Hollowtech 2 vs Square Taper

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I’m going to compare this Hollowtech II crankset to a standard square taper setup

So this bike from 1998 originally had a drivetrain setup based on a square taper bottom bracket.

Square taper bottom brackets seem outdated in a world where a new piece of tech seems to be hitting the market every minute.

But even new bikes today get outfitted with them. And it begs the question “are square taper bottom brackets good?”.

Weight is often cited as a reason why parts are better or worse than other parts. With lighter being better.

A Shimano BB-UN55 square taper bottom bracket weighs in at around 285 grams for the 123mm. length version.

A Shimano Hollowtech II SM-BB52 bottom bracket weighs just over 90 grams.

So yeah, that’s quite a big difference for just a single component. And if you care about shaving off around 200 grams you might consider upgrading from square taper to Hollowtech.

However, my Shimano Deore XT FC-M770 Hollowtech II crankset weighs exactly 600 grams. The 1989 Shimano FC-MT60 crankset weighs less with 530 grams. So the net effect of not using a square taper bottom bracket because of the weight is less than you might be looking for.

Another common argument against square taper bottom brackets is that they are less stiff. And with a larger width, bigger bearings on the outside rather than the inside of the frame, and the spindle co-integrated with the crank that might indeed be the case for Hollowtech II bottom brackets.

That being said, I’ve never actually felt cranks flex when doing steep climbs and really putting the power down. So I don’t know, is it true, and if so, does it matter for the average Joe?

And for the last comparison I look at the argument that that Square taper bottom brackets are more prone to wear.

So based on the video it seems it’s not how many miles you ride with a bottom bracket, but how much you ride with contaminated bearings.

Whereas the Hollowtech crank is pressed flush against the bottom bracket, the open character of square taper bottom brackets does lend itself more to being contaminated.

So my final thoughts are that I’m not convinced that a Hollowtech II setup is markedly better than your standard square taper version. What I do know is that yet again I had to buy another tool to service it.

Referenced video:
Bearing Special:    • Everything You Need To Know About Bea...  

Tools used:
BBT-9 Bottom Bracket Tool – 16-Notch 44mm OD: https://www.parktool.com/product/bott...

I've also written about blog post with more information. If you want to read this article go to https://www.restoration.bike/bikes-an...

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