VehiclesArrma Limitless 120 8S BLX
Arrma Limitless 120 8S BLX
1/7 scale · street and speed-run body · ARA7816
- Top speed
- 82mphstock gearing
- Speed set
- 169mphincluded in the box
- Final drive
- 6.13:1
- Tire
- 100mm
Specifications
Last modified
| Spec | Value | Basis |
|---|---|---|
| Drivetrain | ||
| Pinion | 21TStock | Stock |
| Spur | 46TStock | Stock |
| Transmission & axle | 2.80:1Stock | Stock |
| Spur ÷ pinion | 2.190:1Calculated | Calculated |
| Final drive | 6.13:1Stock | Stock |
| Speed gearing, in the box | 32T / 34Tpinion / spoolStock | Stock |
| Final drive, speed gearing | 2.98:1Stock | Stock |
| Wheels & tires | ||
| Tire diameter | 100mmEstimated | Estimated |
| Rollout | 51.2mm per motor turnCalculated | Calculated |
| Power | ||
| Motor | 1450KVStock | Stock |
| Battery | Up to 8SLiPoStock | Stock |
| Performance | ||
| Theoretical top speed, stock gearing | 82.0mph on 8SCalculated | Calculated |
| Theoretical top speed, speed gearing | 169.0mph on 8SCalculated | Calculated |
| Motor speed | 42,920rpm, no loadCalculated | Calculated |
| Advertised top speed | 120mphMaker's claim | Maker's claim |
| Vehicle | ||
| Part number | ARA7816 | |
| Scale | 1/7 | |
| Class | Street and speed-run body | |
Stock is as the vehicle ships. Calculated is worked from the stock figures on this page rather than stored beside them, so the two cannot drift apart. The top speed is kinematic: an ideal no-load RPM with no slip and no loss under load, so a real car is slower. Speed gearing is the taller set that ships in the box but is not fitted; swapping it in is the owner's job, and the car runs hotter on it. The maker advertises 120 mph, which is their own claim on their own conditions.
How these numbers were settled
The factory 8S Limitless, a separate SKU from the ARA109011 roller: a complete RTR with a Spektrum Firma 4685 1450Kv motor and a Firma 160A Smart ESC rated for 6S or 8S.
- It ships with two gear sets.
- Installed from the factory is a 21T pinion on a 46T limited-slip centre diff; in the box is a high-speed set, a 32T pinion and a 34T spool, which the 120+ mph claim needs.
- The ARA7816 manual prints both: its speed table (p.8) has a '21/46' column (90 mph on 2x4S) and a '32/34' column (120+ mph), page 7 lists the 'High Speed Spool and Pinion' as supplied, and pages 27-28 cover installing them.
- Horizon's standard-parts list for ARA7816 carries all four gears: 21T and 32T pinions, the 46T centre diff and the 34T spool.
- The transmission and axle ratio of 2.8 is not printed for this car; it comes from the front and rear diff gears on that same parts list, a 42T ring (ARA-2807) against a 15T input, 42/15 = 2.8, which matches the 2.8:1 Arrma prints for the Limitless V2 roller on the same platform.
- Stock final drive is 46/21 x 2.8 = 6.13; with the speed set it is 34/32 x 2.8 = 2.98.
- The 100mm tire is carried over from the dBoots Hoons 42/100 2.9 belted set used across the Limitless platform (Horizon prints 3.94in / 100mm); a parts reseller breaking new ARA7816 cars lists the same ARA550063 set as stock.
Sources
- ARA7816arrma-rc.com (opens in a new tab)
- ARA7816horizonhobby.com (opens in a new tab)
- ARA7816towerhobbies.com (opens in a new tab)
- Manual (PDF)horizonhobby.com (opens in a new tab)
- limitless-120-8s-ara7816jennysrc.com (opens in a new tab)
- ARA550063horizonhobby.com (opens in a new tab)
- searchhorizonhobby.com (opens in a new tab)
Every figure on this page traces to one of these. Where they disagreed, the note above says which was used and why.