Far Side of 50

Is it possible to take the individual cogs off of a 13-28 and a 14-28 and make a close ratio 7 speed freewheel? I'm looking at everything on the internet and the instructions don't appear to be posted anymore. I'm assuming that you can use a pin wrench and unscrew the inner ring on both freewheels. Do the cogs come off after you do that?
13-28 is 13,15,17,19, 21,24,28 and
14-28 is 14,16.18,20,22,24,28 and I want to make up a close ratio 7 speed that finishes up with something like 21, 24, 28 to use with a 87 Cannondale ST600 that has a triple Deore with a 28 smal ring. I can adjust the large and midle rings for the desired gearing.

I'm thinking about mazimizing the gear inch choices in the range of 50 to 80 gear inches and not needing anything above about 95 gear inches for a 57 year old not interested in racing or fast group riding.

Anyone with experience? The Cannondale is currently set up with 13-28 and 50-46-28 half step. The 50 x 13 is useless.

Barrettscv 

Hi, and welcome to Bikeforums.

I would go to a touring crank, like a 48, 38 & 26. That will give you a much better range.

Retro Grouch 

I used to do things like that all the time but I haven't done it to a modern freewheel. Sometimes you just have to use 2 chainwhips to spin off the smallest cog or two and the rest just slide off.

Pay attention to the order in which everything comes off. Often the first two cogs are position specific. The spacers might not be exactly the same across the whole freewheel either.

Far Side of 50

I'm leaning towards 50-39-28 with a close range 15,16,17,18,20,24,28. This gives many choices in the 50 to 80 gear inch range.

My question is can I disassemble two Shimano freewheels and mix the cogs?

fietsbob

un like cassettes, freewheel cogs have a few different internal diameters , the hole is bigger on the innermost ones ..

that's where the freewheel part of them is inside the body. & it screws onto the hub..

Shimano & many older ones you could unscrew the smaller cogs from the body and the bigger ones had a couple splined fitting sizes

[Regina used 2 LH threaded largest cogs with a shoulder to screw against on the body]

the newer ones I dont think so .. got pictures of the specific ones you are talking about?

good luck finding a 15t 1st position cog ..

Airburst

If you unscrew the inner ring the freewheel mechanism will come apart and drop about 40 tiny bearing balls all over your floor. As stated above, freewheels are dismantled by unscrewing the sprockets from the body. Some of the time they're all right-hand threaded and screw on from the front, sometimes some of the larger ones are left-hand threaded and screw on from the back.

Thanks to a quiet day at the co-op a few years back I can tell you a few things. A lot of modern Shimano freewheels appear to use a system a bit like Uniglide cassette hubs did - the smallest sprocket is threaded and acts as a lockring to hold all the other sprockets onto the freewheel body, with splines to transfer drive from sprocket to body. However, the splined fittings are of multiple different sizes - the larger sprockets have a larger-diameter hole in the middle, then there are at least two other sizes. As such you may have issues using sprockets in locations on the cassette they aren't designed for.

I found that out by pulling about 5 junk freewheels to bits. Like I said, it was a quiet day at the co-op.

Retro Grouch 

I doubt that's going to work. The first position cog is almost surely going to be position specific so, unless you can find a freewheel with a 15 small cog, I doubt it'll work.

Darth Lefty 

This article shows the two Shimano freewheels. Apparently Harris purged it, I had to get it from the Wayback Machine. All the cogs are splined and held on with a threaded lockring. (The inner ring goes to the freewheel bearings.) It details making several tighter combinations out of 14-28 and 13-28 donors. But it says, "There are a few other combinations you can make with these parts, but the splines are pretty limiting."

Customizing Shimano 7 Speed Freewheels | Harris Cyclery

hueyhoolihan

freewheels as opposed to cassettes are more proprietary as afar a how cogs are attached to the freewheel body or freehub body.

it used to be fairly common practice about three or four decades ago to mix and match cogs on freewheels. not so much anymore.

now if you were planning to make a custom cassette out of individual, let's say Shimano cassette cogs and spacers. well, that's doable.

Bill Kapaun

I PM'd pastorbob in the C&V section to look at this thread.
He rebuilds/overhauls FW's and is the go to guy IMO.

HillRider

+1 DO NOT unscrew the inner ring. It's left hand threaded and if you remove it the entire freewheel comes apart where you don't want it to. Removing Shimano freewheel cogs requires two chainwhips to unscrew the small cog and the rest slide off. None are lefthand threaded.

ThermionicScott 

It would be cool if you could make a 14-15-16-17-19-21-24 out of those two. It's not what you had in mind, but a nice progression.

