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Wacky 48/38/18 crankset on vintage touring bike???

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Wacky 48/38/18 crankset on vintage touring bike???

Old 06-11-20, 02:27 PM
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RoLo50312
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Wacky 48/38/18 crankset on vintage touring bike???

Ok, so I am really hoping someone can enlighten me. I saw a listing for an old Brooks saddle for $20 but it came with a bike I didn’t want. I figured I would take the saddle and donate the bike to the co-op. Once I had the bike I started to think that under the grime and filth it is actually kind of cool. It’s a little small for me - a 54 (I normally ride a 56). So instead of keeping the saddle and getting rid of the bike I started thinking about cleaning it up a bit and selling it - I had been thinking about $100-120 after new tubes, tires, and bar tape. I have been cleaning it and discovered the rims are true, hubs spin smoothly, canti brakes needed slight adjustment...but the down tube friction shifting is all out of whack. So then I looked closer and realized the touring triple crankset is a 48/38/18. It’s a six speed cassette 13-30. The 18T chainring appears to be affixed with some type of bright purple adapter. So I’m thinking this must be an extreme adaptation for steep climbs with a heavy load. But it seems like there is no way that all gear combinations can possibly work. Has anyone ever seen this setup? Is the intent that the rider knows that if using the 18T chainring that it will only work with the largest couple cogs in the cassette? If I shift to the 18 in front and 13 in the back the chain droops down with no tension and massive slack. The setup seems pretty odd and I’m hoping someone can help me understand this setup. The bike is a kuwahara caravan tour.





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Old 06-11-20, 03:39 PM
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LOL. I just checked and the chain is way too long for the 18-30 combo and too short to reach the 48-13 combo. I think I’ll just keep the saddle and donate the bike to the co-op where it can be used for parts. Or if someone were to remove the 18 up front and put in a 28 and then put on a new chain it might be a decent bike. Interesting thing that was done to this bike...
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Old 06-11-20, 04:37 PM
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the purple thing is an aftermarket piece somebody added...

replace the crank ,,a 48 38 28 may work better for you,,
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Old 06-11-20, 05:35 PM
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Looks like a nice touring frame, lots of braze ons, racks.Should be worth something.
Question is why would you need an 18 in Iowa?
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Old 06-11-20, 05:48 PM
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Originally Posted by RoLo50312
LOL. I just checked and the chain is way too long for the 18-30 combo and too short to reach the 48-13 combo. I think I’ll just keep the saddle and donate the bike to the co-op where it can be used for parts. Or if someone were to remove the 18 up front and put in a 28 and then put on a new chain it might be a decent bike. Interesting thing that was done to this bike...
It’s not as silly as you think. Perhaps an 18 is a bit small but I run a 20 tooth inner on a number of bikes with 11-34 and 11-36 cassettes. It works just fine and I find the 15” low to be highly useful in a number of situations. I actually modify 104/64 external bearing bottom bracket cranks to accept a 20 tooth inner. This is a modified crank with a 46/34/20 and an 11-36 9 speed cassette. It’s an even wider range than the one you have.

Untitled by Stuart Black, on Flickr

The purple bit is may be an Avid MicroAdaptor or it might be a Mountain Tamer Triple adapter. It looks like the cog is on old freewheel cog rather than a bolted on chainring. The problem you are having with the chain may be the fault of the rear derailer. It looks like it has a shorter arm that can’t wrap the proper amount of chain. A longer derailer would help. The arm may be sticky as well. It should be folded back further. Put a new derailer on it and I think you’ll find that it works just fine.
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Old 06-11-20, 08:19 PM
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My own with a 22T cog bolted to a crank. Since you mentioned that the small ring only works with the largest two cogs it looks to me like the guy built himself a bailout gear. Even in the Midwest there must be some short steep drops and climbs near creek bottoms. Get off and push or use a gear like this.

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Old 06-11-20, 08:20 PM
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Originally Posted by cyccommute
It’s not as silly as you think. Perhaps an 18 is a bit small but I run a 20 tooth inner on a number of bikes with 11-34 and 11-36 cassettes. It works just fine and I find the 15” low to be highly useful in a number of situations. I actually modify 104/64 external bearing bottom bracket cranks to accept a 20 tooth inner. This is a modified crank with a 46/34/20 and an 11-36 9 speed cassette. It’s an even wider range than the one you have.

