Revisiting old school cranks and friction testing

Discuss light weight issues concerning road bikes & parts.
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Praha19300
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by Praha19300

Playing with some Isis cranks the other day made me realise how horrible our current crop of cranksets really are.Compared to some high end square taper isis are nothing special but with all this talk of friction of lube chains gear rollers etc when is somebody going to compare the obvious friction trap of the current bottom brackets against a mid 90‘s Campag Record crankset?

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Stolichnaya
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by Stolichnaya

As a retro grouch user of square taper still I am...

:popcorn:

But I recall this being discussed some time ago. Can't find the thread right now.

bm0p700f
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by bm0p700f

The main advantage of modern bb's is reduced weight. The stiffness of a square taper BB was alway stiff enough. A Tifosi ISO taper (square) BB weighs 216g for a 68x111mm. So a Record carbon 10 speed chainset is 580g? add a Tifosi BB and you have ~800g compared to about 700g for record 11 speed chainset + BB cups.

I am not sure the extra friction is significant.

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theosaurus
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by theosaurus

The problem with the cup style bb is that it wears out so bloody easily (especially bb30).
yes, but how much does it weigh?

Geoff
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by Geoff

As much as I love the square-taper bottom bracket, I will grudgingly say that it is probably unfair to broad-brush 'modern' designs with the horrible ISIS as the example. I find the BB86 and Ultra-Torque both quite decent...

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theosaurus
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by theosaurus

I use both square taper and ultra torque which I think is great but lasts nowhere near as long
yes, but how much does it weigh?

eric
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by eric

Isis was horrible. The design left little room for bearings so most ISIS BBs had really tiny balls. The only one that lasted for me were the FSA ones with double row bearings.

I can feel a difference in stiffness between square taper and modern external BB large diameter spindle cranks. I don't think it makes a difference in performance however as the system is basically a spring.

The modern BBs allow both reasonable sized bearings and large diameter spindles which can be made lighter than solid square taper spindles. We also don't see the modern spindles breaking, which did happen some times with the square taper spindles.

sawyer
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by sawyer

if this is a spin in the hand test type smoothness then my old Octalink was smoother than anything with external cups i've tried including UT with ceramics and minimal lubrication.

thing spin like a f'kin roulette wheel
----------------------------------------
Stiff, Light, Aero - Pick Three!! :thumbup:

quattrings
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by quattrings

I'm running a BB UN73 on my TT bike with the seals removed. I've never had a crank spin better than this. Of course the TT bike doesn't see rainy weather a lot, but it's been in a few showers and haven't had to touch the BB.
BB30 is the best, but I'll take square taper over ISIS/Octalink anyday.

Also the campy iso standard with preload is very free spinning.

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Rick
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by Rick

I have been using the same UN51 BB on my mountain bike since about 1993 (?) It still spins glassy smooth.
I also ran the loose-ball-bearing style Dura Ace and Sun Tour BB for decades with just a yearly clean/regrease. They spun just as smoothly as any ceramic bottom bracket today.

Now, I have to rebuild my BB30 bracket 4 times per year to get rid if the clicks and squeeks, and my hollowtech BB is NEVER as smoothly spinning as the old ones, although I do admit they remain maintenance free for a long time.

I think BB technology was one of those things that didn't need an upgrade but they just kept changing it anyway to force new purchases.
maybe the new stuff is a little lighter. :|

fdegrove
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by fdegrove

Hi,

Stolichnaya wrote:As a retro grouch user of square taper still I am...

:popcorn:

But I recall this being discussed some time ago. Can't find the thread right now.



We'll indulge your every wish.....

Way back there must have been a Campa Super Record BB with accompanying crank that had a hollow (maybe not hollow) Ti axle, cup and cone steel bearings, right?

Now imagine that ISO BB with cup and cone Cult bearings running on Krytox loaded oil and a Record carbon crank.

Impossible I hear you say?

No, you can build your own relatively easy.

The bearings would be the same as the CULT bearings used in the top end of Campa's wheels. It's simply conform to a plain vanilla 6903 standard size bearing.
Pick a high quality Ti axle, BSA or ITA alloy cups of your choice and you're done. Easy peasy.

No need for seals, you're going to flush these bearings clean and relube them whenever you think you should (probably quite often) and ride happily ever after.

That's the kind of BB a car company such as Alfa Romeo would have offered before they scrapped the car that's going to be replaced by the next model. That was Europe in the Seventies, young man. :lol:

Estimated weight for the BB ? I'd say 140g with room for tweaking.

Enjoy, ;)
Being a snob is an expensive hobby.

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djconnel
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by djconnel

My Lightning is fairly smooth: much smoother than my SRAM. But the argument is that loaded friction is different than unloaded (I'm a sceptic). Contador and other equipment weenies in the pros run w/o seals and do actual hub maintenance.

bm0p700f
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by bm0p700f

Or just buy a Phil Wood Ti BB although that would cost more but finding a bare Ti axle is but this guy has some lengths http://www.retrobike.co.uk/forum/viewto ... 2&t=230737 just not the ones I want. Also for campag Tifosi BB are only 216g and about £2, cheap and light weight.

fdegrove
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by fdegrove

Hi,

just not the ones I want


Complete BB can be found here:

http://www.pmpbike.net/bici/Movimento-Centrale.html

Just keep in mind you'd also have to buy the tool to mount it.

BTW, Royce in the UK used to make very nice BBs as well.

Ciao, ;)

EDIT: The axles can be bought as spares from PMP as well. Not too expensive IMHO.
Being a snob is an expensive hobby.

bm0p700f
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by bm0p700f

Royce BB are £280 retail. Phil wood are £150. I can also buy the Phil woods at trade so that alot less.

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