The standard chainring selections as supplied in the factory packed boxes are:
Road Double 53/39
Road Triple 53/39/30
MTB Triple 44/34/24

We can accommodate customers who want to purchase a Rotor System (“RS”) with different chainrings than the standard configurations.  We will re-pack the RS box with the chainring selection specified by the customer.  Some changes are at no charge and some changes will have a ‘chainring upgrade’ charge, which is the cost difference between the chainrings.

A few comments worth noting:

• The outer chainrings from the RS03 & prior versions have a ‘chain catcher pin’ to prevent the chain from wedging between the crank and chainring in the inadvertent event of an ‘over shift’ to the outside of the outer chainring.  The RS4 version does not have the ‘chain catcher’ pin.
• The outer chainrings have pins and ramps, and a special ‘toothing profile’ that helps the chain shift faster with less chain chatter.
• The middle position chainrings of the triple versions have pins and ramps, and a special ‘toothing profile’ that helps the chain shift faster with less chain chatter.
• The RS mechanism, because of its configuration, required the inventor to use a unique four bolt pattern for the chainrings.  Therefore, chainrings for the RS are a different bolt pattern than other crank system chainrings.

1)  For the outer position:
On road double or triple:
53T with pins & ramps is the standard size that is supplied by the factory.
As options, in lieu of the 53T, we can supply:
56, 55, 54, 52, 50 or 46T.  (63T is expected to be available in Spring of 2004).
Aero rings in 53,54, 55, 56,58,60,63 are now available.

On MTB triple:
44T with pins & ramps is the standard size that is supplied by the factory.
As an option, in lieu of the 44T, we can supply 46T.

2)  For the inner position on a road double:
39T without pins or ramps is the standard size supplied by the factory.
As options, in lieu of the 39T, we can supply:
36, 40, 41, 42, 44 or 46T.

3)  For the center position on a road triple:
39T (with pins & ramps) is the standard size that is supplied by the factory.
As options, in lieu of the 39T, we can supply:
36* (the * indicates that this size does NOT have pins & ramps).
40*, 41*, 42*, 44* or 46T (the * indicates that these sizes do NOT have pins & ramps).
Please note: we currently have 46T & expect to have 42T & 44T with pins & ramps soon.

4)  For the inner position:
On road triple:
30T (without pins & ramps) is the standard size that is supplied by the factory.
As options, in lieu of the 30T, we can supply 26T or 36T.

The most popular sizes for recumbents are:
53/39/30
54/39/30
53/42/30
53/44/30
We suggest that recumbent cyclists carry a 26T chainring in their tool bag so they can change the 30T with the 26T in the event of a very steep and/or long hilly route.

Please note that the finish of the optional chainrings is not always the same finish as the chainrings that are originally supplied with the RCK-03, RS03 or RS4.  In reality, the finish does not matter mechanically, but if a customer is unaware of this situation, they might be disappointed when they receive their RS with chainrings of various different finishes.  The various finishes are:
1) Black anodized & machined, which is an attractive black & silver color (RS4).
2) Hard anodized, which gives a gray color finish (RS03).
3) Clear anodized, which gives a silver color finish (RCK-03 road).
4) Clear anodized to give a slight tinted-silver color finish (RCK-03 MTB).
The reason our inventory of "spare" chainrings has different finishes is because we purchase spare chainrings at various different times, so "we have what we have"!