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Almost got into some bother cycling to my train this afternoon. Noticed I'd lost a rack bolt from the chainstay, replaced it to discover that the threads had stripped on both sides!
Now I've had full panniers bot nothing excessive. When I fitted the rack I did think that those two tiny bolts were pretty weedy.
What beefier alternatives are there?
They're likely M5, I'd run an M6 tap through and use bigger bolts.
Probably need to drill out the rack holes too, there should be enough metal to do this.
Yeah I could do new inserts and drill the rack holes out.
Btw I meant seatstay not chainstay.
I'm considering constructing something chunky that will clamp onto the stay and then provide somewhere really solid to bolt the rack. Also might help put the mounts closer to the rack which would aid stability. Anyone got a CNC machine handy?
the threads will only strip if the bolts weren't threadlocked in and undo themselves a bit/lot, surely?
M5 is fine, you didn't tighten them enough.
I did tighten them enough. I did not threadlock them though.
Part of the problem is that it's a hybrid with a fairly compact style frame, so there's a looong gap between the rack and the seatstay, which really lets it flex.
I've never threadlocked a rack mount bolt ever. Never had one loosen either.
There's ****all stress on the upper ones too, so you can't use any nonsense "flex" excuse!
run a 5mm drill bit through it and tap it out to M6.
...unless they are rivnuts.
There's a lot of flex on these, trust me.
The rack can twist, because of the length of the supporting arms.
You didn't tighten the bolts enough.
End. Of.
Can you use a longer bolt with a nut on the other side?
If you're not precious about the frame you could drill straight through the stay and do that.
I've also found in the past that the same size bolt with a finer thread will hold tight in the old threads.
Just a couple of ideas from a serial bodger! 🙂
You didn't tighten the bolts enough.End. Of
Yes I did, stop being such a bell end. You've not seen or ridden the bike, you don't know the situation like I do. You're trying to tell me you're the big cheese of bike fixing when you thought you could put disc mounts on a frame with glue and sticky tape? All my bikes are in perfect working order despite many miles, I know what I am doing with bike maintenance and I most definitely know how to do up a friggin bolt. Especially ones that are critical and I think look a little weedy when I first see them.
PP - I did think of that yes, makes me a little nervous though, there's not a lot of metal on a seatstay. I just don't think an M5 is big enough to handle the twisting loads. I might try and come up with something sturdier.. I'm now thinking two plates clamped through the frame, the top one with some sturdy wings for attaching the rack bits - but that wouldnm't be any stiffer... hmm..
Shit rack if its flexing like that - pressed steel brackets perchance ?
They are not weedy bolts and are just fine for the purpose.
I have had em vibrate loose over a period of thousands of miles and equally on other bikes ive had them stay solid for thousands of miles
Usually hear em when they come loose though.
sorry, it the top bolts by the seat clamp?
you could try these http://www.jejamescycles.co.uk/ambrosio-seat-clamp-pannier-attachment-id58949.html
if its the lower ones could you use p brackets?
tap it to M6 or just stick a bolt through it.
I always put a spring washer & flat washer on racks as no matter what it is, the rack and frame WILL be moving about against each other so its really worth putting something better in there.
Also alloy bolts, unless you know they are very good ones, don't bother, chuck em and put some quality stainless ones in there if you value your frame.
LOL...gotcha!
I'm still right tho. Try grease.
Shit rack if its flexing like that - pressed steel brackets perchance ?
The first rack I had was the pressed steel kind, now I've got one with the long moveable arms. It's much sturdier but still flexes. It's the compact shape of the frame, the rear triangle is very small.
Stick a decent M5 bolt all the way through with a nylock nut on the end. Standard practice for decent loads (like a kid on a Rhode Gear Taxi or a Burley tag-along). If clearance is tight remove wheel and point the bold out. Trim bolt for neatness. Always add a nut then cut then unscrew nut to chase the threads.
I'd not be bothering with an M6 tap.
EDIT just noticed that it's a seatstay - as others have said, not a load bearing site. I normally only use grease and never had one work loose.