Preparing to order some hydraulic brakes for this fat tire Sondors X ebike. Was considering getting a larger 180 rotor so I went to look at the bike to see if it was post mount. Found this wonky IS mount setup on the frame.
What is the point of this brake system mounting format with two oval holes rather than circular holes? Is it so users can remove the rear tire easier? Does this frame anticipate users may want to go with a bigger rotor so they built that into the design and now there is no need for a 180 brake caliper adapter? Is this style of IS mount common?
Thanks for any input you have?
Now I'm considering staying with 160 rotors just for the convenience of not having to mess with the vertical alignment the caliper to the rotor.
by montysep
2 Comments
It’s to allow the brake to work with the wheel moved slightly for or aft in the horizontal dropout for chain tension adjustment.
You have horizontal dropouts that let you pull the axle back to tension a chain if you ran the bike singlespeed without a derailleur. The slots in the mounting bracket let you move the brake caliper to line up with the disk if the acle was moved back.