The confound to this idea is that the newer (cheaper) Shimano freewheels often have the biggest sprockets riveted together, so you'd have to live with the biggest 3 or so being as-is, or source older freewheels. Perhaps that's why you included this in your initial post.

pastorbobnlnh 

With a Shimano freewheel you are limited to the size of the first cog which is threaded (in most cases). So you could start with the 14T but not the 15T which is notched to slide onto the body. But, as has been mentioned, there is a step in the body, so some cogs have a small opening and others have a large opening. You just need to take two chainwhips and take them apart and see what you can line up.

I can probably build a Sachs 7 speed freewheel in something close to what you want.

Best of luck with your project.

Dave Mayer

Somewhere in my past I inherited a big pile of 7-speed era Dura-Ace freewheel bodies and cogs. Yes, freewheels with the last 3 cogs being 21-24-28 is most of what I have constructed. And, a 15-tooth #1 cog is possible as well. I think junior freewheels were made with #1 16-tooth cogs as well.

The current generation of HG37 freewheels have compatible cogs for the Dura-Ace, when you do a minute of filing to remove one of the inside tabs on the cogs.

The 21-24-28 cogs that you seek are featured in Shimano's 6-speed freewheels. The cogs in the TZ series are not compatible to your unit.

Far Side of 50

The 13-28 on my bike is a HG37 like in the Customizing Shimano 7 Speed Freewheels | Harris Cyclery web page and my daughter's bike has one of the no longer available 14-28 HG37s. They both have the lockring with divots to hold the cogs onto the body. Webpage and "All the cogs are splined and held on with a threaded lockring" credit to Darth Lefty. Since the 14-28 has 14,16,18,20 on the 1st step I should be able to start with a 16 and make 16,17,18,19 on the 1st step using the 17 and 19 from the 13-28 then file on the 21 from the 13-28 so the splines fit the 2nd step of the body and finish off with 21,24,28. The finished freewheel would have 16,17,18,19,21,24,28 with percentage jumps of 6.3, 5.9, 5.6, 10.5, 14.3 and 16.7%. I can use chainwheels of 50 or 52 then 39 or 40 and a small 28 for uphill.

I'll replace my daughter's 14-28 with a 13 - 28 or a 14-34 mega range since she has a long cage Tourney RD.

The alternative would be to get a Shimano cassette hub in 7 or 8 with an 8 sp downtube shifter for my bike and use my 7 sp shifter on my son's bike (Trek 1000).

This is the most knowlegable forum I've ever come across.

Far Side of 50

And I looked at the TZ freewheels and it looks like they cut costs by eliminating the lockring and just screwed the cogs onto the body. It may be all of the cogs or just the smallest one. If I look at the base of the smallest cog I can see some exposed threads on the body. HG37 has a lockring. TZ is threaded cog. Dave Mayer commented in the thread that the TZ cogs won't work and and that HG was compatible with DuraAce but I'm looking at merging two HG37s.

Specifically from Dave's post, "The 21-24-28 cogs that you seek are featured in Shimano's 6-speed freewheels." raises the question of which, if any, would just fit onto the HG 37 14-28 body shown on Customizing Shimano 7 Speed Freewheels | Harris Cyclery.

Would the 21 slide on without filing for different splines?

Darth Lefty 

I've been studying this morning whether it's possible to build a 14-34 with a straighter sequence out of the MF-TZ family freewheels. Between the 6 and 7 speed versions there are 13 and 14 top cogs, and 21-24-28-34 gears. However no one else seems to have tried it. I've found no photos showing them disassembled. I did find a photo of the back side of a Megarange, but it didn't say whether 6 or 7 speed; at least the bottom cog appears to be held to the previous cog by rivets, rather than by splines on the body. I found a review that stated the bottom two cogs are this way. I haven't had any of these in my hands to play with them.

xenologer

if you're getting serious enough to want specific gearing, perhaps it's time to upgrade to a cassette wheel?
not only are cassette cogs much easier to customize, but they come in more readily made configurations off the shelf - what you want may already be available

Dave Mayer

You seek the largest 3 cogs of the Shimano HG22 6-speed freewheel:

Shimano HG22 6-Speed 14-28 Freewheel - Cycle City - The Alameda Trek Bike Shop

I seem to remember using these to build lower ratios for old Dura-Ace 7-speed freewheels. And the Hyperglide cogs shifted better than the original Uniglide cogs ever did. But the metal on the Dura-Ace cogs was certainly harder than the pot metal used on the HG22 freewheel. So the Dura-Ace cogs shifted worse for a lot longer.

The TZ series is actually a better design for weight reduction, as the 2 largest cogs are pinned onto the 3rd largest. The 3 slide off of the TZ body as one unit. But my quick disassembly of the TZ series indicated that cogs are not compatible with the bore diameter and splines of the older HG series.

