Overview
The Axial Boulder 550, 21T Brushed Electric Motor is a high-torque crawler motor designed specifically for RC enthusiasts who demand reliable power and sustained performance in challenging terrain. This 550-sized brushed motor represents a proven choice for RC car UK builders and trail runners who appreciate the combination of pulling power and heat management that longer motor designs provide. Whether you're tackling steep hills, navigating rocky trails, or enjoying weekend bashing sessions, this electric motor delivers the consistent torque needed to keep your RC crawler moving forward with authority.
Engineered by Axial, a manufacturer renowned for quality RC crawler components, the Boulder 550 motor bridges the gap between lightweight motors and heavy-duty alternatives. The 21T (turn) winding specification means this motor is optimised for lower speeds with exceptional low-end pulling power, making it ideal for rock crawling, trail running, and slow-speed precision driving. If you're looking to upgrade your RC buggy or trail crawler with a motor that won't let you down when things get tough, this brushed electric motor is worth serious consideration.
This is a genuine Axial OEM part, listed as compatible with select Axial 1/8 scale crawler platforms. RC car enthusiasts across the UK rely on Axial components for their reputation of durability and engineering excellence. The Boulder 550 motor's extended length provides a critical advantage over shorter motor designs: more surface area for heat dissipation, meaning you can run harder and longer before thermal throttling becomes an issue.
Key Features
- 550-Size Long Motor Design — The extended length of a 550-sized motor provides substantially more cooling surface area compared to shorter alternatives, allowing the motor to handle extended running sessions and higher thermal loads without overheating, which is crucial for serious trail runners and crawlers pushing their vehicles to the limit.
- 21T Brushed Winding — The 21-turn configuration is specifically engineered to deliver maximum low-end torque and pulling power, making this motor exceptionally well-suited for rock crawling, hill climbing, and slow-speed precision manoeuvres where raw grunt matters more than top speed.
- High-Torque Crawler Motor Classification — Axial has classified this as a dedicated crawler motor, meaning every aspect of its design—from winding configuration to bearing arrangement—has been optimised for the specific demands of off-road crawling rather than being a compromise design trying to do everything.
- 3.2mm Bore Diameter — The precisely engineered bore ensures solid, reliable engagement with your vehicle's motor shaft and pinion setup, maintaining consistent power delivery and minimising mechanical play that could reduce efficiency or cause vibration issues during operation.
- Brush-Type Motor Technology — Brushed motors are renowned for their simplicity, reliability, and forgiving nature with basic speed controllers, making them an excellent choice for builders who prefer straightforward electronics and maximum compatibility with budget-friendly ESC options.
Technical Performance
The Axial Boulder 550, 21T Brushed Electric Motor represents a substantial step up from smaller motor alternatives in terms of sustained power output and thermal management. The 550-size classification places this motor in the larger family of RC motor designs, providing more winding wire, higher pole count potential, and greater overall displacement compared to 380 or 480-sized alternatives. The 21-turn brushed winding is the key specification here—fewer turns mean higher torque at lower speeds, which is precisely what modern rock crawlers and trail-running RC vehicles demand. This motor is engineered to produce consistent, controllable power delivery that excels in situations where you need to carefully modulate wheel speed and pull heavy loads up steep inclines. The 3.2mm bore is standard for this class of motor, ensuring compatibility with common Axial drivetrain components and pinion gears. As a brushed motor, it operates on straightforward commutation principles, making it entirely compatible with both basic brushed ESCs and more sophisticated speed controllers. The extended 550-size housing means superior heat dissipation compared to compact motor designs, allowing you to push harder during demanding off-road sessions without encountering thermal cut-offs. Whether running 2S or 3S LiPo batteries (depending on your ESC and vehicle setup), this motor will deliver responsive, linear power curves that are predictable and easy to control—critical traits for technical trail driving and competition-level rock crawling.
What's in the Box
- 1x Axial Boulder 550, 21T Brushed Electric Motor
What You Need to Complete
- Speed controller (ESC) compatible with brushed motors
- LiPo battery pack (2S or 3S, depending on your vehicle and ESC specifications)
- RC car or truck chassis designed to accept a 550-size motor (such as compatible Axial crawler platforms)
- Motor pinion gear and spur gear matched to your desired speed and torque characteristics
- Battery charger suitable for LiPo chemistry
Frequently Asked Questions
- Is the Axial Boulder 550 motor suitable for beginners in RC crawling? — Absolutely. The brushed motor design is straightforward and forgiving, and the 21T winding's low-speed, high-torque characteristics make it inherently easy to control and pilot, even for builders new to technical rock crawling. Brushed motors don't require the specialised ESC programming that brushless alternatives often demand, making this an excellent entry point into serious crawler builds.
- What makes the 550-size motor better than smaller alternatives like 380 or 480? — The 550-size provides increased motor volume, which translates to more winding area, higher current capacity, and critically, superior thermal management through a larger outer housing that dissipates heat more effectively. This means longer runtime, sustained performance under load, and the ability to handle continuous operation on steep terrain without overheating.
- Can I use this motor with a basic brushed speed controller? — Yes, this is one of the key advantages of brushed motor technology. The Axial Boulder 550 is fully compatible with any brushed ESC on the market, from budget-friendly options to high-end programmable controllers. The 3.5mm bullet connector configuration also provides broad compatibility across RC brands.
- What battery voltage should I use with this motor? — The Boulder 550 is designed to work with LiPo batteries, and you can run either 2S (7.4V) or 3S (11.1V) depending on your vehicle's weight, motor pinion setup, and your ESC's voltage rating. Always consult your specific vehicle's manual and ESC specifications to determine the correct battery configuration for optimal performance and longevity.
- Is this compatible with my existing Axial crawler? — Axial has listed this motor as compatible with the Axial 1/8 AXP8 Gilamon 2.2 4X4 RTR Brushed Trail Buggy in both green and red variants. For compatibility with other Axial platforms or different brands, check that your vehicle has a 550-size motor bay and uses standard brushed motor connectors.
- How does the 21T winding compare to higher-turn alternatives? — The 21T configuration delivers maximum low-end torque and pulling power, making it ideal for crawling and trail running where sustained pulling force matters more than top speed. Higher-turn motors (such as 65T or 88T) would sacrifice this torque for slightly higher top speed, making them less suitable for serious rock crawling applications.
Why Buy from RC Model Shop?
RC Model Shop is a trusted UK RC retailer and authorised dealer for all the brands we stock, including Traxxas, ARRMA, Losi, FTX, Hobbywing, Spektrum and more. Based in Walsall, we have a physical store where customers are welcome to come in, view products and purchase in store. Whether you are a seasoned competitor, a weekend basher, or just discovering the world of RC for the first time, our team of experienced RC enthusiasts is here to help you find the perfect setup and provide ongoing support. Order the Axial Boulder 550, 21T Brushed Electric Motor today with confidence, knowing you are buying from an authorised retailer with genuine products, expert knowledge and a commitment to customer satisfaction. Shop online or visit us in Walsall — we look forward to helping you get the most out of your RC experience.
We want to make sure your delivery goes smoothly, so here are some important details about our service:
- For orders above £120, we offer delivery to most mainland UK addresses. For orders under £120, we can still deliver to Northern Ireland and the outlying isles, as long as the item can be sent by Royal Mail, weighs less than 30kg, and fits within 61cm × 46cm × 46cm. Some highland and remote areas may carry an extra delivery charge as couriers often apply surcharges in these locations. If you live in one of these areas, feel free to contact us before ordering so we can confirm the delivery options and costs for you.
- Most of our products include delivery in the price. If your order is under £90, a small delivery fee will apply but do not worry this will always be clearly shown at checkout before you complete your purchase.
- Depending on what you choose at checkout, your order will usually be delivered either the next working day or within 2 working days. For next day delivery please place your order before 2:00pm. Orders are dispatched Monday to Friday only. Some items may take a little longer and if that is the case we will always show the expected delivery time on the product page.
- If your order includes items with different dispatch times we will normally wait and send everything together once all items are in stock. If one of the items is going to take a while we will give you the choice either wait for everything to arrive or let us send the available items now and deliver the rest later. It is up to you.
- We use trusted delivery partners to make sure your order gets to you safely and on time. We use DPD for next working day deliveries and Royal Mail for the 2 day option.
- As soon as your order is on its way we will send you a tracking number by email. If you provide your mobile number at checkout we will also send delivery updates straight to your phone so you can keep an eye on progress.
- If a product is marked as "Dispatched within 3 working days" delivery usually takes around 3 to 5 working days from when your order is placed.
- For customers in Inverness and other parts of the Scottish Highlands deliveries can take up to 2 working days even if you select next day delivery as couriers do not currently offer a guaranteed next day service to those areas.
