Pedal Torque

[axel_knutt]

Does anyone else have difficulty findng the right torque for pedals?
At 45Nm they work loose. At 55Nm they're a hernia job to remove. 50Nm seems the best compromise, but I've even had them work loose at that, after which I tried 55Nm again only to end up cutting a pedal off when the spanner took the corners off the hex. (Pedals with two flats rather than a hex are better from that point of view.)

[NUKe]

I never had any problems with pedals working loose usual do handtight + 1/4 of turn. you could try using Loctite or someother thread lock paste and a lower torque

[Brucey]

At 45Nm they work loose.

do you pedal backwards or something?

For many types of rider/riding, slightly loose pedals tend to self-tighten, if anything.

BTW if you get one stuck, a simple solution is often to strip the pedal down, leaving just the spindle. The spindle can then be held in a bench vice. Sometimes packing pieces are needed to hold the flats, but this is no big problem.

Unless you have to for some reason, it is not a particularly good idea to buy pedals with a full hex at the base; two flats are a wider and stronger connection for the spanner.

cheers

[Brucey]

oh, I've just thought...

are you sure you have a matched set of pedals and cranks? There are some French spec pedals and threads around. M14 threaded pedals will go into 9/16" x 20 tpi cranks, but it is not a happy marriage...

cheers

[theenglishman]

55Nm on an alloy crank? Hells teeth - you can't be far off stripping the thread? My motorbike wheel nuts were only 60Nm and that was 100bhp!

[Mick F]

My Campag pedals should be torqued to 40Nm according to the instruction manual.

I just fit mine with the pedal spanner so they are on tight. No idea what the Nm's are.

[bikes4two]

My Shimano pedals can be tightened with a spanner or an Allen key in the spindle end.

I only ever use an Allen key to tighten although due to the self tightening nature, I sometimes need to use a pedal spanner to undo them.

As has been said already, you may have a pedal/crank thread mismatch?

[Valbrona]

I think the problem might be your pedal spanner. I use one of these http://www.chainreactioncycles.com/Mode ... elID=10005

Or try a long arm hex wrench with a handle if it is hex bolt fitting.

[breakwellmz]

At 45Nm they work loose.

do you pedal backwards or something?

For many types of rider/riding, slightly loose pedals tend to self-tighten, if anything.

BTW if you get one stuck, a simple solution is often to strip the pedal down, leaving just the spindle. The spindle can then be held in a bench vice. Sometimes packing pieces are needed to hold the flats, but this is no big problem.

Unless you have to for some reason, it is not a particularly good idea to buy pedals with a full hex at the base; two flats are a wider and stronger connection for the spanner.

cheers

Retodirect?

[Vantage]

There's waaaaaaaaaaay too much technicallity here. It's a pedal. Tighten with a spanner, then, whack the spanner with a hammer to get it nice and tight. Job done. It's worked for me for some 20+ years.

[Mick F]

+0.5

I don't use a hammer!

[Brucey]

normally you don't need to be especially careful with pedals when fitting them, and things are just fine (until you need to remove them, anyway...).

BUT the fact that the OP has reported that his pedals unscrew themselves almost certainly means that things are not normal for some reason.

cheers

[BigG]

There is clearly something abnormal going on here. In practical terms, there should be no difference between the 45 NM and 55 NM torques. Most of us work to wider tolerances than this and the manufacturers expect this, whatever they might say in their instructions. The combination of a metric (Italian?) thread and a BS thread seems to be the most likely explanation. The cranks will have their thread size stamped on the reverse. It may be possible to borrow a die of the same size to reform (slightly) the pedal threads. I have never used a torque measurement on pedal threads in 60 years and have never had a pedal come loose; neither have I had more than a modest struggle to remove a pedal from its crank.

[Brucey]

there are only three common thread standards for pedal threads in use today;

1) 1/2" x 20tpi (BMX, many one piece cranks etc)

2) 9/16" x 20tpi -nearly everything else, maybe 99% of all pedals-

3) M14 x 1.25mm - some french pedals-

as mentioned previously the M14 will go into a 9/16" threaded hole, and this combination does tend to work loose, creak, and generally cause trouble.

cheers

[axel_knutt]

There's nothing odd about the threads. Cranks are Deore, pedals: Sakae, Union, System X EX331, Wellgo LU939, & currently MKS MT Lite. There's nowt wrong with them either, they're not damaged, dirty or corroded, and at the time I cut the Wellgo off it was still liberally plastered with the grease I had put on 6 months earlier. Except for one instance they don't unscrew themselves, precession sees to that, they just work loose. One of the Union pedals unscrewed, but that was after the bearing had stiffened up prior to disintegrating. 55Nm might sound alot, but I started at 35Nm and just gradually increased it as long as the pedals kept coming loose. Incidentally, when I had to saw the right pedal off the left one came out easily even though they both went in at the same torque. This is quite common: one loose the other tight. They're in at 50Nm again at the moment, so we'll see if they stay tight.

BTW if you get one stuck, a simple solution is often to strip the pedal down, leaving just the spindle. The spindle can then be held in a bench vice. Sometimes packing pieces are needed to hold the flats, but this is no big problem.

Plan A came to an end when the Pozidriv screwdriver broke trying to undo one of the screws holding the cage on ......