Far Side of 50

I had thought about going to 7 speed cassette but I would have to relace my rim with a 7 speed cassette hub or buy a new 27" rear wheel. I finally come to the conclusion after all of this information gathering (Thank You Forum) that I have the parts on hand to try a freewheel mix first. As written previously, "The finished freewheel would have 16,17,18,19,21,24,28 with percentage jumps of 6.3, 5.9, 5.6, 10.5, 14.3 and 16.7%. I can use chainwheels of 50 or 52 then 39 or 40 and a small 28 for uphill."

I threw the original 3 x 6 gearing into Sheldon Brown's on-line gear calculator and wrote it down as gear inches. If you want to make small changes better to have larger numbers to work with. I then rode my bike and saw where I "Sagged" when the incline steepened or the headwind increased and I had no more push; and the necessary downshift overrevved my cadence. Too big of jumps for a 6 speed freewheel. Everything is up and down and the wind always blows so I figured out I should have closer ratios. I went 7 speed half step 50-46-28 and 13,15,17,19,21,24,28 but I got ambitious and I'm geared too high and the 13 is useless. If I go closer ratios and lower gearing on the freewheel 16,17,18,19,21,24,28; and then widen the step on the chainrings I get closer and more usable gearing. The longer chainstays on this touring model will help alleviate chain angle problems.

If I keep it, I'll replace my daughter's 14-28 with a 13 - 28 or a 14-34 mega range since she has a long cage Tourney RD.

My baby was sitting at a pawnshop and available for an entirely disrespectful $129 so I have the leeway to make her perfect for me. The joy of thinking about changes and the pleasure they will bring, and the pleasure of wrenching (no more wenching); makes up for the hour standing in front of a laboratory hood that it takes to produce the money to do it.

Far Side of 50

I need to gring\d a set of channel lock pliers to make the lockring pliers and work calls, but I'm dying to disassemble them.

Far Side of 50

Well, Thus Far, My daughter has a 14 - 16 - 18 - 20 - 24 - 28 - 34 Mega Range freewheel with the 22 removed and a 28 substituted because she is small and needs the lower gearing. This is a Giant Boulder MTB ridden on the road, sidewalks, grass.

I am now riding using a 14 - 18 - 19 - 20 - 21 - 22 - 24 with 44 and 46 chainrings on my Cannondale ST600 because I like fast riding but keeping up a high cadence and not pushing. As was stated and as I found out you are STUCK using the smallest cog as a locking mechanism and if I go down to 14T it feels like I dropped my feet into a bucket of cement. 19 and 21 came from a 13 to 28 HG37 and the 28 from the same freewheel went to my daughter.

I want to dump the 14T so:
You can order a 16T small for HG and make 16 to whatever and I have to buy a HG hub and the 16T, OR you can use a 3/32" track cog (which I have) as the final cog on Uniglide and I was thinking of
17T track cog - 18 - 19 - 20 - 21 - then 22 - 24 for road or 24 - 28 for touring
and 17 - 18 - 19 - 21 - 24 - 28 - 34 for heavy touring and I have to buy a Uniglide hub.

I have 38 - 42 - 44 - 46 or 48T chainrings for 110 BCD for the two big rings and I'm using a 28T small ring. Big rings are better for less stress on the chain and the teeth.

I took off a 50T chainring because I could not spin it with anything without cross chaining on the original gearing.

What do you think about Deore Uniglide in 130 OLD with 7 speed capability? To me 7 speed is bulletproof for durability and not finicky about shifting or adjustment.

ThermionicScott 

I like 7-speed for the same reasons. My bias is toward the Hyperglide cassette system, so getting a 16T starting cog (or 15T -- Niagara and Universal are both out of the 16T), and cobbling something together out of current-production cassettes gets my vote. Just buying a 14-32 "F" and 13-26 "M" cassette would give you a 13, 14, 15, 16, 17, 18, 19, 21, 23, 24, 26, 28, and 32 to play with.

Uniglide anything is hard to recommend unless you already have the parts or "know a guy" who has some, since it hasn't been supported in so long. I'm even seeing the online stores like Niagara run out of some 7-speed cassette combos already, which either means they are between production runs... or something else that I don't want to think about.

Far Side of 50

I finally got a Hyperglide (Uniglide compatible) Shimano hub and put it together with a final 17 tooth Uniglide cog and then HG cogs of 18, 19, 21, 24, 28 and 32. Up front I have 110/74 BCD rings of 46, 38, 28 though I need to lower that 28 to 24 for the hills around here.
Everything is very usable.

cxwrench

Wow...only took 8 years. Congratulations.