Bike Forums - Hmmm...

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- - Hmmm... (https://www.bikeforums.net/classic-vintage/1267216-hmmm.html)

I thought I had seen a similar thread a while back, but I went back 25 pages (into October 22) and didn't see it. Feel free to add odd stuff you come across. If someone does find an older thread on the same general topic, I'll ask the mods to merge them.

I know we've all come across some curious things either while riding bicycles, or working on them. Recently, I was trying to tighten a saddle onto a seat pin so that it wouldn't swivel so easily. None of my wrenches could get a good purchase on the nut though.

https://cimg3.ibsrv.net/gimg/bikefor...c75e8a9e9b.jpg

Pentagon Whitworth? :twitchy:

:roflmao2:

I believe the nut is on the wrong side of the clamp.

Theft-deterrent "security" bolt to prevent your seat from being stolen!

On that style of seat clamp it is easier to just wack the nose of the seat to get it loose to steal the seat. I learned the hard way. I had a seat stolen. While I wasn't there to witness it, I had some friends tell me that that is how it is done.

What the hell? Nuts are made from hexagonal bar stock. Did someone have a sale on barstock that was defective? Fire hydrants (fire plugs) have pentagon nuts to turn on the water valve, so that the common folks can't do it themselves. This one makes no sense at all.

Of course, someone tightened that nut. Whether at the factory or the place it was assembled to be sold. Is the nut proprietary so that you have to go back to the dealer to make adjustments. Did they use a 5 point wrench? A 10 point wrench? I never heard of such a thing.

We now live with all manufacturers coming up with ways to make sure that we cannot service the stuff they make.

Is that on one of those bikeshare bikes?

I'd call that a "flutney" nut or bolt, based on what I remember from Mad Magazine's famous team sport, 43 Man Squamish.
https://43-mansquamish.weebly.com/equipment-needed.html

Gas and water utilities use pentagon bolts (13/16") for access boxes and certain automotive applications as well.

https://www.amazon.com/CTA-Tools-275...A%3D%3D&sr=8-9

Quote:

Originally Posted by USAZorro (Post 22791443)

Are you sure I didn't send that one to you? That's a bike share seatpost clamp, most commonly seen on first and second generation Spin bikes. You can replace the nut if you wish, but you'll be surprised how they'll tighten just fine with an adjustable wrench on one of the flats.

Gen 1 (incomplete, wrong front wheel):

https://cimg2.ibsrv.net/gimg/bikefor...5e5da7939f.jpg

Gen 2:

https://cimg1.ibsrv.net/gimg/bikefor...142b219b9e.jpg

Gen 3 used the same saddle, but a conventional sandwich clamp seatpost (though they're non-remote dropper posts, so not so conventional).

https://cimg1.ibsrv.net/gimg/bikefor...5aea12e4a2.jpg

https://cimg4.ibsrv.net/gimg/bikefor...a466e29d1a.jpg

The Gen 1 + 2 Spin clamps use a carriage bolt on one side and the pentagon nut on the other, similar to some of the Persons and Troxel saddles from the 1960's and '70s.

https://cimg6.ibsrv.net/gimg/bikefor...5bdec8d304.jpg

Need any more of those clamps? Spin closed down for good in South Florida (only responsible operator here, so quite a loss), so wound up with a few more spares from the warehouse.

-Kurt

Kurt,

I'm good thanks. Now that you mention it, the clamp looked quite a bit newer than what I'm used to, so I suspect your care package was the source. Mystery solved.

I am still hoping that this is only the first of many curiosities that forum members explore in the thread.

Quote:

Originally Posted by USAZorro (Post 22791911)

I am still hoping that this is only the first of many curiosities that forum members explore in the thread.

^ You need a few more colors on that bike.

Perfect nut for a pipe wrench.

Quote:

Originally Posted by thumpism (Post 22792125)

^ You need a few more colors on that bike.

I wanted to fit a few more parts, but we only had Spin, LimeBike, and Ofo locally. Would be fun to throw some MoBike parts at it.

-Kurt

Quote:

Originally Posted by 52telecaster (Post 22792267)

Perfect nut for a pipe wrench.

All those dudes riding around with Vise Grips clamped to their seatposts back in the '80s were prepared for this.