Thursday, December 13, 2012

I Come To Bury Square Tapers, Not To Praise Them

By now, it's probably pretty clear that I'm a cantankerous old bastard. I don't trust anything new, anything fangled, and you can bet your sweet bippy I don't trust anything new-fangled. (And don't get me started on threadless headsets, what with their star-fangled nuts...)

However, I'm coming around in the realm of the bottom bracket, having now installed two Shimano external-bearing BBs (one for a friend, one for myself) versus literally hundreds of square-taper BBs. Tonight's adventure was replacing the crunchy Tiagra BB on my Clubman with a new Ultegra (I tend to demolish inexpensive BBs, so the extra couple bucks seemed worth it). Here's a bit more crankiness in the realm of environmental package design, though. This is the "disassembly sequence" I had to go through just to get to the new BB:

Box #1
Box #2, which was inside Box #1, apparently so the instructions had a place to sublet.

Two (count 'em, TWO) separate plastic bags inside Box #2, which, as you'll recall, was inside Box #1 
Now, I don't wear hemp undies or compost my unused compost, but really? It takes that much cardboard and plastic to hold two bearing cups and a plastic tube that weigh all of 95 grams? Uh, OK. So score one for the old-school square taper bottom bracket, at least, since those came in one box with no plastic and the instructions tucked in with the BB. So the instructions got a little greasy... you planning to keep them in archival sleeves and put 'em on eBay? Harumph, harumph, harumph.

(Update: Reader Jeremy tells me that new square taper BBs are just as overpackaged. Thus, I strike my comment... except for the harumphs.)

But, grumpy man, get to the point and replace your bottom bracket. Here are the tools needed:



One Park BBT-9, and one regular old 5mm hex wrench. Simple. So simple, in fact, that I will endeavor to describe the entire removal process without taking a breath: Loosen the two hex bolts on the non-drive-side crankarm, remove the plastic cap on the non-drive side of the BB with the plastic end of the BBT-9, pull the non-drive-side crank off by hand, pull the drive-side crank out, and unscrew the BB cups using the metal end of the BBT-9. Whew!

Having done that, I was left with one toasted Tiagra:


The bearing on the non-drive side still feels good, but the drive side is crunchy. If I feel really bored and/or advanced, I'll try to replace the bearings someday. The rusty gunk on the central sleeve concerns me a little, though not enough that I'm going to go to the trouble to strip down the frame and shoot anti-rust goo in it. Yes, Neil Young says rust never sleeps, but there are so many other things to get uptight about. If the world doesn't end when the Mayan calendar runs out, I'll consider it.

It wasn't until I saw an external BB sitting like this that I had my forehead-slapping moment: It looks like a little headset! In fact, that's pretty much what it is, turned 90 degrees and with cups that screw in instead of press in. At that point, these things stopped being all scary and new to me. You think it's a coincidence that Chris King (maker of maybe the bestest headsets ever) didn't dip a toe into bottom brackets until external bearings became the norm? Did you just slap your forehead too?

So having already extracted my shiny new Ultegra from its labyrinthine packaging, I just had to screw the sucker in (using the metal end of the BBT-9 again):



Did you forget that the drive-side cup is left-hand threaded... unless your frame is Italian... or French... or Swiss? Hell, I don't remember. No wonder all the even-newer bottom bracket standards just use press-in bearings. All the mechanics who could keep track of the different threadings are gone (rest and wrench in peace, Sheldon).

Put the cranks back on by hand, use the plastic end of the BBT-9 to screw the non-drive-side plastic cap back on, tighten the hex bolts on the non-drive crank, and you're good to go. It's simple enough that I'm very tempted to swap the square-taper on my folding bike to newfangled, just so I can get the cranks off with only a 5mm hex wrench and the plastic doohickey from the end of the BBT-9 (it looks removable to me). That could be suitcase-packing nirvana.

Now here's why my once-passionate devotion to the square-taper bottom bracket (even the un-killable Shimano UN-72 cartridge) runs dry. To accomplish the same thing in a square-taper world, you need these tools:


An 8mm hex wrench (middle) to get the crank bolts off, a crank puller (lower left) and BFW (Big, Forceful -- hey, it's a family blog -- Wrench, right) to get the crank arms off, and a bottom bracket tool (upper left) with the BFW to get the cartridge out. All this so you can have a press-fit crank interface with much rounding-out potential and smaller bearings (albeit ones that are protected inside the frame). Meh. I certainly can't describe the process in one breath, though I've packed an impressive number of expletives into one breath when I accidentally left a washer in a crankarm before applying the crank puller and BFW, thus extracting only the crank's threads.

Now, granted, if you're a REAL bodger, the square-taper BB comes in a zillion lengths, which allows you to customize your chainline with dang near every square-taper crank ever made. And yes, most cranks made for the square taper are prettier than the newfangled stuff (Shimano's new elephant proboscis drive-side crank is pretty awful). But man, that install was a piece of cake. The only thing that might sway me back to ye olde times is if this Ultegra BB proves to have short bearing life like its Tiagra cousin... but then again, there's always Chris King...

5 comments:

Jeremy said...

It should be pointed out that current Shimano square taper bb's (still the best on the price/function curve) come in an equally excessive amount of packaging.

Jason T. Nunemaker said...

Thanks for the update, Jeremy... I've edited accordingly.

Sometimes I forget that I haven't worked in a shop for... (counts on fingers) almost 13 years. Of course, at my age, I forget a lot of things. :-)

Anonymous said...

so.. when do we get to see the autopsy of the bad bearing???
What caused the early death? Not enough lube? an ingress of sand? A bearing cracking in half?? I may not sleep until I find out!

Steve in Peoria

p.s. BFW = Big Friendly Wrench, at least in mixed company.

Steve Fuller said...

The BB on my Mukluk got all grindy last fall and I ended up pulling the BB, removing the seals and flushing the bearings with simple green and water. I greased the hell out of it and put the seals back in and it's been fine ever since.

There was next to no grease in it when I pulled it out, and other than one silty ride, it hadn't been abused. I think the BB mfgs are cheaping out on the grease a bit so they can sell more bottom brackets.

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