brazed-on eyelets: strong enough for rack mount?
i read that brazed-on eyelets are not strong enough for rack mounts and should only be used for fender mounts, and that if you want rack mounts use dropouts that have eyelets.
i've also heard that brazing a rack to, say, and touring frame, is "the sturdiest" way to attach racks to a frame. i know this braze could have more contact area than just a brazed-on eyelet would depending on how you do it...
but i've already brazed on dual eyelets for both rear dropouts and i'm wondering if i can get by using these for a rear rack. this is a loaded touring frame.
Older I get, Better I was
A correctly sized and properly brazed rack eye should never fail and in the real world very few do.
Most rack problems IMO are caused by rack stays that are improperly aligned which put lateral stress on the rack eye.
Brazing the racks on IMO don't make them stronger nor does it make sense in the long term. What if you damaged the rack ( easily done in a crash or while shipping) or you found a pannier system you want to use that wasn't compatible with your rack?
I use through bolts with metal lock nuts for trouble free rack attachment
I've used them and gotten by without problems; and that seems to be the case with most people. However, breakage does occasionally occur. It isn't the end of the world if it does, though. Repairs are not difficult, and failure is not very likely in the first place.
Originally Posted by coyotecrust
There are many bikes with dual eyelets, front and rear. Both eyelets were not intended for fenders. The manufacturers' intent was to provide for rack mounting as well as fender mounting. They usually work just fine, even with heavy loads.
the difference that i'm talking about is between dropouts that are forged/cast with eyelets and dropouts that come with one or no eyelets and have eyelets fitted and silver brazed to them by the builder.
Originally Posted by Niles H.
i would think that production bikes would use the former, while a small builder who used traditional road dropouts may choose to braze on additional eyelets.
yeah, that was my thinking as well, i just wanted to make sure. good point about the lateral stress. thanks.
Originally Posted by velonomad
It's not as though those are the universe of options though, both of those options would be on my lower end for any hand made frame. The big issue would be whether you are making your own rack. If you have the option of moving up to 6mm bolt that would be highly recommended. There are also very solid areas other than the drops to mount larger fittings. Some of the expedition bikes use the tube drop junction where the socketed connection is essentially solid material.
If you have to stick with the standard parts then getting a billet drop would greatly improve strength over cast parts of essentially unknown quality. The brazed on barrels when placed in a partial circumference saddle have excellent strength (rear mount), probably more positive than the seat stay junction, so I wouldn't worry about them. keep in mind that the joint is mostly compression, and the barrel material is chromo, or possibly a better grade of bolt steel.
As far as brazing the rack directly to the frame, the main issue there is that it is normally done with fairly stout material, which means possible problems with 9mm pannier mounting hardware. But it also means that the rack is pretty stout. Any stout rack would be very strong even if it wasn't brazed/welded to the frame, and the frame mounting creates better options if the rack gets crashed or whatever and need replacement.
If you braze directly to the frame with lessor diameter tubing I think one runs the risk of a stress riser and having a joint fail. I'm sure there is a workaround, there is usually one for just about anything, but that would be my concern.
If my knees allowed me to do a world tour, I would consider 1/2" tubing in my rack with beefy barstock to barstock mounts and 6mm bolts, however I would also have holes for 5mm racks so that if the worst came to the worst I could slap on a cheapo rack over existing holes.
Last edited by NoReg; 12-14-07 at 04:02 PM.
Even the brazed-on eyelets are usually fine. I don't know who claimed that they were not, but it is entirely possible that whoever it was was not infallible.
Originally Posted by coyotecrust
Have used brazed-on eyelets on 4 of our custom tandems and never had a falure in 200,000+miles.