To run the forums, host the website, and travel, I charge a universal service fee for my reviews. This in-depth review was sponsored by BULLS North America. My goal is to be transparent and unbiased, this video and written review are not meant to be an endorsement of BULLS products.
BULLS is a German electric bike company that was formed through a dealer coop in Europe, striving for quality and value. The GRINDER EVO is their $5,000 gravel grinder model, complete with drop bars, that expands upon the older DAIL-E GRINDER that I covered in 2017. That one used a lighter external Bosch PowerPack 500 battery whereas the new EVO upgrades to an internal Bosch PowerTube 500… same energy capacity, but with a nicer aesthetic and lower weight distribution. This ebike has space for two bottle cage accessories, and comes stock with a magnetic MonkeyLink adapter on the downtube. You can remove this accessory and mount a standard cage, or pay $46 for their special bottle. That bike featured Shimano Di2 electronic shifting, weighed ~3.5lbs less (plastic fenders, lighter battery), and came with integrated Supernova lights… but it cost $800 more. If you want integrated lights on the GRINDER EVO, you’ll have to pay an additional $170 for the MonkeyLink light set. I really appreciate that they’re removable, but wish that the headlight was aimable. Also, I feel that backlight could limit your minimum saddle height when attached and get blocked if you’re wearing a long shirt or coat that hangs down. Unlike the DAIL-E GRINDER, the EVO does not have reflective tires. Instead, you get studded tires for mixed on and off-road use. The volume is a bit lower at 28″ x 1.5″ vs. 2.0″ but they still include puncture protection. BULLS opted for a unique metallic gray color this time around, verses black, that might stand out a bit better in low light conditions. There’s only one frame color choice, but I love the matching motor cover and suspension fork. This ebike looks excellent, and it should fit pretty well with three frame sizes to choose from and a vast network of dealers to visit for test rides. No mid-step or low-step frames here, just the lightweight, stiff, traditional diamond high-step. Body position is somewhat forward, depending on what hand position you take (flats, hoods, drops) and the spring suspension fork really takes the edge off of large bumps. I’d consider swapping the rigid seat post for a suspension post for further comfort, but this might cause problems with the rear light again, because of how it sticks up. I love that BULLS has upgraded the disc brake rotors from 160mm to 180mm to provide better braking power, and you still get incredibly fast motor response and shift detection because it’s running the same Bosch Performance Line Speed mid-drive. BULLS included additional mounting hardware at the rear, so you could use a different rack (perhaps one with a top platform for trunk bags or child seats), and a cafe frame lock. I like most of the changes that the EVO model brings over the DAIL-E GRINDER, especially the lower price, but must admit that I prefer the fender mounted Supernova LED light better. The alloy fenders here are going to reduce rattling noise, but they add to the heavier overall weight. I also miss the removability of the Bosch Intuvia display panel and easier remote button pad. The Purion fits well visually, reducing handlebar clutter, but doesn’t offer a functional Micro-USB charging port. BULLS mounted it higher up, which makes it difficult to reach, and the buttons can be inconsistent at times (aim for the right edge of the + and -, near the LCD screen).
Driving the electric bike is a sport Bosch Speed centerdrive motor. It offers up to 63 newton meters of torque and top speeds of roughly 28mph (45km/h). Even though it’s not quite as powerful as the CX, which only goes 20mph (32km/h or 25km/h in some markets) it’s still plenty powerful if you shift into lower gears when climbing. Note that the GRINDER EVO is geared for speed more than climbing. The cassette offers 11-42 cogs and the chainring is 22 tooth (equivalent to a traditional 55 tooth). The motor relies on a controller that measures rear wheel speed, pedal cadence, and pedal torque over 1,000 times per second! As it responds to pedal input, it also listens for pressure changes originating with shifts, cable movement, and ultimately derailleur positioning changes. This is called shift detection, and the result is smoother gear switching and less wear on the chain and sprockets. This Bosch Performance Line motor weighs about 8.8lbs and is integrated through a custom bottom bracket design that maximizes ground clearance and looks great compared to the standard plastic bezel used by many competing brands… see the Riese & Müller Supercharger for comparison. The motor utilizes a smaller proprietary chainring that spins 2.5x for each crank revolution, and that allows it to be fast, grip the chain well, and produce great power through a reduction gearing configuration inside the motor… but the design does introduce a touch of drag when pedaling unpowered or above the maximum supported motor speed. While I really like this mid-drive motor and trust the consistent performance and reliability of Bosch, I miss the one-way clutch and two-way shifters that Shimano offers vs. SRAM. I also missed seeing a slap guard on the right chain stay, but that might have been due to this being a demo model… and those are easy to get aftermarket if you want to keep the paint from getting greasy and chipped up.
