Quick Answer: All Spank wheel models with 12x135mm rear hubs, or 12x142mm rear hubs, can be adapted to use with horizontal dropout bicycles, such as dirt jumpers or single speed hard tails frames. Most of these frames use 10x135 rear spacing. NOTE, 12x150mm rear hubs cannot be adapted to fit 10x135mm frames.Spank wheelsets come with 12x135mm, or 12x142mm rear spacing, so must use one of two adapter options in order to fit 10x135mm frames with horizontal dropouts.First, if you are using a 12x142mm hub, you must get either a 10x135mm adapter kit, or a 12x135mm adapter kit to achieve the correct hub width.IF you are using a 12x135mm hub, you can pick from two methods: 1. Purchase a 10x135mm adapter kit which matches your model and revision of wheelset. Use a 10mm bolt on axle, or 10mm QR axle, to secure your hub/wheel to your frame. Note: Spank does offer 10x135mm adapter kits, but does not make or provide 10mm axles. 2. Purchase a 12to10mm Step Down Axle, which will allow your 12x135mm hub to fit into 10mm horizontal dropouts, without requiring hub adapters. Note: Spank does not make or provide 12to10mm step down axles.Single Speed Conversion: If you wish to adapt your Spank rear hub to single speed using a Spank Single Speed Adapter Kit, you must first confirm that you have a Shimano standard freehub body. Single Speed Adapter Kits are not compatible with SRAM XD standard freehub bodies. Spank Single Speed Adapter Kits come with a 13 tooth steel rear cog, and the necessary spacers to adjust the centering of your cog. They fit easily over any Shimano freehub body, and make conversion to single speed quick and simple.