The PT Rear 180mm adapter allows you to run a rear 180mm disc rotor on your 160/140mm flat mount road frame (as per the Shimano standard). This adapter replaces the 160mm wedge and uses the existing hardware. Please see the fitting notes and pictures. Verified Shimano fitting only.
The aim here is to increase the thermal headroom of your disc, pads, and caliper pistons if you are a heavier rider trying to dissipate large energies in hilly and prolonged fast braking situations. This will increase the lifespan of the pads and discs. The rear disc brake gets lower convective cooling due to a lower relative air cooling velocity, and also suffers from more contamination than the front. A secondary although lesser benefit is an increase in peak braking force. However, if you brake with the same deceleration as a 160mm disc then the braking force will be the same!
Made from 7075-T6 Aluminium.
Please check the disc to chainstay clearance. Some frames may not safely clear a 180mm rotor.
Note 1: The peak braking force will increase by at least 12.5% over a 160mm disc. The increase in braking force is given by the larger disc diameter and reduction in temperatures at the pad. The small increase in braking force should be well within the bicycle's design safety factor but the use of this adaptor is at the user's own risk. It may not be validated by the user's fork, frame, or wheel manufacturer. Any damage, injury or death incurred arising from such use will not result in any liability incurred by Peak Torque.
Note 2: You may use the current Shimano fasteners if you are currently using the Shimano 160mm adapter. If you are coming from a 140mm rear setup, you will need the 2 additional Type B Mounting screws as found here: https://www.bike24.com/p2284577.html?sku=994751
It is recommended to use a low strength thread locker (e.g. Loctite 222) on all fasteners.
I have a tight angle between the chainstay and seatstay, so there was not enough clearance for the flat mount caliper, and it wouldn't fit under the seatstay for a 140 mm rotor, or 160 mm with a standard 160 mm adapter. The Peak Torque 180 mm rear adapter solved this problem for me! It worked great and everything fit up nicely.
Still testing but they are made well and bolted in with no issues at all.