DMR V8 Pedal Problem

[nickpaton]

Bought a pair of DMR V8 Pedals earlier in the year, as I prefer flat pedals to go with my Shimano MT91 shoes rather than SPD's.

A couple of weeks ago the right hand one started making horrible grinding noises, and I found the Pedal External Shield, which I guess prevents dirt and moisture from ingressing the inside bearings, was loose on the shaft as in the photo (the left one isn't much better).

They've only been used on roads (and OK in rain too!) but never submerged or abused.

The pedals came with a syringe of grease to force grease into the pedal innards via a removable allen key grub screw, presumably NOT for when they are new before use. However I did try anyway before using them, and was unable to force any in so assumed there was already sufficient in (ie the grease simply wouldn't go inside the pedal). BTW I hadn't pushed off the External Shield when I tried.
I also noted this RH pedal particularly felt slightly rough when new but assumed this was just a "new pedal feel". In reality it improved a little with use.

I really like these pedals and they work very well indeed with the shoes, and it seems a lot of long distance touring cyclists use them too so I assume they should be OK. However the External Shield doesn't seems to have any method of fixing to the pedal body other than grease "sticktion".

I have received a full refund from Wiggle but with no explanation of what's actually wrong with them.

Before getting a replacement set (with hopefully better luck), how has anyone else found these pedals? Also does anyone know how these external shields are held in place, as there's no means of securing them to the pedal body.
Or would I be better getting the more expensive V12's but which seem better made.

Thanks in advance.

[Brucey]

V8s are made by Wellgo for DMR. The shield is simply a push fit onto the spindle; the 'O' ring on the inside is meant to hold the shield onto the spindle (but not tightly); the shield is not meant to fit to the pedal body at all.

If you couldn't get any grease in through the hole you probably were not pushing hard enough. I'd suggest that you use a proper grease gun for this anyway.

The more expensive V12 model seems appealing but in reality it is not an improvement. The V8 model has fairly simple ball bearings which (when maintained and adjusted correctly) do wear in to be pretty smooth. You will need to service and adjust the bearings though. It isn't difficult; this is just as well because they often need doing when they are brand new.

The V12 model claims to have 'sealed bearings' but in reality most of the load is taken by a plain bushing. This is nice and simple but has a much higher (think x10 to x100 more) friction to it when under load.

Plain bearings and the friction that arises are pretty much the whole reason for the invention of the ball-bearing; using them in 21st century pedals is arguably like stepping back 150 years.... pretty arcane really...

So imperfect as they are, I'd suggest that you stick with the V8s or just buy some (near identical) Wellgo branded ones. Don't worry about the shield fit; they are meant to be like that, you can't exactly lose them and anyway you can buy them as a spare part if you need to.

If buying alternative pedals, beware those with 'sealed bearings' as many of them (especially if the pedal is low profile...) have bushings not bearings in them, which is pretty hopeless really....

If you want to do a quick and effective service on the V8's inboard bearing, draw back the shield, purge the bearing with WD40 or similar, then relube using aerosol chain grease meant for motorcycle chains. You can add the spray grease directly behind the shield and/or through the grease port. Chain grease is usually very tenacious and contains corrosion inhibitors etc; I've found that several different types work very well in (imperfectly sealed) pedal bearings.

cheers

[nickpaton]

Thanks for your comprehensive answer Brucey.

I'd heard about the link with Wellgo but thought they'd ripped the design from DMR. Also I believe people here have reported that Wellgo's aren't that great, so am thinking about Shimano MX80 Saint flat pedals instead.

I'm temporarily using M324's on the flat side and they're OK except for my shoes sliding around all over the pedal, compared with the V8's where the protrusions keep the shoe in place (and double up as cheese graters for the camping evening meal )

[nickpaton]

Useful review on the Shimano MX80 Saints here; comments section has more information on DMR sleeve bearings versus the ball and needle bearings on the MX80's.

Comments?

[Brucey]

cheap pedals are often (rightly) maligned for having poor sealing and cheaply made, badly adjusted bearings.

Years ago I bought some (fairly horrid I thought) VP pedals (the kind that take clips and straps) for my training bike. The bearings felt terrible and were not well adjusted from new. I later discovered that the sealing wasn't great either; much brown-ness in evidence. Even when the weather didn't get in, I had to adjust them once every 1000 miles or so at first, because they seemed to be wearing quite fast.

Being curious (not to mention a bit tight) I made my own crude seals/shields for the inboard bearings, and added a lube port to the pedals too. I recall noticing that there were not enough balls in some of the races; IIRC I just got some odd ones which were nominally the right size and added them to those that were there already. These days I know better than to do that.... and I guess I did back then too; with my 'that'll do' head on I just didn't think it was worth fussing about these particular pedals TBH.

After that I just used the pedals in all weathers. I guess they got adjusted once every two years or so and lubed once or twice a year, usually with aerosol chain grease. I know that water could get into the bearings because the seals were far from perfect; however the chain grease evidently saved the day; there were few signs of further corrosion.

