UPDATE: The TWENTY9 E FS 3 RSI is still being sold by BULLS, even though this particular review was conducted several years ago. They have since updated the Bosch motor to Gen 3 and the battery to PowerPack 500! This means improved performance, power, and range. I’m leaving the review unchanged since the videos, photos, and writeup all represent the older product that I covered :)
BULLS jumped into the US market for 2016 introducing an impressive range of electric bikes including the TWENTY9 FS 3 RSI shown here (it’s a full suspension cross country ebike with 29″ tires). This model comes in three sizes and could be especially comfortable and fun for taller riders or those with longer legs. The larger wheels elevate the bike but also smooth out terrain, improve traction and carry momentum once they’re up to speed. They aren’t as nimble to steer as a 26″ or the newly popular 27.5″ but for cross country, they work very well. I was impressed with the 120 mm air suspension by Fox, love the rebound adjust and lockout features (remote lockout for the front) and am a fan of the sturdy thru-axles and quick release systems (for easy trail maintenance or transport). The display panel and battery are also removable which makes transporting or charging the bike easier and as with other Bosch powered electric bikes, they are both easy to use and very high quality. You get a two year warranty on the electronic systems and in my experience they age very well but might put a bit of extra strain on the drivetrain (being a mid-drive). Thankfully, Bosch has a software-driven shift sensing system that helps to ease power off, I tend to slow my cadence and ease off when shifting gears to minimize mashing and slipping. This bike is very similar to one that my Uncle has been riding for over two years now which also uses the Bosch system and it’s holding up very well for him.
Some features and design choices that set the Bulls Twenty9 FS apart from the competition in my mind include an aluminum cover for the base of the motor, a chain tensioner that might clear mud and reduce chain slap, narrow wide teeth on the tensioner that reduce slip, an oversized bash guard on the chainring and extra small 15 tooth chainring and 40 tooth large rear sprocket (which combine for efficient starts and climbing power for you and the motor). It’s a beautiful bike, one that’s fun to ride and easy to use. As with other Intuvia operated Bosch ebikes, turning the bike on and choosing from four levels of assist is quick and easy, you can keep your left hand on the grip and operate the display by using your thumb and the display itself is large enough to read in an upright position (and backlit for night use). You can see this e-bike in action on a trail as I rode with my friend Rick the other day in a vlog video here. He has loved the bike so far but only had it for a month and not been able to comment on some sensitive areas I’ve heard about from other riders (for all similar ebikes) about how the remote lockout works and whether the lever is in the way or too sensitive and the possibility of chain suck (where mud gets clogged in the front sprocket area and causes the chain to wrap around and seize the drivetrain). For most riding, the bike should perform very well and I noticed and appreciated the latest of Bosch’s motors called the CX which offers higher torque.
Pros:
- I love the extra tiny sprocket guide / chain tensioner (similar to Haibike’s Sprocket Equalizing System) because it probably helps to clear debris from the chain and lift it above the rear swing arm, it should reduce chain slap on the right chain stay and possibly chain slip as well given the narrow wide tooth pattern
- Despite being relatively new in the US (at the time of this review in 2016 Bulls had only been here for one season) the company has been selling bikes internationally since 1994 with ebikes in 2007 and seems to have a good reputation
- The Bosch CX motor is a higher torque design offering 75 Nm vs. 60 Nm with the older 2015 models, it’s perfectly suited to an off-road model like the Bulls Twentynine
- Extra large 40 tooth climbing sprocket in the rear (11 gears total!) and a smaller 15 tooth chainring for efficient climbing and easier pedaling since the bikes are heavier ~50 lbs with the battery and reinforced frame
- Available in three frame sizes so you can dial in fit, as a 29er you get more traction, rolling momentum and a higher frame position so this could be an excellent choice for taller riders
- The motor seems well protected by an Aluminum skid plate (that is color matched and appears to be replaceable), I also like that there’s a cuff built around the base of the battery so it melds with the frame visually and possibly adds strength or protection, the extra long and thick rubber slap guard also helps with chain slap
- Comes stock with Ergon locking grips! Name brand, very comfortable and solid to ride with… given the cross-country orientation of this bike with 120 mm travel I like that the grips aren’t too thick or wavy like the GP-1 models, I think the grips were a good choice, the end pieces extend forward a bit and might keep your hands from sliding off
- The shocks are both nice, high quality air suspension from RockShox with rebound adjust and lockout… the front suspension fork has remote lockout so you can adjust on the fly (again, good for cross country where the trail might smooth out)
- Quick release on both wheels, this is one of the advantages of a mid-drive system, the axles are both overbuilt with 15 mm thru-axle up front and 12 mm in the rear, improves strength and makes aligning the disc brakes easier
- Solid 180 mm Hydraulic disc brakes from Shimano offer excellent stopping power and the tiny levers are easy to reach and use with just one or two fingers… what you’d expect for off-road use
- The top tube is designed with a steep angle and is able to drop pretty low on the seat tube (where it is reinforced) and this lowers stand over height making it easier to mount and handle, the suspension design itself uses the 4 bar link that is pretty efficient (formerly patented by Specialized, now open in the US)
- I love that the battery pack is removable but can be charged on or off the frame, it secures with a sturdy locking core and just looks great, if you took it off it seems like there would be enough room to hang the bike on some hitch style racks like this
- The Bosch Intuvia display is awesome, large enough to read but easy to remove if you’re bombing a downhill section or parking the bike outside, I love the remote button pad that lets you select between assist levels and explore menus like range, odometer, max speed etc.
- Awesome two year warranty on the electronics (battery and motor from Bosch) with a total of five years on the frame from Bulls, nice since they’re newer in the United States
- I love how responsive the Bosch centerdrive motor is, it kicks in and cuts out extremely fast because it’s measuring pedal speed, rear wheel speed and your pedaling torque over 100 times per second and it even has shift sensing software to ease off and protect your chain and gears
Cons:
- I can’t say for sure but the extra large chainring bash guard could cause mud and debris to build up and cause chain suck (a common issue for Bosch powered ebikes that have super small ~15T chainrings), this probably won’t be an issue unless you ride off-road in thick mud
- Not quite as light weight as some of the other full suspension Bosch powered ebikes I’ve tested like the XDURO Fullseven but that might be due in part to the larger tires and 29er wheel size and extra skid plate and moulding around the battery
- I’ve been told by some riders that the remote lockout mechanism with a lever as used here can be annoying because it gets bumped and switches too easily to locked, I haven’t had that experience but my ride time has been limited
- Being geared, the centerdrive motor does produce some electronic whirring noises which become more pronounced in the high levels of assist and especially when pedaling cadence speeds up
- Even though I trust BULLS and they have been doing well internationally, being new to the USA this and other models may be difficult to see in person and test ride before purchase
Resources:
- Official Site: http://www.bullsebikes.com/product/twenty9-e-fs-3-rsi/
- More Pictures: https://goo.gl/photos/4aSStnabdeukCMAM6
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