Cycling Out Of Sumner (COOS) 2026 #10: Sumner to Mercer Island Loop (Moderate)

We’re excited to announce that Cycling Out Of Sumner (COOS) will once again host a 2026 Spring Training Series with four pace groups available: 

• Steady (12–14 mph)
• Moderate (14–16 mph)
• Brisk (16–18 mph)
• Vigorous (18–20 mph)

The series will take place on Saturdays from April 4th through July 4th.

COOS is designed to help riders build endurance and strength throughout the season. Distances will gradually increase each week, culminating in a 100-mile century ride as the final event. All pace groups will follow the same basic route each week. There may be modifications to routes for the faster pace groups.

Ride #10: 

This beautiful ride takes us through Auburn, Kent, and Renton and up and around beautiful Mercer Island. We will then head west across the I-90 floating bridge and down along Lake Washington back through Renton, Kent, Auburn and home to Sumner.

Riders should register for the pace group they expect to start with. Groups can be adjusted before or during the ride depending on how participants are feeling. Registration is required to join the ride.

We will meet at the southeast corner of the Sumner Fred Meyer parking lot. Restrooms are available at the start location, and possibly at Auburn Walmart (mile 9), Gene Coulon Park (mile 26),  Macrina Bakery & Cafe (mile 45), Seward Park (mile 52), and Auburn Walmart ( mile 73) depending upon need. Please be ready to ride at the start time listed above. A mandatory safety briefing will take place before the ride begins. All riders must attend the safety briefing to participate. While the area typically has good foot traffic, property crime can occur quickly—please do not leave bikes or valuables unattended.

We will climb and descend hills at individual paces and regroup regularly. When riding on multi-use paths, we will observe posted speed limits (generally 15 mph, and occasionally 10 mph).

Please bring a spare tube and the tools needed to repair a flat. Other recommended items include a phone, ID, cash and/or credit card, ORCA card, water, and a small snack. If roads are wet, riders should have full fenders; otherwise, you may be asked to ride at the back of the group.

Ride Leaders will not distribute cue sheets. Riders may view the route online, download it to their own devices, or print their own cue sheet if desired (see the Route Map link).

New riders are warmly welcome! Please remember that helmets are required for all Cascade rides.

Weather and Safety Notice:
If weather conditions meet the cancellation criteria listed in the Weather Status, or if other hazardous or unforeseen circumstances arise, the Ride Leader will cancel the ride and notify all registered riders by email. If a ride is canceled at least two hours before the start time, Ride Leaders will not be present at the start location. Please check for updates before heading out.

 hope you’ll join us!