GPM Racing 7075 Alloy Chain Tension Rear Swing Arm (Larger Inner Bearings) for Losi Promoto-MX Motorcycle RTR FXR (MX057A)
We are the importer of record — the price you see is the price you pay.
Handled by us in the UK under the Consumer Rights Act — no sending it overseas.
What our customers say
A selection of recent five-star reviews, as written.
-
★★★★★
Ordered flishrc cobra. Communication was great. Ordered larger batteries but they were the wrong size. Olly shipped the right batteries and gave a refund for the difference I paid. Couldn't ask for more. Thanks for the help with the order.
Robert, 22 September 2026
-
★★★★★
Very helpful when the vehicle I wanted wasn't in stock. Very fast deliver too.
Anna Abbott, 17 September 2026
-
★★★★★
Excellent service speedy delivery and good customer service
GLYN, 10 September 2026
-
★★★★★
Great product and service. I enjoy buying from these guys. Thanks to radio-controllled.co.uk.
Paul Jordan, 3 September 2026
-
★★★★★
Dealt with customer services over an order I accidently placed, they were prompt and dealt with it will, completely refunded within a small window of time, thanks!
Oliver Galustian, 23 July 2026
-
★★★★★
Really good online rc store with some great products and sales on. The owner is very knowledgeable as well.
Simon, 19 July 2026
-
★★★★★
Product delivered promptly and in excellent condition 👍had very helpful and prompt responses from Olly to all my questions, I will definitely be using them again 👍
Mark Clucas, 30 January 2026
-
★★★★★
The customer service and advice were first class!
Steve Avery, 9 September 2025
-
★★★★★
The seller knew I was after one and very kindly informed me when they came back into stock so now have a Flywing Bell 206. Fantastic bit of kit. Well worth the wait.
Pete Goddard, 15 April 2025
-
★★★★★
Great service, car arrived fast and really well packaged. Also, I had a little problem....(which turned out to be me doing it wrong) but someone replied the same evening! Will definitely be buying from them again.
Graham Rousseau, 10 February 2025
Key Specs
- Weight
- 174 g
About this product
Precision 7075 alloy rear swing arm for LOSI PROMOTO-MX upgrades
This MX057A rear swing arm is a purpose-built 7075 aluminium replacement for LOSI PROMOTO-MX platforms. The component offers improved dimensional stability and wear resistance compared with the stock plastic item while supporting larger bearing interfaces for enhanced load distribution.
The arm is configured to accept oversized inner bearings and the kit includes two 8x16x5 bearings to match the hub interface. Fitment results in a modest change to wheel travel (recorded as +1mm) and retains compatibility with the standard chain tension adjuster, enabling familiar adjustment procedures.
Lengthwise adjustability simplifies chain tensioning during tuning, and the supplied hardware addresses the typical mounting and bearing seating needs for a clean installation. The packing details and part numbering are retained below for reference.
Packing includes
- Rear Swing Arm – 1pcs
- Bearing 8x16x5 – 2pcs
- Grade 12.9 black Cap Head Screws 3×18 – 2pcs
- 4.0 Lock nut – 2pcs
- 3.0 Lock nut – 2pcs
Original Name / Part No:
LOS264000
Compatible Models
- LOSI-1/4 PROMOTO-MX MOTORCYCLE RTR, FXR-LOS06000
- LOSI-1/4 PROMOTO-MX MOTORCYCLE RTR, FXR-LOS06002
For advanced hobbyists seeking a durable bearing upgrade for the 1/4-scale PROMOTO-MX, MX057A delivers a precision-fit 7075 alloy arm with larger bearing support and an easy-to-adjust chain-tension arrangement.
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Made to order: GPM Racing parts are shipped to us from GPM’s factory, so please allow around 14 days for dispatch.
What our customers say
A selection of recent five-star reviews, as written.
-
★★★★★
Ordered flishrc cobra. Communication was great. Ordered larger batteries but they were the wrong size. Olly shipped the right batteries and gave a refund for the difference I paid. Couldn't ask for more. Thanks for the help with the order.
Robert, 22 September 2026
-
★★★★★
Very helpful when the vehicle I wanted wasn't in stock. Very fast deliver too.
Anna Abbott, 17 September 2026
-
★★★★★
Excellent service speedy delivery and good customer service
GLYN, 10 September 2026
-
★★★★★
Great product and service. I enjoy buying from these guys. Thanks to radio-controllled.co.uk.
Paul Jordan, 3 September 2026
-
★★★★★
Dealt with customer services over an order I accidently placed, they were prompt and dealt with it will, completely refunded within a small window of time, thanks!
Oliver Galustian, 23 July 2026
-
★★★★★
Really good online rc store with some great products and sales on. The owner is very knowledgeable as well.
Simon, 19 July 2026
-
★★★★★
Product delivered promptly and in excellent condition 👍had very helpful and prompt responses from Olly to all my questions, I will definitely be using them again 👍
Mark Clucas, 30 January 2026
-
★★★★★
The customer service and advice were first class!
Steve Avery, 9 September 2025
-
★★★★★
The seller knew I was after one and very kindly informed me when they came back into stock so now have a Flywing Bell 206. Fantastic bit of kit. Well worth the wait.
Pete Goddard, 15 April 2025
-
★★★★★
Great service, car arrived fast and really well packaged. Also, I had a little problem....(which turned out to be me doing it wrong) but someone replied the same evening! Will definitely be buying from them again.
Graham Rousseau, 10 February 2025