Powering the BULLS GRINDER EVO is a Bosch PowerTube 500 battery with bottom loading design. It comes with a color matched alloy cover that protects it from impacts and blends into the frame beautifully. Removal is a bit tricky because of the limited space between the downtube and font fender, but the mounting system offers a two-step release to keep the pack from dropping out and taking damage. I love that putting it back in does not require the key to be inserted or twisted in the locking cylinder like many competing designs from Trek and others. You just push the pack up and listen for it to click into place, as shown in the video review above. This battery can be charged on or off the bike frame, and the charging port is located on the left side, which is a bit in the path of the crank arm… Also, I feel that the rubber cover for the charging port can be tricky to get seated again after it is unplugged, but I appreciate the little leash that keeps it from getting lost. For more information on this battery, check out the in-depth review on the EBR forums here. While it’s not as lightweight, compact, or easy to swap between different ebikes as the PowerPack 500, it does look good and open up the frame for more accessories.
Activating the drive systems on this ebike is fairly straightforward. You charge and mount the battery then press the power button on the top edge of the little display panel, which is mounted on an accessory bar just to the left of the stem. This is the Bosch Purion display, one of the nicer compact offerings on the market right now. It cannot be swiveled to reduce glare easily, is not removable for protection, does not show as many menus, and does not have an active Micro-USB charging port like the larger Bosch Intuvia display that was used on the DAIL-E GRINDER. However, it does keep the handlebars open, and probably contributes to the lower price of this model. Even though the display is a bit smaller than some competing products, it’s intuitive enough that you might not look down that often to read it. Also, you might be able to set it and forget it because the motor controller is so responsive. It would be nice if Bosch offered eMTB mode for their high speed motor, because this “all in one” drive mode requires less interaction, and that would suit the less convenient button positioning here. Anyway, I have grown to accept the Purion, but do have a few tips for use as follows. The + and – buttons, which raise and lower assistance, are designed to click in at an angle towards the right. They are attached near the left edge of the control pad and pivot in towards the LCD. With practice, I have found that the right edge is really the sweet spot for consistent clicking. Sometimes the lower left and middle areas can be inconsistent or non-responsive. The screen itself glows faint white at all times, which shouldn’t draw much power. Holding the – button will cycle through trip distance, odometer, assist level, and range. And, the range menu is dynamic, so you can see the bike calculate how far it thinks you can go before the battery completely drains based on the last mile of riding, your current state of charge, and the chosen level of assist. This helps to make up for the very basic 5-bar charge indicator on the left side of the battery and the display which isn’t as precise as a 10-bar or percentage readout seen on some competing displays. On the lower edge of the control pad is a walk-mode button. Press it once and then hold the + button to have the motor slowly assist you when walking the bike (you must be in Eco, Tour, Sport, or Boost for walk mode to work). It’s useful for crowded non-bikeable areas like parks, or if you get a flat tire, and not all companies have it enabled, so props to BULLS. I’ve created an in-depth Bosch Purion review in the EBR forums for more information, just like the motor and battery :)
As always, I welcome feedback and corrections in the comments section below. I’d love to hear your thoughts on the older DAIL-E GRINDER if you owned or borrowed one, and I believe BULLS is still selling that one in North America. You can engage with other owners and share your pictures of the bike with different accessories or modifications in the BULLS electric bike forums, and I wish you many happy and safe rides! I could see this being a fun commuting platform or even work for touring/trekking if you bring the charger in a set of panniers.
