Bike Disc brake bracket frame adaptor bicycle REG / BIG / XL 3 sizes for 140mm /160mm /180mm disc brake rotor (Reg 1/2-7/8 inch for front 160mm rotor) Tell us your rotor size and Front or rear use ! We will custom fit Will work on any bike frame to add disc brakes if we know your rotor size.Also tell us the thickness of the frame tubing near the axle.It Puts the disc brake tabs on any bike right in the same place as welded on Tabs , For E bike axles you need to file the fork area of the bracket to fit on thicker e-bike axles. Bracket Fits on all bicycle frames Front or rear ! For frames with no disc brake Tabs ---Now you can have Disc Brakes.---BIG size is for front shocks that are 0.9" -1.25" thickness. If your front forks are OVER 0.9"thick (like 1.25") then you NEED our BIG 1.25" clamps ( They adjust 0.9"-1.25")--- So Choose BIG for front forks over 0.9" thick. AND XL for front forks that are 1.28"-1.60" thick (this is very rare !) For Rear brakes almost ALL bikes will use the Regular size!(1/2"-7/8" thick) because the rear tubing is very thin on bike frames. ---please tell us what disc size you are using ! There are only 4 disc sizes ! 140mm (very rare) 160mm (very common) 180mm and 203 mm(8 inch disc). If we know your disc size then we can double check and make sure it will work on your bike ! Our REG. size is 1/2"-7/8" thickness. All rear brakes will use this size. The other size is BIG 0.9"-1.25" thickness. The only reason we repeated this size twice is because is has 2 diff. applications. One is for front shocks (usually 1.25"-1.30" thick) OR for BMX or beach cruisers with those really fat forks which CAN be anywhere from 1.0" thick to 1.35"thick. BUT normal front forks are just 1/2"-7/8" thick so they use the REGULAR size ,It's really simple ! Is the tube on your fork thicker than 1.0" or thinner ? Specially made by Busettii Bikes for use on e-bikes and all bikes. Now everyone can have disk brakes. For rear just use this regular bracket 1/2"-7/8" thick pipes. ONLY need to tell us if you are using on FRONT shocks OR very thick front forks (over 0.9" thick). Only BMX bikes have these thick forks ! Most shocks are 1.25" thick so they need the BIG bracket. Just order this item and tell us you need the BIG size bracket !