austy37

Noticed this ? Crack on the seat tube of my r2. I sanded it down a bit and it seems to continue through. Its a used frame but i dont think its had any crashes. I tried the tap test which did seem a bit duller over the area but is it accurate? The more i read about so called cracks the more confused i am.

Asi

It's definitely cracked!

Seek a CF repair shop to salvage that frame.

Diy is possible but you need special materials and confidence in your work. Sanding a wide area around the crack and wrap with carbon fiber woven mesh with the appropriate adhesive (some kind of resin - very important, look at the instructions of the carbon mesh spool to see which is recommended). Making a slight bulge at the area, smoothing it out, and paint it. - this is mostly what a CF repair shop would do anyway.

If still unsure about the crack: put some penetrating dye to see the full extent of the crack. But what i can see look like a positive crack on the ST near the BB - which is a normal place for cracks due to fatigue. The bike stresses there at every stroke on the cranks.

CliffordK

So, that is the Seat Tube, just below the Front Derailleur Hanger. One might expect the stress peak being closer to the bottom bracket, but that may well be near a junction between a reinforced bottom bracket, and a thinner seat tube.

I assume you already verified that you don't have warranty coverage.

You may be able to visualize flex by pushing on the pedals/cranks while holding the seat or seat tube fixed above that spot.

austy37

Thanks for the replies. I'm a puny guy so I'm surprised I cracked it, I'm certainly not putting any watt bombs through.

austy37

Thanks for the replies. I'm a puny guy so I'm surprised I cracked it, I'm certainly not putting any watt bombs through. Yeah no warranty as it's a used frame I've had for about a year