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Review: 3T e-Exploro RaceMax will Boost your e-bike gravel range and your average speed

3T Exploro Race Max Boost gravel e-bike powered by ebikemotion, bikepacking still life
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I’ve been riding the new 3T e-Exploro Race Max Boost gravel e-bike for the past month or so, and have come around to a number of actually good reasons to electrify a gravel adventure bike. At least in its European version, this e-Exploro isn’t really going to make you a lot faster – you’ll quickly ride past its pedal-assist speed limit. But with the relatively smooth power boost & lighter battery of the eBikeMotion e-bike system, it can truly extend the range of your adventures. And add on the optional external battery, and it’ll take you much further than expected…

In-depth Review: 3T (e)Exploro RaceMax Boost carbon gravel e-bike

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, riding

When 3T told me that they had a new (e-)Exploro Race Max Boost e-bike coming soon, I wasn’t yet sure what to think of the idea. The good old-fashioned pedal-it-yourself Exploro RaceMax was already a great-riding carbon gravel bike. I rode & reviewed it last summer. And I’d be happy to continually rotate it through off-road, fast gravel & bikepacking modes…

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, non driveside

So, why would I want a 3.5kg heavier version with a little motor and battery hidden inside? I’ve ridden a number of e-bikes over the years, and plenty of them had been fun to ride. But outside of maybe an e-cargo bike or commuter e-bike, I haven’t felt the burning desire to replace any regular bike in my stable with an e-bike.

Could the e-Exploro change my tune? What new kind of riding would it open up for me? And what type of other cyclists would really benefit from an Exploro RaceMax Boost?

Let’s find out, shall we?

Why e-gravel in the first place?

3T Exploro RaceMax Boost gravel e-bike, stealth ebikemotion X35 pedal-assist, Xtra Power external battery

What makes the 3T Exploro RaceMax Boost (or as I’d like to call it, the e-Exploro) unique is the lightweight, relatively smooth & low-ish power Mahle ebikemotion X35 e-bike powertrain. It’s not a brand new system, and this isn’t the first or most affordable e-bike to get it.

But, then there’s the fact that 3T fits all of that into what is effectively the exact same frame as the standard 3T Exploro RaceMax gravel bike. So you get the same off-road adventure-capability in an e-bike that weighs around 12.4kg (without pedals or cages) and doesn’t look actually like an e-bike.

Actual gravel e-bike weight

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, actual weight 12.375kg

Let’s first talk about that weight.

Comparing it to a dozen mid to high-end gravel bikes I’ve ridden in the last 18 months or so, those weighed an average of 8.7kg (8.3, 8.3, 8.5, 8.6, 8.6, 8.7, 8.7, 8.7, 8.7, 8.8, 8.8 & 9.4kg). So, 10-12kg (depending on spec) for e-gravel sounds totally manageable.

You could even compare it to the very niche, but still real 13.4kg for the steel Bombtrack Hook EXT ADV with an MRP gravel suspension fork, dropper post & MTB tires (or its later 11.6kg incarnation with lighter wheels, tires & no dropper). That’s a very different gravel adventure bike, but it helps put the extra weight into perspective.

The 3T Exploro RaceMax Boost isn’t light for a gravel bike, but it’s actually manageable to pedal even without the Boost.

Actual gravel e-bikepacking weight

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, actual weight

In fact, when I took the e-Exploro bikepacking, I quickly tacked on an extra 9kg with everything I needed for a relatively quick, lightweight weekend trip. That included three bikepacking bags loaded up with tent, sleeping bag, mat, regular tools, warmer camp clothing, and 1 1/2 days’ worth of food & water.

Sure, that did also include the optional extra 1.7kg for the external 208Wh Xtra Power battery & its special cage – because I was afraid how far the e-bike’s built-in battery would take me without recharging. But you could do without that if you aren’t riding super far or are camping/sleep somewhere with electricity to recharge.

