warranty. The reason he asked that question is because the central crank arm compression bolt was cross-threaded!
So here’s what was wrong: apparently the center crank arm bolt was cross-threaded on by whoever originally built my bike at the shop. There are also two pinch bolts that hold the crank arms on, but the cranks were not firmly seated all the way back when they were tightened down. The force of pedaling combined with road vibrations finally caused the cross-threaded crank arm bolt (which is made of plastic–are you freaking kidding me?!) to pop out a few millimeters, and that’s what created the lateral play in the crank arms.
The mechanic did all the work right in front of me, and he proved to my satisfaction that it was not a bearing or frame issue. Using the original bearings, he replaced the cheap cross-threaded crank bolt with a metal one and tightened everything to spec. After doing that there was no longer any play in the crank arms–and we really pulled on them. He even had another mechanic (I think he was the head wrench at the shop) come over and give a second opinion.
Now, check out the difference in the condition of the two bearings: the drive side bearing (shown on the left) is in pristine condition, while the non-drive side bearing is a mess. Because the crank arms were not tightened down properly, water and sand was able to get into the non-drive side bearing. The non-drive side bearing was covered in rust and sand, and it did not rotate smoothly. The drive side bearing was smooth as silk.
After showing me that the crank arms were 100% solid with the original bearings, the mechanic took everything apart again and put in a fresh set of bearings. Also, as mentioned above, he replaced the cheap plastic crank arm bolt with a metal one.
Because the issue was not the bottom bracket issue mentioned in yesterday’s blog, the over-sized “V2″ bearings were not required.
While the bike was being worked on, I talked to the mechanic about the known bottom bracket issue. He said the earlier Madone carbon frame bikes (model year 2008-2010) were more prone to the problem, and that the 2011 carbon frame was the third generation and had been greatly improved. While there’s no guarantee that the issue won’t affect my bike down the road, odds are it won’t. If the problem happens to occur at some point, the shop promised to make it right (the frame has a lifetime warranty).
So I am very pleased with the service I received yesterday. The two mechanics who worked on my bike were friendly, knowledgeable and forthcoming with information. I never felt like they were attempting to sugarcoat the issue, only that they wanted to get my bike repaired quickly and properly. I also greatly appreciated that they fixed my bike while I was at the shop, and allowed me to participate in the repair.
Good job David’s World Cycle!