First-Hand Experience the Lewis LH4 Disc Brakes on the Santa Cruz Hightower

Installation and Bleeding Process

We updated our 2021 Santa Cruz Hightower with the new Lewis LH4 disc brakes. We opted to install them today as we're testing new brake compounds on our new bikes, and didn't have a spare new bike available. The installation process started by removing the existing brakes.

The bleeding process, facilitated by a Shimano bleed kit and bleed cup, was surprisingly straightforward. Despite the absence of specific instructions from Lewis, we successfully completed the bleeding with the Shimano OEM bleed kit, keeping a Park Tools professional bleed kit as a backup.

Handling Internal Cable Routing

A potential challenge was the internal cable routing, especially concerning the fit of the Lewis Kevlar braided hose through the frame. This, however, proved to be a non-issue, with the routing and cutting to length of the rear hose being completed in less than two minutes. We left extra length on the hose, considering possible future use on our downhill bike.

Bleeding Technique

The bleeding technique involved removing the bleed screw from the lever, setting up the Shimano cup in an upright position with a plunger, minimizing leakage when removing the bleed screw from the caliper.

We flushed Shimano OEM mineral oil through the system, followed by resealing and removing the syringe. After securing the lever with zip ties and checking for air bubbles, we noted excellent brake responsiveness, light lever action, and almost instant wheel lock. The ease of bleeding and the smooth movement of the pistons in the caliper were particularly impressive.

Setting and Adjusting the Brakes

Post-bleeding, we customized the brake settings, focusing on lever adjust and bite point using the included small tool from the Lewis LH4 brake set. The adjustment process was straightforward, resulting in a light feel and an instant bite, aligning with our preferences.

Choosing Brake Pads

We decided against using the supplied metal compound brake pads, opting instead for our Enduro Pro Ultimate pads for the rear and Enduro Pro Resin pads for the front. Initial tests in the Gorilla Brakes HQ car park, even before bedding in the brakes, showed powerful braking capabilities, with both wheels locking up easily.

Bedding in and Overall Impressions

The bedding-in process was seamless, adding to the simple and straightforward overall setup. The performance of the Lewis LH4 disc brakes left us highly impressed. We are yet to conduct a real-world test, which we plan to do soon, and will provide updates on our experience with these upgrades.