What do you do if your new frame uses Boost spacing, but your wheels don’t? Before you shell out for a new rear hub, D.Fender might have a simple solution. There are a number of factors to consider before you mount up that 142mm rear hub, but it’s worth a look…
The premise for the UN-Boost spacer kit is pretty simple – two 3mm spacers are placed on either side of the hub over the 12mm axle. This centers the 142mm hub in the 148mm dropouts allowing you to keep your current hubs. However, in order to make this work, first you will have to shim out either the rotor or the brake caliper. This shouldn’t be too hard using products like the Syntace rotor shims, or various washers under between the brake adapter. Above, Jarrod Bunk is using one pack of Syntace shims and a small shim on the brake and he says the set up is completely solid. It probably goes without saying that this is likely to void some sort of warranty somewhere, so take that in consideration but I’ve had to do similar things to fat bike forks over the years without issue.
The use of the spacers will also change the chainline of the cassette and move it inward. But if you’re using a non-Boost crankset this won’t be an issue, as the chainline is the same as non-Boost. Finally, it will also probably complicate wheel changes slightly, but if it’s saving you from buying a pricey King hub to replace your old one, it might be worth it. Best of all, the kit is priced at just $8.00 and is made in Pennsylvania. Shipping isn’t included, but it would be a good chance to order up one of their D.Fenders and double up on shipping. Jarrod tells us that UN-Boost spacers for the front are currently in the works along with a few other exciting products coming soon!