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Technical FAQ: Overhauling bottom brackets and freezing feet

  • By Lennard Zinn
  • Published Dec. 18, 2012
  • Updated Dec. 18, 2012 at 1:44 PM EDT
A skilled tech may be able to re-tap shredded bottom bracket threads, but Luke's shell may be too far gone. Photo: Lennard Zinn | VeloNews.com

Editor’s Note: Lennard Zinn’s regular column is devoted to addressing readers’ technical questions about bikes, their care and how we as riders can use them as comfortably and efficiently as possible. Readers can send brief technical questions directly to Zinn.

Frequent overhauls

Dear Lennard,
Obsessive, Compulsive Overhauler?

I noted in your comments about your ’cross setup that you overhaul your bottom brackets at least once a month. Ok, so granted, you’re a fine mechanic with all the best tools, etc., at your fingertips. And granted, cyclocross is a very dirty sport…

But how much overhauling is too much? When does the maxim “if it ain’t broke, don’t fix it” gain traction?
—Andrew

Dear Andrew,
That completely depends on the bottom bracket and the usage it sees. In the case of my ’cross bikes, I did not start with that frequency of overhauling, but I adjusted to that based on experience.

Since we make our “Zinntegrated” custom-length cranks to fit them, the only (current) bottom brackets I’ve raced cyclocross on are SRAM GXP external-bearing threaded bottom brackets, and those are the ones I was talking about. I discovered every time that the non-drive bearing felt rough when I checked it a few days after either a wet ride or a ride in the mud that was followed by a bike wash. In every case, when I pried the seal off of the bearing, the balls were completely rusted. In some cases, the bearing was not even turning—the spindle was instead sliding inside of the bearing’s inner race in order to turn. The drive-side bearings usually looked ok.

Anyway, I tried on a number of occasions to rehabilitate these rusted bearings to no avail. I invariably ended up throwing out the bearing and replacing it. As I found this tiresome and expensive, I began to overhaul my bottom brackets after every muddy race. By this I mean that I always pried the bearing covers off, blew out the bearing, wiped it with a clean rag, packed it with clean grease, and pressed the cover seal back in place. This resulted in longer bearing life.

On the other hand, all of my road and mountain bikes also have GXP bottom brackets, and I do not overhaul them any more than a time or two a year. That’s because I rarely ride them in the rain. I also have hybrid ceramic bearings in two of my road bikes, and of course the ceramic balls cannot rust.

I rode for three days in the rain from the Eurobike show in Germany to Lugano, Switzerland, this fall on my titanium travel bike, which has ceramic bearings in its GXP bottom bracket. When I returned home, I opened the bottom bracket. The grease was black inside, and the bearings felt very rough. But the ceramic bearings have plastic bearing retainers, which, unlike steel retainers, can be removed without being ruined. I pulled out the retainers, shifted the balls to bunch them together on one side so that I could pull the inner bearing race out. Then I polished the inner and outer races with rubbing compound, cleaned the ceramic balls, and reassembled the bearings. (Again, I put all of the balls together on one side so that I could snap the inner race in, then spread them out with an awl, and then installed the plastic bearing retainer.) After I got done, the thing spun like a charm and still does.
―Lennard

Seatpost recommendation

Dear Lennard,
Quick question in regards to your article about seatposts, I’m sure frame material plays some role in the equation. I have a titanium road frame, would a carbon or Ti seatpost be better for this frame (for longer road rides, centuries, mostly smooth roads)?
—JM

Dear JM,
I don’t think I could make a blanket statement about that. As you saw in the article, there were carbon posts that outperformed the Ti posts in deflection, in damping, or both, and the Ti posts also outdid a number of carbon posts in those tests as well. So it depends on the post. If you want the smoothest ride, which your titanium frame is already smoothing, I’d get that FSA K-Force Light SB25 carbon setback post.
―Lennard

