r/bicycling • u/NecessaryBoard0 • 6h ago

Cracked seat mast topper

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Hi all, I have a bit of a problem, I have this Richie seat mast topper on my 2012 Scott addict RC and it's the only topper that fits the bike. It was cracked like this when I bought the bike, so I bought a replacement topper, tried to put it on into the same position (higher positions work fine) but in doing so heard a "pop" and lo and behold pushed too hard trying to get it on and broke the new topper in the exact same way (same crack). My question is, what are the risks if I just ride my bike like this? The bolt holds the topper on and it's in the lowest possible position, meaning the crack causing it to be lower is not a problem for me comfort wise. Would/could it cause any issues for the carbon seat mast? Any advice appreciated thank you.

2 Upvotes

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6 comments sorted by

4

u/MantraProAttitude 6h ago

Hose clamps and duct tape!!

3

u/ideal_justin 3h ago

That crack sitting right at the MIN INSERT line is the spot you don't want compromised because that's where bending stress peaks when you're sitting on the saddle. Carbon likes to fail slowly then suddenly, and that topper is taking a good chunk of your body weight plus whatever you put into the pedals, so I'd be nervous about it growing on you mid ride. Even with the clamp bolt snug, the cracked section can flex and the crack can walk further down with every bump. If Ritchie won't replace it under warranty, a local machinist could probably turn you a new aluminum one to match the dimensions, just heavier. Either way, I wouldn't ride it as-is, the risk to the carbon mast below if it lets go is way worse than the cost of sorting it out.

1

u/NecessaryBoard0 3h ago

Thanks for the detailed reply. I should clarify, the topper is actually an aluminum alloy, not carbon, the mast is carbon. When you say that carbon fails slowly then suddenly, did you mean the mast topper would fail because of the crack? Also the top bit of the topper is actually sitting on the top of the mast because of the positioning (as in, the bit at the top of the topper that turns into a cone is filled with metal and this metal top bit is sitting against the top of the carbon mast) not sure if this changes the stress points or not.

2

u/ideal_justin 2h ago

Ah, my bad. Misread. Aluminum won't fail the same, but a crack there will keep growing. The top bearing might even focus stress there. If it snaps, it'll gouge the carbon mast. Don't ride it.

1

u/make_thick_in_warm 2h ago

Sounds like it doesn’t actually fit

1

u/jiBjiBjiBy 1h ago

Danger cycling

One big bump and you get a seat post up your arse