Electric bike frame size guide

Inside leg range Frame size
24 - 29" (61 - 74cm) 14" (35.56cm)
25 - 30" (64 - 76cm) 15" (38.1cm)
26 - 31" (66 - 78cm) 16" (40.64cm)
27 - 32" (69 - 81cm) 17" (43.18cm)
28 - 33" (71 - 84cm) 18" (45.72cm)
29 - 34" (74 - 86cm) 19" (48.26cm)
30 - 35" (76 - 88cm) 20" (50.8cm)
31 - 35" (79 - 88cm) 21" (53.34cm)
32 - 37" (81 - 94cm) 22" (55.88cm)
33 - 37" (84 - 94cm) 23" (58.42cm)

The Bulls E-Stream EVO 2 27.5 is a fabulous electric mountain bike that wont break the bank. It has the most powerful street-legal e-bike motor on the market: the 90 Nm BROSE unit.  One of these will whiz you to work effortlessly during the week and take you to the top of the mountain at the weekend. It incorporates a high-capacity 650Wh removable battery, and 120mm travel SunTour XCR-32 RL AIR forks.

If you’d like a test-ride please call in at our London, Leicester or Suffolk branches, or email to arrange a date.



For larger image please see bottom of page.

Motor Power
Battery Location
In Frame, removable
< 110
Battery Chemistry
and Capacity

Li-Ion, 650 Wh
(37 Volt x 17.5Ah)

650 37 17.5
  • Overview
  • Delivery
  • After Sales Service
  • E-STREAM EVO 2 Hard Tail 27.5

    The E-STREAM EVO 2 27.5 is a great commuter and a fine off-roader. The high-torque BROSE motor is capable of taking you to the top of almost anything, and 180mm TEKTRO ORION hydraulic disc bakes provide ample stopping power if your nerve cracks on the way back down! As with all BROSE powered e-bikes when switched off or at speeds over 27.5kmh the 90 Nm BROSE e-bike drive system is disengaged completely so does not cause any pedaling resistance. Yes the price is low, but few compromises are made: the EVO 2 Hard Tail also features quality 20 speed XT gears from Shimano XT. All up weight is only 21.5 Kg.

    With a whopping 90Nm BROSE toque on tap it has a huge power advantage over its non-Brose rivals.

    Rotwild electric bike motor

    The beating heart of this BULLS is the peerless BROSE 2.0 Drive Unit. For 2016 the Brose has new software giving more low-speed torque and smoother power delivery across all speed ranges. Its main ingredients are aluminum, magnesium, experience, enthusiasm and …helical epicyclic gears! Designed in Germany, its made there too.

    Where other well known e-bike motors are built to a price point, the Brose 2.0 is designed and manufactured to a quality standard, incorporating precision engineered helical epicyclic gears. These are much more expensive to manufacture but offer dramatic performance and wear rate improvements over the cheaper spur gear tooth profiles that the completion use.

    In the simplest terms spur gears transfer power from the driving gear to the driven gear via only one or two teeth at a time, whereas with helical gears power is transferred by three connecting teeth at a time. This results in less wear, less noise, less friction and a smaller and lighter drive unit.

    Despite its small physical size the BROSE 2.0 produces a market leading 90 newton meters of torque. It does this quietly, reliably and without fuss. The company’s sensor concept is the only one of its kind on the market today: it measures rider pedal force no fewer than 420 times a second, delivering smooth, vibration free assistance. Production began in July 2014 and by August this year the Rotwild/Brose test team had covered 69’445 miles of Brose e-bike motor shaftarduous Alpine trails.

    Brose Drive Technology is a division of the Brose Group, one of the most innovative and successful suppliers to the international automotive industry, employing some 22,000 employees – 2,500 of them engineers – at 57 locations in 23 countries around the world. Their annual turnover exceeds €5 billion. Last year Brose manufactured 100 million electric motors. They know what they’re doing.

    Decades of experience specialising in mechatronic systems for the automotive sector mean they’re perfectly placed to produce this innovative e-bike drive unit. Development and production of the Brose e-bike motor is carried out entirely in-house at their Berlin engine plant, where a dedicated team of engineers design, build and test the system at their purpose built e-bike center of excellence .

    The BULLS goes much further than the rest:

    The removable Li-Ion battery is integrated into the aluminum bottom tube, ensuring the lowest possible center of gravity, and at a class-leading 650Wh the battery will drive you further than any other electric MTB in it’s class. It’s not just me! Many of our customers have had first hand experience of the Brose motor efficiency – of course the range between re-charges on a BULLS is greater than any of its competitors because it has a higher capacity battery, but that does not explain how a BULLS with 30% more power than its rivals can run flat out for so long on one charge. Clearly, much of its range advantage is down to the efficiency of the Brose drive unit.



