Diamondback Bicycles Avaliações 

tl;dr: Two assembly issues. One of them could have hurt me badly. Both Diamondback and Summit (assembly store) failed to take ownership of issues.

After a few months of use, the front wheel came off while riding. Thankfully I was OK, but bike finish got cosmetic damage from friction with tire. Diamondback showed no interest in owning the issue, and pushed it to Summit Bicycles (who assembled it). Summit also took no ownership, but at least offered to inspect the bike to ensure the damage wasn't structural.

A few months after that I took the bike in to another shop to get a personal fitting. On putting the bike on the trainer for measurement, the tech discovered that the rear derailleur had been badly installed. The piece that held it in place had not been properly threaded onto the axle, and was now jammed. He made a temporary fix, and encouraged me to reach out to Diamondback and Summit.

Diamondback again refused to take ownership. Summit offered to request and install the part free of charge, even though the rear wheel apparently comes installed from the factory (i.e. Diamondback's responsibility).

Nice offer. Unfortunately they never made good on it, even after I followed up with them.

I've now ordered the required part to fix the rear wheel myself, and will get the shop that diagnosed the issue to install it. They will also sell me my next bike. It will not be a Diamondback.