Originally Posted by
hhk25
Investigating further, the underlying problem is that the tubing on my Marinoni fork is large diameter. Compared to my 80s era 520, it's a good 5-7mm larger. Because of that, I can't get the Tubus rack to mount on top of the QR skewer like in Rick's photo. The only reason I can think of for the larger tubing is to have more welding surface for the disc brake caliper mounts.
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Newer forks with disc brakes have to take a lot more stress than older rim brake forks like on your 520. On the 520, when braking with a rim brake, the stress on the fork is mostly up near the fork crown. Disc brake on the newer bike puts a lot more stress on the left fork blade.
Originally Posted by
hhk25
My worry with using spacers is that you're applying load to a long lever (the screw), stressing the eyelets and screw itself. I think the stand-offs are better because the flange sits on the surface of the fork and spreads the load over that area and not just on the threads of the eyelet.
While I agree that you are best off without spacers or standoffs, since the front rack usually takes a much smaller load than the rear, I would expect that some spacers or a short standoff could be used. And on a Tara there is no platform, so you are talking about the weight of two panniers and nothing else. (If there was a platform, someone would likely add a 12 pack to the platform on occasion too.) The rear rack where you might have more than twice the weight is where spacers could be much worse when you are using the same diameter of bolt as the front rack