moogyboy

hey all

So, my first tech question: in the interest of cheap parts for an old wheel-less Alpine MTB that I'm rescuing from my best friend, I picked up a fairly groaty Huffy (gack!) 18 speed from my local Volunteers Of America thrift shop for $20. The wheels are what I'm mainly interested in, although I may do something with the rest of the bike eventually, if nothing other than something to learn bike repair on. The Huffy has a 6 speed freewheel on the back, I believe the Alpine takes a 7 speed. I've never replaced a freewheel, although my understanding is that it's not terribly difficult. The one on the wheel right now has a couple of chipped teeth so I'm not concerned about trashing it to get it off.

I want to first get the hub and freewheel cleaned up as there's a lot of grease caked up around the center, just to see what I've got and what kind of removal tool I need. I had thought about going at it with a toothbrush and naphtha or denatured alcohol; is this advisable? I don't know if it will screw up the lubrication in the hubs, although this might be a good opportunity to clean and relube the hubs anyway.

Other question is whether changing from a 6- to 7-speed freewheel will present any problems regarding fit, spacing, etc. The Alpine has some sort of Shimano rear derailleur, and I believe it is an index shift. Also, please confirm that the various aftermarket freewheels are essentially interchangeable as far as threads, cog spacing, etc....maybe??

Anyway, I turn it to you. Thanks for your help.

cheers

Billy S.

rccardr 

Assuming the Alpine has a Shimano 7 speed indexed shifting system of any kind or sort, then any 7 speed Shimano freewheel (except Dura Ace, but they are too expensive for you to use one by accident) will fit and work just fine. All Shimano freewheels made in the last 30 years use the same removal interface- either buy the slug for under $10 and use a wrench, or take it to the LBS for removal. Cleaning the hub with a brush and solvent is unlikely to hurt anything.

For more information regarding this type of stuf (like how to clean and regrease the hub bearings, and tools required) check out the Park Tool web site. They have diagrams and everyting to make it clear for you.

Bill Kapaun

"Regular" 6 speed has a 5.5mm spacing between cogs, while 7 speed is 5.0mm.
There is a SunTour Ultra that had 5.0mm spacing, but it's getting pretty rare.
So- No indexing.

Often a 7 speed can be substituted, but may need a thin washer added to the DS to move the smallest cog away from the chain stay to prevent rubbing.

There's about 6 or more different FW removal tools, depending on the brand of FW.
A picture of the DS, looking straight at the axle would be helpful to tell you which one you need.
Or possibly just reading the brand.....

BTW, I simply refuse to work on Huffys. Everything is the cheapest of the cheap. Just look at how much spring is in the brake calipers when you squeeze the lever hard.

dsbrantjr

Those "chipped teeth" may well be shaped that way on purpose to aid in shifting. If you check closely you may find that they are arranged symmetrically around the cogs. Also, indexed shifting systems (with a few exceptions) need the shifter and cassette to be the same number of speeds.

CliffordK

As far as cleaning, I generally just do the manual method with a rag and a screwdriver, and no solvent. But, I suppose it might depend on how dry the grease is.

If the freewheel is mounted on a wheel, you can saw a rag back and forth between the sprockets.

Most of the new freewheels will use the Shimano freewheel tool, Park FR-1, or for deep freewheels FR-1.2 (which is backward compatible with the FR-1).

Older freewheels can use quite a variety of tools.

As above, be careful of indexing.

If you just need a freewheel, check with your local bike CO-OP (recycler). They often have piles of them.

moogyboy

Good news: it's a Shimano freewheel. Should be easy to remove once I get the right tool.

Also, I think those "chipped" teeth might actually just be wear. Or not...I dunno.

Bill Kapaun

Look at the cassettes/freewheels on other bikes and compare.

CliffordK

Each tooth will have a pulling side and a back side. It is easy enough looking at how the chain pulls.

Old freewheels had more or less symmetrical teeth.

On new ones, the pulling side of the teeth should be uniformly square (sometimes some mashing of the teeth is visible). Worn teeth tend to be sloped some, and can cause skipping.

The back sides of the teeth can be sloped, or ground off, and aren't the same for all teeth. Sometimes looking at profiles on the flat side of the cogs, one can predict where a ground tooth should be.

Photos always help.

moogyboy

Yeah, I hear ya. This one looks like it hasn't been particularly well taken care of, although it looks like the previous owner did put some upgraded parts on it. Some rust, some cobwebs, looks like a refugee from a garage or basement cleanout. The rear derailleur is disconnected and the shifter is gone. I took it out for a spin around the block this evening; it's rideable but I'm just like, meh. I basically bought it for the wheels, tires, and whatever components I can strip off of it.

moogyboy

I finally took a picture of the rear freewheel as mounted on the donor bike...well actually, I'm now planning to rehab the POS in its own right and buy new wheels and freewheel/freehub for the Palo Duro when I eventually get the thing. Since everything is already in place (except the shifters) it might be better/more effective to just work with it.

After cleaning the gunk off the cogs I think my suspicion of wear and damage was premature. The chain will likely be replaced but my feeling is that the freewheel is probably okay for the time being. It is, as I said previously, a Shimano, so replacement should be simple in any case.