Rennen Rollenlager
Single speeds are really taking off. The bike industry is seeing lots of frames being produced for single speed setups. This trend isn’t exclusive to park riders and dirt jumpers - even our trail/XC brethren are starting to build up single speed bikes to use on the trails. This single speed renaissance has spawned a whole new series of devices to take multi-speeded bikes and convert them to single speeds. These devices all attach to the derailleur hanger in some manner to provide tension on the chain since the frames lack horizontal dropouts. Rennen Design Group is one of those companies. Rennen Design Group is made up of two guys, Ken Avery and George Costa. You can read more on their bios on the Rennen Design Group website.
Rennen's single speed converter is called the Rollenlager. Unlike most chain tensioners, this one does not use any springs. Once set, there are no moving parts to the device except for the chain roller. The kit comes with instructions and various small parts to complete your installation. The Rollenlager has a black plastic roller mounted on two ball bearings to provide smooth action of the chain - the roller is smooth and does not have chain teeth formed into it. The arm that extends to hold the roller is made of thick aluminum and is definitely capable of taking abuse. The interesting thing about the Rollenlager is that it actually strengthens the derailleur hanger.
Installation of the Rollenlager was a little difficult. The instructions supplied with the device are a little simple for something that is moderately difficult to get setup correctly. Supplied in the kit is a half link to get the chain length to the correct length. Of all the installations I have seen on both park/jumping bikes and XC bikes, the half link is necessary and not optional. It should should be noted that this half link supplied with the Rollenlager is not 8 or 9 speed compatible - it is only compatible with 1/8” chains (a fact I shortly realized after trying to install the Rollenlager with my ready supply of 9 speed chains). My gear choice was a 32/16 setup for my Evil Imperial. The first problem I encountered while installing the Rollenlager was QR skewer compatibility with the supplied axle washers. The stepped washer to be used with QR did not fit into my nut for the axle. I had to search in my spare parts to find a QR nut that would work with the stepped washer. It should also be noted that if you have thick dropouts such as those on an Evil Imperial, Banshee Morphine, etc. and are going to use a QR on your hub, you need to have the longest QR you can get (so far the longest QR I have found is the Hope skewer which works great). The other compatibility problem faced with the Rollenlager are wide chainstays. Wide chainstays prohibit you from tensioning the chain by swinging the Rollenlager upward against the chain; instead, you have to swing the Rollenlager downward. While pressing down on the chain works equally as well as upward, you may loose tension in the chain if you happen to hit the device – something I have yet to do. The reason behind this problem is the lack of lateral adjustment in the roller. You can only adjust the roller inward or outward by approximately two centimeters. This can be fixed by using a longer bolt from the hardware store.
Once installed and ready to go, further adjustments are usually not needed. Performance of the tensioner is excellent. Because the roller is smooth with no chain teeth formed into the plastic, there is no noticeable noise while you are riding the bike – chain movement is smooth with very low resistance. During my riding, never once did the chain come off either chain ring or rear cog. This was my first single speed bike and I have to say I am sold on the idea. Less complication, no chain poping while sprinting, no loud noises when landing, etc. all makes for a more enjoyable ride. The Rennen Rollenlager, with its no spring design, keeps the chain tensioned at all times as if you were running a frame with horizontal dropouts - absolutely no bouncing or chainslap!
Despite its installation problems, the Rennen Rollenlager performs well once installed on the bike. The price for the device is a little on the rich side at $50 but it is to be noted that it is 100% USA made. I would recommend this device to someone seeking to make a single speed out of their multi-speeded bike but with the caveat that buyers be aware of potential installation hassles. I think these hassles could be overcome by reworking of the installation instructions to provide more detail and troubleshooting tips for overcoming some of the possible incompatibility problems that may occur with frames and bike setups. It’s very hard for a component manufacturer to assure 100% compatibility between their product and all of the bikes out on the market.
The score card for the Rennen Rollenlager reads a 7 out of 10. Function is excellent but documentation could be better. I expect future refinements of the Rollenlager to turn this into the best single speed converter on the market.
If you would like to purchase a Rollenlager you can do so directly from Rennen at this page.
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Posted on Sep 24, 2006 18:07:25 -0400 by Brady.