Triplet’s Are Tough on Drivetrain Components

During the Georgia Tandem Rally the triplet’s drivetrain seemed to be wanting for some attention, more than could be resolved by simply trimming or fine-tuning the derailleur position with the in-line barrel adjusters.

In fact, at one rest stop where I found our friends Ric & Marsha from House of Tandems had set-up shop I borrowed a rear cassette lock ring wrench just to make sure the lock ring was fully torqued and not contributing to some chain skipping we were experiencing in our highest gear.  No, that was good and the rear derailleur hanger also looked to be straight and secure.  My guess was, the chains were probably about due for replacement.

Once I had the triplet back at home a quick measurement with the Park chain checker confirmed was I suspected, the chains were indeed in need of replacement. It should come as no surprise, a triplet with three adults driving the bike clearly put a lot more wear and tear on the chains as compared to a tandem, never mind a single bike. Once I pulled the chains off it also seemed like the front & rear FSA Mega EXO bottom brackets were in need of attention.  With the cranks and chains pulled and tires removed the triplet got a wipe down and was put back in the rafters to free up floor space — a triplet definitely takes up a lot of room where ever it is — until I had some time to work on the bike and/or get any needed parts.

It was Wednesday when I did some checking and confirmed  I had enough left-over O-rings and outer seals from when I overhauled our friend Lisa’s triplet back in July 2012 to service the 2 FSA Mega EXO bottom brackets on our triplet.  I had to go back and check my blogs to see when I’d actually done that work on her Mango triplet as I thought it was before we acquired our own triplet.  But, no… it was shortly there after in the summer of 2012.  And, yes… working on these really long bikes can be a bit of a challenge if you don’t have a large work space.

Given I had the parts I needed for the rebuild I went ahead and pulled down the triplet and set it up in a pair of workstands in the middle bay of our garage, which was open since our Tacoma was in the shop for its 20,000 mile service. As often times is the case, the plastic outer seals usually end up damaged when you remove them which is why I had extra ones on hand.  Same thing with the O-rings; they’re usually a one-time use item as well.  With the outer seals removed I was then able to use my blind bearing removal kit to pull the four bearings out of the bearing cups which remained in the frame.

Upon inspection, the cups and inner seals were in good shape as were the outer seal  blade seals, so I did indeed have everything I needed for the rebuild.  As for the bearings, the front two definitely felt like they were due for a cleaning and relube but the rear bottom bracket bearings felt really good.

After removing the pressed-in seals from all four bearings, as suspected, the front bearing grease was pretty nasty which makes sense since the front bottom bracket ends up being mucked up by all of the dirt and water thrown up by the front wheel.  The rear bearings, on the other hand, looked like new under the seals.  I probably didn’t even need to flush them out and re-grease them, but went ahead and did it anyway. After that, the cups were cleaned, the bearings were pressed back into the cups, followed by the new outer seals with the re-used blade seals and then the cranks went back in with their new O-rings.  It’s all rather straight forward.

I’m still in awe of how much torque is spec’d for the BB8000 type rear cranks but it seems to work just fine but also explains why we still find a lot of tandem teams riding around with creaky FSA bottom brackets. Your average shade-tree mechanic and a lot of shop mechanics don’t appreciate how much 30ft lbs of torque feels like.

As a closing note,  our triplet is a bit odd in that it has three different types of FSA bottom brackets and cranks, not a matched set.  I had to do that in order to get the right length and style cranks and was buying new old stock off of ebay when I rebuilt our triplet.  Anyway, the bottom brackets and cranks are all back together and spinning much better than they did before the rebuild.  All I need to do to have the triplet ride-ready is get some new chains ordered and installed, so that’s next on my to-do list.

About TG

I've been around a bit and done a few things, have a couple kids and a few grandkids. I tend to be curmudgeonly, matter-of-fact and not predisposed to self-serving chit-chat. Thankfully, my wife's as nice as can be otherwise we'd have no friends. My interests are somewhat eclectic, but whose aren't?
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