    frame size geometry Bulls

    Frame Size XS(41) S(46) M(51)
    Seat tube length A 410mm 460mm 510mm
    Top tube length B 575mm 595mm 615mm
    Chain stay length C 450mm 450mm 450mm
    Bottom bracket offset D 40mm 40mm 40mm
    Head tube length E 110mm 110mm 130mm
    Head tube angle α 70° 70° 70°
    Seat tube angle β 74° 73° 73°


    Fork Suntour XCR-32 RL CTS Air, 120 mm, remote lockout
    Drive Train Brose 250W
    Rear derailleur Shimano Deore XT RD-M786 SGS, 10-speed, shadow plus
    Front Derailleur Shimano Deore XT FD-M786DT
    Shifters Shimano Deore SL-M610
    Handle FSA, 38/24T
    Cassette Sprockets Shimano CS-HG50-10, 11-36T
    Brakes Tektro Orion HD-M730 hydraulic disc, 180/180 mm
    Handlebar STYX aluminium
    Stem STYX aluminium
    Seat post STYX aluminium
    Saddle STYX
    Hubs Formula
    Rims BULLS HC-30D LITE
    Wheel size 27.5 Zoll
    Tyres Schwalbe Rapid Rob 27.5 x 2.25
    Pedals Wellgo
    Extras Powerpack: 37V/17,5Ah/650Wh / 3 modes: Eco, Tour, Sport / Charging time: approx. 3,4 hrs to 80%, approx. 5 hrs to 100%

    Specifications correct at product launch date and may vary during production year.

    Commissioned and road tested e-bike

    Before being delivered your electric bike is checked and road-tested by our expert staff to make sure everything is perfect.

    Fully assembled and delivered direct to you by our expert staff

    We don’t believe your e-bike experience should begin with a white van dropping off a brown cardboard box. This is a whole different delivery experience – our experienced staff will gladly spend time with you to make sure you’re happy with your choice and understand all its features, so be ready to put the kettle on!

    no brown box delivery1

    One of our team will deliver your e-bike to your door fully assembled and tested at a pre-arranged time, and will work with you to ensure every thing is perfectly adjusted to suit your size and preferred riding style before that all-important test ride.

    After your test ride, when everything has been fine-tuned to your liking and you are comfortable with your e-bike we will fit any accessories you may have ordered – or those you might already have – a favourite old saddle perhaps, a particular bell, or pair of trusted hand-me-down panniers.

    Only when we are certain you are completely confident in your e-bike choice and understand how everything works will we leave you to enjoy your new found freedom.

    The cost of this personal service varies depending on your location and whether you would prefer evening or weekend delivery, please email or telephone us for an estimate.

    No quibble 100% money-back guarantee:

    In the unlikely event that you’re not 100% delighted with your e-bike after the test-ride we simply take it back and either return later with alternative model of your choosing, or give you a 100% refund*.

    *Note: After you have inspected the bike, completed the test ride and agreed that this is the right bike for you, the sale will be complete. Please be sure you are happy with everything before we leave as we cannot accept returns once our delivery staff have driven away unless the e-bike can been shown to have a design or manufacturing fault. We then retain the right to determine the appropriate remedy, be that on-site repair or replacement of a part, a replacement electric bike, or full or partial refund. If the reason you decide not to accept the bike could have been established easily before you ordered it (eg order a white bike and later decide you prefer black) we reserve the right to make reasonable charges for delivery and or any work done to the bike prior to delivery.

    Parts and labour warranty:

    A solid manufacturers warranty is a key benefit of choosing one of our quality European made e-bikes. In the unlikely event that a component fails a replacement will shipped to us from Holland or Germany, usually within 24hrs, and fitted free of charge either at our Suffolk workshop, or at your home if you have purchased our on-site service option.

    Note: All our e-bikes carry a minimum two year warranty; please see e-bike specification table for model-specific variations.

    Evening and weekend delivery:

    Because few of us are at home during working hours these days, we offer the option of our personal home delivery service on Saturdays and Sundays, and evenings during the week.

    On-site service:

    Convenient dates for your service visits are arranged with our staff when we deliver your bike.

    Experience has taught us that regular preventative maintenance is much better than simply reacting to problems as and when they occur. By choosing our on-site service option you’ll have the peace of mind that potential problems are likely to be identified and dealt with before they arise, thereby helping ensure your e-bike is safe and in good working order.

    In the unlikely event that an unexpected problem arises – for example a puncture or broken front light – simply call or email us to bring forward a scheduled service and we will visit and carry out repairs.

    Note: If you would prefer to bring your e-bike to our Suffolk workshop for servicing, the cost is £40 plus VAT.


    The table below summarises the delivery and after sales service packages we provide. Please note that the guide prices below for home delivery, onsite servicing and insurance costs may vary according to your location. Please contact us by email or telephone for an accurate quote.

    Bronze Silver Gold
    FREE £199 £399
    Fully commissioned and road tested e-bike
    Fully assembled e-bike delivered direct to your door by our expert staff
    No quibble 100% money-back guarantee
    Parts and labour warranty
    Evening and weekend delivery
    2 on-site service visits
    Courtesy e-bike


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