Untitled by Stuart Black, on Flickr

The purple bit is may be an Avid MicroAdaptor or it might be a Mountain Tamer Triple adapter. It looks like the cog is on old freewheel cog rather than a bolted on chainring. The problem you are having with the chain may be the fault of the rear derailer. It looks like it has a shorter arm that can’t wrap the proper amount of chain. A longer derailer would help. The arm may be sticky as well. It should be folded back further. Put a new derailer on it and I think you’ll find that it works just fine.
I would love to have an 18-30 (or 34, or 36) and a 50 or 52-11 on the other end and a good selection of choices in between. To me the wacky thing is that it appears that this setup was done in a strange way - basically with components that cannot handle the range. I was wondering if this is somewhat common and people just know which combos work and which don’t work. I had never before seen a configuration where the chain is far too long on one end and too short on the other. Seems odd, but to be honest my knowledge of bikes and practices related to setup is pretty limited. I love biking and love learning about it but I have soooo much to learn.... and yes I guess a longer cage might help but wow it’s a darn big difference
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Old 06-11-20, 08:25 PM
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Originally Posted by dedhed
Looks like a nice touring frame, lots of braze ons, racks.Should be worth something.
Question is why would you need an 18 in Iowa?
Need? I suppose I don’t need 18, and don’t need this bike at all. I just wanted the saddle for $20 but it came with the bike and I found the bike to be kind of neat and interesting.
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Old 06-11-20, 08:45 PM
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Originally Posted by RoLo50312
Ok, so I am really hoping someone can enlighten me. I saw a listing for an old Brooks saddle for $20 but it came with a bike I didn’t want. I figured I would take the saddle and donate the bike to the co-op. Once I had the bike I started to think that under the grime and filth it is actually kind of cool. It’s a little small for me - a 54 (I normally ride a 56). So instead of keeping the saddle and getting rid of the bike I started thinking about cleaning it up a bit and selling it - I had been thinking about $100-120 after new tubes, tires, and bar tape. I have been cleaning it and discovered the rims are true, hubs spin smoothly, canti brakes needed slight adjustment...but the down tube friction shifting is all out of whack. So then I looked closer and realized the touring triple crankset is a 48/38/18. It’s a six speed cassette 13-30. The 18T chainring appears to be affixed with some type of bright purple adapter. So I’m thinking this must be an extreme adaptation for steep climbs with a heavy load. But it seems like there is no way that all gear combinations can possibly work. Has anyone ever seen this setup? Is the intent that the rider knows that if using the 18T chainring that it will only work with the largest couple cogs in the cassette? If I shift to the 18 in front and 13 in the back the chain droops down with no tension and massive slack. The setup seems pretty odd and I’m hoping someone can help me understand this setup. The bike is a kuwahara caravan tour.
How's the chainline? It might be a "quad."

Generally these came from MTBs, from when 24t was the smallest granny and a standard 28t cog rear and a 34t wasn't low enough for MTBs. This provided a more noticable difference and one could keep the preferred 12-28 cassette.

Some products off the top of my head:

Mountain Tamer Quad
Limbo Spider
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Old 06-11-20, 08:53 PM
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Originally Posted by dedhed
Question is why would you need an 18 in Iowa?
Hey now! The driftless region in Eastern Iowa is no joke for hills, especially in my neck of the woods with the steep river bluffs of the Mississippi River. It's hard to find a 50 mile road ride that won't net you 3,000-4,000 feet of elevation, and pretty easy to find 100 ft per mile if that's what you're looking for. The rolling hills are steep and relentless. I am no slouch up an incline, the low gear on my touring/commuter is a 24 /32, and does get used from time to time!
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Old 06-12-20, 12:30 AM
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Definitely somebody's homebrew set-up, probably they just knew its idiosyncracies and rode accordingly. I rode a bike like that for years, no problem as far as I was concerned, but my brother borrowed it and declared it a "lapdog of satan."

I'm pretty sure Kuwahara bikes are fairly nice, maybe even very nice--check around the C&V forum and see what they have to say about it. Apparently their road bikes aren't very common in the US, for what that's worth.

That rear derailleuer is really rather good, although it probably needs a clean and a lube. If nothing else, it's a brand some people are very fond of.
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Old 06-12-20, 05:35 AM
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One interesting feature on that bike are the spoke holders along the drive side chainstay. they serve a double function, also providing protection from chain slap on the stay when you use them to carry spare spokes
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Old 06-12-20, 05:54 AM
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Originally Posted by RoLo50312
Ok, so I am really hoping someone can enlighten me. I saw a listing for an old Brooks saddle for $20 but it came with a bike I didn’t want. I figured I would take the saddle and donate the bike to the co-op. Once I had the bike I started to think that under the grime and filth it is actually kind of cool. It’s a little small for me - a 54 (I normally ride a 56). So instead of keeping the saddle and getting rid of the bike I started thinking about cleaning it up a bit and selling it - I had been thinking about $100-120 after new tubes, tires, and bar tape. I have been cleaning it and discovered the rims are true, hubs spin smoothly, canti brakes needed slight adjustment...but the down tube friction shifting is all out of whack. So then I looked closer and realized the touring triple crankset is a 48/38/18. It’s a six speed cassette 13-30. The 18T chainring appears to be affixed with some type of bright purple adapter. So I’m thinking this must be an extreme adaptation for steep climbs with a heavy load. But it seems like there is no way that all gear combinations can possibly work. Has anyone ever seen this setup? Is the intent that the rider knows that if using the 18T chainring that it will only work with the largest couple cogs in the cassette? If I shift to the 18 in front and 13 in the back the chain droops down with no tension and massive slack. The setup seems pretty odd and I’m hoping someone can help me understand this setup. The bike is a kuwahara caravan tour.




