I have a Trek X1 Cyclocross bike and I want to get a rear rack for my bike. I went to a bike shop and none of limited rear racks they had would fit my bike. The reason was because the eyelets or braze-ons on my bike are not on the outside of the seat stay as typical for a bike, but are on the inside. The second picture shows what I mean. Does anyone know which rear rack will work without adding any attachments? Much appreciated!
Most racks that use the common stainless flat stock type upper struts can be made to fit. Planet Bike Eco, Topeak MTX, and many more. Getting them on will require reworking the struts. Usually one must flatten the twisted end of the strut and put the twist back in further up to snake them in on arrangements like this without interfering with the brake cable. I always use a vise to do the flattening, dummy it up, figure out where the new twist needs to be and mark it, then put it back in the vise clamped at the mark and use an adjustable wrench to do the twist.
Tubus and the many racks that copy their strut design can usually work by flipping the strut carriers in opposite from normal, which means they then have to be accessed with a ball-end tip only. But it depends on whether they have a clear shot at that point, because the aluminum rod type struts they use shouldn't be bent around.
The Pletscher quick rack system will attach directly to the seat tube, so no need for the eyelet. https://www.pletscher.ch/index.php/en/products-en/carriers-en/quickrack-carriers-en They carry up to 25 kgs, as other racks.
Otherwise, the regular thing to attach the rack can probably be swapped inside/outside or left/right to attach the rac to your eyelets.
Both Topeak and Tortec racks (many, not necessarily all designs) have a fair bit of adjustment from rails that can be slightly bent to fit. I'm sure other brands do too but these are the ones I'm most familiar with.
The Tortec Velocity (I've got the slightly wider Velocity Hybrid) for example has support rails that pivot and slide. They're also aluminium and can be bent a little (though if bending near the holes, grip the whole flat bit in the jaws of a vice to avoid bending right at the hole). As pictured it wouldn't work, but swap the arms over and you'd probably be close enough to bend them.
The Topeak Super Tourist (several versions available) uses flat steel arms with a twist in. They're slightly easier to bend, but it's harder to cut off the excess if that sticks out. I've had to bend the arms to use a clamp on the seatstay with the noodle of a V-brake in the way.
This will all be much easier if you have a small bench vice and some mole grips (vice grips/self locking pliers), or just 2 pairs of the latter. An adjustable spanner is also a good metal bending tool at this scale