Never seen something like this before. Anyone familiar with it?

Vaguely. I temember these as coming on relatively low end bikes from Germany, or elsewhere in northern Europe, in the late sixties and seventies. I sort of recall that it was something with an "H", like Heinemann or similar.

I hope that helps.

As I said, it's been a long while, but if you don't have the crank, I suspect that you won't find one easily.

There is a BB spindle on eBay with hexagonal ends Don't think it's quite the same as yours. But you might finds some hints in it's description to get you started googling for more info.

https://www.ebay.com/itm/284486113024

. However I wouldn't have any issue tossing that one in your bike and putting something more normal in it. Assuming the BB shell matches some standard in common use today. If not, I'd toss the bike to the recycling scrap yard too.

Toss out a bike that has hair growing out of it's joints? Pretty unusual phenomenon I think. Smiles, MH

https://www.ebay.com/itm/184865893648

I, too, have seen this type of crank/axle fitting. And like Francis I can't remember the brand or model names (although seem to think it was on a BMX/Freestyle bike) and agree with the speculation of not finding a replacement. If you pull the BB there might be some info marked on it. Andy

Apparently suntour made a hexagonal one called Hexon.

https://www.amazon.de/-/en/SR-Suntou.../dp/B002NN7JVU

Fixed that for you!

SR and actual Suntour are different companies, let's not get them confused. Maeda Industries went out of business and SR bought out the name.
SunXCD was founded by the former President of SunTour so it really has the lineage from SunTour

Odd, the photo shows a hex drive with the appropriate name "Hexon", yet the product description says ISIS. ISIS is a splined interface, not a hex.
So not sure what is going with the conflicting info.

You have to be careful with Amazon's descriptions of a lot of products. Many are improperly described and you have to know exactly what you are looking for. Bicycle components seem particularly prone to incorrect descriptions.

Um, no. SR never owned SunTour.

According to Frank Berto (see his "Sunset for Suntour" article), SR was bought out by Mori Industries (a Japanese steel tubing company) in 1989. In 1990, Mori bought out Madea SunTour, combining the two entities shortly thereafter. The resulting company was called SR SunTour (likely to make use of both SR's and SunTour's name recognition).

The bottom bracket under discussion in the Amazon link above was apparently made after Mori combined SR and SunTour. Given SunTour's extensive expertise with bottom brackets, I'd guess it was made by the old SunTour division - but that's only a guess.

Ok yes, technically Mori bought SR and then bought the name of actual SunTour. The bottom bracket from that link is pretty new with the SR ST logo. Maybe not current new but not old enough to be actual SunTour.

That document was a nice read. Thank you for that.

Mori far bought more than the SunTour name in 1990 - they bought SunTour's operations and facilities from Madea Industries, essentially by assuming SunTour's debts. Mori continued to produce both SR and SunTour products under the SR Suntour name for several years before deciding to get out of the bicycle components business entirely in early 1995. At that point, two of SR's former owners arranged a management buy-out of SR's operations and the SunTour name and the SunTour production facility in Taiwan from Mori and contined operations as SR SunTour.

Unfortunately, the new SR SunTour management team either chose not to purchase (or were perhaps unable to purchase) SunTour's intellectual property, other facilities, and other tooling as part of the 1995 buy-out. Berto says Mori sold SunTour's remaining tooling for scrap (which included the tooling for the Superbe groupset) and sold the rest of SunTour's remaining facilities individually. He doesn't say what happened to the IP rights.

I did some further checking, and it appears that SR SunTour produced products using the Hexon crank interface as late as the early 2010s. (Unfortunately, I've been unable to determine when it first appeared.) Based on that fact, I'd guess you're probably correct in thinking it was developed after the 1995 management-buy-out vice something developed by the old Madea SunTour development team.

You're most welcome. I especially enjoyed the late Paul Brodek's insider commentary at the end of that version of the article.

Got a copy of the latest edition of Berto's The Dancing Chain as a Christmas present. If the book is anywhere near as good as his "Sunset for Suntour" article, IMO it's worth every penny it might cost.

In general it seems like a strange move to go for a hexagonal axle like that. Only works with 6-sided cranks and square axles have been the norm for 100 years or so.

6 corners will be harder to shear off than 4 corners.

When was the last time some one sheared off a crank or an axle like that?

Don't know. Of course it's rare. Crank arms are built to take the forces expected to be put on them.

But you'd mused earlier and thought it strange......I was just telling you why they might have tried it. Spreading the load around the hole in the crank arm potentially allows other potential benefits of design and maybe weight savings. And IMO for the last 50 of those 100 years, square taper cranks are mainly found on low tier bikes. So I wouldn't consider them the norm.

The fact they didn't catch on shows that other designs for the spindle and crank arm interface were better than just the hexagonal. ISIS and Octalink being very common today.

Old thread, but kid came today with an old Tony Hawk 20'' bike that needed a left hexagon crank arm, and a search led me here. Anyway, while I later found one currently on Ebay (RARE Hexagon/6 sided spindle Left Crank Arm, from St. John's, Newfoundland) for about $45, he had no $ to spend anyway, and I replaced it with a one piece crank from an old one-piece single speed, same size chainwheel and bearings, and it works fine, for free (except for new pedals at cost), thank God.

Tthanks for the info on this thread, and may it help certain others come come looking for obscurity.

Perhaps not. Yes, more corners. But at 30 degree angle to rotation circumference. Square drive is 45 degrees, more oblique. Hex drive bolts had a nasty tendency to strip the corners off the head when trying to break loose aircraft bolts that had been on a while in humid Vietnam. The air force tasked Snap-On to work on the problem and they invented Flank-Drive, with corners of 6-point box wrenches and sockets relieved so that the drive force was a bit inboard from the hex corners, and it worked. You'll see it on other brand wrenches these days, either the patent expired or they paid a licensing fee.

12-point aircraft bolts still have the 30 degree drive angle, but 12 drive points overcomes that.

Fascinating. Any chance of there being any military grade 5/16" x 9" bottom bracket bearings?

There is no such thing as "military grade", except in marketing.

after being in the military, and working at a NG Repair depot.. trust me... you wouldn't want true Mil. Spec. parts of any sort..
but i'm sure, if you look long and hard enough., you'll find someone willing to sell you some!

"Mil.Spec." is a MINIMUM requirement standard, and most similar parts are above that minimum.

please explain what a ' 5/16" x 9" bottom bracket bearing' is...

if you meant a 5/16" x 9 caged balls bearing, used primarily in low grade, one piece Ashtabula cranksets......
search Ebayt: Bicycle Bottom Bracket Bearing 5/16 x 9, Bike 1 Piece Bearings

Usually "marine grade" is more stringent than "aircraft" or "military", at least for corrosion resistance. AN on the bolt spec is Air Force/Navy. But last I checked, all US AN and aircraft bolts were only in US English threading. That might have changed by now, don't know, but the US auto industry went full metric decades ago.

I have a box of new bolts in storage got cheap at a surplus sale and each individually packed with cardboard tube around shaft to prevent nicks, *grade 9*; Usually highest you find here is grade 8.