I have a friend who lives in Des Moines who sets up his bikes like this. He rides a 54 but I don't think this was one of his bikes. In any case, he was quite the tourist and he's up there in age so yeah this gearing would make sense for some people.

If you ride a 56-57 and want to do a swap, I'd think about it. 56-57 is my size but I have a friend who would use a 54. I live in D.M. as well.
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Old 06-12-20, 05:56 AM
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Originally Posted by SalsaShark
Hey now! The driftless region in Eastern Iowa is no joke for hills, especially in my neck of the woods with the steep river bluffs of the Mississippi River. It's hard to find a 50 mile road ride that won't net you 3,000-4,000 feet of elevation, and pretty easy to find 100 ft per mile if that's what you're looking for. The rolling hills are steep and relentless. I am no slouch up an incline, the low gear on my touring/commuter is a 24 /32, and does get used from time to time!
+ 1 on this. There is some fine riding in NE IA, SW WI, and SE MN. The hills can be unrelenting and steep.

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Old 06-12-20, 06:09 AM
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My first impression from the photo is a rear derailleur problem. Should be possible to get a derailleur with more capacity than that one.
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Old 06-12-20, 06:38 AM
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That bike has potential. Looks like a nice touring frame with some cool details. Easy enough for someone to replace the worn out stuff and kludge gearing. Please don't junk it.
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Old 06-12-20, 07:15 AM
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I don't see the problem. Riding bikes is sometimes different than working on bikes.

The mechanic in me wants to be able to take up the chain slack in every gear combination on the bike. The rider in me only cares about the gear combinations that I'm likely to actually use. The only time that I'd use that 18 chainring would be grinding up a steep hill. As soon as I'd clear the summit, I'd shift into a different ring. What's wrong with that?
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Old 06-12-20, 07:20 AM
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I'd clean it up and modernize the drive train a bit.
But, an 18 chain ring???? That is whacked.
I'm running a 22 on our mountain tandem and it is almost overkill.
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Old 06-12-20, 08:04 AM
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That looks like a very good touring bike and not strange at all to me. I rode a section of the GDMBR with 42/34/19 crankset using a mountain tamer for the 19. Cassette was a 12-36. I didn’t set it up like that to be using a 19/12 combo so how much droop there might be in the chain in that combo is irrelevant. I still did some walking.
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Old 06-12-20, 08:41 AM
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It's a good frame, for sure. Kuwahara made frames for other companies and their own were comparable to, say, Nishiki, or Panasonic. It likely began as a "12-speed" and the original owner added the tiny granny ring. Sometimes, you can add a ring on front or another gear on the rear stack with friction shifters and the derailleur can be adjusted for enough travel to cover it, as long as the chain is thin enough. My Nishiki designed Kamra Aero II has a Suntour rear "touring" stack with a big jump to the granny gear. (I'd have to go count the teeth to know exactly how many.) All I can say is I'm 64, and I've never had to get off it in a climb. I'm no powerhouse, but that 3rd ring must have been for someone with noodly legs. If I were going to sell it, I would remove the tiny front ring--- I think it would be worth more without it.
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Old 06-12-20, 08:45 AM
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Wide range drivetrains like that often require knowing what chainring you are in and adjusting gears accordingly. Usually you can run the entire cassette in the middle ring, higher T cogs in the granny ring, and low T cogs in the big ring. Once you get it it's easy peasy.
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Old 06-12-20, 09:03 AM
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Originally Posted by bakerjw
I'd clean it up and modernize the drive train a bit.
But, an 18 chain ring???? That is whacked.
I'm running a 22 on our mountain tandem and it is almost overkill.
There may be people who can use this. I have a friend who is in his 70s and this is what he uses to climb. YMMV but it's not "whacked." He's still out there riding.
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Old 06-12-20, 09:46 AM
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Originally Posted by RoLo50312
I would love to have an 18-30 (or 34, or 36) and a 50 or 52-11 on the other end and a good selection of choices in between. To me the wacky thing is that it appears that this setup was done in a strange way - basically with components that cannot handle the range. I was wondering if this is somewhat common and people just know which combos work and which don’t work. I had never before seen a configuration where the chain is far too long on one end and too short on the other. Seems odd, but to be honest my knowledge of bikes and practices related to setup is pretty limited. I love biking and love learning about it but I have soooo much to learn.... and yes I guess a longer cage might help but wow it’s a darn big difference
I’m not sure that the components couldn’t handle the range...at some point. It may have been able to when the derailer was new but the derailer could have worn out over the years. It would be worth putting a new derailer on and see if it works better. Here’s what my bike drivetrain looks like in various gears.

