Square Taper or Octalink ?

one that is not inaccurate.

;)

The allen bolts are like tiny threaded cotter pins.

Despite the good reviews for octalink, i decided to buy the DA 7600's. I dont know why, probably because it's a system i'm used to. I bought them fairly cheap from an ebay shop - Australian ebay. Guy who runs it is called Alex-Japon. the shop's called something like; buy direct from Japan. Anyone heard of it?

Sounds like the guys I bought my DID pro chain from. Faultless transaction, nothing more to say really.

The allen bolts are like tiny threaded cotter pins.

like this^

....baby steps

Sounds like the guys I bought my DID pro chain from. Faultless transaction, nothing more to say really.
That's good to hear.

The allen bolts are like tiny threaded cotter pins.

Yours words mean nothing to me, I haven't rocked cottered cranks since oooh about 6 months ago.

And yeah, those little allen bolts holding your cranks on seem a lot like cotter pins: shite?

like this^

....baby steps

You're gonna have to tell him they're metric.

me trick
you metric

Yeah, I know they're not THAT recent... just I have a rep' for being a luddite, you see.

one that is not inaccurate.

;)

Well, I'd take issue with that. Some people think that cycle design peaked at around 1970, and everything after that is just increasing the built-in obsalesence that makes us all BUY MORE STUFF and throw out perfectly great things in the Name Of Progress.

I'm not one of them, though, where would scally kids be without full sus and disc brakes? What about downhill? BMX? Crabon-everything roadies? Ergo? Cassettes? It's obviously bollocks, but there's a hint of truth in there about the obsession with technological advance making us assume that old=bad.

I might have to sell a load of stuff soon, watch this space.

Guys, just so nobody gets confused reading the last page, Dura Ace track cranks in Octalink are NOT external bearing types like the ones pictured. The Octalink 1 system is just a normal BB with a splined axle instead of square taper.

It's still quite rare for ext bearing hollowtech systems to be used for track, because of the Q-Factor. FSA do one however, not sure what it's like.

Oddly, Evans cycles have a neat little page explaining the many types of BB available
http://www.evanscycles.com/buying-guides/bottom-brackets

It's still quite rare for ext bearing hollowtech systems to be used for track, because of the Q-Factor. FSA do one however, not sure what it's like.

Fecking knew there was a disadvantage that I'd forgotten.

goes to edit post

Guys, just so nobody gets confused reading the last page, Dura Ace track cranks in Octalink are NOT external bearing types like the ones pictured. The Octalink 1 system is just a normal BB with a splined axle instead of square taper.

It's still quite rare for ext bearing hollowtech systems to be used for track, because of the Q-Factor. FSA do one however, not sure what it's like.

Oddly, Evans cycles have a neat little page explaining the many types of BB available
http://www.evanscycles.com/buying-guides/bottom-brackets

Thans for that RPM, jeebus, those other dudes have been leading me up the garden path. OK so splined axle three piece crank isn't the same as two piece external bearing ones. I like the sound of those.

Not sure the Q factor is actually any larger is it? I use an external BB and the Q factor feels normal, although I will have to go and measure it now!

Not sure the Q factor is actually any larger is it? I use an external BB and the Q factor feels normal, although I will have to go and measure it now!

I was giving it as a reason why manufacturers haven't all jumped on it for track yet.

There have been issues with some of the FSA ones, esp. on Fuji track pros where they come as standard

Not sure the Q factor is actually any larger is it? I use an external BB and the Q factor feels normal, although I will have to go and measure it now!

They generally come out as 47-50mm, a step away from the normal 42mm chainline.

The Q factor issue is neatly solved by moving to the BB30 standard, oversized axle, oversized bearings and a standard width BB shell.

Works perfectly on my road bike.

That said I have the 7710 cranks with Octalink on my track bike and that works perfectly too.

Q factor of track cranks is normally in the 130s (131-139 for the popular models)
http://www.businesscycles.com/tr-refspec.htm

The narrowest (that I know of) outboard are the DA road at 145 (I think), most outboard road are up in the 150s

Edit - and I read somewhere that the truvativ omnium have a 148mm Q factor

Despite the good reviews for octalink, i decided to buy the DA 7600's. I dont know why, probably because it's a system i'm used to. I bought them fairly cheap from an ebay shop - Australian ebay. Guy who runs it is called Alex-Japon. the shop's called something like; buy direct from Japan. Anyone heard of it?

Got a frame, rims and other stuff from him in the past - no problems at all!
Everything is sent EMS so you can track it - had stuff outside ebay as well.

I've got a hunch that those nasty BB30 bearings are going to creak and walk in the ally shell eventually- a bit like those nasty integrated headsets bearings- I have heard of campy and shimano bearings having to have a bit of subtle glu-ing (erm bearing retaining compound) to stop them creaking. I think it's a crap design in headsets, even worse in BBs to have the bearings sitting in the ally- not even a press fit! What next, you'll want me to ride a plastic (erm, carbon composite) frame!!!!!

Goes back to hand polishing his beloved square taper DA track crankset.
S.

They generally come out as 47-50mm, a step away from the normal 42mm chainline.

but that is chainline not Q factor.
Q factor could easily be addressed by design of the arms in relation to axle if any manufacturers could be bothered.
And looking at gizmonds comments it would appear they need to to satisfy the 130mm Q factor hungry track racer. But we all know teh track market is so small than it will always come a poor second or third anyway!

but that is chainline not Q factor.
Q factor could easily be addressed by design of the arms in relation to axle if any manufacturers could be bothered.
And looking at gizmonds comments it would appear they need to to satisfy the 130mm Q factor hungry track racer. But we all know teh track market is so small than it will always come a poor second or third anyway!

But your feet need to clear your chain.

I was looking at the KCNC K-Type MTB cranks fr my 29er (sexy and light). Turns out all the racers are snapping up the older ISIS version for a bit of weight saving (very little), and the better Q-factor.

but that is chainline not Q factor.
Q factor could easily be addressed by design of the arms in relation to axle if any manufacturers could be bothered.
And looking at gizmonds comments it would appear they need to to satisfy the 130mm Q factor hungry track racer. But we all know teh track market is so small than it will always come a poor second or third anyway!

FYI - Just *quickly measured my Omniums. 140mm

*Very

But your feet need to clear your chain.

and guessing they easily would. To design an external BB chainset with low Q factor is still easy enough. The spider controls the chainline and can be whatever is required while the shape of the arms determine the q factor. If both arms curved inwards to the point they were almost touching the chainstays they the Q factor would be as low as possible.

I had better crank up the CAD/CAM :-)

Can anyone give me a definitive answer on the issue of DA 7600 taper specification?

I am literally tearing my hair out, having read everything I can find on the net about it.

The loose consensus seems to be that Hatta BB's are as good as any for 7600s and Sugino 75's. I'm under the impression that 75's are ISO, but most of what I've read says that the 7600's are JIS.

Alex from Cavendish swears that although he can't prove it, 7600's are ISO.

I have a Campag 111mm BB which will apparently give me a straight chainline, but a man in Condor said that he wouldn't run the 7600's on an ISO taper as they will eventually round, or crack.

Please help, before I take to the streets with blood-lust!