- Gravel grinder electric bikes are pretty rare, but they follow a popular trend in the industry that combines efficiency and sporty ride feel with versatility of trail bikes, BULLS pulls it off very well here
- I was impressed that the bike only weighs ~52lbs considering that it uses thicker thru-axles, has wider gravel tires, comes with metal fenders and a rear rack, a suspension fork, and utilizes the heavier Bosch Performance Line Speed motor and PowerTube battery
- BULLS upgraded the disc brakes on this new version of the GRINDER compared to the one I covered in 2018 which only had 160mm vs. 180mm rotors, the larger size provides a better mechanical advantage over the wide 700c wheelset which I believe is important for riding at higher speeds, hydraulic brake levers offer adjustable reach to fit different hand sizes
- The front wheel connects with a sturdy thru-axle for added strength and steering response, both wheels have quick release so you can perform trail maintenance easily and adjust for disc brake rub
- High quality gravel grinder tires with higher air volume, puncture protection, and studded tread provide traction, float, and comfort in a range of conditions, they compliment the adjustable suspension fork which offers 63mm travel and can be locked out for efficient performance in smooth environments
- BULLS has added a little alloy guard to reduce pant leg contact with the chain and chainring, I love how compact they managed to make their motor casing, and appreciate the color matched casing and tough skid-plate below
- Available in three frame sizes so you can really dial in fit and comfort, I think that this is especially important for more aggressive bikes built for longer rides and higher speeds
- I love that BULLS has included MonkeyLink magnetic light and fender connection points, if you do add lights to this ebike, they will run off of the main rechargeable battery for convenience and are super easy to attach and detach for different rides or safe keeping
- There’s actually enough room for two on-frame accessories here because of the integrated PowerTube battery pack, it ships with a magnetic MonkeyLink downtube bottle adapter (though the bottle is sold separately), and there’s another set of bosses on the seat tube… yes, you can remove the MonkeyLink adapter and just use two standard bottle cages if you want
- Great kickstand position and hardware, it doesn’t get in the way while pedaling and won’t cause pedal lock, the stand is adjustable length so you can position the bike in uneven terrain
- BULLS chose to build their battery lock design with an ABUS locking core, and the keys come with a little card that has a code on it, so you can order matching locks and other accessories, this is a unique program that could help you reduce clutter on your keychain and order replacement keys more easily
- Given the high-capacity Bosch PowerTube 500 battery, it’s nice that BULLS opted to include the faster four amp Bosch charger, it’s relatively lightweight at ~1.7lbs and fairly compact, so you can bring it along on rides to top off when taking a break
- With the Bosch Performance Line Speed motor, you get access to relatively high torque output, 63 newton meters, and can consistently ride over 25mph (up to nearly 28mph with increased effort) which could shorten commute times and feel more comfortable when riding with traffic
- The Bosch motor controller is extremely smart and consistent, it measures rear wheel speed, pedal cadence, and pedal torque over 1,000 per second while also listening for pressure changes from shifting and then easing off, this protects the drivetrain a bit from mashing
- The bike has walk mode enabled, which is especially useful if you encounter a section of trail that you aren’t comfortable riding or maybe you get a flat tire, considering that the bike weighs ~52 lbs and has pannier racks for cargo, it’s nice to get help moving it along in some situations
- Another great feature with Bosch Performance Line motors is that they can support higher pedal rates without fading out and losing power, you can reach 120 RPM (pedal strokes per minute) and the motor will still be there for you, this allows you to downshift when going into a hill without losing support or just spin faster because you prefer that
- Excellent two year warranty covers everything on the bike, including the motor, battery, and display system with a vast network of dealers in the US and other parts of the world who can help with fit and maintenance
- The SRAM drivetrain offers an 11-42 tooth cassette with 11 sprockets so the steps between each shift are more subtle, it offers low enough for climbing but still feels comfortable at high speeds
- With all of the Bosch motors, there’s a shift detection software system built in that can sense that gears are being changed and it tries to ease off of the power to reduce strain on the drivetrain, it’s not perfect but it’s better than nothing, the only other drive systems I know of which do this are some Impulse motors and some customized Bafang systems which are usually installed as kits
