The Alter Cycles Reflex 300 has a unique bicycle design that utilizes a spring steel down tube and arc shaped top-tube that work in unison to pivot and flex. The dynamic movement looks to extend the length of the pedal stroke while absorbing road bumps.

Alter Cycles represents the latest thinking from Mark Groendal’s refining and tuning his unique flexible top-tube, flexible down-tube bicycle design over the past 35 years. As always, the goal is to maximize the rider’s effort into forward motion. The technology revolves around allowing the rider to increase his power stroke; additionally, some of the spring’s rebound provides momentum to the bike. The company defines this as ARC technology. The crew tested the Alter Cycles Reflex 300 commuter.

The customizable Alter Cycles Rider Fit Tubes.

The bike’s aluminum frame and fork was artful in black matte, nicely offset by a steel spring down-tube powder coated a vibrant red. It should be noted there are six other colors available for this section. We selected a number two spring which is the softest available after trying out a number three and deciding it was too stiff. The “300” was equipped with a mixed SRAM, Shimano drivetrain, Tektro hydraulic disc brakes and an SR saddle. The 700c wheels were shod with Arisun Metro Cruiser 38 mm tires, new to us but not for long considering their performance. They’re fast and handle really well, in both the dry and the wet.

We rode the bike on its intended road surface and found it to exhibit excellent habits. It accelerated rapidly and decisively and rode very smoothly. While we didn’t evaluate the system quantitatively, it was evident that the bike performed as intended. The components, while lower level, functioned perfectly during all phases of the test.

What was surprising was how the bike generated enthusiasm when taken off the beaten path. Trails that are normally for mountain bikes only were dispatched easily. We went with the story the bike was telling us and outfitted the ‘300’ bike in some dedicated off-road regalia, after first swapping out the heavier spring to the #2, our choice for the best performance. We also added Schwalbe CX Comp 700×32 tires, Thomson stem and seatpost, Profile Design riser bars and Brooks Flyer saddle, for adding some extra cushion over larger ruts and holes. Adding a rear rack and we’d be ready for whatever tour or trek that may come our way.

Background Details

The genesis of Alter Cycles was 37 years ago when Groendal removed the top tube of his BMX bike and replaced it by grafting in a piece of his Hexcel ski. Realizing the need for support he modified the frame even more by adding a cable and spring system that replaced the down tube. The flexing design was touted to briefly extend the duration of the powerstroke delivering power more consistently and more efficiently.

The company Groendal formed, Greendale Bicycle Co, manufactured Slingshot BMX, mountain, road, time trial bikes and even one trials bike on which Bobby Lawson won the 1993 NORBA national finals. Their mountain bikes received excellent reviews from the cycling press and John Kukoda, Bicycling Magazine, called it “the fastest mountain bike he had ever ridden”. Generally, consumers did not trust the cable which doomed commercial success. However experienced (old) cyclists, throughout the US quickly recognize the Alter as the obvious evolution of the Slingshot. The Sling Shot Bicycle Company has had several owners but is still manufacturing bicycles.

Fast forward 35 years and Alter Cycles has the latest iteration of the original design. It consists of a patent pending top tube specially designed for vertical flex while remaining structurally stiff in the horizontal direction and a patented arc-shaped flexible down tube. The goal continues to be to turn the rider’s effort into speed as efficiently as possible. To date, it has been reported that some of the staff at Road Bike Action magazine have achieved personal best times when ascending and / or descending favorite routes. Our editors rode the city version with 700c X 38mm road tires on both road and off road trails. While we didn’t collect quantitative data, the bike rode very smoothly over all surfaces.

We’ve enjoyed our time with the ‘300’ and look forward to seeing how Alter Cycles will use their frame design to further improve the bicycling experience.

Frame:Alloy 6061 Aluminum
Fork:Alloy 6061 Aluminum
Tires:Arisun Metro Cruiser 700x38
Brakes:Tektro Auriga Hydro Disc
Rear Hub:142x12mm, Reynolds
Front Derailleur:Shimano Altus
Rear DerailleurShimano Acera
Shift Levers:Shimano Acera
Cassette:Shimano CSHG30 11-32t
Saddle:SR Lookin
Seat post: Aluminum alloy
Handlebars:Aluminum alloy
Headset:Sealed bearing 1.125”
Wheels:Double wall alloy
Weight:17.2 pounds