Urbana Offers Strongest Bicycle Rack “Bar None”

Urbana RNR bike rack is strongest available with 150 pound load capability

Urbana has created what it calls the strongest rack available, bar none. From the press release:

The RNR is designed with a reinforced lateral plate that allows the rack to hold up to 150 lbs in dynamic weight and serves as an anti-wobble mounting point that keeps the bike stable when there is heavy load on it. So, not only is it capable of withstanding enormous vertical forces, it can take the real life horizontal forces that challenge a commuter in an actual commute.

It’s designed to accommodate just about any typical pannier, grocery or other common bag and mounts at the standard attachment points near the dropouts and top of the seatstays.

Comments

Meshkat - 11/07/11 - 1:44pm

That may or may not be true but I can tell you one thing; these are the worst bikes I have ever seen. The company is a pain to deal with and the bikes are designed to fit no one. Additionally they weight more than a house and ride about as well as trying to pedal a motorcycle with flat tires.

Robin - 11/07/11 - 2:56pm

It’s comforting to see that the marketeers are still refusing to let technical details get in the way of selling something. Instead of going with the ol’ “forces”, they threw out that scary “dynamic weight”. And just when I thought the lowest common denominator had been found, the marketeers take it to a new, lower level.

nplus1bikes - 11/07/11 - 7:14pm

You can make a rack as heavy duty as you wish, but the load it will carry is limited by the strength of the attaching bolts and dropout eyelets.

raphael - 11/07/11 - 10:02pm

their site says 120lb capacity. sounds fishy already.

mkrs - 11/08/11 - 8:19am

Without a vertical bar to mount panniers to, many models will be quite useless with this rack. And by the way, who the hell needs anything more than a Tubus Logo or Cargo with 40 kg of max load and 30 years (yes, THIRTY years) of warranty?! Moreover, Tubus make all of their racks out of steel (excluding titanium equivalents to the most popular models) so you can weld them in the remotest location in the world should such a need emerge and still their racks are much lighter.

If you add this to the info provided in previous comments, all this sounds like a serious pile of BS and a really crappy product.

King County - 11/08/11 - 9:21am

Super strong rack held on with the same thin bolts

Ron - 11/08/11 - 12:19pm

It’s aluminum; its welds will fail. It also has limited pannier attachment points which look like guaranteed heel-strike. And, as others have noted, the weight limit of any rack tops out at the shear strength of an M5 bolt. I’d rack-surf my Surly Nice Rack long before I’d try it with that one.

Fred Zeppelin - 11/09/11 - 2:15am

Ron, I get what your’e saying, but it’s also worth noting that there are a few racks out there that mount to the Q/R, and a couple that mount to a nutted axle. So the M5 bolt isn’t always the limiting thing.

Robin - 11/09/11 - 3:27am

For reference, the max shear load on a crappy, steel m5 bolt is about 144 lbs. So that means that with crappy m5 bolts and only counting the two at the back (which will give a lower shear yield), those two crappy bolts will take a shear load of 288lbs at least. If you factor in the connection at the front end of the rack above, that number goes up. Likewise, it goes up if you use a higher quality steel bolt. So, the max load of the rack is well within the design shear load of m5 bolts. I suspect that it’s also well within the typical max loads of rack mounts. Just an FYI.

mkrs - 11/09/11 - 9:18am

@Robin

Please note that the data you have provided relate to static loads. If you hit a pothole, “effective weight” of 140 lbs of cargo might be much higher than 288 lbs (as the g-force is higher than 2g on impact – if you don’t believe, try to measure it with your smartphone if you posses one – most of them have accelerometers).

What is more, shear force is just one factor. Another one is fatigue of the material – I don’t think I want to be a guinea pig to test how long a bolt will stand such forces before it breaks or strips a thread in an aluminum frame.

Kristibee - 11/11/11 - 2:26pm

From Urbana Bikes:

In response to some of the comments on the following article posted on your site Nov 7th:

We would like to say that like any other rack, RNR is held onto the bicycle frame by 2(two) M5 bolts. We Spec high grade bolts (12.9). It is the highest Standard Grade currently available for bolts. To address the issue of strength, the single sheer thread strength for an M5 12.9 bolt is 10.7kN which is equal to 1092kg or 2402lbs (on earth!).

To address the issue on fatigue, the rule of thumb to get near infinite fatigue life is specifying the bolt strength to 10 times the max load it will encounter in real life.

Additionally the rack has been tested in real-life conditions and we would encourage bike Rumour to give the rack a try if you have time to do so this spring.

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