bike-izle

Hi,

A bike I ordered came w/ torque specs stuck on/near relevant components. On my stem, for example, is this:




Can anyone make sense of this?

There're four specs listed. Number 1 is also engraved on the handlebar side of the stem (4 bolts), while Number 2 is stamped on the fork side near the bolt that pushes the stem downward (sorry, forgot the name). There are two other bolts which clamp the stem onto the fork of course.

Soooo....what bolt(s) does each spec map to? I guess the first is for the handlebar bolts, but the rest?

There's also a similar sticker on my seat post just under the seat and has three specs. There's only one bolt holding my seat on. Any ideas?


Thanks

HillRider

I don't think the numbers refer to any special order on the bike but to various bolt diameters. So, for example, any M5 bolt should be torqued to 5-6 N-m no matter where it is on the bike.

Oh, and the diameter referrs to the actual bolt diameter, not the size of the allen key that fits it.

bike-izle

Oh...thanks. I didn't think of that.

What does "M" stand for?

tomacropod

Metric. It refers to the diameter of the bolt in mm. Typically, on bicycles, you can subtract 1mm from the "M" designation to give you the allen/hex key size the bolt uses. This only works up to a certain point.

- Joel

HillRider

M=Metric so an M5x.8 bolt has a threaded shank 5 mm in diameter with a thread pitch of 0.8 mm. That nomenclature holds for all sizes of metric bolts.

Small SAE bolts are sized by an arbitrary sounding number x the thread pitch in threads per inch for example a #10-32 bolt is about 3/16" (actually 0.201") in diameter with 32 threads per inch. Larger SAE bolts are specified by their diameter in inches x the thread s per inch, e.g an 1/4"-20 bolt.

You will often see a third number specifying the length of the bolt in mm or inches like M5x0.8 x 25 or 1/4-20 x 2

bike-izle

Cool.

Thanks guys.