Stripped hub - feck!

I've had a good search around and I know this sounds like a novice question but I'm in a bit of quandary so please don't jump down my throat before you've heard me out... I have the immense misfortune to live in Paris where bike shops are crap, so when a scooter swept away my rear wheel at a set of lights (then vroomed off while I was lying on the floor trying to work out what had just happened) and I tried to find a replacement rim I was screwed. Thankfully Planet X shipped me their AL30 D track wheelset which didn't completely break the bank (it dented it) and did arrive within three days which was better service (by three or four times) than anyone French could even dream of offering.

Now, because I've lost my chainwhip and didn't fancy spending 50euros on one in the only place in Paris that sells tools I took it to an LBS that's done some reliable work on a bike of mine before and asked them to thread on a pair of sprockets (the hub's fixed-fixed) and lock them tight with the lockrings planet x supply.

This is not the first time I've put cogs on a fixed hub so after they'd put 'em on I softly peddled 50m up the road, 50m back and when the lockring slipped I took it back into the shop for the 'mechanic' to retighten it.

Before I know what's going on he's telling me - with a horrid little French shrug - that the hub's stripped and that it must have been faulty/it wasn't tightening properly and therefore not his fault. He also told me I should have been using Miche!

He then took to the other side, made sure the lockring was tight, gave it to me to climb aboard and the bloody thing started unscrewing on a track stand before I even set off.

Now, I tend to trust my LBS but in this case is he pulling my pisser? Did he fuck up? Was the hub fucked to start with? Or was it me and my tremendously strong legs? Also, what should I do about it?

Are you talking about the sprocket or the lockring, I'm not sure from your post.

If its the lockring then not all is lost. There are 2 common lockring sizes and its not the first time that a shop has supplied the wrong size, thinking that they're all the same. Trying to fit the wrong size lockring will give exactly the symptoms you describe.

http://www.sheldonbrown.com/gloss_l.html#lockring

Thanks for your reply Yoav. Actually I was back into the shop today because they were trying to close last night and I left my bike with them...

They've now had a proper look at what happened and their mechanic feels quite confident that the threads on the hub had been overmachined and so were too fine for the lockring to grip. In answer to your question the lockrings in question are those supplied with the wheel so I don't imagine it's an issue with a different sizing.

I got straight onto Planet X who couldn't have been more wonderful and are in the process of arranging a courier to pick the wheelset up (from Paris!) to see exactly what's happened.

It seems unlikely that there was a manufacturing problem but to their complete credit they didn't start denying the possibility - I guess anything can happen and I'm sure it isn't the first time this has.

I'm not sure if it interests many people but I'll try to remember to keep this thread updated of whatever ends up happening.

Glad Planet X are being helpful. All I can say is that when I bought a set of track wheels, the shop did supply the wrong lockring. Actually as it was double fixed, they supplied one correct and one wrong size, we led me to realise there was a difference.

Definitely interesting and reassuring (in a weird way) to know that this kind of thing can and does happen - ie. that it's not just me and my rubbish luck!

I'm assuming you got satisfaction out of whoever sold you the wheelset?

Should have been using Miche.

They gave me the right one when I pointed out the mistake. It just me me realise that even the pros don't always know best. To be fair, I didn't know either until it happened.

Thanks DHD, it's already become my stock response to anyone who says anything's gone wrong.