The simple tension seeker (STS) by DMR Bikes should not really be called a chain tensioner , but rather a slack-remover. It's an incredibly simple solution for those looking to convert a bike with vertical dropouts for single speed use. DMR is a UK-based company that specializes in downhill, freeride, and dirt jump chain devices, and the STS reflects this design experience in this burly device. Installation is a 5-minute job (assuming you have already replaced your cassette with a cog, and shortened your chain as much as possible). Simply remove the skewer nut and slide the black aluminum mounting bracket onto the dropout. Then loosely bolt the stainless steel arm to the bracket and the derailleur hanger with two 5mm bolts. Replace the skewer nut. Rotate the cranks until the chain is at its tightest. (Very few chainrings and cogs are perfectly round.) Lift up on the arm so that the red pulley pushes the chain upward, removing the slack, and tighten the two 5mm bolts. That...
Time for the scientist to weigh in. Firstly, always read the original paper if possible, journalists regularly misreport or over-sensationallize.
ReplyDeletehttp://injuryprevention.bmj.com/content/early/2011/02/02/ip.2010.028696.full.pdf?sid=a2ed422a-9dbe-409a-b762-40e0ffbcedc6
In this case, The Daily says streets are 28 times more dangerous that separate paths, which is totally incorrect. When six paths were compared with eight street segments in the same area of Montreal, five had higher risk on the street and three had higher risk on the paths. Only three of the comparisons were statistically significant. When averaged together, the paths were 28% safer (not times as the Daily article says, percent).
But its more complicated than that. They did not use the streets the paths run along for the comparison, but other refrence streets. They looked at car crash rates to determine how dangerous the reference streets are to the streets the bike paths are on. On average, they came out the same but the average hides the real story. Two of the reference streets were much more dangerous than the bike path streets - one 10x more dangerous and one 5x more dangerous. Those two streets are two of the three values were the bike path tested safer and showed the highest difference between path and street. Eliminate those two outliers and the whole study falls apart. There would be no difference in safety or it might actually tilt the other way.
The only thing they really succeeded in proving is that streets that are more dangerous for cars are also more dangerous for bikes, so it might be best to stay off them. Whether you take a light traffic street or path makes no difference.