testertips

79pmooney

Those are standard toe-clip size screws, the most common size and thread on a bike. I want to say M5x 0.8 but I have had them confused with M4s forever so I'll let the next poster call that out. (The info is all over the place. Not hard to find. The most common metric screws at Ace hardware will be those.

cyccommute 

Yes, most commonly they are M5X0.8mm. If you can’t find metric, a 10-32 SAE screw will also work.

RCMoeur 

Troul 

do not use anything but the appropriate sized hardware. This is why standards exists, & should be more invoked into the bicycle industry.

LarrySellerz

A m5 hole is drilled a bit larger than a 10-32 hole, but the threads per inch are almost identical. A 10-32 bolt should thread into a m5 hole but a m5 bolt shouldn’t fit into a 10-32 tapped hole. Since the M5 hole is bigger, there is less thread engagement (I believe the standard atleast for imperial is 75% thread engagement) so the bolt will feel “sloppier,” the location is less precise and the connection not as robust.

That being said, for most applications 10-32s will work just fine (until they vibrate loose) Some people prefer not to deal with communist metric stuff.


edit: could an advantage of 10-32s be that they are less likely to fully bind/sieze when they rust because there is less thread engagement?

smd4

You do realize that the metric system predates communism by a couple hundred years, right?

testertips

sooooo... M5? I mean Mao5?

RCMoeur 

I just posted this elsewhere at https://www.bikeforums.net/22962937-post6.html :

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For attaching items to most bicycles, in my experience most fasteners are 5x0.8 or 6x1.0 metric threading. A selection of bolts in lengths from 10 mm to 30 mm should fit most needs, along with nylon-insert nuts. I would not recommend using common USS sizes like 8-32 or 10-24, as they may not fit well and probably will not thread well at all into most eyelets or fittings.

Locally, I buy them in bulk from Copper State Bolt and Nut in 100-packs. 100-packs are big for most casual users, but I end up working on a lot of bikes. One option would be to buy a 5 mm or 6 mm bolt assortment, and then invest in a near-lifetime supply of nuts.

I personally prefer hex head bolts for most uses. It seems many bikes and accessories use button head socket (hex) screws, but many of these require a 3 mm hex wrench, which can easily round out under higher torque.

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Nearly all threaded fender/rack eyelets on bicycle frames are M5x0.8. A few are M6x1.0, but they are an exception and probably outnumbered by no-thread eyelets.

LarrySellerz

10-24 would never work and 8-32 is way too small lol

Gresp15C

#10-32 would be equivalent to 4.8 mm x 0.794

For a low number of engaged threads it would fit and only be a bit sloppy. A drawback is needing yet another size of allen wrench. And it would be an odd size to find in a typical household.

My advice about all threads is make sure they go in easily with your fingers before using any tools. That way, you can stop and investigate if you notice that things aren't going well.

https://www.boltdepot.com/fastener-i...-diameter.aspx

PDKL45

Not by coincidence either. Basically, communism can be traced to the malign influence of the metric system. Think about it. Fractionally.

cyccommute 

A couple of things about using a 10-32: They can be used in a pinch when you can’t find a metric bolt, especially in the US and with stainless bolts. Stainless metric bolts can be a bit difficult to find at times. Yes, the fit is a little loose but not as much as you think. Additionally many bicycle rack fittings are paint filled which actually makes the fit a little closer since most people don’t chase the threads on rack mounts. As to the wrench size, it uses a 4mm allen wrench. Fits quite well.

cyccommute 

It amazes me that we in the US use a decimal monetary system that replaced the confusing English monetary system from the inception of our country and have no issues with using it. The metric system is just our monetary system for distance. A demonstration that we had to do in beginning chemistry was to measure our thumbnail in both imperial and metric then convert it to the various measurements in the respective systems. To make it even more difficult, no calculators were allowed. Converting to the metric system…from millimeters to centimeters to kilometers…as simple. Just move the decimal point. To convert from imperial, you have to decimalize the fractional inch measurement. Divide by 12 to get feet. Divide by 36 to get yards. Divide by 5280 to get miles. It’s laborious and fraught with error.

Liquids are even more confusing. Quick, without Googling, how many teaspoons in a quart? How many cups in a gallon? How many gallons in a hogsheads? Or a barrel? Now how many milliliters in a liter? (Hint, it’s in the name)

ralphs

I bought a bag of M5 x 0.8 x 12 and M5 x 0.8 x 14 Stainless Socket Head Cap Screws from https://belmetric.com/
They work for all the eyelets on my bikes.
I've used Bel-Metric for over 30 years (back to when I was working as a mechanic.) They have had everything I've ever needed (metric or automotive-hardware related). They're only 10 miles from me, so I can order and pick up at their warehouse same day. Pretty sure everything on their website is in stock (although my needs have never been that obscure.)
I see that they now have black stainless fasteners- I don't need them, but might be nice on darker bikes.

LesterOfPuppets

That one's pretty easy. 2 in a pint x 8 pints in a gallon = 16

Bald Paul

"Cross thread is better than no thread." - old auto tech expression
Finding metric hardware isn't exactly like searching for the Holy Grail. Much easier than finding some of the "specialty" bolts.

JohnDThompson 

Twelve pennies to the shilling actually works well, since 12 is divisible by 2,3,4, and 6, while 10 is only divisible by 2 and 5.

Maelochs

The problem wit using a slightly loose bolt for a rear rack is that under heavy load and a lot of vibration, the screw could end up making the hole even bigger.

smd4

The malign influence of the metric system?

Please.

unterhausen

The inch has been based on the metric system since before I was born, and I'm retirement age.
So the call is coming from inside the house.

smd4

You mean the inch that predates the metric system by at least 400 years? That inch?

Gotcha.

PDKL45

One world, one system for all? Sure sounds like communism to me. I mean, sure, the US decimalized its currency, but that has been shown to have been a communist plot, to insert a fifth column of decimalization into US society, before the main metric communist invasion.

smd4

Oh.

RCMoeur 

I will keep my conscience clean by continuing to purchase my metric fasteners from free market sources.