Monday, September 9, 2013

Bike Rack Hack

This isn't uniquely a "retrogrouch" issue -- but if you like bikes with fenders, like I do, then you've probably run into the problem of carrying a befendered (I don't think that word actually exists) bike on a roof rack. You remove the front wheel and attempt to mount the fork into the rack, but the tail end of the bike's fender interferes with the wheel tray, making it impossible to fit the bike unless the fender is removed -- which would be a major pain hardly worth the effort.
Roof racks like this are very secure, but they are
NOT fender-friendly.  (image from
I have seen products that mount into the rack's fork attachment and essentially act as a "riser" to lift the front of the bike high enough that the fender will clear the wheel tray. They are actually meant (I believe) for bikes with disk brakes, which apparently also have clearance issues with this type of rack. These "riser" products are fairly expensive for what they are, and they don't seem particularly secure to me -- no matter how tightly the mounts are tightened, they can still allow the bike to move a bit (such as pitching forward when stopping the car, for example), at least on some models of racks.

I managed to make my own fork riser for befendered bikes (I like the word so I'm sticking with it) out of some inexpensive supplies from my local hardware store, and some cast-offs from my old bike parts bin. For lack of a better name, I call it the Bike Rack Hack. It raises up the front of the bike by roughly six inches, enough to clear even long fenders.

This riser lifts the front fork over 6" -- enough to allow
even long fenders to fit. It is also triangulated and won't move.
Here's what you'll need to make one: aluminum bar stock, 1" wide by 1/4" thick, and another piece 1" wide by 1/8" thick. You'll need about 14 inches of the 1/4" stock, and about 22 inches of the 1/8" stock. You'll need threaded rod in 3/8" diameter, plus four 3/8" hex nuts, four 3/8" nylon lock nuts, and eight washers. You'll also need an old hollow axle from a front hub, plus the appropriate lock nuts (you could also use the bearing cones from the hub -- don't worry if they're totally gouged or pitted -- in fact, it's probably better if they are), and a front wheel quick release skewer. Lastly, you'll need a block of wood -- preferably a piece of treated lumber, but if you paint it, then treated may be unnecessary.

You'll need two 7" long pieces of the 1/4" bar stock. Bend them in your bench vise in a slight offset bend as shown -- only about 1 cm. -- and they should be like mirror images of one another. These will be the risers. Take two 11" long pieces of the 1/8" stock, and bend them in similar fashion -- about 3/4 inch this time, and again, they should be like mirror images of one another. These will be the braces that extend down along the sides. When you drill the holes into the riser pieces to accept the threaded rod and the old hub axle (four sets of holes altogether), the exact location of the holes isn't crucial, but it IS important to make sure the holes line up as mirror images of one another, otherwise things will come out a little cock-eyed. The most crucial measurements on the whole thing are for the width between the risers -- they have to match up with the rack's fork mount, and with your bike's fork. Remember that standard road hubs are 100 mm wide, so that should be the width at those attachment points. The nice thing is that you can "fine tune" the fit by playing around with the threaded rod and hex nuts.

When assembled, the lower part must be 100 mm wide on the inside faces (same as a hub width) to fit into the fork mount. At the top, it should be about 80 mm on the inside faces. When the axle and locknuts are installed at the top, it should measure 100 mm outside the locknuts -- just like a normal road hub. That way, your fork will slide right in.

The side pieces help brace the riser so that it doesn't pitch forward with a bike attached -- mine are 11", but they could just as easily be 10" or 12" -- 11" just looked right to me. I drilled a hole through the wheel-tray of my rack to accept a carriage bolt and wing nut -- it goes through the block of wood which fits into the wheel tray. You can cut some bevels on the wood to better fit the inside profile of the tray.


Here you can see the wood block (cut from a piece of scrap 2x4), shaped to fit into the wheel tray. A carriage bolt, some washers, and a wing nut secure the piece into the wheel tray, bracing the whole riser and keeping it from pitching forward under braking.

The roof rack's fork mounting skewer goes through these holes at the bottom of the riser.  Locate these holes so that the legs will still clear the cross bars on the roof rack -- centered no more than 3/4" from the end should be fine, but it could vary a little depending on different roof rack brands and models.

One thing worth pointing out is that using a basic quick release skewer to attach the bike to the rack doesn't provide a way to securely lock the bike should you need to leave it unattended. Most of the racks today do have a locking mechanism for that, but this little homemade hack doesn't offer that. What I do, if I have to leave my bike unattended while on the roof rack, is I simply run a cable lock through the frame and around the rack crossbars or the roof rails on my car.

There you have it -- a fairly simple riser for befendered bikes. Cost: about $12, and maybe an hour to make. Paint it flat black, and it will match right up with most roof racks. It can be mounted or removed in just a couple of minutes without tools. 

Warning: if you carry bikes on a roof-mounted rack, make sure you don't drive your car into the garage with the bikes on the roof. It happens! Here's a tip -- when loading bikes onto the roof, put something in front of the garage door, or just inside it, and leave it there -- for example, a sawhorse with a big sign on it that says "BIKES on the ROOF!" When you come home, you won't be able to pull into the garage without getting out of the car to move the sawhorse -- your bikes will be safe. 

There you go -- useful hacks from the Retrogrouch! 


  1. Interesting. I've been pondering a similar design myself. As it happens, I'm not a huge fan of roof mount systems, so I have built a stable easy-in/easy-out rack that fits into the back of my van. I can get three bikes in, side-by-side, but the problem has been transporting my bikes that have fenders - compounded, of course, by my preference for the longest fenders I can install. My idea was to tool an aluminum extension that would, at the bottom end, fit into the quick release mount on my interior rack. On top of the elevated extension would be another quick release mount.

    Then I wind up stumbling across your blog, and voila! You've been thinking along similar lines. Despite the pay scale, we high school teachers just might solve all of the world's problems.

    Or at least those involving fendered transport!

  2. Hi,
    Bike roof racks. The theme of your blog is very beautiful and the article is written very well, I will continue to focus on your article.Thank you.

  3. This would also be nice for those of us with old style racks who have recently purchased our first disk brake bikes.