Servicing pedal bearings: left / right hand thread

[Frank9755]

I've just acquired a second hand pair of pedals and they are spinning very freely, which digests to me that they need grease.

I've never serviced pedals before but I don't think it should be too hard, as long as I can undo them to get in.

The pedals have a dust cap, which I've taken off. Then there is a bolt that I need to undo, but it is extremely tight in both pedals. Before I really apply maximum force I want to be sure if it is likely there will be a left handed thread and, if so, which pedal will have it. I assume the left might but expect someone will know for certain!

[rogerzilla]

What model are they?  If Shimano M323 or M324, don't take them apart just yet...

[Frank9755]

They are Pedaling Innovations Catalyst pedals, which are made by VP Components.

Is it not a standard thing...?

[dat]

Standard threading on most pedals. They tend to have loctite applied due to low torque as it normally applies preload to the bearings.

[hubner]

It's only the left hand side pedal to crank threads that has a left handed thread, ie the threads that screw into the left crank.

All other threads are normal right handed, I think.

[LittleWheelsandBig]

Don't know those pedals specifically but some pedals have reverse threaded cones/ locknuts on one side, so I understand why you are asking the question. If the nuts are differently threaded, usually the Nyloc insert (if used) will be a different colour on each side.

[rogerzilla]

It isn't always possible to tighten the locknut against the cone if both are recessed into the body.  You can try to jam the cone with a screwdriver.  Shimano make a concentric socket tool for their pedals that have this "feature".  It costs as much as the pedals.

[Brucey]

also some pedals don't have a tab washer between the cone and locknut; this makes them impossible to put back together unless you have the correct set of nesting sockets.

Suggestion; if there is no play in the bearings, you could just force grease through from one end, and sidestep the issue.....

cheers

[Frank9755]

Thanks everyone. They are meant to be easy to service, and no special tools required, beyond an 8mm socket, which I have.

There's a YouTube video made by a guy showing how to do them and he says one pedal is reverse threaded, but he never says which, and I can't tell by looking at the video

if I can get grease in without having to undo the nut that would do. Or I'll ask the guy who made the video...

[hatler]

I think that the handedness reverses at each rotation point.

RHS - BB LH thread - Pedal RH thread

LHS - BB RH thread - Pedal LH thread

Which would sort of imply that the thread direction for the bearing for the pedal should reverse again.

I'll see if I can dig out confirmation of that.

ETA  This wiki piece on precession should help.

And, from that wiki piece : -

Shimano SPD axle units, which can be unscrewed from the pedal body for servicing, have a left-hand thread where the axle unit screws into the right-hand pedal; the opposite case to the pedal-crank interface. Otherwise precession of the pedal body around the axle would tend to unscrew one from the other.

[yoav]

My only advice is to place a towel or similar under the pedal as you disassemble it. To catch the ball bearings before they fall on the floor and are lost forever.

[aidan.f]

 Get  imaginative with rubber bungs and grease guns plenty of ways to force grease into the body, especially as you now have the dust  caps off  -

[Asterix, the former Gaul.]

Non-breathable gas bottle fittings have left hand thread to avoid accidents e.g. stopping someone breathing.  The nuts are identified so by having a small nick in the corner of each flat.

They could do that with pedals and stuff.  In fact once you have identified the left handed nut you could do it yourself.

[Brucey]

FWIW there is not 100% consistency in how pedals are put together.  There are left handed threads found in the following places

ALL-  where the LH pedal screws in the crank
NEARLY ALL- if there is a bearing system retaining collar/sleeve/hollow bolt (PD-M520, like that) that screws in the left side of  RH pedal body
SOME- on the RH pedal cone and locknut

re the cone and locknut threads; this isn't even consistent in one model of pedal. E.g. for years shimano SPD bearing cartridges had RH threading on both spindles for cones and locknuts. They have been making them (not in all models starting at the same time, that'd be too easy) using LH threading on the RH cone and locknut for the last few years.  The only clue is that there is usually a blob of paint on the end of the spindle.

cheers

[Frank9755]

So, if my question is: 'Given that I know there is a left handed thread on one of the pedals, which one is it likely to be? ' it seems the answer is the right pedal.

[hatler]

Yes, the right pedal.

[Frank9755]

Yes, the right pedal.

Thanks very much!

One I had the confidence which way to turn, it just took a bit of force to undo them. No drama like ball bearings going everywhere, the bearing is a sealed cartridge. I just cleaned the axle, put in lots of grease and put it back together.

Axles were quite pitted with rust so may need to be replaced at some point, but seems better now, doesn't fly round as before.

Also did another set while I was at it.  I've got another three after those, so good to know how to do it. First time I'd ever serviced pedals, always ignored them and have never had a pair fail on me.  Satisfying to learn a new skill!

[hatler]

Cool. New knowledge put into action is always fun.