Bicycle Mechanics - Freehub or Freewheel

Can one of you experts help out a complete amateur? I'm trying to determine if this Zipp Disc is Shimano compatible? I have a Shimano 9-spd bike and was wondering what it would take to make this work. Thanks

from the first photo, it look like you need a freewheel. I don't know of anyone that makes a 9 speed freewheel.

i see stepped threads, which would mean it's track...

info on their wheels here:http://www.zipp.com/products/wheels/840900disk.shtml

That is a track hub on there, not made for any gear cluster.

That means you can't use it, so send it to me. :)

I just saw online last week that Sachs made 6,7, and 8 speed freewheels - and some bike shop had them for sale. I can't guarantee the Sachs (German) will index correctly with Shimano. Search for that Sachs site. They had chain and spacer widths listed - maybe you'll get lucky and it will work with an extra click leftover.

Track hub, that means fixed gear or single speed freewheel.

That is a track hub on there, not made for any gear cluster.

Dunno if you noticed but that is a gear cluster..Likely Sachs as I can see the made in france stamp on the small cog

Dunno if you noticed but that is a gear cluster..Likely Sachs as I can see the made in france stamp on the small cog
Intresting, I have never seen a freewheel that'd thread on in the middle of the cluster like that. I assumed he had just slipped a shimano cassette over the existing hub, but now that you point it out I realize you couldn't do that (wouldn't fit)

So that hub was designed for dual purpose as a freewheel or fixed eh? Neat stuff!

i see stepped threads, which would mean it's track...

Those arent stepped threads, its the nondrive side of the hub body.

Thanks for the info everyone. The guys at the LBS weren't able to help me on this. I should have mentioned that the photos are of each side of the wheel. The bare threads are on the opposite side of the cogset.

AH, so a dual-purpose wheel, neat! Fixed-gear track cog on one side and you flip it over and you have freewheel! :)

While you can make a 9-speed freewheel like I did 12 years ago when 8-spd was de-rigeur, I don't think it makes much of a difference. I had a 13-24t 8-speed Sachs freewheel similar to what you've got and I ground down a 12t Suntour cog to the proper thickness for Shimano spacing. Then brazed it on top of the 13t cog on the freewheel (removed the cog from freewheel 1st ;) ). Since there weren't any 9-spd shifters on the market, I had to use friction-shifting, no big deal.

I did however, have to move a 5 washer from the left side of the axle to the right to give enough room to clear the extra cog (and redish the wheel). This ended up bending axles every two years or so. Although the large-diameter axle on that Zipp wheel looks pretty beefy, but I'm not sure how adjustable the hub-spacing is. You'd really have to get a longer axle and widen the spacing to 135mm in order to accomodate the wider freewheel while keeping the disc centered.

What you can do with that wheel however, is to remove the cogs from the freewheel and grind/replace the spacers between the gears. You want to narrow the spacing (c-c) between the gears from 4.8 to 4.34mm to have it match the 9-speed Shimano spacing. You may also need to add spacers on the hub-body itself to move the freewheel laterally so that the gears are in the same location as the Shimano cluster. Do this by measuring the distance between the drop-out to the 2nd gear on the Shimano 9-spd. This distance should then be the distance between the drop-out to the 1st gear on the Sachs freewheel. What you'll end up with is an 8-speed freewheel, with Shimano 9-speed spacing. Basically a 9-speed with the smallest cog removed. Then adjust your RD's limit screw to not go into the smallest cog, or just remember not to shift into it. :)

If this doesn't make sense, I can draw some pictures.