3xD 1.5-rc2 release notes
10 November 2026 · Release candidate · Pending physical validation and approval
This release compares the previous complete kit, 1.2-rc3, with the new complete kit, 1.5-rc2. It brings together the faceted battery sliders, matching arm/brace dot markings and the updated 5 mm front-spring specification.
Changes since 1.2-rc3
| Area | 1.2-rc3 | 1.5-rc2 |
|---|---|---|
| Battery fore/aft sliders | Plain bars with rounded external ends. | Angular swept shoulders, faceted tooth ends, top chamfers and recessed blade details. Battery-contact faces, screw-clamping area, 2 mm thickness and ±4 mm adjustment travel are preserved. |
| Arm identification | Written caster-camber labels on the eight focused arm variants. | Two rows of recessed dots: caster above camber. Four or seven dots on the first row; zero or one on the second. Zero camber leaves the lower row empty. |
| Matching upper braces | Written setup labels on four upper-brace variants. | The same dot code as the arms. Markings remain underneath the brace, facing up in its supplied print orientation. |
| Front springs | 6 mm free length, 6 mm outside diameter. | 5 mm free length; 6 mm outside diameter retained. Two medium 0.42 mm-wire springs per car; optional soft 0.40 mm and hard 0.44 mm grades retained. New solid heights, rates and installed fit remain unmeasured. |
Both kits retain 45 distinct STL selections and 46 required part instances, including the two fit-pending rear-bearing inserts. Thirteen STL selections change: eight arms, four upper braces and one battery-bar design used twice. The other 32 STL files are byte-for-byte identical. The spring change is recorded in the hardware lists and does not add a printed part.
Download the complete kits
- Download 1.5-rc2 — complete 3 mm GRP kit (ZIP, 4.6 MB)
- Download 1.5-rc2 — complete 4 mm printed chassis kit (ZIP, 4.5 MB)
Each complete pack includes the current required parts, optional matched arms and braces, shims, hardware list, cutting files, CAD pictures, validation records and checksums. Choose one arm pair and its matching upper brace; optional alternatives are not all fitted together. Default setup remains 4° caster / 1° camber. STLs are unsliced; no G-code is included.
Faceted battery sliders
The new outline follows the chassis blade and chevron styling. It uses straight swept edges, tapered external tooth corners and shallow blade recesses with a 1.7 mm floor. The 3.3 mm screw slots, 14 mm screw spacing and 47.6 mm battery-contact spacing remain. Existing rails, swivel supports, fingers and shared M3×8 screws are reused.
Reading the setup dots
First row: caster. Second row: camber. For example, four dots above one dot identifies 4-1. The arms and matching brace use the same code for 4-0, 4-1, 7-0 and 7-1.
The dots are 1.1 mm in diameter and 0.16 mm deep—two nominal layers at the current 0.08 mm print setting. Depth is measured normal to the marking face; tilted arm faces are stepped by the slicer. Existing kingpin bores, double-D seats, mounting holes, centred bosses, wheelbase and brace seating geometry are retained.
Updating an existing car
To adopt the new appearance on the default 4-1 car, replace both arms, their matching upper brace and the two battery bars. Existing text-marked arms/braces and plain bars remain mechanically compatible. Owners already using the intermediate dot-marking or faceted-slider update can reuse those exact parts.
Follow the new 5 mm front-spring hardware specification. Check preload, retention at full droop and coil bind with the actual spring stack. The old 6 mm medium spring’s reported 1.4 mm solid height does not establish the new spring’s solid height.
Use the complete pack for your chassis: GRP retains its 3 mm chassis and printed retains its 4 mm chassis, with their separate bumper and rear-bearing geometry. Both keep a 3 mm pod plate. The chassis logo and cutouts, wider lower spring pockets, original unreinforced A1 retainer, selected P2 cups and official rear guide are inherited unchanged from 1.2-rc3.
Validation and remaining checks
Both frozen complete manifests, all STL hashes, ZIP integrity and part quantities were checked. Each packaged mesh was checked as a closed connected solid. Geometry comparisons confirm changes confined to the arm/brace marking areas and cosmetic slider regions; dot counts, recess depth and rims were measured, and battery clamping, clearance and capture cases checked.
Physical dot visibility, slider strength, new front-spring stack, backed rear-bearing fit, full steering/suspension movement and endurance still require inspection. This is a release candidate; publishing it does not establish those physical results. No print job was sent.