DMR V8 pedals: replacement cones

dmr-v8

The DMR V8 flat pedal, introduced some time before the Millenium, is apparently still a best-seller at MTB specialists Chain Reaction Cycles, along with the V12 and V12 Magnesium. I've used the V8 since 2008 and the lighter V12 Magnesium since 2009, but both on road bikes, not MTB. Next time I'm feeling extravagant I'll buy titanium axles for the V12s to make them even lighter. My V8s are supposed to be fully maintainable but actually they're not. The cone nut on the outer end of the axle is the one part you might need, and DMR don't supply them as replacements. I managed to get some though, from DMR.

Like saddles and handlebars, pedals are a contact point and tend to be a personal thing. I don't like being clipped in, and DMR pedals are a grippy alternative with projecting pins screwed into the aluminium pedal body. I removed some of the pins as they catch your shins; my right shin is permanently scarred. But I do like the simple design of the pedals and how they are easy to keep clean. Viewed end-on they have a parallelogram profile with the centre of pressure a little forward of the axle, which suits my style of pedalling.

Unlike some other designs of flat pedal the DMRs have two bearings spaced well apart and the V8 has a grease port in the body, near to the inboard bearing. They are supplied with a small grease syringe and an allen key for the pins. Supposedly, the pedals come pre-greased – so the grease port seems a strange feature. When grease is squirted in the port it goes through the inboard bearing only. I suppose the idea is that you can regrease the outboard bearing by removing the dust cap at the end of the axle.

dmr-v8-pitted-cone

Pitted outer cone from a DMR V8 bicycle pedal

Anyway, the bearings in my pedals had become rough, or 'gritty'. There was also a slight amount of play between the pedal bodies and the axles. A good way to check the bearings is to remove a pedal, hold the body in one hand and turn the axle between a finger and thumb of the other. Any 'grittyness' can easily be felt through the thumb. When I took the pedals apart it was evident that the outer cones were pitted – a roughened surface on the 'race' where the ball bearings run, squeezed up between cone and cup. This outer cone is simply a nut with a concave head, and the inner cone is part of the axle. The axles were fine, as were the cups inside the pedal bodies. So I just needed some new outer cones.

My local bike shop is an official DMR stockist and they weren't able to obtain any. When I phoned DMR they said these cones never need to be replaced. Mine do, I said. You must have let the pedals come loose and run them with no grease, he said. I didn't, but to be fair, they sent me a pair of new cones free of charge. I put in new ball bearings as well. Photos:

dmr-v8-ball-bearingsdmr-v8-cone-on-axle

1. Balls laid in grease (add more before axle replaced) 2. Fitting new cone

dmr-v8-dust-capdmr-v8-tools

3. Dust cap replaced 4. Tools: grease gun, tweezers, socket spanner

The only tricky part is setting the tightness of the cone against the ball bearings. There isn't enough space for a socket spanner inside the hole so you use a flat bladed screwdriver or tweezers to wind it down so it just rests lightly on the balls. Then a washer, followed by the lock nut. A socket spanner does fit over the lock nut. It's best to clamp the inboard end of the axle in a vice so you can tighten this nut hard against the cone again.

Now hold the pedal in one hand and turn the axle with the finger and thumb of the other, to feel if it's 'gritty'. A little trial and error may be required: there should be no play between the axle and the pedal body but it should spin smoothly with no roughness. Unscrew the lock nut and adjust the cone as required, then put on the dust cap. My V8s are now spinning sweetly.

This is the first time I've taken bicycle pedals to pieces. Like Hilary, I decided to give it a try. I assume the loose bearing types are pretty much the same principle and can easily be dismantled to replace ball bearings and grease. If the cones are damaged and replacements aren't available then I suppose it's new pedals, or refit the old cones and take a risk. What ultimately fails to destruction is probably the balls. Does a pedal still turn with broken ball bearings? I don't know.

Magnesium V12s, incidentally, have a plain bearing (with no rolling elements) inboard and a sealed, replaceable bearing on the outboard end.

13 comments on “DMR V8 pedals: replacement cones”

  1. Mick F wrote:

    Well done Patrick, and nice report on pedal maintenance. I think cup-and-cone pedals are always difficult to strip and adjust, and those balls are tiny! Like you, I always had to use a small screwdriver to turn the inner nut. Trial and Error is the only way with adjustable bearings, and sometimes it can take ages until all is sweet.

