Dirt Rag Magazine

Inside Line: Pacenti PDent Shorty Stems


With all the tire size and hub width standards getting pushed around lately, it might have been easy to overlook something as simple as a dent in a handlebar. But with the industry ready and willing to throw convention out the window these days, why not rethink bike sizing as well?

The PDent is Kirk Pacenti’s patent pending idea to allow for stems shorter than what is possible with current 31.8 and 35 mm handlebars. Since the bars will run into the steerer tube once the stem is any shorter than 32 mm or so, companies that wanted to experiment with even shorter stems had to resort to placing the bar clamp above the steerer tube. That is a simple solution to the shorter stem problem, but it pushes the clamp height up a good bit, which is an issue for modern bikes where riders want lower bars along with longer travel and bigger wheels.

040715-5 Pat Pending CU

So the PDent was created, an engineered recess or dimple in the center of the bar that allows the bar to wrap around the steerer. Depending on the size of the dent, stems get get as small as 15mm. For now Pacenti is focusing on stems between 15 mm-30 mm. Lab tests proved the dimple doesn’t weaken the bar in any important way, and in fact the bars will break in other places long before the dimple is under enough stress to cause issues.

040715-2 alt Bar+stem top-down.
This idea isn’t so much about the shorter stem, it is more about rethinking geometry. Top-tubes have gotten progressively longer, and with shorter stems, can get longer still.  The long front center that results from long top tubes results in more stability, particularly when combined with modern slack head angles. Pacenti is a proponent of going even further, with trail bikes getting even slacker and longer. In reality, what we are looking at are almost downhill bike numbers, but made rideable up and down with a steep seat angle.

Pacenti isn’t after cornering the short stem market with Pacenti branded stuff, although he will be selling them soon.  Instead he would like to licence this technology to stem and bar manufacturers, and in turn, bike companies, as these short stems are going to need bikes with even longer top tubes than are currently on the market. Although since modern standover heights are so low, most riders could ride a size larger to get the reach needed to make a shorter stem work.

040715-3 Bar Top-Down
Are tiny stems the next big thing? It’s hard to tell at this point. Mondraker has been pushing the tiny stem thing for awhile, and even the Athertons experimented with similar ideas (before going back to more “normal” stem lengths). It should be interesting to see where this goes. Kona proved with its Process line that shorter stems are not a hinderance to all-around riding when paired with a long enough top tube, although those bikes use slightly steeper head angles and super short chainstays, two things Pacenti advocates pushing in the opposite direction.

040715-7 beauty shot

We are on the short list for media samples, so expect more info about how this all works later this spring.

 

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