Reviewed by Andrew, 4WD Suspension fitment team
Tough Dog rear leaf springs for the Isuzu D-MAX RT (May 2012 - August 2020), delivering approximately 40mm of lift. Sold as a pair. Choose the rate for your constant load - 0-300kg, constant 300kg, or constant 500kg for heavily equipped work utes - then add fitting hardware and optional Tough Dog bellows airbags from the options.
Tough Dog leaf springs are a genuinely progressive design: each leaf is set slightly proud of the one above it, so the leaves stay in contact along their whole length instead of slapping together under load.
Two-stage packs carry a lighter primary stage for everyday ride quality, with heavier second-stage leaves that only come into play as the load goes on – that's what stops the rear sagging with a canopy, tools or a camper on the back. Choose the rating by the constant load the vehicle carries, counting only permanent weight.
The matching U-bolts, greasable shackles and pins, and bush kits are available from the option dropdowns on this page – if the originals have been on since new, replace them while the pack is out rather than reusing stretched U-bolts.
Doing the whole vehicle at once? We also stock the matching front Coil Springs and assembled Front Struts for the Isuzu D-MAX RT 2012-2020.
Matching rear shocks complete the rear end.
Count only constant load: general use → FS214C; permanent 300kg (canopy, drawers) → FS214L; permanent 500kg (service body, camper) → FS214LL. Towing does not count. Contact us if unsure.
| Make | Model | Series | Years | Position |
|---|---|---|---|---|
| Isuzu | D-MAX | RT (MY12+) | May 2012 - August 2020 | Rear |
Choose the load rating for the weight the vehicle carries most of the time, counting only permanent fitments such as a bar, winch, canopy or drawers. A heavier rating than you need rides firm when unloaded; a lighter one sags once the gear goes in.
| Part number | Lift | Load rating | Suits / notes |
|---|---|---|---|
| FS214C | 40 mm | 0-300 kg | - |
| FS214L | 40 mm | Constant 300 kg | - |
| FS214LL | 40 mm | Constant 500 kg | - |
Leaf springs are replaced as a pair with the axle supported, the U-bolts removed and the spring unbolted from the front hanger and rear shackle. Fit new U-bolts, and replace worn shackle bushes and pins at the same time. Torque U-bolts to spec and re-check them after the first few hundred kilometres. Raised springs need shock absorbers with the correct extended length for the new ride height. In most states a suspension lift of up to 50 mm is allowed without certification under VSB14; larger lifts can require engineering approval, so check the rules for your state.
Last updated: 10 September 2026
Genuine Tough Dog suspension from an authorised Australian dealer.
New to D-MAX and MU-X suspension? Read our D-MAX and MU-X suspension problems guide.
| Specification | Detail |
|---|---|
| Brand | Tough Dog |
| Type | Rear leaf springs |
| Position | Rear axle |
| Sold as | Pair (both sides) |
| Vehicle | Isuzu D-MAX RT & Holden Colorado RG |
| Lift options | 40 mm |
| Load ratings | 0-300 kg, Constant 300 kg, Constant 500 kg |
| Part numbers | FS214C, FS214L, FS214LL |
| Construction | Designed and made in Australia from micro-alloyed spring steel; shot-peened, scragged and load-tested |
| Fitting hardware | New U-bolts recommended; bush and shackle kits available as options |
Load ratings refer to permanent extra weight over the axle. Springs do not change the vehicle's GVM or towing capacity.
Yes for builds from 05/2012 to 04/2016 - Tough Dog specifies the TDSK-021 bracket on all lift kits for those vehicles. Builds from 04/2016 to 08/2020 do not need it. Select it in the options if your RT is a 2012-early 2016 build.
Every spring in this listing is approximately 40mm raised, so the matching Tough Dog bellows kit is the 40mm Lift version (TDAA-104) - the OEM-height kit does not suit these springs.
These suit the following applications: Isuzu D-MAX RT (MY12+) May 2012 - August 2020 Rear. Check your build date and variant against the fitment table on this page – if you're not certain, contact us with your rego or VIN details and we'll confirm fitment before you order.
Match the rating to the weight the vehicle carries all the time – count only permanent additions (bar, winch, canopy, drawers, long-range tank), not luggage or towball weight. The options on this page cover 0-300kg, Constant 300kg, 300kg, Constant 500kg, 500kg. If the vehicle is mostly unloaded, stay at the lighter end; going too firm hurts the unladen ride. Still unsure? Send us your setup and we'll confirm the right spring.
The options on this listing are: 40 mm. Lift is measured at ride height with the vehicle's normal load. Raised springs need matching shock absorbers with the correct extended length.
Yes. The price covers both Tough Dog springs, one for each side.
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