WVDave

I’m getting a bad feeling about availability of the FSA MegaExo-7000Tandem Sealed Bottom Brackets that fit my Comotion Speedster with FSA Tandem cranks. I’ve been proactively replacing the BB’s every 6,000 miles. My last purchase was through BikeSomeWhere.com in 2021, but their website does not appear to work. An internet search for the BB resulted in only one vendor which list them as out of stock so my suspicion is that they are discontinued. FSA’s website (FullSpeedAhead.com) no longer lists the 7000 model, or for that matter any tandem specific bottom bracket. I seem to remember finding their site unhelpful in 2021 also. What Bottom Brackets are Comotion users installing now, the 7100? As poorly as these FSA BB’s have lasted, I would consider another brand.

TobyGadd

I emailed FSA about this a couple of months ago. Here's their response: "The BB-7000 has been discontinued, but the correct replacement is simply an MTB MegaExo bottom bracket. Our part number is 200-1969, and you can find it here on our website: https://www.fsaproshop.com/products/...ttom-bracket-3"

Rick

Phil Wood, Chris King and possibly White Industries. These brands are very high quality and would likely have a longer service life.

merlinextraligh

This begs the question why you replace bb’s prophylacticly. It’s not lie a failing bb leads to catastrophic failure. Why not run them till they start being a problem, I.e. making noise.

If a failing bb would lead to a crash, or being stranded on the side of the road, I would get it. However, I’ve never heard of such a failure. IMHO, replacing them before they start to fail is just wasting money.

Russ Roth

I would get the wheels manufacturing version of the BB and just not worry about it. Personally have a poor view of anything FSA that involves bearings and understand being worried about replacement rate. Wheels prices theirs midway between the standard sram, shimano or fsa and king, WI or Phil but I don't think they give anything up in quality compared to the top end stuff. From there I'd agree with Merlinextraligh, if it isn't broke, don't fix it. BB's can go an amazingly long time with no issues whatsoever.

Artmo 

We have run our Macchiato on the original BBs for at least 30,000 miles and they don’t appear to be any the worse for wear.

WVDave

Thanks so much for the quick reply and the exact information I needed.

WVDave

Thanks for the suggestions. I've had mixed success with Phil Wood BB's in the past on other tandems, actually, only one failed prematurely.

WVDave

Actually, running them until they began to fail used to be my policy as I tend to monitor them closely. However, several years ago our FSA BB started making a slight noise but then within 20 miles (on the Green Briar River trail) it deteriorated to a crunching noise with us holding our breath until finally getting to the parking lot. I've noticed since then that the stoker's BB starts to show signs of wear as early as 7,000 miles so I've just started to replace them both every other winter, at about 6,000 miles. I'm not very good at trying to ignore sounds of impending failure coming from the driveline. On a 1,000 mile tour this past year our tour companions on a Speedster had a noise develop somewhere in the drivetrain early on in the tour. Even though it wasn't my bike, it felt like the Sword of Damocles hanging over us. After the tour, it did turn out to be a failing BB.

TobyGadd

I can certainly understand the desire to preemptively replace parts--especially before long & committing multi-day rides. While I agree that BBs don't usually fail catastrophically without some warning, peace of mind is sometimes worth the extra money.

Rick

My 1990 Burly Bongo got outfitted with Phil Wood hubs when the stock hubs continually bent axles. I bent the front crank axle standing on the pedals pulling a rather large two wheeled cart with my three children and groceries in it. I pressed a Phil Wood SS square taper axle into the eccentric and it was trouble free after that. Nothing lasts forever but you can find higher quality products. It is hard to find suitable long lasting parts for Tandem bicycles. I consider Phil wood parts to be among the sturdiest.

mikemelbrooks

A little late to the party I know but it's very easy to replace just the bearings on a MegaExo BB and cheaper and probably more environmentally friendly Enduro and many other companies supply them.

LV2TNDM

Did you ever source some alternatives? When I spent six weeks completely rebuilding a Co-Motion Co-Pilot, I was planning on replacing the BBs and Headset with gold & purple Chris King components to compliment my tri-color fade paint. Thought it would be fun to mix & match colors while I was at it. But I ended up scrapping the idea, as it was gonna run around $600 just for bling factor. Plus, I found that once I overhauled the FSA headset, I realized it was pretty stout. And I just figured I should get the lives out of the BBs before spending some pretty serious cash on King BBs.

But my point is this: you couldn't possibly go wrong with King BBs on your bike. They will be the last bottom brackets you ever purchase for this bike - or for future tandems with the same crank & frame dimensions. It will just require your BB shells are properly prepped. That is, the faces are perfectly flat & parallel. This should only entail facing the stoker BB shell, as pretty much any eccentric should already be flat & parallel (no welding deformation). This will ensure proper bearing seating, will allow you to achieve proper bearing adjustment, and ensure almost endless service life. If properly installed & cared for, most King bearings will outlast the bike they're on. (King utilizes angular contact sealed cartridge bearings. They don't suffer "failure" like radial contact bearings that once they develop play, they require replacement.)

The other alternative for you to at least try is to source replacement cartridge bearings for the BB cups. I realize they're not considered "serviceable," but that doesn't mean you cannot press out the worn (radial contact) sealed bearings and press in new replacements. I've considered trying this, but have never embarked on the experiment.

PS OMG, I totally forgot to inquire further, given my experience. By "bad feeling," what do you mean exactly? I ask because as my wife were on our France trip, I began to notice a really strange feeling on the captain down, left pedal stroke while about only 5 days into our trip. This is our third tandem, and I've never felt anything like it before. (Nor on any of my half-bikes in 50 years of riding and wrenching.) Sure felt like a bearing was giving out. Well, I pulled over to the side of the road to check things out. Timing chain tension was fine. No "play" in the BB at the cranks. BB cups nice and tight. And obviously no loose crank arm either. So I went to the next thing to check and put an Allen key into the Bushnell eccentric and sure enough it wasn't THAT tight. So I gave the bolts some extra torque all around and that totally resolved our issue. I was a little wary of the Bushnell developing this problem, but it has not returned. So that's definitely something you should double-check. And to be clear, I use AMPLE grease throughout the eccentric, its bolts, clamp mechanism and everything else.

WVDave

The bad feeling was the result of not being able to find the exact same FSA Bottom Brackets I purchased previously. I have only minimal understanding of the measurement details as well as the different types of BB's, so I feel safest just replacing with the exact same part. When I was younger, I would possibly have experimented with opening up the cartridges and replacing the ball bearings, but now I'd just spend too much time searching the garage floor to find out where the rolled off to hide. After your post, I did take a look at the Kris King website. Perhaps if I was younger I could justify the prices, but at my age, a lifetime guarantee is not really promising that much.

mikemelbrooks

You don't change the individual ball bearings, they are cartridge style, the races, bearings and seals are all together. This video is for Shimano but the principle is the same,