(In the end, I used about 70% of the combined capacity riding 75km loaded in the mountains, with a bit of friendly pushing another loaded rider up a few steeper climbs).

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, s24o bikepacking

But really, I usually don’t think twice about loading 8kg of bikepacking gear onto a 9kg gravel bike for a weekend adventure ride (not to mention the fact that I weigh 80kg). So does 3.5kg of battery & motor, or 5.2kg if you want more range, does that really matter?

Is a gravel e-bike going to make me faster?

3T Exploro Race Max Boost gravel e-bike powered by ebikemotion, riding

One of the big issues that keeps people from accepting e-bikes (myself included) is the perception that e-bikes will make riders faster, and that they didn’t earn that extra speed. Here is where it gets a bit complicated, varying depending on where you are.

In Europe (where I am, and 3T is), the 25kph pedal-assist limit means that once you get above that speed, this e-Exploro isn’t going to help you anymore, and you’re pedaling on your own. (In reality, there’s a 10% margin of error / fudge factor allowed in the EU regulation, so you’ll really still get some support up to almost 27.5kph). My regular gravel rides tend to average 22-25kph, so about half of the time the e-Exploro was helping me, and half the time I was riding above its assist speed.

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, road

In practice, anytime the road or terrain was pointed downhill, flat, or even a gentle <2% rise I was cruising faster than the motor would give any extra pedal-assist. When I rode with my wife on her regular gravel bike, she would make sure we were always cruising along at 29-30kph so I had to really work for it.

But once we started climbing and the speed dropped a bit, the smooth power of the ebikemotion motor really kicked in, and it felt like a tailwind blowing you up the hill. Topping out at 250W of support in Turbo mode, you get the most of that power around 20-22kph. The second Medio support mode tops out around 150W of pedal-assist around 15kph and remains steady for longer.

3T says Eco mode delivers around 60-85W of even more constant support, but I never really felt like that was enough to justify the fact that you spent 7000€ on an e-bike and were carrying the extra 3.5kg around. If you have it, why not use it!

I suspect that Medio & Eco modes might make more sense for the US market where the support continues to quite a bit higher speed of 32kph/20mph. There you’d want to both extend the battery range and maybe not rely so much on the extra support even while riding on the flat.

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, off-road climb

But for me riding in Europe, Medio mode offered a nice smooth transition on and off of pedal-assist support while riding smoother surfaces and over rolling terrain. And Turbo mode delivered the full, strong support when trying to maintain a high climbing speed up gravel & other off-road climbs, as well as when I was just trying to maximize my average speed overall.

So did I get faster? Yes, my gravel ride average speeds generally went up from 22-25kph to 25-27kph riding the 3T Exploro RaceMax Boost gravel e-bike. But my max speed didn’t go up at all. I did have to set some rides on Strava to e-bike mode and make them private so it wouldn’t mess with KOM stats, though.

How easy is riding a gravel e-bike really?

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35  review, commuter

Another controversial issue is the thought that e-bikes are the easy way out, taking the real physical effort out of riding. That certainly can be the case. One of the great side benefits of testing the e-Exploro over the last several weeks has been commuting to work in Prague on it. In the morning, I can cruise uphill spinning a quick cadence in Turbo mode, just below the pedal-assist speed limit, and barely break a sweat.

Then, I can either take a leisurely after-work ride home, or tack on an extra 20-30km with a gravel detour at a much quicker pace. The Exploro RaceMax Boost definitely increased the average speed of my ride to the office. And now that weather has gotten warmer, the no-sweat commute will be the thing that I miss most when I send the e-bike back to 3T.

(I guess I can’t wait for the e-cargo project bike I’m thinking about next…)

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35  review, physical effort
6hr effort – gravel bike (left) vs. gravel e-bike (right)

But it doesn’t have to get easier. The smooth power transition, and the fact that support tapers off at 25kph meant there was plenty of opportunities to push it too.

