Will new balls make me happy?

[nuttycyclist]

A silly question, and I think I know the answer.      I was out on a ride the other day and the pedal seized up.    It's a folding MKS PD-6.

I stripped it down, de-greased, re-lubed, and rebuilt with original parts, but it's still spinning really rough.    The balls didn't look bad (to the naked eye) but I suspect they are no longer spherical, and the cones had minor signs of pitting....   not to mention the lovely silver glitter all over the kitchen sink once I'd finished washing them.

So, is it worth sourcing a cheap set of balls (12 per cone, but I'm not sure the size) to see if I can get some more miles out of this - or just binning it all and getting some new pedals (as and when the unicycle needs its pedals back).

[LittleWheelsandBig]

If the cones are pitted, everything is on borrowed time anyway. Get new pedals.

You can easily check bearing surfaces by running a ballpoint pen over them. Anything other than butter-smooth is not worth trying to save, in most cases. I bin bearings as a rule anyway, as loose Grade 25 bearings are pretty cheap bought in bulk.

[nuttycyclist]

Cheers.   That was my thought when I'd stripped them.    But it was easier just to try putting back together and adjusting in hope than sourcing new balls

Thought I'd throw it out to the old jury for thoughts.

Any suggestions for decent but cheap folding pedals please?

[Brucey]

Most MKS pedals with two flats for the pedal spanner use 12x 5/32" balls in each bearing, whereas models using a spindle with a hexagonal base use 1/8" balls. IIRC the FD-7 model is of the former type; I'm not familiar with the PD6 model.


FD7

Pieces of metal suggest that either one of the original balls broke up or the cup/cone did.

FWIW any folding pedal like this can see truly horrible scuffing loads in the outboard bearing. This is one of the few occasions where I would recommend a small preload on a cup and cone bearing, else the loads are not shared well between balls. Any free  play in these bearings is fatal; the balls scuff and the usual result is that the cup starts to go oval and then break up. You should check the cup carefully to see that it isn't cracked; the seating for the cup is square and the cup is curved, so it is not well supported.

With FD-7 pedals (assuming they use 5/32" balls) the good news is that if the outboard bearing starts to break up, you can rebuild it using parts from an old set of Sylvans (or similar) which share the cone and outboard cup design, I think.  The cups just knock out of the pedal body; I don't think I've ever seen a set of sylvans actually wear out; they seem to last for very long time anyway.

Are you sure you don't have FD-6?




which looks very similar to FD7 in many respects?

FWIW there is no such thing as 'decent and cheap' when it comes to folding pedals of this style. Cheap ones will succumb to exactly the same kind of bearing failure as you have seen, only faster. MKS pedals have bearings that are considerably stronger than most others. A new set of FD7s is a popular choice even though they are liable to cost about thirty quid.


cheers

[nuttycyclist]

Sorry, yes they are FD-6 and not PD-6.    My mistake with a typo.

At ~£30 for new FD-7 (which I'd already researched) you can understand why I was asking whether £5 of balls would be enough (rough estimate from LBS when chatting but I'm sure I could source cheaper if I knew exact size) as a 'project' to get the already stripped parts back together ok, or whether to just bite the bullet and get new ones - which is against my overall principles of recycle and reuse.       Just to get new parts (balls+cones) to get these back running has to be significantly less than £30, and lasting long enough to not be false economy.

[Brucey]

If I'm right about the parts commonality, all you need is a set of old sylvan pedals and you can rob the necessary spare parts (including the RH bearing cup which is very likely to be damaged) from them.

I bet someone has some lurking in their shed, with broken or bent cages, just right as a donor.  FWIW the parts you need (cone, cups) are the same between left and right pedals, so pretty much anything will do.

cheers

[LittleWheelsandBig]

Where are you going to find dead Sylvan pedals? Those things are up there with the cockroaches for being bombproof.

Metals are easily and very commonly recycled. Just get new pedals that are going to last.

[Brucey]

a 'wanted' ad might elicit a response?  Also, near me there are several LBSs that do a lot of repairs. They often keep boxes of odd pedals (often one is broken and they keep the other) and if they do, the chances are that they will have something suitable; all you need to do this repair is one MKS pedal that uses 5/32" balls, so that you can remove the cone and outboard bearing cup from it. It surely won't hurt to ask.  Come to think of it, the AR2 model uses the same cone and the same bearing cups too; these have a one-piece cast body so often get broken in a prang, leaving perfectly serviceable bearings.

I don't think that there is a folding pedal of this sort that is appreciably  better made than the FD-7/FD-6 type.  Once the bearings are rebuilt there is no reason to suppose that they will last any less time than a new set; in fact they arguably ought to last longer, hopefully being full of (better) grease and correctly adjusted.

[edit; the current model MKS AR2 has a hexagonal base to the pedal spindle so I don't think it has compatible bearing parts. However the AR3 and the older AR2 model (with two flats on the pedal spindle) I think  is compatible.



 Here

https://www.pedalpedlar.co.uk/products/mks-ar2-vintage-single-right-quill-pedal

they list just one such pedal which you can use for spare parts

cheers