"but would you trust your life to it"
Not at the moment, but am interested in trying to determine how (un)safe it could be made, even if I don't ride it
Nick its how wheels are held onto trains, just interference fit, and lots of bits inside your car engine, axle, etc etc..
When I bought my last motorbike the fork stanchions were so bent the wheel was on the frame, i bought it as right off to build into a road/track bike, the stanchions were straightend and I checked nothing else bar going over the bike as best as possible, it was entirely at my own discretion as your repair is for you.
Old nail built up from scrap stuff.
and after the first track day.
The frame your forks were on is prebably a week point to be honest and I would keep a close eye on it.
It's an unknown as to whether the frame/crown will have been weakened – and you may not find out until you experience similar forces again – in which case you are crashing badly anyway.
Who replaces the frame after bending forks?
If the steerer goes in easily I don't think I'd ride it as the crown will have stretched.
cynic-al, but you could ream the crown hole and go up a size on the new steerer if he was to go down the route of getting one made. Were only talking hundredths of a mm here.
The thing is, if in doubt bin em out. Give you postage for them 😉
"Just throw it away "
Its not my bike to throw away, its my brothers, I don't think he wants to have to drop £1200ish on a new frame when he 'can' still ride this one. Plus you can't get a QUAD-link frame frame-only
"but you could ream the crown hole and go up a size on the new steerer"
As new, the part of the steerer tube that press fits into the crown is the same outer diameter as the part where the headset crown bearing race sits, (presumably 30mm as per that RST one, so that all crown races fit all forks), then tapering back to 1 1/8" for the rest of the fork? (the bend is above this transition point, probably about 40-50mm higher
My mate fitted an alloy steerer to some single crwon Marzocchi shivers. The original was steel and way too short. He did the heating the crown up trick and then freezing the alloy steerer tube. Thus making a press fit. He even used a different steerer tube, think it was a Rockshox one he bought cheap. Bike has been running no problems, hes a fairly burly lad too. I doubt the crown strength will have been compromised. Just dont go too much with the heat on the crown, boiling water will be enough. Heating it a lot with a blow torch too much would compromise the crown strength though.
The most annoying thing about the whole thing, is that had the bike not had a handbuilt front wheel and some poorly tensioned with some miles under its belt factory built front wheel, the front wheel would probably have pringled and left the frame and fork completely unaffected. Thanks merlin!
yes but I thought he said the headtube had gone oval after the crash? Why not just hit the headtube and make it round again. Stick a bit of round pipe in it for a guide and hit it until the headtube is round again, a bit like a blacksmith!
I will sell you a new CSU at trade if it helps you NOT press in a new steerer.
Please don't mess about with stuff like this. An impact that has damaged your headtube and split a set of forks could easily happen again and you will not get lucky twice.
If you want some help then please drop me or Colin and email to mdownie@thebikechain.co.uk with the exact model and i will sort you a price.
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Steerer, Crown + Stantions. Oh I see, CSU, stantions being uppers
Erm maybe yes, I don't need to get the fork off of my brother, just that if rideable would be better than the MX pro on my HT
Its just that the costs could be a bit preventative, though I'd be prepared to swap at home with the help of the rockshox manual
A complete 'CSU/SCU' assembly would put my mind at ease
I'd be more worried about the frame and the headtube than the forks. Forks can definitely be fixed and the best way is with complete new upper section. Frame on the other hand sounds like it needs the attention of someone with experience of aluminium fabrication at the least (e.g. fix by welding and re-machining headset cups), and may be destined for the bin.