cnnrmccloskey

I was getting ready to leave on my cruiser today and since I have a very slow leak that I've been reluctant to try and patch/replace I have to pump my tire up before every ride, But this does give me a little extra opertunity to look over my bike and one of the things I noticed as I was pumping the tire up was that my NDS crank arm was waay too far out on the spindle so I grabbed it and sure enough it wasn't on there at all (just slid back and forth). Needless to say I was pretty perplexed at this point, but not to be deterred I went and grabbed my 14mm and went out to tighten every thing up, now every thing gets even weirder, the wrench wont engage, but thankfully (in a way) the bolts wern't even finger tight, so I pulled them out and looked at them as I walked them back into my repair space, I wasn't familiar with the look of them and when I got down I relized they were 16mm bolt (oh which I own 0, I hadn't even ever taken my 16mm socket out of the case.) I replaced them with some different fixing bolts I had laying around and all is good but I am still perplexed beyond belief.

cnnrmccloskey

This bike lives outside through a gate held closed by a bungee cord locked to a pipe, so pretty accessible

DieselDan

A 16mm bolt?

cnnrmccloskey

yup a 16mm fixing bolt

CNY James

so what was the odd part, that it was loose or that it was held on by a 16mm bolt when you expected it to be a 14mm bolt?

cnnrmccloskey

well, both
As far as I've seen cranks that are even severly under torqued won't just slide off.
And given as how I had assembled the bike myself and never used my 16mm socket (I know for a fact because I hadn't removed the bit from the packaging of my socket set), I was working on the bike and took the crank off and put it back on less than a week ago and I never used my socket I just used my park wrench.

Its just odd enough I don't expect anyone to believe me, I just had to say somthing.

billyymc

Was this a bikesdirect bike?

cnnrmccloskey

Huh?
No it wasn't it was an old fuji road bike that I converted to a cruiser after its former owner ran every component into greater disrepair than I had ever seen and gave it to me after taking the wheels for a new ride

Nermal

Bolts are usually designated by diameter, by the way. Not wrench size.

CB HI

https://wheelsmfg.com/content/view/495/54/

cnnrmccloskey

What do you mean?
I referenced it as a 16mm bolt
and I referenced grabbing my 14 mm wrench

CCrew

Was it a 16mm bolt, or a 16mm head ON the bolt? Sizes aren't based on what wrench fits it Cause 16mm on a crank arm bolt is darn near 3/4 of an inch in diameter.

DX-MAN

C'mon, stop the nitpickin'; I've spent the last decade building bikes, and we always refer to various bolts by the wrench/socket size, mainly cuz it doesn't matter what the threaded diameter is, it's what tool we need to secure it that matters.

Interestingly enough, on modern bikes, many hex-head bolts/screws ARE the size of the tool; most M5 bolts on bikes are 5mm-compatible, etc. Standard socket-head bolts, of course, are different. But let's be real, we all know what we're referring to, and nobody needs ego points for fastener nomenclature.

stapfam

I am alittle concerned about the fit of the cranks now. Even if a moron had got to the bike and loosened the bolts- you would still need an extractor to get the cranks to disengage from the BB. Unless you have a bad fit of crank to BB spindle. And if that is the case- as the bolts come loose- you would feel it while pedalling- the crank would just float about.

And on the bolt/ socket size. I have always called a 6mm bolt a 6mm bolt. The fact that it takes a 10mm spanner for the head doesn't matter. It is a 6mm bolt to me- but in the last few years- I have come across several mechanics calling it a 10mm. Think it may be a college thing in that the Numbskulls we are training to look after the trucks at our place are thick. Start giving them two things to think about and our trucks would never leave the workshop.

cnnrmccloskey

I thought about that, just adds to the perplexity to me, they were loose to the point of being unridable though

cnnrmccloskey

Maybe its dependant on geography because over the last 3 years of becoming a mechanic I've never heard anyone specify a bolt by the thread diameter unless it was a comparison of two bolts using the same wrench diameter, even going to the united bicycle institute and hanging around a shop with two guys who have wrenched for 30yrs plus.
also in this context its kinda nesiccary to refer to it by socket size as the two bolts are the same threading with different engagement diameters
Thats odd


edit: if I had been saying somehow someone greatly enlarged the thread of the spindel that would have been a whole new level of intrigue.

novacoke

That being said, how do you classify a carriage bolt? You do it by thread diameter.

The size of the nut/bolt head determines what wrench you grab.

CCrew

Grow up with a machinist as a father... ya know, the guys that actually MAKE the stuff. It's diameter and thread pitch.

genec

Doesn't matter what the threaded diameter is??? What?

Try buying a bolt they way you specify them and you won't get something that fits... cause it IS the thread and diameter that designates a bolt.

cnnrmccloskey

Yup, doesn't matter when your refering to two of the same fasteners with different head diameter and the same thread diameter and pitch.
Cause no ones talking about any variation on anything except the diameter of the bolt head

genec

OK but you are getting into a bad habit by calling a bolt by the tool that drives it...

Typically a bolt is called out by diameter, thread pitch, length and head type... like "2 inch quarter-20 with socket head." Material and strength may also be specified...

Here, check out this wiki on screws and then teach your buddies too. https://en.wikipedia.org/wiki/Screw

Oh and bear in mind that this stuff applies to the world beyond bicycles... not everything has "a fixing bolt of one thread type."

cnnrmccloskey

I'm well aware of the proper nomenclature its just not necessary in this situation, in the real world if I were to ask for a crank fixing bolt I would not ask for a 14mm bolt, I would ask for a crank fixing bolt as there is no deviation in the thread of them., I understand your confusion but I think that in this situation of discussing variations on the same bolt (thread wise) it would have complicated things. Thank you none the less

DX-MAN

When we're building at work, the issue of having to buy a replacement bolt doesn't arise, so NO -- IT DOESN'T MATTER. That's the circumstance I was referring to.

And, when I have replace a bolt, I take a good one with me, along with the threaded piece it goes into, because I don't trust labels on bins in stores. Had to do that, oh, let's see, twice in a decade of building my own, as well.

NOTHING is as sure as test-fitting a fastener....

CNY James

I'm with DX-Man, in the context of this thread, we all knew exactly what was being described. any subsequent debate is stupid...

chalk another one up to the ongoing persuit of internet superiority & the quest to prove that "I'm smarter than you..."

DieselDan

The only place I have ever seen a 16mm bolt were panel fasteners on a Caterpillar D6 bulldozer. The company I worked for had to special order the wrenches and sockets for those bolts.