Look at those heart rate summaries from two long, 6 hour gravel rides I did in the last month, over a similar hilly mix of road and technical off-road in the same cool & mildly windy weather. The one on the left was on an 8.7kg carbon gravel bike with my wife at an average of 22.1kph and about 2.5hr, 41% of the ride at Zone 3 Tempo or above – meaning when I was really pushing hard to maintain that pace. It was a fun but generally tough ride. Strava calling it Historic seems a bit exaggerated, but does mean I’ve not been doing enough all-day efforts over the last half-year of COVID restrictions.

The one on the right was a solo ride on the 14.4kg setup of the Exploro RaceMax Boost with the extra battery. I spent 52.2% of that e-bike ride at Z3 or above (51 mins more than on the bike) and averaged 26.2kph. It was, by all means, a harder effort, even with the pedal-assist support along the way.

Actually, trying to get the most out of the battery and motor can be a lot of work. It gives the most continuous support if you keep it in the sweet spot around ~22-24kph and maybe a cadence of 80-100rpm. Maintaining that over varied terrain and changing grades required decent power output from my own legs, and was sure to keep my heart rate up.

Looking back, I’d be curious if I could track/log the power output of the hub itself and be able to compare that to rider power input via a set of power meter pedals.

What’s the range of a lightweight e-bike?

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, long distance mode

Here’s where all the variables come in, but you can really go pretty far. Note that I rode 166km on the internal 250Wh battery, plus the 208Wh extender. I got home with just 3% of the internal battery remaining, and support up the last hill maxed out around 20-25% of the 250W total power.

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, range
displaying real-time power assist (W), battery level remaining (% of 250Wh), estimated assist distance remaining (km)

This is where part of the fuzzy math comes in. With any e-bike (or any battery-powered electric motor for that matter) as the battery drains, battery voltage decreases, and the peak power output does too. Essentially when you hit 25% battery level, the e-bike controller button shift to red, and you’ll be getting only about half of the original 250W pedal-assist. Under 15% battery remaining, support power decreases again, and under 5% it felt like you’ll never get more than a quarter of the original power.

All this energy rationing is both to protect the battery, but also to help get you home those last few kilometers. If you have a phone that feels like it lasts forever at 1% when the screen brightness automatically dims all the way down… it’s a feeling like that.

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35  review, riding view

With the regular internal 250Wh battery alone, I could usually get 60-70km of quick-paced on & off-road riding (500-600m of climbing) before I got to that 25% tapering threshold. At which point you could easily keep riding for another 30km, but the support level at the end of the ride would end up noticeably decreased.

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35  review, app tracking
ebikemotion app: full external battery on, external battery exhausted, external battery charging internal battery (l-r)

What I did realize though is that adding the external battery had a big positive effect on the range before the reduction of power. Since the system drains the external battery completely to keep the internal battery topped off. That way, I rode 83km before the external 208Wh was drained (internal still at 90%), then I crossed the 25% noticeable support reduction after 133km total. The smart battery management effectively gives you an extra 10% of range before it needs to dial back the assist.

So real range at full assist was about 65km for me with the internal 250Wh battery, 130km with the extra 208Wh battery attached.

Complete range down to <5% battery and reduced assist at the end was about 90km with the internal 250Wh battery, 165km with the extra 208Wh battery attached.

3T Exploro RaceMax Boost gravel e-bike, stealth ebikemotion X35 pedal-assist, biekpacker

An important point to note, 3T intentionally put the charging port in the rare position under the bottom bracket to actually improve longer-range usability. That means if you do buy the optional extra external battery (I recommend it if you want the most versatility), that extra 1700g mounts the weight very low. And it doesn’t take up any room for water bottles or bikepacking bags inside your frame.

The battery doesn’t care about mud & water, so put it down there out of the way. And while the charging port seems exposed, it is fully waterproof, gets a snug-fitting rubber cover, and is forward facing so it doesn’t get that much mud.

So what are the e-bike downsides of the Exploro RaceMax Boost?

