Slight play in crank - replace, grease, shim etc?
 

Hi

Very quick q - basically, question of degree rather than anything else.

I hit the l/h crank on my fixie on the kerb trying to avoid a taxi, and since then have had a tiny bit of vertical play in the crank - about 3mm or so. It feels like the play you'd get from a properly tensioned chain, but it's just on the crank - if I hold the r/h crank still and rotate the l/h crank, it moves the 3mm or so up/down.

I figured at first I'd just loosened it, so removed the crank, greased the bolt and the spindle, torqued up the crank bolt and the movement went.

It's now come back - within about 20 miles of riding - so I figure I might have slightly rounded either the BB taper or the crank socket.

So - any suggestions on what the best course of action would be? I'd prefer not to replace the cranks or the BB as they're only about a year old, but if it's an accident waiting to happen I will.

Cheers!

edit - Sugino RD square spindle cranks, matching BB.

It sounds like you damaged the the crank taper. Time for a new crank arm.

+1. You could ride it until it fails, which you wouldn't like, or get a new one.

thanks for the responses.

re replacement - that's what I feared...

in the very short term, would a beer can shim keep it from worsening? just until the new cranks arrive in the mail.

Non drive side crank arms are cheap! I bet your LBS has one laying around you could use.

No need. It'll get worse with time, but nothing else will be damaged. Avoid the temptation to over-tighten the bolt.

Don't bother with a shim. Just get it replaced.

+1

> Don't bother with a shim. Just get it replaced.

I meant while I was trying to find a replacement.

> Non drive side crank arms are cheap! I bet your LBS has one laying around you could use.

Actually, no - I went to most of the shops in London and nobody had a matching crank that would fit my bottom bracket. I was trying to find a match to avoid having to shell out £100 for a new crankset. Hence the need for the shim in the meantime.

Just in case any of you are curious - beer can shim worked a treat for my 10 mile commute for the three or four days until I caved and shelled out the £100. On the plus side, the new cranks are much better.

£100 ($135)? :eek:

What kind of crank do you have on that commuter?

It's not a commuter, I just happen to also use it to commute. What's the point of getting on the underground if I have a perfectly serviceable bike? And what's the point of spending even more time in the gym when I can do some of my cardio work out on the road?

And £100 was for cranks, chainring and BB - the previous setup was a cheap Sugino crankset that, irritatingly, was only compatible with itself. Plus everything's expensive here compared with the States - the same set-up would cost you $100.

I'd be surprised if a "cheap sugino crankset" was only compatible with itself. I think the Sugino 75 (nice higher-end crank designed for single-chainring) has ISO tapers (Campy-style) but I think all other Sugino cranks use the standard JIS (shimano-and-others-style) taper and should have tons of compatibility options.

edit: The Sugino RD crank has a standard JIS taper and you should be able to use pretty much any square-taper left crankarm with it. You'll want one that was designed for a similar bottom bracket spindle width (so the left pedal ain't lots further away from the frame than the right) but this shouldn't be hard to find.

Sugino 75s are lovely, but they're approaching £200 once you add a new chainring and BB. BCD is 144 on the 75s and 130 on the RDs.

Anyway, the main problem was that the Sugino RDs come with a 103 bb. Almost all pista cranks I could find in London took a 107 or larger bb. The only pista cranks I've ever come across that take the 103 are the Sugino RDs (the 75s take a 109, FYI), and I think that's mainly because they're a repurposed road crankset that Sugino decided to rebadge as a cheap pista crankset - it comes with a 3/32 chainring, which is a bit of a giveaway.

Anyhoo, pretty much every shop I tried in London had sold out of the Messenger RD (which appears to be the only variant of the RD crankset you can get in the UK) so it was either order a matching set online with a 2-3 week wait and pray that the beercan shim doesn't fail (not cycling is not an option), or stump up for a whole new crankset. Oh, wait, that's not entirely true - there's a shop at the other side of the country that still has Sugino RDs in stock (rebranded as On-One), but they're 170mm, not 165mm, and I couldn't really justify buying the same ****ty crankset all over again if I couldn't use the current ones as spares. Plus I prefer 165mm for fixed - pedal strike is a *****. Ironically.

Given that the Sugino BB had been pissing me off for a while before I discovered the size problem, it wasn't so painful a decision.

And no, nobody was willing to sell me a single left arm that would fit. I did ask.

In NYC look for an abandoned bike.

If you don't mind me asking, which cranks did you end up getting?

Miche Pista.