# Vintage Japanese Crank Mystery



## onespeedbiker (May 28, 2007)

I bought this on ebay a while ago without any purpose really, it just looked in good shape and the shipping was more than the winning price. When it arrived it turned into a real mystery crank. The markings on the chainrings are three intersecting arrows, which appears to be a symbol for Takagi. What is really bizarre is the old JIS symbol on the inside of the crankarm. I say bizarre because the square taper is larger than JIS and subsequently larger than any square taper spindle I have ever seen or own. A somewhat knowledgeable bike friend said he had heard when Japan first started experimenting with square taper some manufacturers went to a larger square taper size prior to settling on the current JIS standard. This kind of makes sense, except if that is true, why is it stamped JIS? Check out the photos and tell me what you think.


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## josephr (Jun 17, 2010)

On the second pic, there are markings near the center of the crank, can you take a closeup of those? Also, looks like there's a stamped marked on the backside of the chainring. 

The marking patterns suggest SR-Sakae and if you told me it came off an entry level older Trek, I'd even lean stronger towards SR-Sakae. Its certainly above dept store, but not high end for sure. Shimano usually put their name and part number on all of their stuff. I don't know much about Sugino though. Looks like it'd make a great fixie/single speed crank.


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## bicyclerepairman (Mar 12, 2003)

It bears a resemblance to the Sugino Maxy (mid 1970's), but the large chainring is different, and the Maxy logo is missing from the crankarm, and the casting pattern of the crankarm is different. I don't have anything else. As far as it making a great fixed or SS crank, I've ridden bikes with Sugino Maxy cranks, and they are nothing to write home about. The rings aren't stiff & they go easily out of true. They do take straightening well, and stay straight until the next time you ride.


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## onespeedbiker (May 28, 2007)

josephr said:


> On the second pic, there are markings near the center of the crank, can you take a closeup of those? Also, looks like there's a stamped marked on the backside of the chainring.
> 
> The marking patterns suggest SR-Sakae and if you told me it came off an entry level older Trek, I'd even lean stronger towards SR-Sakae. Its certainly above dept store, but not high end for sure. Shimano usually put their name and part number on all of their stuff. I don't know much about Sugino though. Looks like it'd make a great fixie/single speed crank.


Here are the markings on the inside of the crank arm, they appear to be from the casting itself. The markings on the inside of the chainrings are the 3 arrow design next to the chainring size 52 and 40, in a circle. The problem with using this crank for anything is the oversize square taper that doesn't match any spindle I've ever seen.


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## onespeedbiker (May 28, 2007)

bicyclerepairman said:


> It bears a resemblance to the Sugino Maxy (mid 1970's), but the large chainring is different, and the Maxy logo is missing from the crankarm, and the casting pattern of the crankarm is different. I don't have anything else. As far as it making a great fixed or SS crank, I've ridden bikes with Sugino Maxy cranks, and they are nothing to write home about. The rings aren't stiff & they go easily out of true. They do take straightening well, and stay straight until the next time you ride.


Well it's nice to know they don't go out of true while sitting in the garage  but really thanks for your reply. Do you know anything about the oversize square taper? Ever heard of such a thing?


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## bicyclerepairman (Mar 12, 2003)

No on the oversize square taper. I have heard of (and this was a long time ago, not recently) people over torquing the crankarm fixing nuts/bolts to the degree that the softer aluminum gave and was spread to a dimension larger than could be secured when said crankarm nut/bolt bottomed. Having said that, I've wrenched these pretty hard myself without problems.

Something I have seen first hand is people stripping the threads of their crankarm fixing bolts & riding anyway. Pedaling as the crankarm loosens opens up the size of the square tapered hole......if you look close where this has happened, it's asymetrical.


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## onespeedbiker (May 28, 2007)

bicyclerepairman said:


> No on the oversize square taper. I have heard of (and this was a long time ago, not recently) people over torquing the crankarm fixing nuts/bolts to the degree that the softer aluminum gave and was spread to a dimension larger than could be secured when said crankarm nut/bolt bottomed. Having said that, I've wrenched these pretty hard myself without problems.
> 
> Something I have seen first hand is people stripping the threads of their crankarm fixing bolts & riding anyway. Pedaling as the crankarm loosens opens up the size of the square tapered hole......if you look close where this has happened, it's asymetrical.


No, I have placed several spindles into the crank. The spindles bottom out and still rattles around.


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## Crashman1 (Feb 11, 2012)

I have a pair that's almost identical. Those actually look to be a debranded version of mine.

Mine are SR, and early SR cranks used an oversized taper. I really only registered and responded because the web appears woefully inadequate in regards to SR's oversized taper.

I just saw a guy selling some old SR arms and a spindle separately on eBay. I almost bought the spindle just because it's a rare part that wears out:

ebay item number 300660314542 A link would help more but this forum has rules against me helping more.

The only problem is, I don't know if this bottom bracket is early oversized SR or later JIS.


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## sdjolley (Dec 28, 2020)

If anyone stumbles on this old post and needs an oversize taper bottom bracket spindle, there are 4 sizes here:








5K Oversize Taper 130mm Bottom Bracket Spindle


Good condition. Rare oversize square taper - 13.3mm at outside edge of taper. Fits some vintage '70 and '80s cranksets from SR (Sakae Ringyo), Three Arrows (Tagaki), and Bridgestone. 130mm spindle length. For 70mm bottom bracket shell. There is one minor pit on one of the bearing surfaces...




www.hoopriderparts.com












3H Oversize Taper 132.5mm Bottom Bracket Spindle - NOS


New old stock. Rare oversize square taper - 13.3mm at outside edge of taper. Fits some vintage '70 and '80s cranksets from SR (Sakae Ringyo), Three Arrows (Tagaki), and Bridgestone. 132.5mm spindle length. For 68mm bottom bracket shell. 3H Oversize Taper 132.5mm Bottom Bracket Spindle - NOS




www.hoopriderparts.com












3K Oversize Taper 130.5mm Bottom Bracket Spindle - NOS


New old stock. Rare oversize square taper - 13.3mm at outside edge of taper. Fits some vintage '70 and '80s cranksets from SR (Sakae Ringyo), Three Arrows (Tagaki), and Bridgestone. 130.5mm spindle length. For 68mm bottom bracket shell. 3K Oversize Taper 130.5mm Bottom Bracket Spindle - NOS




www.hoopriderparts.com












5F Oversize Taper 133mm Bottom Bracket Spindle


Good condition. Rare oversize square taper - 13.3mm at outside edge of taper. Fits some vintage '70 and '80s cranksets from SR (Sakae Ringyo), Three Arrows (Tagaki), and Bridgestone. 133mm spindle length. For 70mm bottom bracket shell. No pitting on the bearing surfaces. Tapers are good. 5F...




www.hoopriderparts.com




There were early cranks by SR, Bridgestone, and Three Arrows (Tagaki) that used these spindles. Most of them were models with three arm spiders.
Hope this helps someone in a bind.


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