Now you can trim weight from your bike with alternatives to heavier steel chainring discs, by using your favorite chainring and a new lightweight spider that mates to our freewheels.
The spiders are made from AL 6061-T6, an "aircraft" grade aluminum alloy with high tensile and yield strength and superior resistance to corrosion. At 4.8mm thick they are strong and resilient yet still save well over half the weight of an equivalent size steel chainring disc. They fit onto our flanged crankset freewheels and our chainring adapter, attached through one of two sets of five holes in the spiders. One set of holes handles countersunk screws, especially for spiders set on the outside of the freewheel flange. The other set of holes handles any standard flat-bottom machine or cap screw.
For some builds you are going to want that steel disc, but for many setups the steel is overkill.
Posted by Jay Guess on 11 15 2015
This is a quality machined part - however it does not bolt directly to the HD flanged freewheel as stated. The bolt hole circumference is too small, I will need to drill out 5 of the mounting holes to suit. It also looks slightly different to the image.
SBP Comment: Jim is checking this. Never had a problem before.
Posted by aaron thies on 03 21 2013
constructed well, however, it does not have the five smaller holes shown in the picture, so i could not use this part, and had to go a different route. ONLY HAS THE 10 FREEWHEEL HOLES, AND THE 5 110MM HOLES, NONE FOR SMALLER SPIDER, LIKE IN PICTURE!!!