46x11


20x11. The chain is a little slack but I wouldn’t never use that gear anyway.


20x36. That’s a 15” gear. In terms of “development” or the distance the bike move with each pedal revolution, that’s 1.2m (a bit over 6’). It’s 4 mph at 90rpm. I may not be able to go very fast in that gear but I can ride up most anything...slowly...but I’m still pedaling.


36x36



46x36. This is the only fly in the ointment. The derailer is stretched to it’s limit but I would never, ever put the bike in this gear. I would shift down to the middle range long before I even got close to this situation.



By the way, your gearing isn’t quite like mine. Here’s what your’s looks like with a 20 tooth inner. The calculator won’t allow for an 18 tooth inner but if you do the math, the 18x30 is a 16” gear which is just a little higher than my 15” gear. Your high is also a little lower than mine. Looking at the gearing, it is kind of smart as well. It what is called a “cross over” gear...not to be confused with cross chaining”. The shift from the outer ring to the middle ring is about the same step as downshifting the rear. For example look at the 40x24 gear. It’s 65” gear. Downshifting to the 40x28 gear goes down to a 54” gear. Down shifting on the front to the 38x20 gear is a 51” gear. Assuming that you start in the 30x30 gear, you would shift the bike in the rear to the middle gear (20 or 17) and then “cross over” to the outer ring and continue up the cluster to the high gear. Just reverse it to go back down.

The 18 tooth ring is used as a bailout when the hill in front of you just keeps going towards the clouds. When you hit the top of the hill, just shift up to the middle ring and start upshifting. It’s actually a really good shift pattern.
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Old 06-12-20, 09:50 AM
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Originally Posted by SalsaShark
Hey now! The driftless region in Eastern Iowa is no joke for hills, especially in my neck of the woods with the steep river bluffs of the Mississippi River. It's hard to find a 50 mile road ride that won't net you 3,000-4,000 feet of elevation, and pretty easy to find 100 ft per mile if that's what you're looking for. The rolling hills are steep and relentless. I am no slouch up an incline, the low gear on my touring/commuter is a 24 /32, and does get used from time to time!
Hills east of the Rocky Mountains make up for their lack of altitude by having attitude. They are kind of like attack chihuahua’s...little but damned mean!

Out here in the west, you may need a spare lung to ride but we don’t run roads straight up a mountains. We can see where our roads go and no one in their right mind would go up “that!” In the east, the hills are usually covered by trees and no one can tell if the hill is stupidly steep.

I hate riding in the east. It’s just too damned hard!
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Old 06-12-20, 09:58 AM
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RoLo50312
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Originally Posted by cyccommute
I’m not sure that the components couldn’t handle the range...at some point. It may have been able to when the derailer was new but the derailer could have worn out over the years. It would be worth putting a new derailer on and see if it works better. Here’s what my bike drivetrain looks like in various gears.

46x11


20x11. The chain is a little slack but I wouldn’t never use that gear anyway.


20x36. That’s a 15” gear. In terms of “development” or the distance the bike move with each pedal revolution, that’s 1.2m (a bit over 6’). It’s 4 mph at 90rpm. I may not be able to go very fast in that gear but I can ride up most anything...slowly...but I’m still pedaling.


36x36

46x36. This is the only fly in the ointment. The derailer is stretched to it’s limit but I would never, ever put the bike in this gear. I would shift down to the middle range long before I even got close to this situation.

By the way, your gearing isn’t quite like mine. Here’s what your’s looks like with a 20 tooth inner. The calculator won’t allow for an 18 tooth inner but if you do the math, the 18x30 is a 16” gear which is just a little higher than my 15” gear. Your high is also a little lower than mine. Looking at the gearing, it is kind of smart as well. It what is called a “cross over” gear...not to be confused with cross chaining”. The shift from the outer ring to the middle ring is about the same step as downshifting the rear. For example look at the 40x24 gear. It’s 65” gear. Downshifting to the 40x28 gear goes down to a 54” gear. Down shifting on the front to the 38x20 gear is a 51” gear. Assuming that you start in the 30x30 gear, you would shift the bike in the rear to the middle gear (20 or 17) and then “cross over” to the outer ring and continue up the cluster to the high gear. Just reverse it to go back down.

The 18 tooth ring is used as a bailout when the hill in front of you just keeps going towards the clouds. When you hit the top of the hill, just shift up to the middle ring and start upshifting. It’s actually a really good shift pattern.
WOW! It’s truly amazing what I am learning through this forum! Really interesting and useful info! Thanks!
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