Traxxas Spring Shock Rear Blue GTR Progressive 1.042 Rate Pair TRX8445A

Overview

The Traxxas Spring, shock, Rear (Blue) (GTR) (progressive, 1.042 rate) (2 pcs) TRX8445A is an essential suspension upgrade for serious RC enthusiasts in the UK looking to fine-tune their Traxxas UDR Unlimited Desert Racer. These custom-wound progressive-rate springs are engineered specifically for the GTR shock platform, offering precise tuning capabilities that allow you to optimise your RC car UK performance for different track conditions and driving styles. Whether you're a competitive racer, weekend basher, or dedicated hobbyist, having the correct spring rate is crucial to unlocking the full potential of your short course truck.

Progressive-rate springs work differently than linear springs because they provide a soft initial response for absorbing small bumps smoothly, then transition to a progressively stiffer rate when encountering larger impacts. This dual-action performance means your RC car responds more sensitively to minor track imperfections whilst maintaining the structural support needed for aggressive jumps and hard landings. The blue colour coating is both visually distinctive and provides a protective finish that resists corrosion and UV damage over time.

These suspension components represent genuine Traxxas engineering and are manufactured to exacting standards. If you own a Traxxas UDR ready to run RC truck or are building a custom setup, upgrading your suspension springs is one of the most cost-effective ways to dramatically improve handling, consistency and driver feedback. The 1.042 rate sits at a balanced specification suitable for general off-road driving, making these springs an ideal starting point before experimenting with softer or stiffer alternatives.

Key Features

• Progressive-rate spring design — These springs feature a progressive rate that starts soft for small bump compliance but becomes progressively stiffer as the suspension compresses, providing both comfort and support in a single component rather than requiring two separate springs with different rates.
• Custom-wound construction — Each spring is custom-wound to precise specifications ensuring consistent performance and longevity, rather than using off-the-shelf generic springs that may not match the GTR shock platform correctly.
• 1.042 spring rate — This specific rate provides a balanced setup that delivers responsive control across a range of driving conditions, suitable for both recreational bashers and competitive drivers seeking mid-range suspension tuning.
• Blue colour finish — The distinctive blue coating protects the underlying spring material from corrosion, oxidation and UV degradation whilst making the suspension components easily identifiable during maintenance and setup.
• GTR shock compatibility — These springs are precisely engineered for the 139 mm GTR shock platform, ensuring perfect fitment and optimal performance without modification or adaptation.
• Sold in pairs — The package includes two springs, which is the complete set required for rear suspension setup on your Traxxas UDR, eliminating the need to purchase multiple sets.
• Tuning flexibility — GTR springs are available in different rates allowing you to compensate for lighter or heavier vehicle configurations, experiment with different driving styles, or adapt to specific track conditions and weather.
• Higher rate equals firmer suspension — If you find these springs too soft, stiffer rates are available; if too firm, softer options exist, giving you complete control over your RC car's suspension behaviour.

Technical Performance

The Traxxas TRX8445A represents advanced suspension technology specifically designed for the UDR platform. The progressive-rate characteristic means the spring resistance increases as compression increases, creating a non-linear response curve that professional RC drivers and engineers have proven delivers superior handling across varied terrain. The 1.042 rate specification indicates moderate stiffness—neither too soft for loose driving nor excessively stiff for rock crawling—making these springs versatile for multiple driving scenarios. The 139 mm GTR shock length is precisely calibrated, and these springs are wound to match that exact specification, ensuring the suspension geometry remains correct and the shocks extend and compress within designed parameters. The blue finish is applied using Traxxas's proprietary corrosion-resistant coating process, protecting against moisture, salt spray from outdoor tracks, and UV radiation from extended sun exposure. These springs work in conjunction with your existing GTR shocks, which themselves provide damping; the springs provide the load-supporting function whilst the shock absorbers manage the speed of compression and extension. For UK RC car enthusiasts running their vehicles in damp British weather conditions, the protective finish proves invaluable for maintaining long-term performance and appearance.

What's in the Box

• Traxxas Spring, shock, rear (blue) (GTR) progressive-rate — Qty 2

Frequently Asked Questions

• What Traxxas RC models do these springs fit? — These springs are compatible with the Traxxas UDR Unlimited Desert Racer Pro-Scale 4WD RTR Short Course Truck, specifically the TRX85086-4-RGD1 (Rigid Industries variant) and TRX85086-4-FOX1 (Fox Racing variant). They mount to the rear GTR shock platform on these models.
• Why would I need to replace or upgrade my springs? — Springs wear over time and lose their original stiffness, or you might want to change spring rates to suit different driving conditions, vehicle weight modifications, or personal preference. Softer springs improve bump compliance; stiffer springs reduce body roll during cornering.
• What does progressive-rate mean for my RC short course truck? — Progressive-rate springs start soft to absorb small track imperfections smoothly, then become progressively stiffer as the suspension compresses further, providing active support during jumps and hard landings. This gives you the best of both worlds in a single spring rather than making compromises with a linear-rate spring.
• How often should I replace my suspension springs? — Springs typically lose effectiveness after 12-24 months of regular use depending on driving intensity and storage conditions. If your truck feels less responsive over bumps or you notice excessive body roll, springs may need replacement.
• What is the difference between the 1.042 rate and other available rates? — The higher the spring rate number, the firmer the spring. A 1.042 rate provides balanced performance for general off-road driving. Softer rates (like 1.038) suit lighter vehicles or smoother tracks; stiffer rates (like 1.046) suit heavier setups or aggressive driving styles.
• Are these genuine Traxxas parts? — Yes, these are OEM Traxxas springs manufactured to exact factory specifications. When purchasing from an authorised Traxxas retailer like RC Model Shop, you receive genuine parts with Traxxas quality guarantees.
• How do I know if I need softer or stiffer springs? — If your truck bottoms out easily or feels wallowy and unresponsive, try stiffer springs. If the suspension feels too harsh and bouncy, soften your spring rate. The 1.042 is an excellent starting point before experimenting.

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 Traxxas Spring, shock, Rear (Blue) (GTR) (progressive, 1.042 rate) (2 pcs) TRX8445A 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.