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Bottom bracket spindle length for Dura Ace 8 Speed(9 posts)

Bottom bracket spindle length for Dura Ace 8 SpeedHaydnG
Nov 4, 2003 2:15 PM
Can someone help with the correct BB spindle length for an 8 speed Shimano Dura Ace Chainset on an English frame.
The Shimano part no. of the Chainset is FC 7410.
Shell width is presumably 68mm.
I'm putting together some old components, but existing BB which was just about OK with older style 600 Ultegra C/S is too long with the FC7410, hence chainline way out.
re: Bottom bracket spindle length for Dura Ace 8 SpeedMShaw
Nov 4, 2003 2:38 PM
If its the traditional square looking crank, the length of the BB is going to be 115mm. If its the Super Low Profile (looks "swoopy") then its 103mm.

re: Bottom bracket spindle length for Dura Ace 8 SpeedHaydnG
Nov 4, 2003 9:23 PM
Thanks all, yes it's the "Swoopy" design.

Finding that length in the UK may prove a challenge in original DA spec. In the cheaper UN72/52 series the shortest is 107mm, as stated.

There is the FSA Ultimax available in 103mm at £28.99 online. Can anyone confirm whether this has the Japanese standard tapers (Shimano compatible) rather than the European tapers?

I ask because I have previously had the chainset on what I have now measured to be about a 103mm Campag Chorus bb in an Italian frame, but because of the sharper taper it went on a bit too far and the inner chainring (which is a 42) only cleared the chainstay by the mearest of gnats. In fact it may well have kissed it when things were flexing under load (least that's my excuse for grovelling up the climbs). Furthermore, I understand that mixing the two standards is not to be recommended.

Thanks again.
103mmDave Hickey
Nov 4, 2003 2:44 PM
103mm BB for 7410 crankset. You can find a used one on Ebay for about $25. New are still around if you look but they are getting pricy$$$. I have tens of thousands of miles a these BB's and haven't worn one out yet.
re: Bottom bracket spindle length for Dura Ace 8 Speedstinkyhelmet
Nov 4, 2003 3:09 PM
finding a 103 mm square taper spindle is a pain in the butt. Call all your LBSs and see if they have any laying around. I finally went with a FSA one...nice. Good luck.
Like others have said, it's 103mm........MR_GRUMPY
Nov 4, 2003 5:59 PM
You should be able to find one. If you can't, you might be able to get away with using a 107mm, which is common. It's only 2mm on a side, wider. It is possible, that you might have minor chain line problems, if you use it. It's a last resort.
Another optionDave Hickey
Nov 5, 2003 4:27 AM
Look for an Italian threaded 7410 BB. They are usually easier to find and cheaper. Swap out the cups with any english threaded Shimano tapered BB. Here a couple from Ebay
Another optionMShaw
Nov 6, 2003 11:18 AM
All it takes to swap the cups is a vice and a hammer.

I've done this on several Shimano BBs...

All ya gotta do is to put the fixed cup into the vice and tap on the spindle till it comes out. When you go to put it back in, all ya gotta do is turn the cup over, and tap the BB back into the cup.

Thanks Guys (and Gals?)HaydnG
Nov 11, 2003 8:59 AM
Got a new English DA 7401 BB via the Internet, but actually from an outlet only about 30 miles away. Cost £45 which is a bit dear for what is only for a Winter bike on which I'm recycling most of an 8 speed DA groupset, Fitted last night, usual cursing and grunting getting the old one out, 'cos had been in there for at least 5 years. But all seems OK and chainline much improved (can get onto big ring comfortably).

Only the briefest of rides so far, but with the additional benefit of a new chain (my first SRAM), shifting much improved, but am going to also fit the recycled DA STi leavers shortly because the old Ultegra ones are shot.

Also got another pair of SPD-SL pedals so have same system on race and winter bike. DA for racing, Ultegra for hack iron. I'm just too old for the relative inconvenience of Time when occasionally commutting by bike.

Just when I'm recycling my 8 speed gear, everyone else will be recycling their 9 speed kit now the DA 10 speed is on general sale.

Thanks again.