Need advice on sizing a rear bicycle rack

May 16, 2015 7:04 PM

I have a pannier and bicycle, and I need to mount the one to the other. The bike is a ~1985 Schwinn and the pannier is a Blackburn EX. I’ve tried a Blackburn MTN rack, but my heels bump the bag. Ideally it’d be about 4-6 inches further back and still level along the top (currently tilts slightly back). Do racks come in different sizes I need to know? Are there some bike/bag combos that don’t work? Do people shorten their cranks instead of moving the bags? Is there some crucial measurement I should learn?
posted by migurski to Sports, Hobbies, & Recreation (10 answers total)

Pretty much all racks are going to place the lower attachment point of your bag above your rear axle. The variable you can change is the bag. Some bags come with adjustable attachments where the hook can be moved forward or back on the pannier to move the whole bag forward or back. That's the kind you want.

You might be able to gain an inch or so with a rack that angles backwards, but that doesn't sound like it will be enough.

You probably don't want to shorten your cranks (and the difference you can make with reasonable shortening is small anyways).

Racks come with adjustable attachments to your seat stays to keep them level, so you should be able to adjust any rack to be level.
posted by ssg at 8:24 PM on May 16, 2015

Best answer: Do people shorten their cranks instead of moving the bags?

Some bikes (touring bikes, generally) have longer chainstays so there's plenty of heel clearance no matter what rack or bags you're using. And some racks have more room to adjust things rearward (this one from Axiom is a decent example). And many panniers aren't rectangle-shaped for this reason (lots of them are narrower on the bottom than the top, so there's more room for avoiding heel strike). Or else the panniers are able to be mounted at an angle so that the bottom of the bag is farther back than the top. Or they're able to be mounted farther back on the rack (different panniers have different mounting mechanisms. Some work better for this than others.)

Unfortunately, trading in your feet for smaller ones is probably not an option, but I can confirm that having small feet does make the whole thing much simpler. Since you can't, probably best to change the rack, panniers, or bike. Easiest first option is probably to try to mount the panniers you've got as far back on the rack as possible while keeping them on (and I think the mounting apparatus on these is just velcro, right? So... do what you can, and if they don't work, get different bags.)
posted by asperity at 10:14 PM on May 16, 2015

Also: with the rack tilting backward and rectangular panniers, you're gonna have the bottom corners of the bags closer than they should be. Leveling the rack is likely better in this case.
posted by asperity at 10:15 PM on May 16, 2015

Oh yeah, and one more thing with these bags and trying to mount them farther back: they might be kinda floppy if you can't attach them to the tube-that-goes-down-and-attaches-above-axle part of the rack. You could put something in there to stiffen them (corrugated plastic is a good option) so they don't get too floppy and get messed up in your spokes, and sew on another rack attachment point (velcro tape is available at craft stores) closer to the forward end of the bag. If swapping out your bag/rack/bike isn't an option, get creative.
posted by asperity at 10:29 PM on May 16, 2015

Are there some bike/bag combos that don’t work?

Yes.

There are also rack/bike combos that don't work.

I don't think you are going to have much luck with your current panniers. They are designed for a bicycle with longer chainstays.

Good touring panniers generally taper backwards to avoid this problem, take a look at Ortliebs back-roller classic for an example.
Staying with Ortlieb's gear, you can see how they got around the rectangular pannier problem by angling the mount of the bag here: Officebag.

The best racks in my opinion are from Tubus, specifically the Cosmo. They make some small, sturdy extensions to raise and move backwards the lower attachment point.

Expensive stuff, though.

Best of luck :-)
posted by Thug at 4:13 AM on May 17, 2015

I think the safest (and coolest) way to avoid heel strike with that bike is to turn it into an Xtracycle. Look into what people are doing with Freeradical.
posted by oxisos at 8:44 AM on May 17, 2015

Best answer: Look at some of the racks made by Axiom. They come with extenders that will shift the rack back several inches. It's intended to help clear disc brake calipers on newer frames, but can solve your problem as well.

Also look up "bucket panniers" - if you don't mind making them yourself you can adjust the location and angle to fit your bike perfectly. Besides, they're waterproof and durable and about 1/10 the cost of Ortliebs or other fancy bags. :-)
posted by sibilatorix at 9:00 AM on May 17, 2015

Response by poster: Thanks, all. One of my other bikes is modified with an Xtracycle Free Radical, so I’m very familiar with it!

The Tubus extensions are interesting. They’re not quite right, but I looked into cutting something similar and custom for my needs with Ponoko.com. Their prices for steel are prohibitive.

I love the bucket pannier idea.

Looks like my first next step will be the Axiom uni-fit with its 4" extension. If that doesn’t work, it still looks like a great rack and I’ll either look for tapering panniers like the Ortliebs or buy a couple of buckets. I can work my way up to the expensive stuff more slowly. 💸
posted by migurski at 10:29 AM on May 17, 2015

I'd find some junky old rack, cut off the deck and lash that deck to the rack you've got with cable ties so that it extends 4-6 inches further back.

That would add some weight and alter the balance slightly, but big as you must be to ride that big frame set up like that, you won't even feel it.

Nice creative arrangement for a fixie, by the way.
posted by jamjam at 10:38 AM on May 17, 2015 [1 favorite]

Response by poster: The Axiom works great!
posted by migurski at 10:20 PM on May 19, 2015 [1 favorite]