Shredded BB shell

Dear Lennard,
My bottom bracket was making some noise today so I decided to pull it apart and clean and re-grease everything (I had ridden the bike in the rain for a few days). As I started to remove the non-drive side, it became stuck and would just spin. The BB would not thread back in or come out. As I fiddled around with it more (and probably made the damage worse) I saw a few small threads of silver metal come out and stopped. Is my BB shell ruined? Can a shop fix this? It’s a 2008 Felt F75 with Shimano 105 and Hollowtech II cranks.
—Luke

Dear Luke,
Wow. Your frame’s threads are probably toast. Generally, the threads on the cups themselves are harder than in frames other than steel frames (and perhaps titanium ones) and never strip. But aluminum frame threads are relatively soft and can strip. There are so many threads fully engaged, though, it is rare to hear of one doing this, especially if you had no cross-thread wrestling match with your bike putting it in the first place.

If the frame threads are stripped, it’s certainly worth trying to have a shop re-tap them. But if it’s stripped to the point that the cup just spins in there with advancing in either direction, the chance of success with tapping the BB shell is minimal.
―Lennard

Freeze away foot pain

Dear Lennard,
In response to your discussion on Morton’s Neuroma, you should know that a procedure that freezes the nerve through a 0.5cm incision and the insertion of a probe that has (liquid) nitrogen passed through it is awesome. I had it done on a Thursday, WALKED 18 holes of golf on Saturday, and did a 55mile bike ride Sunday. NO MORE PAIN!!! Check “footfreezer” Not many qualified practitioners, but better than a six-month rehab.

“Manageable” for me is absolutely no pain. I could not believe that I would have to go through six months of rehab and try to keep racing fitness, skiing, basketball, tennis and golf. It has not hurt since, except for a couple of twinges. The guy I went to is retired in Livingston, New Jersey, but a colleague is continuing. I know there is another in Florida, but I’m sure if you contact the guy in New Jersey, he could give you a list. My guy was training two people from the Midwest when I had it done. Please research this procedure and put it in Velo; it could really save a lot peoples’ race seasons. Google has the info.

Glad I got to you and have a Merry Christmas.
—Rich

Dear Rich,
I think I found your link. I, too, hope that this offers relief to some sufferers out there.
―Lennard

Follow-up on corrective lenses

The following letter follows up on my column covering corrective lenses and, specifically, bifocals for cycling.

Dear Lennard,
I’ve been quoted as saying that the money I spent on the first generation Dual Eyewear glasses was “very likely the best 50 dollars I’ve ever spent on anything cycling related.” The Duals replaced a pair of Oakley half-jackets with Oakley prescription progressive lenses with Transition shading. The Oakley lenses were never as tight a fit as the standard Oakley lens, and one fell out; by the time I found it, I had stepped on it on a concrete floor; not breaking it, but seriously scratching it in the area which I would be looking through most when riding. Oakley would not sell me a single replacement lens, only a new pair at close to $500.

The Duals were a great alternative, but after a few months, I decided I wanted something for more diverse light conditions, including not just cloudy days, but something for night riding as well. Sport Rx provided the answer: new lenses for my Oakleys, lined bifocal with Transition treatment — more than a hundred dollars less than the Oakley lenses. The lenses fit the frame as well as the non-scrip OE lens and the lined bifocal did not create the distortion or excessive magnification that I experienced with the progressive lenses from Oakley (small holes looked like craters, a piece of gravel like a fist-sized rock — not great for trail riding or cyclocross). I’ve used the lined bifocals on virtually every ride since I got them and can’t recommend them highly enough — still not inexpensive, but what glasses are these days? Sport Rx sells most major brands of sport-specific eyewear, not just Oakley. Service was exceptional in every way.
—Thom

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Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, as well as Zinn and the Art of Triathlon Bikes and Zinn's Cycling Primer: Maintenance Tips and Skill Building for Cyclists. He holds a Bachelor’s degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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