Bottom brackets old style vs new, what's it all about

[faster]

There's absolutely nothing wrong with Shimano HT2 imo - miles better than square taper.

Lighter, stiffer, lasts 10,000 miles plus in all weathers with no maintenance if installed correctly, cheaper (about £12 for ultegra when on offer!), doesn't need any special tools to change, can be changed in minutes and is creak free. The only disadvantage I can think of is that they give very little warning before failure compared to ST.

If you're heavy, ST cranks can easily become loose over time and then become irreparably creaky. An expensive mistake.

Has anyone else fitted a new UN55 lately? I have - useless. The one that it replaced had one plastic cup - this worked well. The new one has an aluminium cup which is a sliding fit onto the cartridge. As you'd expect, this metal on metal interface creaks. A lot. Great.

 

[rualexander]

Has anyone else fitted a new UN55 lately? I have - useless. The one that it replaced had one plastic cup - this worked well. The new one has an aluminium cup which is a sliding fit onto the cartridge. As you'd expect, this metal on metal interface creaks. A lot. Great.

UN55 has always had a metal cup I think, UN25 has a plastic one, as do other brands.

 

[IanSmithCSE]

Good morning,

Have seen a couple of snapped hollow axles. Has anyone seen a snapped sold axle?

I believe that the Campag Super Record Titanium BB was prone to failure in the late 1970s. :-)

Fortunately this was an upgrade, so you had to buy the Super Record Chainset and then the BB, so if you could afford one you were either a pro or never rode your bike as you were too busy working.

Bye

Ian

 

[rogerzilla]

Titanium spindles usually have a weight limit. Usual problem of replacing a part dimensioned for steel with one made from another material, although with titanium vs steel, stiffness is likely to be the biggest problem.

 

[Foghat]

I believe that the Campag Super Record Titanium BB was prone to failure in the late 1970s.

A very high-profile example happened to Laurent Fignon in the 1982 Blois-Chaville (a race sometimes run as Paris-Tours or Créteil-Chaville).

Fignon was away and on course for an almost certain win in this Classic when his titanium Super Record bottom bracket axle broke as he laid down the power going pretty fast out of the saddle, and dumped him unceremoniously, and very painfully no doubt, on the road, allowing the big-name chase group to cruise past.

Caught on camera, of course:



Video of such racing was rare this side of The Channel, but the following image was heavily featured in the periodicals such as Cycling (which became Cycling Weekly), Cyclist Monthly, Miroir du Cyclisme and Vélo. I imagine sales of titanium bottom brackets fell through the floor after that - not just for Campagnolo, but probably other titanium bb manufacturers of that era such as Zeus, Stronglight, OMAS, Edco too. Having winced severely at Fignon's misfortune, it certainly put me off ever buying one.

 

[Smokin Joe]

A very high-profile example happened to Laurent Fignon in the 1982 Blois-Chaville (a race sometimes run as Paris-Tours or Creteil-Chaville).

Fignon was away and on course for an almost certain win in this Classic when his titanium Super Record bottom bracket axle broke as he laid down the power going pretty fast out of the saddle, and dumped him unceremoniously, and very painfully no doubt, on the road, allowing the big-name chase group to cruise past.

Caught on camera, of course:



Video of such racing was rare this side of The Channel, but the following image was heavily featured in the periodicals such as Cycling (which became Cycling Weekly), Cyclist Monthly, Miroir du Cyclisme and Vélo. I imagine sales of titanium bottom brackets fell through the floor after that - not just for Campagnolo, but probably other titanium bb manufacturers of that era such as Zeus, Stronglight, Omas, Edco too. Having winced severely at Fignon's misfortune, it certainly put me off ever buying one.

View attachment 462925

I remember that.

A company called Rolls introduced titanium bottom brackets IIRC. Thy cost an absolute fortune at the time.

 

[midlife]

After that Campag ordered a different design of axle from OMAS who made them for Campag (solid not hollow)....

 

[Foghat]

After that Campag ordered a different design of axle from OMAS who made them for Campag (solid not hollow)....

And when the C-Record groupset replaced Super Record in 1986, the axles were back to steel.

 

[fossyant]

There's absolutely nothing wrong with Shimano HT2 imo - miles better than square taper.

Lighter, stiffer, lasts 10,000 miles plus in all weathers with no maintenance if installed correctly, cheaper (about £12 for ultegra when on offer!), doesn't need any special tools to change, can be changed in minutes and is creak free. The only disadvantage I can think of is that they give very little warning before failure compared to ST.

If you're heavy, ST cranks can easily become loose over time and then become irreparably creaky. An expensive mistake.

Has anyone else fitted a new UN55 lately? I have - useless. The one that it replaced had one plastic cup - this worked well. The new one has an aluminium cup which is a sliding fit onto the cartridge. As you'd expect, this metal on metal interface creaks. A lot. Great.

Metal cups are far better. Fit with lashings of grease.

 

[Blue Hills]

Outboard bearings solves the problem of fitting a large hollow axle inside a small, legacy BB shell.

Sorry. I can't see that you have identified a functional problem there.

 

[Blue Hills]

The only issue with the UN55 is its weight. Shimano have reverted to solid spindles, probably to make the product less attractive so you "upgrade" to HT2. Tange BBs still have hollow spindles.

It is incredibly heavy for its size, yes. But to me that is a source of wonder. And I find it reassuring? It's hardly as if the rest of the bike is that matter-dense.

 

[Yellow Saddle]

Sorry. I can't see that you have identified a functional problem there.

No, it addresses a marketing problem that poses a functional challenge.

 

[Blue Hills]

I have a square taper bb on my Claude Butler bought new in 2010 and has done 14000 miles and still going strong. It may be old hat to some but if it works then why not ? I am not sure who made my bb as I have never had it out. If I get a creak then it must be my joints !

Not saying there is anything wrong with it (i am a ST fan) but I'd take that out soonish, grease everything on the thread interface and put it back in? Or you may find that it has stuck. Damn ST, so reliable it is easy to forget about them.

 

[Nigelnightmare]

A hollow spindle is perfectly strong and stiff enough but does need to be made from a better grade of steel. Solid ones are just cheaper to make, no other advantage.

Or disadvantages either. They just keep on on and on in all types of terrain and weather.