    I've done cup-and-cone pedals a few times in the past, but these days I'm surprised that pedals like that are still made.

    Pedals get a great deal of hammer. They need to be lightweight to keep the rotating weight low and they need to be robust. Two facts at odds with each other.

    Since going over to clipless, the pedals – mine at least – have sealed cassette bearings. Mine have three in there on a thick shaft with chunky bearings. I've stripped one pedal down to see inside to satisfy my curiosity, but other than that, I don't ever expect to do anything to them. I would think that the clips and springs would pack up before the bearings needed to be changed.

    Regards,
    Mick.

  2. Chris wrote:

    I removed the dust cover from left one of my Shimano M324 pedals, Patrick. That annoying creaking noise has gone after I packed the space with lithium grease. It may only be a temporary fix – it does seem that I have to get special tools for a proper repair. Oh, well.

  3. Patrick wrote:

    What special tools Chris? As far as I can see (looking at pics of what I think is your pedal) you should be able to remove the outer cage – the U-shaped part round the outside – with an allen key, then access the locknut with a socket spanner.

  4. Chris wrote:

    I know what you mean. I did exactly that with another pair of pedals. It was just that I'd read the following link and others like it:

    http://yacf.co.uk/forum/index.php?topic=13165.0

    Something to do when I give the bike an overhaul soon.

  5. Patrick wrote:

    Well, it seems to be the same principle: a cone nut and lock nut on the outboard end of the axle. According to the last comment (in the link), a normal screwdriver and/or tweezers will do it, plus the right size of socket for the lock nut.

  6. Hilary wrote:

    I've a pair of Shimano M520s that are no longer on my bike and came with the bearings very tight on one pedal. There is apparently a special tool for taking these apart which is quite cheap. Perhaps that should be my next project – as they're not actually on my bike I won't get stressed about wrecking them. Then again perhaps I'd be better employed weeding the garden......

    Great photo sequence there Patrick.

  7. Patrick wrote:

    Yes, it seems you need a tool called PD40. See Ray Hosler's Shimano M520 pedal overhaul video. He calls the cone a race nut and axle a spindle. The garden will still need weeding though. A job for a rainy day. :)

  8. Mary wrote:

    Excellent stuff Patrick. My hubby uses these pedals, I was thinking as I read your blog that the pedals must hurt if you contact them with your shins, and then you said your all scarred from doing just that!

    With you and Hilary getting your hands dirty this week, its getting me all fidgety to give it a go myself... (Just need a small problem first! :) )

  9. Patrick wrote:

    Well Mary, I'm no bike mechanic but I built my wheels in November 09. Still going strong, never been adjusted since. With the mystique surrounding wheel building, once you've made some you realise that nothing is difficult on a bicycle. It's purely a question of being methodical and having a spare bike while you mess with the other one.

  10. Garry wrote:

    I've used those pedals in the past. In winter I favour those kinds of pedal with hill-walking boots. Much warmer.
    In summer I use SPDs.

  11. king wrote:

    where can i get these cones at ? i am in need of them in bulk

  12. sbarner wrote:

    Bicycle cones don't need dirt or lack of grease in order to pit. It can result from the material used and the amount of bearing surface, which is dictated by design. French components from the 1970s were famous for almost universally developing pitting after fairly limited use, in spite of grease and lack of contaminants. One would be hard-pressed to dissemble a Normandy hub or Atom pedal that had been ridden for any significant amount of time and find unpitted bearings. Certainly, dirt or water accelerate the process, and this is why your pedals don't have provision for injecting grease into the outboard bearing. The grease port is intended to flush out water and grit which may find its way into the inboard bearing, past the spindle seal. In order to be effective, this needs to be done immediately after a ride through water, as otherwise any water inside the bearing will cause rust that will start the pitting process.

    The advantage of cartridge bearings is not so much that they are better sealed, though this is often the case. If the bearing lacks an additional labyrinth seal, water can get past the rubber seal quite easily. The real advantage is that, when the manufacturer has used standard-sized bearings, replacing the entire unit can be done quite cheaply and quickly. Usually, cup & cone designs require changing the axle and often the cups are not replaceable, making a damaged pedal potentially unserviceable.

  13. Renuka wrote:

    Lubrication is the important factor in pedaling so using lubrication in correct position will retain machineries life.

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