How do I mount this Topeak rack onto this road bike with disc brakes?

Question

I've browsed several closely related questions already, but haven't found one quite like my issue yet.

I have the following rack, a Topeak Tourist for Disc Brake bikes (with a matching Topeak trunk bag with panniers)

http://www.amazon.com/gp/product/B000ZKHN6Y/

And I have a 2014 Diamondback Century Sport Disc. It has 700c tires, which the reviews for the above rack suggested would be fine. Anyway, clearance isn't the issue at hand. Here's some pictures of the bike - hopefully they're helpful.

https://i.sstatic.net/EPybu.jpg <-- More pictures of bike!

Up until now I've been using a hybrid bike with no panniers... so I have next to no familiarity with racks. I've looked into the issue, but feel increasingly suspicious about whether there's any way to mount these. If I can I'd be most pleased, although I'd need the method pointed out (and I've experimented; for example, you notice the two bolts above the quick-release lever in the last picture? those are too large to work double duty for the rack; they don't fit the thing) - but if not:

• I've heard stuff about p-clips (like Halfords 19mm Luggage P Clips - again, no link). I'm not sure what problem they exist to resolve; it looks like it's mine, but - there's always two different places to attach a rack (triangles and all that), plus more than that in different styles of rack (some attach to a seat post, apparently) and I'm not entirely sure if these would help my issue or the one I'm not having.
• I heard a recommendation for the "Tubus Adapter Set for Quick Release Axle Mounting." Ignoring quality concerns (I can make a judgement call), would that be a good purchase for me in that it might resolve my problem?
• Same for the "Tubus Clamp Set - Rack Eyes for Seat Stay Mounting," which is apparently related to p-clips.

Answer 1

You have the seat stay mounts on the frame (those are the two thin tubes that go from the rear wheel drop outs to the top of the seat tube). What you need is mounts on the rear wheel drop outs. Typically, they are part of the dropout and/or frame. In your case, you have none.

That being said, the P-Clips and Tubus Clamps will not be useful.

The Tubus Adapter Set for Quick Release Axle Mounting should solve your problem. It is built for a Tubus rack which has two mounting holes at the bottom that are meant to be used simultaneously, thus the two slots. You can choose which one is appropriate once you loosely install the rack and check how level the top is. Installation instructions and a drawing to go with it can be found here.

I should say I have not done this actual installation myself, but I see no obvious reason why this would affect anything else. There are comments from people that have used this with discs and there's a spacer to keep the mounting plate away from the frame, so you should be good.

The only concern I have is there seems to be nothing to prohibit the mounting plate from rotating fore or aft. You may want to invest in a couple lock washers and a proportionally longer quick release.

Answer 2

You will probably have to go with a seat post beam rack option if you want to stick with the Topeak setup (Topeak MTX is a great setup, my family uses it for commuting and shopping). This will serve you well for lighter loads, and you can move that Tourist rack to the hybrid for the more serious tasks and hauling. All the disk option of the rack does is provide a spacer so the rack will clear disk brake calipers. It will work with a none-disc bike, it would probably work better. My cables and fender stays get in the way of my rack.

If you don't want to go that way then looks like you are stuck with p-clamps but I can't speak to how well (or if even) they will work on the bottom. The Tubus option does not look like a fun option to me. Every time you have a flat (and you will with a road bike) you will have to unload the rack (which isn't hard with the MTX, I have to do it with my mountain commuter setup anyways), then completely undo the skewer to get the wheel off (so much for quick release). While the wheel is off there is nothing holding the rack in place and it is flopping around. As somebody else pointed out, who knows if that will keep the eyelets in the same place while on the go.