3T EXPLORO RACEMAX BOOST REVIEW

3T’s Exploro RaceMax Boost adds power

The famed Italian component maker (and bike brand as of late) 3T spent a lot of time ensuring that the standard pedal version of their Exploro RaceMax gravel frame is as aerodynamic as possible. As it turns out, the Italian brand was able to use the same sculpted aero frame to accommodate a battery with only minimal changes.

While the aero benefits may be minimal considering the motor limits assist after you hit 20 mph, efficiency is still efficiency, and owing to its rear hub motor, the Exploro does have some beneficial properties that may surprise you.

THE FRAME

Regular readers might recall the first time we tested the non-assist Exploro (RBA, September 2020) where we reveled in the tire-clearance amount. They made sure the frame accommodated wide tires (up to 61mm) while still maximizing the aero benefits as much as possible.

At its widest, the downtube measures in at 75mm wide, which is ultra wide compared to most road or gravel bikes. Although the original design intent was to “hide” the water bottles from the wind, it also played into 3T’s hand when it came time to house the battery.

“It was more beneficial on slight inclines or just flat areas where you don’t need much torque to keep the motor engaged and actually helping you.”

3T is offering a higher and lower end of the drop-bar bike, as well as a flat-bar version. The frames are available in six sizes, from XXS to 61cm. The frame also has mounts for up to three bottles, including two on the inside of the frame, as well as bosses for one on the underside of the downtube. The underside bosses will also serve as a mount for an optional second battery. The underside of bottom bracket is where you’ll find the charge port with a rubber cover.

THE PARTS

Our Exploro test bike rolled on 45mm deep 3T Discus aero carbon wheels (with a 29mm internal width) and 35mm Pirelli Cinturato tires. An Ebikemotion motor is laced to the rear rim and provides 40 N/m of torque, which equals out to about 250 watts. The motor has four levels of assist that are actuated by holding down the power button (located on the top tube) and then tapping it again to move up through the modes. Inside the down-tube is where the 250Wh rechargeable battery is hidden.

Distinguishing the power assist frame from the non-assist Exploro is nearly impossible.

The 1x drivetrain duties are courtesy of Shimano GRX with a 40T chainring and an 11-42T cassette. The bike slowed down with flat-mount GRX brakes using 6-bolt/160mm rotors. The 3T cockpit components included a 42cm-wide Superego Pro handlebar with a 100mm Apto Stealth stem and an aero Sqaero Team seatpost mounted with a Selle Italia ModelX Superflow saddle.

THE RIDE

The Exploro doesn’t come stock with the widest tires that it could fit, and for the most part the Pirellis are a versatile choice. They roll okay on smooth roads and provide decent traction on hardpack fire roads. On particularly steep dirt climbs, we were challenged to keep traction. What did help was being able to lean further forward than we normally could on the non-assist version, thanks to the added weight in the rear hub. This has been a common theme on many of the rear hub-driven e-gravelers we’ve tested.

An issue that we found was that when we were on a hill and wanted to get going again, it was difficult to anticipate when the motor was going to kick in. The motor didn’t give us much help when we were going up steep climbs. It was more beneficial on slight inclines or just flat areas where you don’t need much torque to keep the motor engaged and actually helping you.

One last detail about the motor is that when it reaches its assist limit it has a constant feeling of engaging and disengaging, which was not pleasant on the bike path where you’re almost always at the limit.

THE VERDICT

The handling shined most in the dirt, and there is a weight advantage in the rear that helps the rear wheel stick to the ground. That seemed to give the front end a lighter feel when we came into tight singletrack corners, which also made us more cautious in general. When it came to steeper climbs in the dirt, we felt like a wider tire would be a great help with traction.

If you’re looking for some extra assist on the climbs or a bit more power to keep up with some friends, there is no doubt that the Exploro packs a lot in this bike. From the aerodynamic frame shapes to the fact that you can hardly tell it’s an e-bike, just remember that with the Class 1 motor, which cuts off at 20 mph, you’ll have a tough time keeping up with a group ride or other Class 3 e-gravel bikes.

Shimano’s GRX gravel drivetrain utilizes a wide range with a 40-tooth chainring and an 11-42 cassette. 3T’s symmetric dropped chainstays allow a max tire clearance of 61mm.

We think the biggest thing holding this bike back is actually the motor and battery. Like we said, if you’re just on flat bike-path stuff and not charging hard, the bike is helpful. For us, every gravel bike we ride also does double duty as a road bike, and the 3T’s power-to-weight ratio works best in slower-speed applications. If you plan on working out hard on the bike, you’re almost better off leaving the motor off so that you don’t have to feel the bike kicking on and off.

“3T made sure the frame accommodated wide tires (up to 61mm) while still maximizing the aero benefits as much as possible.”

3T offers the flat-bar and drop-bar versions at $6999, and the higher-end build will come in at $9999. Ebikemotion offers an app that allows you to see stats like mph, range and odometer, which should take any confusion about
which power mode you’re in.