This listing is for an adaptor that will allow you to fix a 104 BCD chainring onto a standard MTB freehub with a Shimano pattern. Working on the same principal as General Lee, OneUp and Hope T-Rex style adaptors. The difference is you can use any size you choose and it can be adapted to many 7/8/9 and some10 speed systems.
And when it wears out you can of course reuse the adaptor with a new chainring. Please check carefuly the back of the cassette you plan to use with a 104BCD chainring to see if there are any clearance issues with the chainring bolts and the arms of the sprockets/carrier that cannot be worked around. Particularly with some 10 speed cassettes that use a carrier for the last 2/3 big sprockets. It requires the end user to be able to make adjustments and modifications to suit their particular setup.
If you are unsure how to fit this or have any questions please contact me BEFORE purchasing. The very tight tolerance on the splines for the freehub may require you to file a small amount of material away for some types of freehub - the steel version in particular. (the item must be undamaged and not modified in any way) Discounts are available for multiples. Please feel free to contact me if you have any questions I will be happy to try and help. The item "40t 42t sprocket/cassette/chainring adaptor/expander MTB 7/8/9 speed" is in sale since Sunday, November 3, 2019.This item is in the category "Sporting Goods\Cycling\Bike Components & Parts\Cassettes, Freewheels & Cogs". The seller is "nathoet" and is located in Bristol. This item can be shipped worldwide.