Wednesday, August 10, 2016

How To: Install Osymetric Chainrings

No doubt, the most popular thing I have ever posted has been my review on Osymetric Rings. In this post I won't be speaking to any of the three camps that exist  on them (Camp A. has no opinion, Camp B. Classifies them as Snake Oil, or even worse... Biopace... and Camp C is the hype beast.) but we'll just be looking at the technical aspect of installing them and getting them to shift properly. Worth noting is that I have the original Osymetric's, not the new/improved model that should have better shifting due to their ramps. Mine are just two flat sheets of metal!

First lets talk about what you get. Besides the rings themselves, you'll get a FD wedge spacer or two (for use if your derailleur is too low and needs to be moved up and back.) and some small washers for use to spread the cage of your front derailleur if you end up with bad chain rub.  You should leave all of this stuff alone for now. Don't start using these parts until it becomes obvious that you need to. The less extra stuff you need to add on the better your setup will end up.

included shims

There's nothing particularly special about installing the rings onto the crank, there is a small screw and pin that are installed on the large ring before going any further, but otherwise no challenges. There is talk as to what position you should set your rings up in... There are many opinions as to whether the "recommended" setting is optimal (most of this comes from the study on non-round rings) and I'll let you research / decide for yourself, it shouldn't effect the actual installation. For what it's worth, in my opinion for a TT or Tri bike you should leave it as it's supposed to be installed, (numbers hidden by crank arm) and possibly adjust the position for a road bike. YMMV of course.

rings installed... with a little optional bling...

Once the rings are installed it's time to figure out if you are going to need the FD spacer. Of course if you are installing yours on a bike with a clamp on front derailleur you will probably not need the spacer as you have all the room in the world to work with. That isn't most Tri/TT bikes though, so lightly tighten your holding bolt on the FD at what eyeballs as the right height and give the crank a spin. You should have the requisite "penny width" between the outer cage and the outer ring (at it's tallest/closest point... look close, it isn't exactly at 12 o clock.) and you should also have plenty of clearance at the back of the derailleur.  (It's possible the chainring will hit the bottom of the cage if you don't have it right.) You should also probably give the front derailleur a hand shift, as what looks like plenty of clearance in the small ring may be not quite enough in the big ring. Shifting up and down from here is a good idea, as you'll pretty quickly figure out whether or not you've got it close.

It's possible that with your bikes setup you will need additional spacers (again, primarily this is an issue for the bigger chainrings) and the best of these is made by Rotor for their Q-rings. These angled spacers will help solve some of the headaches you might run into (again, chain rubbing bottom of FD in small/small is common. Without this angled spacers it's tough to get the back of the FD down enough while still keeping the outer cage high enough to clear the big ring.) Of course you shouldn't be in small/small combo ever anyway, but sometimes things happen.
Rotor's combo pack... although  a longer bolt is going to be necessary for the bigger one.

I also highly recommend installing a inner chain keeper. (I use K-edge, but perfectly fine cheaper options are out there) Yes, I know many people say it's not necessary, but in my opinion there are often times the chain has a longer than normal amount of distance to drop (like if you start shifting down at the largest part of the pedal stroke and the chain lands at the smallest of the small ring...) and there have been times even with a keeper and "clutching" I've felt like I got lucky not to throw the whole thing. It has certainly sounded like all hell breaking loose.  Of course, a keeper has it's own risks, as it is certainly "possible" to drop the chain between the frame and the keeper if it's not perfectly set (it may be "possible" even then under the right conditions) This is one of the reasons I moved away from my Osy's in 2013, after having a dropped chain in a big race at the end of the season. That was on my Planet X, and that particular day/race I had other mechanical problems which almost certainly directly contributed to that dropped chain, but nonetheless it was enough for me to pull the plug on it at the time. (Call that full'ish disclosure) Back on topic however...

chain keeper installed to keep the chain in the right spot

Once that's squared away, it's time to get the chain on and check that that hasn't messed anything up in the FD area. Again, the primary thing you are looking for at this point is whether the chain will move down from the big ring without getting stuck between the outer cage and the ring.

Also make sure if you have a braze on hanger, the front of the FD cage is not hitting it. This is something that can happen if you raise the FD to near the max height without using any spacers. This is easy to miss at this step but will cause a lot of headaches later if you don't check.

Small ring

Big Ring

Now you are ready to cable your derailleurs as normal. I took the above pictures after already cabling my bike, and like an idiot didn't get a picture of me checking the limit screws on the front derailleur beforehand. To do this I stick a long T-handle allen wrench behind the front of the derailleur (between the inner cage and the frame) and leverage it out to the large ring. (You could also do it by hand but I personally find it awkward to try to turn the crank and move the FD at the same time) You'll know very quickly whether you need to bring in (or out) the limit screws, just make 1/8 or 1/4 turns of the limit screw and try again until you get it close. You can fine tune after you get it cabled.

After you get everything cabled and adjusted you'll likely have to decide whether you want to spread the front derailleur cage or not. (If your FD allows for it)  On the one hand, adding the spacers to spread it can often eliminate some rub in certain gear combinations (mostly crosschaining, but some gears I wouldn't exactly consider meet that criteria) but on the other hand, you are spreading your derailleur cage, which *probably* won't effect shifting up/down, but could in theory.  Personally, I don't add the spacers any more. The first time I set them up I did. In both cases they rubbed some, so I don't see any reason to add it unless you are rubbing in very straight chainline gear combinations.

Now do a little test shifting and make sure you've got everything smooth. With a little time I can get mine to shift very smoothly, and again, that's without any ramps... I'm sure the new ones are much nicer.

A lot of these steps are likely unnecessary if you've picked a more common size of rings. You certainly won't run into any more difficulty than you will on this size combo, so hopefully this is fairly comprehensive. My advice is to not use any "extra" small parts you don't absolutely need when setting them up.

Hopefully this post will help you out if you searched it up having trouble with installation.  I am still a pessimist when it comes to the % power increase that gets claimed, but I also think there is some merit to non-round rings other than more watts. Maybe in the future we'll revisit my old review of them with some updated thoughts.

Thanks for reading! I've been messing with this post for a while now and just seem to keep getting side tracked! Until Next time!

-Christopher Morelock

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