Not unlikely I guess, if a gap opens up and the bolt starts flexing? Dunno
Exactly, I’ve got m8 bolt into m8 nylock now - the design should have a hex sink which a nut sits in rather than threaded aluminium. Would be stronger, better, etc.
It is nice that it doesn’t bounce around as much now.
I'd always assumed the block was steel, but I've just been out to test it with a magnet and it definitely isn't.
Agree that it's asking a lot of aluminium threads.
I think it's less the threads, more that bolts are rubbish with handling shear force, especially in fatigue. Which when you cantilever a load on it, will inevitably happen. A single stay can take a lot of this stress, it may be enough to attach the stay even higher to still allow some flex in the rack.
I've sheared one of the original carradice bolts before (granted I was definitely overloading).
Since then, have replaced both my bagman clamps with a high tensile m8 allen bolt, which doesn't slot as nicely into the countersunk part of the bottom block, but has been (anecdotally...) completely fine with quite heay loads. I do also keep a spare in my tool bag just in case...
I wonder if it would work to drill out the block and put a bigger steel bolt, nut and washers in. Or would the shear forces kill any standard bolt? I guess they are not designed to cope with that kind of force so maybe that wouldn't work.
Do the shear forces increase a lot when the bolt gets even slightly loose or are they an issue even when it is bastard tight?
I can't remember exactly how much material there is to play with, obviously you wouldn't want to drill it out so much that there's not enough left to stay rigid under the compression from the bolt.
My guess is that if you got an appropriately sized M8 shoulder bolt you would improve the situation. Hi tensile bolts are actually worse under shear, but if it's done up tight enough and stays that way then I guess you can reduce the shear loads anyway. I'm sure if we got @gbj_tester involved he'd have a valuable opinion. Although I suspect it might just be to fit some stays. At some point, the additional weight of an aluminium stay and an M5 bolt will be less than one crazy overbuilt bolt.
Is there much of a shear force on the bolt? If the load is cantilevered off the block, isn't it mostly just a tensile force & a bending moment? I've not had any problems with mine, but I rest the bag on a rear rack, so I guess it's not actually seeing much of a load.
I think that as soon as you get even a small extension of the bolt due to tensile stress, you get a lateral movement of the 2 parts of the block (bottom backward, top forward?) which introduces a shear element
Ah yes, that would make sense - was thinking the saddle rails might constrain this, but in mechanical engineering everything is rubber and all that.
I definitely had a heavy load in there and it was (thankfully) at the end of a long rough weekend tour. I've been intending on adding the stays but if there's a simple-enough bolt upgrade that would be cool.
anyone has a carradice long flap small/medium saddle bag in not exceptional condition? ratty is fine.
drop me a PM if yes.
Who on here had been dumb enough to put a bagman qr on a carbon saddle rails?
I did for swift tour of Normandy, with a very heavily-loaded Nelson longflap.
Didn't die. Probably exerted worse loads on the rails with my butt.
I’m thinking it would only be about 7kg max but it is an mcfk saddle barely weighs anything.
Quick trip back home, loaded up the aged Carradice
Turns out the straps of a Barley are just too irresistible for the foxes of SE15.
What are my options here, is this an easy DIY / local dry cleaner repair?
Have you tried contacting Carradice? IME their support is fantastic and other reports in this thread support that. Would mean posting ofc.
Yeah, though it's been 3 days and counting...
Use a couple of Chicago screws to connect the damaged strap and a new seat post strap.
IIRC they'll repair it, but may also just sell you a replacement strap and recommend you get a local cobbler to sew it on.
Otherwise get one of these straps, cut the buckle off, and sew it on/use it as an extender for the chewed one? https://www.carradice.co.uk/products/accessories/leather-straps-pair-20cm
If you want I’ll make you a new one for the cost of postage. You’ll have to get it to me ( in Reading ) but it’s a very simple repair.
If you want to just send the old strap ( cut through stitching ) I’ll copy it and post it back. Then all you have to do is see it back on ( I’ll put holes in it to simplify that )
I might make 2, as it would be unlikely I can colour match exactly. I could also make them longer.
Ah thank you! They've come back to me, they'll repair it with a new strap if I send it up. Thanks though!
Too late to this. But those straps were only £3 in Condor: https://www.condorcycles.com/products/carradice-leather-straps
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