jet sanchEz

I hope this isn't too stupid a question but I was wondering if the 7-speed cassette on an older Dura Ace wheel set be switched out for an 8-speed cassette? This wheel set on my local CL is what I am specifically thinking of, maybe someone can tell me if this is possible?

Thanks!

https://toronto.en.craigslist.ca/tor/bik/1802783201.html

Ex Pres 

wrong freehub body width, unless you have a 7s cassette on a DA 8s hub (FH-7403). The 7403 is the Uni/HG cross compatible model.

I'd say it's highly unlikely since the ad states 126mm OLD. The 7403 is 130mm.

theschwinnman

You could put 8 of the cogs from a 9 speed cassette on the hub, but then you'd have to use 9 speed shifters too...

Or you could change out the freehub body for a 8/9 speed one, but you'd have to put an extra spacer on the drive side of the axle (4.5mm, I believe) to make it work.

jet sanchEz

Ah, too bad, it sounds like it will be more trouble than it is worth. I thought that the 8-speed stuff was still spaced at 126mm...

theschwinnman

Nope, 8/9/10 speed stuff all used the same freehub body (for Shimano at least.)

I believe that 8 speed hubs were always 130mm, if I recall correctly, the first 130mm (8 speed) hub was meant to be shoe horned into 126mm dropouts, with no cold-setting required.

It sounds like it's worth it (to me at least) since the stuff is Dura-Ace, so you could just re-space the rear hub and shoe horn it into your 126mm dropouts.

Chombi

Yes, you will be at the limits at 126mm spacing for 7 speeds. You will need to step up to a 130mm spaced hub if you want to jump up to 8 speeds. The later generation of Mavic hubs (501?) have the option to be spaced at 126 or 130 with the simple deletion of a spacer at the drive end of the axle. Maybe some Shimano hubs might have the same feature?? But I think you could do the same for most hubs anyway, as long as you have a long enough axle.....

Chombi

bobbycorno

I'd be willing to bet that you wouldn't need to replace the 126 OLD axle. R hub axles are usually long enough to accomodate another 4mm of spacers. And with DA hubs, replacing the FH body would be cost-effective. If we were talking 105s, it'd be a different story.

SP
Bend, OR

dvs cycles

I've converted 2 7-speed hubs to 8 sp.
You need 8 speed cassette body and the axel to match it.
Check out Sheldon Brown's site for more details and other solutions.

rccardr 

...except that they are out of 7403 hub bodies. But there's a guy on eBay who's selling 135mm hubs with what looks like a 7403 hub body that can be removed and put into that hub. OR, there's another guy on eBay selling really nice DA 7403 Uni/Hyper wheelsets for $299 with free shipping. That's a stone deal.

RobbieTunes

I've done it, but not sure where LBS found the 8-sp hub body. Took off the 7-sp hub, swapped in the 8/9/10, a longer axle, redished, and rode it with 9-sp Tiagra shifters, worked great with a 9-sp cassette. Some frames need a spacer and a bigger redish to clear the stays.

Ex Pres 

I gave up on finding a 7403 body for cheap. You'd also need a special tool, which my LBS has. Just couldn't find the body.

roccobike

+1, Go Robbie! I've converted several Shimano hubs from 7 speed freehub to 8/9/10 speed freehub. My only concern is the DA, I'm not sure if there was something special about the DA hub, I doubt it. However, once you follow Robbie's advice, you should go to 130mm spacing which will require that you either force the 130mm hub/axle into the dropouts or cold set the frame to allow for the 130mm spacing. Personnally, I've forced the wheel into the existing space. When the rear wheel is removed from a 126mm spaced frame, the frame relaxes, typically to 128mm. Therefore the new 130mm rear wheel only requires that you pull a tiny 2mm additional space to pull the revised/new wheel into place. No big deal.

miamijim

Some good info here and some incorrect info here.....

1. Keep in mind that Dura Ace is Dura Ace. NOTHING interchanges with it except Dura Ace.
2. An 8s freehub body from a Dura Ace can be interchanged with the 7s body. It must be from a DA hub only. Nothing else will work.
3. The axle and right sided cones/spacers from the donot hub must be used as well. Shimano tweaked the seal setup over the years. If you dont use the cone/spacers from the donor hub you'll have seal mismatch which is not good.
4. 7403 weren't designed to allow installation in a 126 without cold setting. The left side locknut is designed to facilitate quick installation in 126 frames.

For what 7403 hubs cost I wouldnt bother converting a 7400 to 7402/3.

jet sanchEz

Thanks guys for all the great information and insight.

The reason I was thinking of buying these wheels is because they are relatively cheap and because there is a nice bike listed near me with a full Dura Ace 8-speed group EXCEPT for the wheels. The wheels are Chris Kings laced to Mavic Open Pro rims and I figured that I could purchase the bike, take off the Chris Kings to keep and then re-sell the bike with a complete Dura Ace 8-speed group, essentially getting the Chris King wheelset for a very cheap price. I'd use them with an Ultegra 9-speed setup that I have on my Serotta.

I will keep searching and see how things go....