Anyone else had their rear rack bracket (that originally holds the tool box) crack at the bolts on them? My 2022 Trail with 2K miles had this break from normal street commuting. My warranty just ended and the dealer won’t replace. Definitely surprised this cracked from vibration. Picture added.
Hey, actually got same setup!
Suggestions & ideas from Kritou (!), oldschool, dmonkey, m in sc … me agree with thee, think it’s small, repetitive flexing concentrated at factory rack piece where it cracked.
So Varoom, that bracket you and I both bought to attach the sub tank+strap+hardware (sold via eBay, Webike Japan, etc.) is a pretty hefty chunk at 4mm thick steel with a full edge angle leg, and it's pretty inflexible in its role; side-to-side motion of the assembly gets relayed to the thin section of the factory rack bracket, which itself then plays the role of fulcrum as the whole mass jitters left-right.
Probable forcing function behind the left-right jittering: sub tank/strap/hardware C.G. doesn’t hang directly beneath the factory bracket, but instead the mass's center is about ¾” or so left, cantilevered toward the outside. Riding/rolling along, normal vertical bumps cause the left-cantilevered mass to bounce and flex inward (small amplitude, invisible oscillations). Eventually the metal fatigues and fails in the spot where it’s getting stained cyclically.
It's not Honda's fault or a defect IMHO; their little factory plasti-toolbox hangs on-center with its mounts' locations, and it probably doesn't matter how much weight's in it; it still wouldn't crack that bracket because it hangs pretty much vertical under its C.O.G. and so doesn't oscillate. In your own case, Varoom, if they knew the sub-tank kit was mounted the way it's been done, even if the bike was still under warranty, Honda may not cover it anyway. IMO, if there's a 3rd party fault it might be MINIMOTO for selling folks brackets with insufficient DFUs that introduces the opportunity for the problem.
When mounting the MINIMOTO bracket, I offset it inward as far as possible (about ¾”) and turned it around backwards (drilled holes in different spots to accommodate tank strap) so that the angled edge faced rearward and allowed it to contact (be supported by) the rear fender more closely. The fender appears to be quite strong and it’s also reinforced from the inside via a separate rigid plastic structure. This method accomplished two things: a) locates the C.G. closer vertically beneath the Honda rack bracket’s mounts, and b) prevents/dampens things from oscillating because it’s supported by the rear fender itself. I doubt lateral loads on the fender will cause damage, but I'm keeping a close eye. See pic (BTW my rack is black and so looks different, maybe a little hard to recognize features).
Now this introduces a rubbing/contact spot on the fender, so I fastened a thick piece of protective PE film there (replacing it w/Delrin piece later), and also smoothed/buffed the bracket’s edge along there so it won’t chaff-cut over time. It’s seems pretty tight and stable, but time will tell.
Wish I could claim credit for any foresight, but to be honest it’s actually hind-site from several past similar situations - others' as well as my own (what can I say, I’m getting old but can still remember my screw-ups). Maybe this time I learned…maybe I only think I did, we’ll see!
Oh, BTW all bets are off on the C.G. hanging in the right place when riding with the sub tank fueled - then it'll be depending on the fender to support the cantilevered load from oscillating too much.
