Sugino 75 goes external BB


Product news - Sugino SG75DD Crankset

“Dolan bikes”

Did it need to be changed? Track cyclists were fine with square taper, werent they?
Be interested to know the q-factor- bet its increased.

Some people (me included) prefer external bb systems.

I cant beliebe it.

And now there’s a choice away from Omniums.

So did they come with because track riders were requesting it i wonder?

Without quoting some marketing hype… is there some evidence of improved performance, reduced friction or alike?

Fairwheel tested road cranksand found external to be far stiffer than square taper.
I don’t know about anyone else, but I’ve had heaps of square taper BB-crank setups and found they need to be re-tightened regularly, otherwise you risk having them come loose and round off the crank female square.
External also doesn’t need a crank puller.

One theory I’ve heard is placing the bearings further out reduces the horizontal spindle flex. Imagine if the bearings were in the dead centre of the BB, then anyone could flex the BB.

Also having the bearings housed outside of the BB shell means bigger bearings/less friction.

That’s a dumb test … not accurate. Older crank, slim profile and nowhere near as much beef around the centre. Not nearly as stiff not becuase of the square taper BB but becuase of the crank shape/profile.

They do mention it’s the crank but that’s half the problem, old square taper cranks are terrible in design we have not seen a modern design with square taper to get a clear indication but my bet is external is still miles stronger, smoother for longer and lighter.

Maybe the other stuff, but I’m not so convinced by this bit ^

Overall, in my experience, square taper BBs last longer than ext BBs, and spin smoother with less seal drag out of the box and often well through the service life. (Here I’m comparing anything of UN52 level and up to anything 105 level and up.). SKF square taper are better again with maxed out bearing sizes and needle bearings on the DS.

Wider bearings also forces Q factor out. But in that case, BB92 etc would be preferable for bearing spacing.

BB bearings are 1/4" (6.35mm), Hollowtech II uses 6805 bearings, which are 25x37x7mm, with a bearing in the cartridge that’s ~5.8mm (7/32"?). The new 11sp bearing cups are a smaller OD with the same 24mm spindle, so that means smaller bearings again.

Ain’t nothing wrong with a properly setup square taper crankset, if there was there would be flogged out cranks after every match sprint.

Blakey, is it (reasonably) possible to overtighten the crank bolt on square taper cranks?
Just curious for the future

Yeah, totally doable if you hamfist it. Especially if you grease the crap out of the taper and use a big wrench. (that’s a whole nother bucket of worms, grease / no grease…)

(No grease, tighten to specified torque)

looks almost the same right? :S

Important with square taper to resist the temptation to re-check/re-torque crank bolts, they do not ‘hold’ the original setting and you can blow them up by repeated re-tensioning. And, FWIW, I am a greaser.