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, cockpit view

Remember how I said it was 7000€ (or $), that’s a big downside. And that extra battery will probably cost at least another 600€. Yikes.

Other than that, I’m still not a huge fan of 3T’s single cable routing right behind the headset, or the fact that the front brake line always seems to rub against the headtube. That cable routing sometimes gets in the way of bar-mounted accessories, and always complicates top tube bag placement.

Now, the e-Exploro complicates things further with the ebikemotion iWoc One control button behind that. A toptube pack is my first & favorite bag for any long-distance gravel or adventure riding, and it’s not realistically possible here. Even strapping on a bikepacking frame pack was tricky to get around the button.

The Exploro RaceMax & Exploro RaceMax Boost would both benefit from fully internal cable routing in my mind, even if that is a pain for setup or cable replacements.

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35  review, commuter fenders

The Exploro RaceMaxes also includes hidden mounts for a set of custom 3T fenders, but I’ve never seen those and they don’t appear to be available on 3T’s website. Fenders would make this e-bike much more versatile (it’d be great if they were included). I pushed some SKS Raceblade Pro XL fenders to the limit to get enough coverage for commuting in the rain on the road.

Also, the tight clearance between the tire & downtube limits the use of my favorite Ass Savers Mini Mudder, which results in more tire spray on my glasses, even around the massive frame tubes.

Final Thoughts: Has the 3T e-Exploro RaceMax Boost made me an e-bike convert?

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, mud

Am I an e-bike convert, now? No, not exactly. But I can see the rationale. And I totally understand how this e-bike could open up gravel riding and even bikepacking to a new group of cyclists.

While e-bikepacking sounded like a silly idea at first, I can see how the e-Exploro RaceMax Boost could really open up this type of adventure to a lot of riders who want to take shorter bikepacking trips or lightweight multi-day credit card touring trips. Those who are afraid of pedaling a loaded down bikepacking bike around will get all the sense of adventure and even the same sense of accomplishment from riding the 3T Exploro RaceMax Boost e-bike.

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35 review, gravel riding

And for those cyclists who ride regularly with someone much lighter than them (remember I said I weigh 80kg, well my wife weighs 50kg) and struggles to keep up, some extra watts of boost might be a big help. My wife and I ride at a similar level, so even though she generally climbs faster than me, this e-bike would make that much dynamic much more lopsided in my direction. If she rode the e-bike, I would never see her again on the climbs!

3T Exploro RaceMax Boost gravel e-bike ebikemotion X35  review, commuter

I do often ride with one guy who’s both lighter and always more fit than I am. But, I’m happy to make him wait for me at the top of the long climbs, or ride with me on his rest days, or just for me to have to push harder. I could possibly see having an e-gravel bike in fifteen years when my kids get fast and build endurance, and I… well, get old. Or if I ever had an injury or other health issue that kept me from pushing my body as hard, then an e-bike might be great.

But until then, I still have enough energy in my legs to pedal, so I’ll stick with the regular Exploro RaceMax.

Apidura City Backpack, waterproof bikepacking tech in city commuter bag, riding

But when I send this 3T e-Exploro RaceMax Boost back to Italy, I’m sure I’m going to realize how much I miss it. And my short ride to work is going to become a workout again, instead of just a way to get some morning fresh air.

Hmm… maybe a gravel e-bike would be nice to have around?

Check out the full tech, pricing, options & availability in our e-Exploro launch coverage. 


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3 years ago

You must be a pretty weak rider if a 15mph ebike is gonna help increase your average speed…

3 years ago
Reply to  nooner

you must be pretty weak at math if you don’t understand averages…

their top speed will not increase. they will be faster when accelerating from stop, or any other time they would normally be going slower than 15mph.

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3 years ago

Damn, that’s cold.

3T enthusiast
3T enthusiast
24 days ago

Hi Cory,
is it possible to convert the boost (e-gravel) bike to be a normal gravel bike by knowing that is basically the “boost” is only a module that was installed in the frame and can be pulled out from the frame.

Any thought about that?

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