Bicycle Mechanics - Dura-Ace 7400 series??
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08-26-01, 11:12 PM
I recently purchased a Dura-Ace 7400 series 7 speed Uniglide cassette off ebay (fixing up my old 6 speed ride). I'm about to bid on a Dura-Ace 7400 front and rear hubset. Am I right to assume that the freehub body on the 7400 rear hub is correct for the 7 speed Uniglide cassette? If not, what questions can I ask the seller to find out if this freehub body will be correct for the 7 speed Uniglide cassette?
Uniglide and Hyperglide are not the same, although you can alter Uniglide cogs to fit. Check to see if these are Uniglide or Hyperglide. D/A cogs are noted for wearing out quickly, though.
08-27-01, 09:58 AM
Go over to sheldonbrown.com and read his article on this. If I remember correctly, he specifically discusses the issue of using one cassette on the other system. If you are lucky, the hub may be Uniglide. If it is Hyperglide, it will have one wider spline which is used to correctly position the cassette or individual cogs you may replace later. If I remember correctly SB says you can grind one of the notches on the cogs and spacers wider so they will fit on the HG freehub. Don't take my word for it; go read the article. You will learn a lot. I think it would be easier to get an HG cassette. 7-speeds don't cost much - $20-30 for HG70 (105), a little more for Ultegra and DA.
Is your aim to assemble a pure DA group? Because you can purchase a 7-speed freehub body and slap it on just about any Shimano hub. I just ordered one from Harris Cyclery to use on a new 105 hub to use in place of the original 6-speed freewheel rear on my old Bianchi.
I think I would use an HG-70 cassette (steel) for most of my riding and only put on the DA (aluminum) for actual racing. It seems like the aluminum would wear out faster and they are much more expensive to replace. Cassettes are expendables. I don't think using an HG-70 cassette makes it any less a DA group for day to day riding.
08-27-01, 09:19 PM
Thanks folks. I'm replacing most of the components because they are just flat wore out, plus I like taking stuff apart. I'm replacing with a mixture or Dura Ace and Ultegra NOS. Ebay is great for this stuff. I'll be keeping the 105 cranks and brakes and I'll use the 105 hubs for spare wheels.
Thanks for the info on the Dura Ace cogs. I wasn't aware of this.
Sheldon has a lot of great info. Thanks for the link.
Dura Ace cog spacing is NOT compatible with ultegra indexing, or any other indexing. I hope you didn't buy ultegra shifters, expecting them to work with D/A cogs.
08-28-01, 06:49 PM
This is a uniglide system. It's not hyperglide. What is the difference between a Dura Ace Cog and an Ultegra or a 105? I'd assume the spacing on shimano SIS is the same, regardless of what group. I'm currently using 105 shifters and derailleur and am shifting fine on the Dura Ace cogs. Could you please explain further.
08-28-01, 07:50 PM
This was cut and pasted from the Sheldon Brown site:
"Myth: Dura-Ace cassettes have a different spacing, and are incompatible with other derailers/shifters.
Truth: No, all Shimano cassettes and freehubs with the same number of speeds use the same spacing, and index with any system configured for the same number of sprockets."
The only thing Sheldon said was different with Dura Ace was the amount of cable travel on pre 1997 Dura Ace shifters.
Well, these are WAY pre 1997 shifters! I think that Uniglide goes back to the late 80's, doesn't it?
08-29-01, 12:15 PM
I'm not using Dura-Ace Shifters. I'll be using Ultegra with a Dura-Ace cassette. I'm currently using 105 with a Dura-Ace cassette. I appreciate you bringing this up, though. It made me do a lot of reading and I found out all kinds of good stuff.
I've done a lot of things which bike "experts" said couldn't be done. Sometimes they were right, but not often. You may find that a mix-and-match setup will work, at least "fairly" well, though.
Uniglide is older style as the separate cassettes are not "grovved" specially to pick up chain more efficient.
Hyperglide is newer stull with all cassettes specially machined to make chain pick up easier.
Will you care? Most likely not. They will both shift and get the job done.
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