The rack is not braced on but fixed to the braze-ons on the seatstays. These braze-ons are asymmetrically located as seen in the photo. As long as yr rack allows for customised fitting where the seatstay fixtures can be individually adjusted, u're probably ok. The rack in the photo is the Pletscher Athelete 4B for 20in wheel bikes, and ThorUSA assured me they'll fit P20 before I got it from them.