Shimano Tiagra 4800 - Centre Spline Wear

[Rooster1]

I have been very fortunate - I have a spare 172.5 mm Tiagra left arm crank so I don't have to fork out £49.99 for a new one.
They are hard to get a hold of too, only two or three UK suppliers have them in low quantities - and none are available in grey.
The one I have is however Silver a so I will have to prime and spray it for the time being. I'll replace the crankset next year.

 

[Ming the Merciless]

A loose bb wouldn’t do that, a loose crank arm would.

 

[Rooster1]

A loose bb wouldn’t do that, a loose crank arm would.

...and (I) put the crankset back on, then on a steep section weeks later I noticed some weird play on the left - thats when it must have got very chewed up!

Hey ho - my bad. I killed it.

 

[si_c]

I have been very fortunate - I have a spare 172.5 mm Tiagra left arm crank so I don't have to fork out £49.99 for a new one.
They are hard to get a hold of too, only two or three UK suppliers have them in low quantities - and none are available in grey.
The one I have is however Silver a so I will have to prime and spray it for the time being. I'll replace the crankset next year.

Good you had the right size around, the rest as you say is paint. I've got a spare 105 left arm but it's 175mm which is even less help.