Are aluminium Blackburn racks guaranteed in any way? Has anyone known them to crack under their intended weight limit? (Whatever that may be?) I'm going coast to coast across Scotland soon with about 30 -35lbs total front and back. Will be doing a fair bit off road on tracks. I need to get a decent set of racks. Is it false economy not to buy SJS steel ones? Thoughts appreciated, Joe
Joe,
I've broken a number of Blackburn racks and similarly-designed competitors, but it took some specific circumstances to to it. With light to normal loads, they last for decades and I am still happily using some that have never given trouble. Based on my experience, here's what I've found:
1) If you do what has come to be called "American-style" touring, the racks will likely be fine. This is a fairly new term to me (an American), but seems to refer to touring mostly on paved/smooth roads, and with a maximum of about 40 pounds on the bike in panniers and atop the rack (or racks, plural, meaning a front rack as well). If you do this and distribute the weight evenly, I don't envision a great likelihood of problems. If you use the triangulated alloy racks (Blackburn or otherwise) only to support the bottom of a large Carradice saddlebag or a racktop bag, I don't think you'd ever have a worry.
2) If you add rough roads or off-road riding to the mix, the likelihood of breakage is much greater, even with lesser loads (still in the recommended range).
3) If you push the weight limits, the likelihood of failure will increase commensurately. Still, on smooth roads, one will probably get away with it.
4) If you ride on rough roads or off-road *and* push the weight limits (as I did with every single triangulated aluminum rack I've broken), then it is only a question of time, and a breakage can be nearly immediate. This style of touring is coming to be regarded as "World Touring", "Adventure Touring", and yes, "Trekking" (effectively extended "hiking" with a bike and very heavy loads).
Most of my early touring was done in the US before the advent and ready availability of Tubus and other tubular steel racks. Compared to the old cast alu Pletscher that clamped to the seatstays and had only a single pair of rivet-attached legs, Blackburn's welded, triangulated alu rod rack was a revelation and truly worlds better. Trouble is, they are still aluminum, they are small-diameter aluminum, and they are welded; the three together make for problems when used at the extremes. Here's what I have found to fail, and where:
1) Inadequate welds that didn't surround the joint but effectively comprised "tack welds" that were never completed. The greatest number of my failures were where the last (and typically lightest) stay joined the rack-top. This stay was always smaller in cross-section (could be bowed with light finger pressure) and always had only a light welding bead on the underside, amounting to a tack weld. These were simple fatigue failures.
2) Undercut welds, such that welding created a stress riser below the joint, leading to failure.
3) Sharp differences in materials section, usually where the lower leg had been pressed or rolled into a flattish section for piercing or drilling the mounting eye. Again, these comprised stress risers in design or execution.
4) Inadequate material left around the mounting eye leading to outright fractures.
5) Tubular aluminum rather than solid aluminum rods, now found mostly on Chinese or Taiwan-produced racks. It just does not hold up, usually because the tubular wall section has been undercut by the welds. The larger-diameter tubular structure would otherwise seem a better choice.
Back in the day, all of these possible flaws were aggravated by panniers that did not mount securely and allowed bounce (i.e. non-surrounding steel top hooks and bottom spring-hook retention that allowed bags to sway, bounce, and loft -- and sometimes to leave the bike). The result was pretty substantial and severe second-order vibrations -- go through a pothole, and you get one impact. Fine, that's a first-order vibration. Trouble is, the bags would loft slightly above the rack and then crash down again for a
second impact with the full bag weight concentrated about the mounting hooks, which were usually placed hard against a joint to locate the bag. Do that often enough, and it is like beating on the rack with a hammer, and greatly increases the chance of failure. This is what caused me to wrap my bags with external straps to compress the load against the rack, stabilize the contents, and secure the load limpet-like to the rack. It did wonders, and my breakage rate went way, way down. It does work and I always suggest an external compression strap or two regardless of rack, but I really think they're a necessity with aluminum racks.
As for warranty claims, well, I've never had any luck getting a replacement rack for my efforts. Blackburn claimed a lifetime replacement warranty for awhile here. I no longer see that except on their overseas products, and it appears Blackburn (nee' Bell Sports) is largely out of the rack business here in the States. My failures were largely in the pre-Internet days (late-1970s, 1980s, 1990s), and I never found a local bike shop willing to go through what they described as "the hassle and cost" of warranty replacement. I waited till there was a sale and replaced my own, substituting another bike for touring in the meantime.
I still use Blackburn front and rear racks on a number of my bikes, but only for lighter loads or for smoother roads and always with compression straps if I carry something other than a rack-top load. The last failure I had was with a factory-supplied copy on my 1989 Miyata 1000LT. It didn't survive Belgium's cobbles.
For heavy-touring use, I have gone to tubular steel racks of good quality and have yet to experience a failure. Tubus is widely used and highly regarded. I have personally seen several fail at the joints when the bicycle blows over in the wind and the rack impacts something on the way down (parking rack) or the ground itself. Online searches reveal this sort of damage is not covered by warranty, as it is not a normal "in use" sort of failure which seems fair to me. My Sherpa uses the Thorn Low -Loader Mark V front pannier racks and I went with a Surly Nice Rack Rear that weighs a lot -- far more than a Tubus and probably more than it needs to. I selected it because I preferred the design (smooth corners, extra crossbars, a closed "return" at the front that serves as a handle to swing the bike, tubular steel mounting tangs instead of alu, etc). I had a Surly Nice Rack Front and sold it on eBay (for more, see:
http://www.thorncycles.co.uk/forums/index.php?topic=2264.msg16241#msg16241 ). For me, it was wonderfully solid vertically and a wobbly disaster laterally because of the thin stainless mounting plates that allowed flex even unloaded. Others have had stellar luck and actually prefer them. Thorn make a very nice expedition-grade rear rack. If one prefers the Ortlieb/Tubus design and doesn't mind alu, then their budget-oriented RackTime line work beautifully with Ortlieb bags.
The full-custom, short-leg, triangulated cr-mo racks I bent-up and brazed for my Folder project are immensely strong. The rear one easily withstood my 172lb/78kg body weight standing on it when mounted to the bike's suspended swingarm. It is also possible to make a rack that is stronger than the eye it is mounted to or the bolts that secure it, so that is something to watch if you make your own.
The recipe for rack "non-failure" (or as close to it as you'll get) is:
1) Properly designed, welded and/or brazed tubular steel racks that are well-triangulated and mount securely.
2) Bags that mount securely.
3) Using one or more external compression straps per bag
to secure the contents and bags to prevent second-order vibrations.
4) Keeping within the rack maker's maximum weight rating, and well within on bad road surfaces. South American Ripio, really bad American washboard, and Belgian cobbles all stress racks unduly, but the effects are greatly minimized with compression straps. They do wonders.
5) Distribute the load around the bike using front and rear panniers and front and rear racks; this way, each rack carries less weight.
Hope this helps,
Dan.
