I am setting up a bike with a rack and fenders for loaded touring. As far as I can tell you need to use the same fastener screw for both the rack legs and the fender supports. I don't like it because by all reports the 5 mm fastener has a tendency to shear, and the eyelets of my rack supports being just bent wire will likely add additional uneven stress on the fastener head.

What do you lace first with the fastener the rack leg or the fender supports?

This must be an FAQ, but a search or rack and fenders gives me too many strings to search through.

Any suggestions?

I would put the rack leg closest to the eyelet to minimize the leverage exerted by the rack leg on the fastener. What kind of rack are you using? I'd be curious to see a picture of the rack support.

Some rear racks, such as the Tubus Cargo, have mounts on them where you can attach fenders. So you would attach the rack to frame mount, and the fender to the rack.

I don't think that is true, but if it concerns you, just carry a few extra bolts

I think you may need a better rack, the wire will give way long before the bolts

With my Tubus Logo rack, the rack stays have to go outside of my SKS fender stays because the fender is completely surrrounded by the rack. And isn't this true on all rack / fender set ups?

Rack bolts shear off, that's true, but if you don't overload the rack and use stainless steel bolts, it's hard to imagine that the extra couple of mm's from the fender stay will provide so much more torque on the dropout that the bolt will shear that much more easily. I've never worried about it and have had no mishaps.

If a bolt does shear off, you might be lucky enough to have a bit protruding enough that you can get a bite with vice grips. But it will likely shear off right at the bike frame and you'll need to improvise with zip ties instead. A sheared off bolt is usually remedied only by a machine shop.

Try using a steel alloy 10 x 32 aircraft bolt, maybe with a nylon lock nut (they'll fit through a 5mm braze-on). They're much stronger than a stainless bolt and will probably never break.

I agree with rogerstg, I've never had a bolt shear, approximately 12,000 loaded miles on two bikes (total). I did not appreciate the benefit of fenders for quite awhile. Depending on your fender stays and rack configuration, the fender stays may need to go on first. My wife's and my touring bikes both require this. I carry exra bolts, but never had to use them. I believe more trouble is casused when they loosen up so I check them regularily while on tour.

If it's a real concern, a person could use a bolt long enough to protrude from the other side of the eyelet and lock it with another nut. That will ensure enough bolt for removal with the added benefit of a locking nut to keep things tight. Hmmm, I may do that for the last reason alone.

"I don't like it because ..."

Those are real issues though not many complaints are heard. With my bikes the problem has all been for the front rack. With two eyelets to the rear, I was able to separate those two contact points. What I did up front was purchase a piece of 1/8" SS sheet, and a 1/8" rod (the rod that comes with my fenders is plated so should be set aside). I cut out a notch in the postage sized sheet for the notch (just on the top not necesarry to insert it). I welded it in there (today I would probably braze it as it is tricky with welding not to overheat the parts). I then drilled a hole for the 5mm bolt. This concoction replaced the looped fender support, and allows full tightening pressure to be brought to bear with no chance of opening the looped stay. There is also good support for the bolt and the eyelet.

If you didn't have the gear to weld or braze, you might just get a little piece of sheet and drill one 5mm hole through it and an adjascent 4mm hole, tap this last hole to 5mm. You could bolt this with the rack up front, and then mount the fender eyelet to the threaded hole. That should work fine as the looped ends are certainly strong enough for rack mounting. If you don't have a tap, you could mount with a nut and bolt, and epoxy them for a permanent attachment.

Since I now make my own racks, I mounted fittings so that the fender attaches to the rack so that the rack is the only thing mounted to the eyelets. I am not working on frames and the next step is to make the frames so that racks mount without eyelets which are a weak point by themselves