Bicycle Mechanics - is this a free wheel or cassette?

http://farm4.static.flickr.com/3176/2563220240_64cdf28102_b.jpg

this came off my old 1980s lotus unique. its a 6 speed. the first two cogs are slipping. i was wondering if this is a freewheel hub or cassette? sorry for the noob question.

That's a very old Shimano cassette. One way you can recognize that it's a cassette (or shall I say, a freehub) is that there's no interior cavity around the axle to slip a freewheel-removal tool into.

:)

Do you mean the chain is skipping on the first two cogs? You probably need to replace the chain and the whole set of cogs. The outer cog probably needs to be unscrewed and the others slip off.
If it's an older uniglide hub, you either have to get new old-style cogs with the right tabs to fit the grooves on it, or you may have to grind off the one wide tab on the new cogs to make them fit. That's what I did recently.
If you can't find a screw-on 13 tooth outer cog, you can try flipping it the other way around and screw it back on and see if that works and doesn't skip. I did that and it worked.
Or you can get a new wheel.

It's a Shimano Uniglide cassette hub. You remove the cassette with a pair of chain whips and a fair amount of grunting. This Park Tool page:
http://www.parktool.com/repair/readhowto.asp?id=48
shows how- just scroll down to "Older Cassette Hubs (non-lockring ring type freehubs)"

The cogs actually look to be in OK shape- do they still slip/skip with a new chain? The Uniglide cogs were pretty durable (more so than the later Hyperglide), so I wonder if you've just worn out the chain.

If it does continue to skip, replacement cogs are still available from Loose Screws:
http://www.thethirdhand.com/index.cgi?c=Cassette&sc=Loose%20Cogs&tc=Shimano%20Uniglide
Note that they no longer have any of the small, threaded cogs (which hold everything together) except for the 12-tooth.

Looks like a freewhub. It's a freewheel mounted onto a spline on the hub, with the bearing cup located on the outside of the freewheel. If it is one, once you remove the axle, it should slide off. You will have to get a used replacement or purchase a new wheel. They don't make freewhubs anymore. BTW, freewhub is not the official name. -FTU

Pretty sure that's the one that you need a TL-FH30 tool to remove (properly, anyway).

Regarding the chain-skipping issue, DongDong, also check the chain for stiff links. Pedal the bike and shift the chain onto the smallest gear on the cassette, and then pedal backwards and watch for stiff links, which will usually "jump" visibly and audibly as they travel around the cog and the derailleur pulleys.

Here is a neat trick: Take the worn cogs off, reverse them (place an additional spacer to compensate for the lost "lip" of the dual-duty lockring cog), and put your new chain on.

Not perfect, but it saves having to dig up NOS cogs, and squeezes quite a bit of extra life out of what are usually marginally worn Uniglide freehub cogs. In my experience with them, they seem to wear down quicker then most freewheels of the era.

-Kurt

Here is a neat trick: Take the worn cogs off, reverse them (place an additional spacer to compensate for the lost "lip" of the dual-duty lockring cog), and put your new chain on.

Not perfect, but it saves having to dig up NOS cogs, and squeezes quite a bit of extra life out of what are usually marginally worn Uniglide freehub cogs. In my experience with them, they seem to wear down quicker then most freewheels of the era.

-Kurt

what would i use as spacers?

what would i use as spacers?

A bike store probably has the spacers.

cudak888/Kurt - where do you need the one spacer - the very inside?

One spacer, from a recent 7-speed or a disposed-of 6-speed UG cassette. Fits between the reversed threaded cog and the second smallest cog. Makes up for the fact that the spacer lip that is built onto the threaded cog has now been reversed.

If your chain can handle it, it might be wise to go with a 7-speed spacer, as it will allow the cog to screw on just a tad more. Compensates for the fact that a few of the threads on the "lip" of the cog may end up slightly outboard of the cassette. Beware, as an original 6-speed UG or Wal-Mart Bell (TAYA) chain - the latter being a surprisingly good quality UG copy - will likely ride up on the second cog as it exits the freewheel, if the 7-speed spacer is used.

-Kurt

One spacer, from a recent 7-speed or a disposed-of 6-speed UG cassette. Fits between the reversed threaded cog and the second smallest cog.
-Kurt

Thanks, I remember now - the outer screw-on cog is the only one with a lip on one side that acts like a spacer - the other cogs are flat on both sides and separated by actual spacers. So when you turn the screw-on cog around, its lip points out, so you need a spacer inside it.

When I tweaked a uniglide hub recently and flipped the outer cog, I got a spacer off an old worn cassette I had lying around.

I also managed to loosen the outer cog with just one chain whip, by keeping the wheel in the bike and bracing the pedal with my foot.