As the newest engineer for Surly I have been working on a large assortment of projects. I was finally given the opportunity to begin working on a complete bike, which means lots of validation work. Even in the early stages of development it's necessary to make sure you are following certain standards and that your design is going to be compatible with existing Surly product (and other non-Surly products). It has always been our thing to provide options...rack options, accessory options, drivetrain options etc. You get the point. Well, somebody has to make sure all that shit is in order, a responsibility which normally falls on the engineer’s shoulders. In the course of this validation I realized we have been saying that the Salsa Down Under rack is compatible with our forks, and in theory it is, but nobody has actually taken the time to check it out.
There is a certain standard we follow in this building when it comes to rack mount spacing. Salsa maintains the same distance between their mounts as we do, but there is a caveat. Their intent for the Down Under rack was to mount it on the axle eyelets, and the mid blade eyelets. We maintain this spacing as well, but it is between the barrel bosses on our lower fork legs, and the mid blade eyelets.
There are a few reasons for these differences, but the main one is tire clearance/compatibility and rack placement. This doesn’t mean that you can’t mount a Salsa Down Under rack to a Surly fork. The rack is designed with two separate pieces which allows it to work with a myriad of tire sizes and hub spacings.
So, let’s say you want to run panniers on your ECR but a Surly front rack won’t fit. Can you throw a Salsa rack on there?
Salsa Down Under Rack
The Down Under rack should work with most Surly Unicrown Forks. It isn’t a guarantee, because it also depends on fork blade thickness, head tube angle, fork offset, and geometry (curved vs. straight blade). Since the rack sits cantilevered out in front of the fork, there is no issue with disc brake caliper interference.
The mid blade mount is spaced pretty narrowly, but it is easy enough to spread it out and make it fit around a wider fork blade.
Salsa Down Under HD Rack
This rack is designed to function similarly to the standard Down Under rack, but carry a heavier load. This causes a few issues with fitment. The barrel boss mount needs to be spaced outboard approximately 3mm with washers to prevent interference with the fork blade. The brake caliper interferes with the rack unless spaced out about 5mm with washers.
It is possible to get it to work, but you have to be someone that is willing to tinker with it to get it just right.
So the short answer is yes, it will fit, but not without a little TLC. The good news is the Surly front rack will fit on all of our unicrown forks besides the ECR (assuming it has proper mounting eyelets). Safe travels!