Hmm, I thought I remembered using grade 12.9 bolts for that reason, but they're actually A2-70 stainless :/cycle tramp wrote: ↑31 Jan 2023, 4:07pm Good Lord! That's a might spacer- are you using carbon steel bolts or stainless? Any more photos of your bike, please
Nevertheless I actually think they're pretty secure, there's a decent flat area on the fork mount, the bolt passes through the fork which has a threaded insert the whole way through. I have them dogged up pretty tight with thread lock applied and a nut on the inside.
The spacers are pretty stable too, they are the heavy steel 8mm hex nuts you get on some really cheap v brake pads that have quite a lot of surface area on each end to contact and provide stability and friction. Consequently I don't think that the bolts see as much shear force as one might think. I have changed the bolts periodically and they've never been even slightly bent.
I can't really bend the u-bar of the rack due to the design of the dropout mounts and clearance. But I am satisfied with the strength and support as I have it fitted.
Here are some photos of the bike on tour: