I never knew that the left pedal has a little groove where it threads into the crank arm.
The amount of time I’ve wasted trying to attach the wrong pedal wants to make me weep.

Read the instructions!

Different pedals have different systems. It used to be quite common that the left hand side had some knurling on it. Some even have an L on them

I just look at the thread. A LHD thread is pretty obvious!

I just look at the thread. A LHD thread is pretty obvious!

Can be tricky if you’re looking at it upsidedown, though.

With enough for you can get them to go in either side.

I wondered why one had tape on it then saw it was Crap Brothers.

Can be tricky if you’re looking at it upsidedown, though

But not if you look in the mirror 😉

Looks like the left hand one has a tapered thread too!

Pedals are easy. They do up in the same way the wheels rotate when going forwards, and undo the way the wheels rotate when going backwards. Forwards = positive = doing up; backwards = undoing = negative.

Once you remember this then you can easily see which is which. Also, DMR pedals have L and R stamped on.

Pedals are easy. They do up in the same way the wheels rotate when going forwards, and undo the way the wheels rotate when going backwards. Forwards = positive = doing up; backwards = undoing = negative.

I like this a lot. Thank you.

I do have my own method but posting it after reading this just makes it stupid.

Do you need a “method”? The left pedal is left hand thread, the right pedal is right hand thread.

I always think “they undo toward the back of the bike” which seems to work out easier in my head when the bike is upside down and back to front 🤣

I think the original poster had learnt something he/she thought was useful to pass on. It was a while after working in a bike shop that I realised that on cheap bikes that the left pedal had lots of milled lines parallel to the axle, some did have L/R but not all. Nobody told me, the shop I was in was good but not hot on training – even basic. We should appreciate the original poster passing the info on to help others!

The amount of time I’ve wasted trying to pick at that groove thinking it was a pedal washer welded in place with old copper grease 🙄

The biggest problem for me is the little nut on the end of the axle, some brands are reverse thread others use normal, its easy to ruin a nut or axle on the first service. The thread into the crank is obvious imo.

That little groove saved me a crank arm when I bought a brand new set of deities that came with 2 RH pedals in the box.

It’s more general than pedals – the same applies to LH threads on gas bottles etc. The nuts normally have a groove in them to denote LH thread.

Like this:

I can’t see what @zippykona means in the picture in the OP, but if a pedal doesn’t have L or R stamped on the end (and most do IME) I just look at the thread.

That’s worth knowing though @euain, ta.