Bottom bracket length for specialized (flag emblem) touring crankset?
 

Hi,

I was wondering if anyone can tell me the correct bottom bracket length for 80's specialized triple crankset. I think it's made by Sugino.
I checked velobase.com but couldnt' find it.
Thanks.

Is it this guy? http://www.velobase.com/ViewComponen...115&AbsPos=255

They don't list the BB spindle length, but given the resemblance to Sugino's other cranks from the era, you're probably looking at something in the low 120's.

Yes that is correct.
By the way, I just found specialized catalog from 1984 and it lists the spindle length as 115mm. But this is for asymmetric spindle. So for newer BB's with symmetric spindle I guess I am looking for a longer spindle. Am I right? hmm maybe 118mm?

Hmm, interesting. I almost wonder if it's a typo, as a 115/116 ought to be symmetrical (32-52-32), and would be kind of short overall for a triple even if it were asymmetrical.

I'd probably buy a 118mm cartridge BB first (it'll be symmetrical), along with a 1-2mm BB spacer so that you can just scootch it over if you're in the ballpark but need a little more clearance on the drive-side. If it's still too short, you should be able to guesstimate and get it right with the next cartridge. Good luck! :thumb:

Just was about to post this...

http://i.imgur.com/MJJcDzH.jpg

Looks like you found the same info. Since you are only talking a couple mm you arent going to affect your chain line much. Worst case is you lose a couple bucks trying one and having to resell it. I say go for the 118 as well.

I'm running a "flag" triple on a 113mm Shimano UNxx bb and the chain line is just fine. Nice low "Q" too.

SP
OC, OR

I'll be darned. Good thing cartridge BBs are relatively cheap. :lol:

I usually get the exact same length spindle, and use a 2mm spacer on the drive side. This mimics the assymetric spacing.

Spindle?
 

I have the double version of the "Flag" crankset (looks like the one on velobase but is a double) and want to put it on a 1972 Schwinn Super Sport, which has a 65mm BB shell ... should I get the 107mm or 110mm sealed cartridge?

Attachment 553366

According to the spec posted above, it seems to call for the 107mm (or possibly 112mm if the crankset is really a Sugino?) - but is expecting a 68mm shell. The conversion kit I'm using seems to have the same amount of lip as the original BB cups outer edge (not sure if this affects spacing) and also seems to only allow for spacers on the drive (R) side - to go between sealed cartridge lip and BB conversion adapter.

Is adding 3mm to the spindle (because of 65mm shell) OK? Necessary? Equivalent to using spacers?

More info on cranks. Mine do have Specialized dust caps, but not the Specialized stamp, has Flag instead.

Early on, were not the Specialized cranks essentially Avocet?

At least that is what many thought way back.

I rebuilt my wife's '85 Specialized Allez a few years back that came with a Specialized flag double crankset (144mm BCD). It came with a 107mm symmetric spindle and I replaced it with a Shimano UN55 107mm sealed BB. Other than having to paint the faces of the BB, it was an exact match.

I'm not familiar with 65mm BB's. If I were to guess, a 3mm DS spacer would be what I would do. I know some people really dig old fillet brazed Schwinns, but you're putting an expensive and somewhat rare item on a low end bike. Those Specialized flag cranksets go for good money.

Spindle Size
 

Thanks for the info and suggestion. This seems to confirm the document references the correct spindle size and Flag cranksets can be thought of as Specialized.

I initially bought a 107mm UN55 sealed cartridge with some 1.5mm spacers, but since I seemingly can only get spacers on the drive side, I thought maybe it would be better to get the 110mm sealed cartridge, though I imagine there could be exposed threading. Additionally, 2x 1.5mm spacers on the DS seem even uglier and more unstable than 1x -- I may look for a 3mm spacer as you suggest.

As for whether or not the frame warrants such a nice crankset ... I imagine some would happily debate. It has a reputation for riding comfortably, is a bit of a historic curiosity in that it was made here in Chicago, USA, and has attractive brazed joins.

In my case, I got a decent survivor condition '72 Kool Lemon Super Sport for a good price and am using the opportunity to lightly restore a bike from the ground up for the first time.

I'm hoping to make this Super Sport a daily commuter and the original crankset is a boat anchor.

I have experience with the later Specialized ST-4 triple, with very fond memories. I paid $70 on eBay for the double Flag version, and am OK with that. But you're right, it cost close to half of what I paid for the bike, I appreciate the disconnect you highlight.

To quote Lennon: "Whatever gets you through the night, it's alright, it's alright." :thumb:

I'd give my left hub nut for a flag triple, but it'd probably cost more than what I paid for my wife's bike.

So, does anyone know what taper these guys are? I picked up a 112mm spindle and was wondering what cranks I'd be able to use it with.

I don't see why that conclusion should be true. For me, a BB geometry (there are several key parameters) is correct i it fits correctly and acheives some key parameter values. The ey values for me are:

1. Drive side chainset position for a triple, places the second chainring the same distance from the frame center plane as the distance from the center of the freewheel cluster to the frame center plane. Note this may imply the rear triangle needs to be made centered on teh BB shell.
2. The chainring bolts/nuts and the chainring teeth themselves do not touch the chainstays. One may need to change the bolts on the chainring attachment, as part of choosing the BB.
3. The clearance from the pedal end of the drive side crankarm and the chainstay is the same as for the non-drive side - symmetrical pedaling position. This inherently has nothing to do with acheiving a certain desired or promised value of Q factor. Some chainset/BB pairings are designed for excellent Q factor, such as a Campy Record double from the 1970s or the next generation, mid 1980s design. They tend to have harrow BB spindles and a crank arm design where the arm settles in close to the frame.

To me the goal has to do with fit, clearances, and lateral symmetry of the chainset and foot positionings. Not with BB symmetry, BB spindle length, or being labelled for a triple.

It's right if it works. If it doesn't work it isn't right.

I’m using a 110mm Shimano UN-55 with a Specialized “flag” triple crankset, with 3.0 mm spacer under the DS “cup” to create asymmetry. I’m picky about my chainline - 43.5-45mm from frame centerline to middle ring - and I like a low Q Factor, which is 148mm for this setup. The pedals may not be exactly symmetrical here, but I’m not symmetrical, either.

FWIW, my Sugino AT on the other bike uses a 126mm SKF BB with 5.5 mm of spacers for the same chainline and Q-Factor

So, would you say that the flag crankset appropriately slid onto the JIS taper of the UN-55?

Yup.