Weirdly the pedals just got smoother and smoother the more I used them, and needed adjusting less and less often. In the end they were retired after about 15-20 year's use (what, about 30000 miles on that bike maybe...?), mainly because the outsides looked so corroded. By then, blindfolded, I would have mistaken them for campag or something, the bearings were that smooth...

So.... some cheap pedals wind up being pretty good pedals, but only if they are looked after properly. I have little doubt that without a little TLC they would have been fit for the bin inside 18 months otherwise.

I think that VP ball bearings and Wellgo ball bearings are about on a par with one another; neither are especially good when they are new but can (with a following wind and a little TLC) work pretty well in practice.

cheers

[Brucey]

Useful review on the Shimano MX80 Saints here; comments section has more information on DMR sleeve bearings versus the ball and needle bearings on the MX80's.

Comments?

That review is (frankly) a crock of **** and so are the comments. The latter imply that the V8 and V12 have a common bearing design; they don't.

Here is a V8 axle (for loose ball bearing design)



Here is a V12 axle (with ground diameters for inboard bushing, outboard weedy cartridge bearing design)



The review mentions 'needle bearings in the PD-MX80'. More twaddle; this pedal has axles etc as per PD-M647 which are almost identical bearings to those found in PD-M540 SPDs; these differ only in detail (the retaining sleeve and finish) from those found in PD-M520s.

You can see the tiny tiny tiny ball bearings in the techdoc here;

https://www.paul-lange.de/support/shimano/explosionszeichnungen_archiv/PD/PD-MX80-3390.pdf

these bearings also need to be adjusted and serviced (see the 'SPD compendium' thread for details) but are fairly well sealed; it takes a real drenching to get water in the bearings with this design.

Ever wondered why you shouldn't believe every (unsubstantiated) thing you read on the internet?

QED I think....

cheers

[nickpaton]

Thanks very much once again Brucie. I'm familiar with the same SJS pages and then allowed myself to be influenced by one review - doh!

What always attracted me to DMR's was the ease of servicing, and here's what seems to be a sensible set of how to instructions, confirming too the use of twin ball bearing sets etc.

I think I'll go for another set of V8's but make sure I get grease into the bearings with a grease gun before fitting. On the other hand the Shimano ones have proven innards but do need specialist tools to repair!

[Brucey]

that overhaul page is OK but there is always more than one way to skin a cat.

I like to clamp the pedal spindle in a bench vice when rebuilding the pedals. This makes it easy to get the bearing adjustment just right.

Some other points;

1) you can use a screwdriver with a slightly magnetised tip to pick ball bearings up. Unlike a proper magnet this does not magnetise the balls.

2) Both RH and LH V8 spindles have RH threads for the locknut and cone.

3) Be careful with the torque setting of the locknut. If you overdo it you can strip the tab washer or perhaps the locknut. Better the locknut than the cone or the axle though, eh...

In general terms I don't see much point in a full strip down on pedals unless they have become dirty/rusty inside or they are clearly wearing rapidly. Otherwise using the lube port is going to work quite well. Even if some cleaning is required it'll likely be the inboard bearing and purging/relubing a couple of times in a month will usually do just as good a job.

BTW you only need one special tool to service the shimano PD-MX80 (et al) bearings and that tool (unlike the one for PD-M324 etc) is cheap, so don't let that put you off pedals with those bearings.

cheers

[nickpaton]

Thanks again for the hints on servicing the pedals. I've gotta say as I liked the last DMR's I'm going to get a new pair and make sure I push through more grease before using them.

I'd suggest that you use a proper grease gun for this anyway.

What grease gun would you recommend, and does it have a small enough nozzle for the pedal grease hole?

[Brucey]

I use a Wanner (Wanner-Abnox) 'MiniWanner' grease gun which I have fitted with a pointy nozzle. This allows grease to go into holes 2mm (or a touch less) in dia. I have no hesitation in recommending such to others; they are easily the best grease guns you can buy and have been for many decades. The snag is that whilst you can still buy them (and all the spare parts)...

a) I had to make my own nozzle (I'm fussy) and

b) a New MiniWanner is about £70.

You can buy bike-specific grease guns (with the right kind of nozzle) which accept grease tubes; these work OK but it soon works out a bit pricey because the grease is expensive that way.... but if all you have is your pedals to do, that might be the best choice.

cheers

[nickpaton]

If I was servicing a lot of bikes the MiniWanner would make perfect sense, but as I've only got the one I'll probably go for a bike specific one.

On the other hand there's always the motorcycle aerosol chain grease you mentioned earlier.

[gregoryoftours]

For a cheap and good grease gun that you can refill with grease of your choice you can't go wrong with these -
http://www.evanscycles.com/products/dua ... lsrc=aw.ds

[nickpaton]

Thanks for the suggestion Gregory.
I bought another pair of V8 pedals but this time pushed in a whole lot of grease using an Exus Eco gun who's nozzle easily fits into the tiny grease hole http://www.chainreactioncycles.com/mobile/exus-grease-gun-eco/rp-prod35285.
Pedals now a lot smoother, but the film of grease didn't keep the external shield in place as I managed to knock it with a shoe quite easily. I'll be using a couple of small cable ties to keep them gently pressed against the pedal side walls.