- Battery and motor weight are kept low and center on the frame which improves stability and handling, with the main triangle section open on this electric bike, you can more easily lift it and hang it from some car and bus racks
- The battery pack can be charged on or off the bike frame (for convenience, battery protection, and reduced weight for transport), I recommend storing packs in a cool dry location to keep the cells healthy
- Not every electric bicycle company has mastered the design aesthetic of integrating the Bosch motor as well as BULLS in my opinion, look at how it’s angled up and incorporated into the seat tube and downtube to raise ground clearance and just not stand out as much
- During this ride test I hit 42 miles per hour (coasting down a large hill) and the bike felt stable and stopped pretty well, note most electric bikes allow riders to go beyond their maximum assisted speed, they just won’t help you do it
- BULLS found a nice drop handlebar that’s a bit wider and flared to give you leverage when riding off-road, I’m glad they didn’t just go with a standard narrow drop bar
- I like how to optional MonkeyLink lights have side windows to create a larger visual footprint and keep you safer, the headlight could still be a little blocked by the drop bars and your hands though, so keep that reflective clothing and consider additional lights
- It’s a small detail, but BULLS uses thicker 13 gauge spokes in the rear wheel to add strength and support cargo that might be mounted to the rear rack
- Unlike some other Bosch PowerTube battery implementations, this one can be forced into place without using the key to unlock the core, just push on it and listen for a click to know that it’s securely mounted
- They did the best they could with the display panel positioning (where you select the level of assist and interact with the display) but it’s very near the stem and kind of high up on an accessory bar, and that means you can’t brake with the left hand while pressing + or – to raise and lower assist, your hand has to be on the center flat section of the bar and you have to reach somewhat awkwardly to press the buttons, check the video around 11:51 to see what I mean
- I like the MonkeyLink concept, being able to add and remove lights that will run off of the main ebike battery easily, but the price of the lights ($170 for a front and rear light) just seems high
- The positioning of the headlight is good in many ways, it’s up high, points where you steer, and is sprung vs. a lot of suspension fork arch mounted lights I see that can bounce around, but you cannot aim it up and down… it’s set in one position based on the head tube and stem angle
- Minor consideration: the Bosch Purion display panel is compact and provides plenty of space for accessories, but it isn’t removable, doesn’t have a 5 Volt Micro-USB charging port like the Bosch Intuvia or some of the Brose displays on other BULLS models, and doesn’t show power output, avg speed, max speed, trip time, clock or shift recommendation (some shops will let you upgrade to the larger Intuvia display panel if you pay an extra $200 for the part and labor, but that might not work here because it requires a special mount, the older DAIL-E GRINDER did use the Intuvia, which you can see here in the fifth picture)
- The alloy shield on the PowerTube battery adds weight, is paint-matched to this ebike (even though it would be cross compatible with other BULLS models that also use the same battery design), and it’s just physically longer and larger than some competing products or the older Bosch PowerPack or a naked Bosch PowerTube… be careful removing and transporting it because there’s no handle
- One relatively minor trade-off that Bosch has made with their Performance Line motors is to incorporate a reduction gear so when you turn the crank one time the chainring actually goes around 2.5 times, and this does create some mechanical friction, the upside is fast response, improved efficiency, and better chain retention, I like how BULLS has included a chainring guard but I didn’t see a slap guard and the SRAM derailleur doesn’t have a manual one-way clutch like the Shimano Shadow+ setup, consider adding one yourself aftermarket or using a clear piece of box tape on the right chain stay
- The saddle can’t go all the way down to its lowest position if you’re using the MonkeyLink rear light, noticie how it sticks up above the seat collar in the photos above, this could be an issue for riders with shorter inseams and the light could actually get blocked by a long shirt or coat hanging down in other situations so double check on this and consider getting an independent rechargeable LED light for your backpack or helmet
- The minimalist rear rack looks great and reduces weight but doesn’t have a top platform for using a trunk bag and might not work with cloth panniers that fold over the top of some racks (they could hang down too far), the upside is that this allows the rear MonkeyLink light to shine without being blocked… but it would be better to have the rear light built into the rear rack in my opinion
