Bike polo mechanics & fixing

^ you're right. It doesn't need to be straight. I ran my badly cut p2s that we're about 4mm off without issues. It just looks bad if you ever sell them on or someone else works on yer bike!!!

Use two old stems as steerer tube cutting guide.

Great advice, thank you Rupert.

I said that ages ago.

Also ACI spokes are 2/1.7/2, probably still fine though.

Super advice thanks rob

S'alright baby.

Did this at the weekend, worked great. Thanks Rupert.

(using two stems as a guideline to cut steerer tube with hacksaw)

Pretty sure I mentioned it first.

Looks like I only said one stem, I'll just take half a thanks.

Are all 4-bolt chainrings 104mm bcd?

Apart from the 64mm ones, I mean.

Like - there's no 4-bolt 110mm, or 130mm bcd. ?

Generally speaking it's 104/64 although the below have been used on Shimano XTR M960, M950, M952 and some Sugino cranks

BCDs:

146
112
104
102
68
64
48

OK thanks for that

I noticed today that there's about 3mm of horizontal free movement between my cranks and BB (hollowtech midleburns onto shimano BB).
I assumed it was the adjuster ring that had come loose and needed tightening back up to the BB, but there are no threads on the axle section that becomes visible...
Does it need more spacers or have I messed up somewhere?

Please excuse the quality of the following images: http://m.imgur.com/Zhqjam0,XHNPVeV,zRD56OW,Qu8OPFb

There should be threads on that axle, which the adjusting ring spins on. There are only about 4-5 though.

The BB cups might need spacing out more. I had to space out my 68mm shell with 3 spacers, which takes it up to about 75mm.

Hope that helps!

73 mm is the ISO oversize, 68, normal, so it'll be the difference.

On a 68mm shell, with an MTB BB you'll have 3 spacers, normally one on the left and two on the right. All would be 2.5mm.

With a 73mm shell, you still have one spacer on the driveside, unless you're running an e-type (bb-plate-mounted) front mech or chain device, which noone does for polo.

I think you have not done up that ring thingy beside the crank arm. It has a small allen bolt, loosen that and you should be able to twist the ring towards the BB which should remove the gap.

Wasn't that sam's first comment about adjuster bolt Ben? :)

He can't see the threads on the axle because they are on the arms.

And looking at his photo, I suspect that the ring is done up all towards the arm side hence the space between the arm and bb and not the lack of spacers for the BB.

Jaja, I got all that, I initially screwed the adjuster right up to the BB, but it came a little loose. There was no allen bolt included in the sale (Ben), so I found a cross-headed bolt with the same (or very similar) threading.
I've managed to block the space at the moment by unscrewing the adjuster ring entirely from the threads and tightening it past the limit (near the BB). I think it still needs spacers fitting properly though, because this solution is obviously not ideal.
Ben, you know if these cranks were originally on the bike when Adam used it? If so, I'd have thought that the spacers that he installed were correct and shouldn't need adding to?

http://m.imgur.com/u6Q6r9I,qFVS7y4

Yep, the same cranks and BB Adam used to run on the bike. You'll be playing tonight right? Will have a look.

I certainly will be, thanks!

So what's the latest and greatest in (external) cranks for bike polo?

I could just get another Uno
Chainring, but the compatibility is an issue when things go wrong

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Holy shit, have you contacted them about that?