Having just replaced the rear axle on my lad's Gillard for the third time in about a month I'm wondering how long axles are expected to last.
We're about a year into X30 having moved straight from cadet and up until recently haven't had any issues with axles (other than bending due to on-track shenanigans). Having said that, it's only in the last month or so that we've managed to find a setup which puts us firmly back on the pace having been miles off over the winter. All three axles failed after running at PFI (which I know to be hard on axles. See http://www.karting.co.uk/Notice/Message.asp?FID=2&MsgID=0000461464).
We've had two Gillard "Extra Soft" axles fail by circumferential cracking at a hole on the brake keyway - one after only about three hours running. Yesterday a Medium axle failed similarly at a hole on the sprocket keyway. Though to be fair this axle had done a lot of hours around PFI.
Looking closely it seems like the studs on the keys are very slightly loose in the axle holes, leading to a hammer effect when hitting the brakes/throttle. I'm guessing this work-hardens the edge of the hole which then cracks due to fatigue. This isn't helped by the keys riding up a little on one side.
I've spoken to a couple of people in the paddock and they're of the opinion that this number of failures in a short timeframe is rather unusual. I've asked my lad if he's riding kerbs more frequently but he seems to think not. So does anyone have an idea of some other chassis issue which may cause excess loading on the axle? I'm expecting the answer to be "no - it's just PFI" but thought it was worth asking!
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