- The location of the battery charging port on the left side of the bike frame is pretty close to the left crank arm and actually blocks the rotation path when plugged in, just be careful not to bump the pedals when the bike is plugged in, or consider charging the battery off the bike, the rubber cover protector for this port is also a bit finicky to get in (at least for me)
- I’m not a fan of smaller rubberized pedals like the ones included with the BULLS GRINDER EVO because they don’t offer a lot of surface area and aren’t as grippy as alloy with pins, consider swapping for some Wellgo alloy or magnesium platform pedals if you’re concerned about slipping off or have larger feet
- The Bosch Performance Line motors are heavier and larger than the Brose S, Shimano E8000, and Yamaha PW-X while also having a wider minimum Q-Factor (so the bottom bracket can be wider), but it’s rare to find a Class 3 speed mid-motor from a European company so this is a minor gripe
- I love the way this ebike looks, how they matched the frame color to the motor casing and suspension fork perfectly, but it only comes in one color option, and it’s fairly dark… there are no reflective stripes on the tires so you rely on the lights a lot more in dark riding conditions (I’d definitely wear reflective clothing and get panniers with reflective fabric or patches)
- Being a Class 3 speed pedelec, it seems like the lights automatically come on whenever you power up the bike and you cannot turn them off, which bothers me a little bit because sometimes I don’t want to blind my fellow riders on an evening ride
- BULLS chose a bottom-up battery mount design and this can feel a little snug when there’s a large 700c wheel with a fender in the front, I appreciate the two-step dismount for safety, but it can still clunk out when released and is heavier than it looks, take your time and be careful
Andrew4 years ago
Would you prefer this over the urban evo?Reply
Court4 years ago
Good question, Andrew! My first choice would be the ICONIC EVO because it offers full suspension. I do like the drop bars on the GRINDER EVO and feel that the URBAN EVO is similar enough that if you didn’t want or care about the drop bars, it would be fairly comparable :)Reply
Amazer984 years ago
I’ve put about 400 miles on my GRINDER EVO over the past two weeks and wanted to add just a few comments.. Firstly, the shift detection works great… there’s no need to stop pedaling before shifting, as the BOSCH motor instantly adjusts.
Secondly, the PURION display does allow you to turn the headlight and taillight on and off. you simply press the + button for two seconds to do this. I agree that the MONKEYlink lights are not impresdive, but thankfully it is simple to use the pre-wiring to install better aftermarket lights. I removed the MONKEYlink adapters and had the dealer wire in a B&M headlight, and removed the fenders and rack so i could install a Blackburn rack that could accommodate a trunk bag… then crimped on a nice SUPERNOVA TAILLIGHT and mounted it on the back of the rack.
I agree that the Purion display is frustratingly limited… no clock and its odometer doesn’t even show tenths of a mile– what is that all about? But the bike rides very nicely, the tires are quiet and have good grip, and the APEX shifting and braking is excellent.
I swapped the uncomfortable saddle for a BROOKS, which worked out very well, so the bike is all dialed in now!Reply
Court4 years ago
Hey Amazer, great comments! I’m glad the shift detection is working well for you, that has always been something that impressed me about Bosch drive systems for ebikes. Good tip about the Purion, which dealer has been helping you! Sounds like they are doing a great job :D
Lights and safety are a big focus for me, sounds like you’ve got a good setup going now. If you did want to upgrade to an Intuvia someday, it sounds like your dealer might be able to do that and then you’d get more info and details. Thanks again for the great feedback :DReply
Jonathan Kaplan3 years ago
I’ve read your your review of the Grinder EVO, The Wabash, and Crossrip+. I have a chance to get all of these for the same price range due to discounts. I’ve ridden the Crossrip+ and was impressed. the wabash tires are too skinny and i want a speed motor. the grinder evo is impressive, but heavy. i own a Super commuter+ 8s and could share batteries with the crossrip+. that being said all the reviews for the wabash and crossrip+ say “jarring ride”. this leaves the grinder evo. this bike will be mostly used for road. the super commuter will be used for rail trails. any opinion regarding suspension would be appreciated.Reply
Court3 years ago
Hi Jonathan! I’m a big fan of suspension and the GRINDER EVO is one of the few road bikes with drop bars that offer this. The bike looks amazing, has great lights, fenders, and that awesome rear rack. I really like it… especially as a speed pedelec. Sure, you can’t share battery packs… but as someone with a sensitive back, neck, shoulders, I’d lean this direction because it would make riding more fun and comfortable. On the contrary, the fact that you’re using your Super Commuter+ 8s for gravel, without any suspension, may illustrate that you’re not as sensitive as me. All of the bikes that you mentioned are pretty great choices. I hope this helps, and I appreciate your comment :)Reply