Setups
Have a setup for the XB8 '25?
Share your setup sheet with the community — we'll fill in the details automatically.
Gearing
Stock gearing for the XRAY XB8 '25, with common pinions and their ratios.
| Pinion | Spur ÷ pinion | FDR |
|---|---|---|
| 12T | 4.00 | 14.16 |
| 13T | 3.69 | 13.07 |
| 14T | 3.43 | 12.13 |
| 15T | 3.20 | 11.32 |
| 16T | 3.00 | 10.62 |
| 17T | 2.82 | 9.99 |
| 18T | 2.67 | 9.44 |
| 19T | 2.53 | 8.94 |
Shaded rows are the pinions most 1/8 4WD buggy setups run on the stock spur.
What pinion should I run?
Tell us your motor and track and get a starting pinion for the XRAY XB8 '25, with the range racers in the class run.
Get a recommendation →Shop pinion gears at AMain →What pinion gear should I use on the XRAY XB8 '25?
It depends on your motor and the track. In the 1/8 4WD buggy class, racers gear by final drive ratio: 1800–2300 kV near 10.06. On the XB8 '25's stock 48T spur that is about 17T for 1800–2300 kV. Tight tracks gear down, open tracks gear up. For a starting pinion matched to your motor, use the So Dialed Pinion Recommender with the XB8 '25 selected.
What is the internal ratio (transmission ratio) of the XRAY XB8 '25?
The XB8 '25 has an internal ratio of 3.539:1. Final drive ratio = spur ÷ pinion × 3.539. With the stock 48T spur, a 12T pinion gives an FDR of 14.16 and a 19T gives 8.94.
How many teeth is the stock spur gear on the XRAY XB8 '25?
48 teeth. Changing the spur moves every pinion's ratio at once; most racers leave the spur and tune with the pinion.
Kit setup
Kit shock setup. Part numbers link to AMain.
- Front
- 600 cst
- Rear
- 550 cst
- Front
- 10,000 cst
- Center
- 7,000 cst
- Rear
- 3,000 cst
What shock oil does the XRAY XB8 '25 come with?
Out of the box the XB8 '25 runs 600 cst front, 550 cst rear (XRAY oil), on 8 x 1.2mm (#358032) front, 8 x 1.3mm (#358032) rear pistons. That is the kit setup; you will need to adjust it for your track conditions. The RC Setup App can help dial it in.
What springs does the XRAY XB8 '25 come with?
The kit springs are 69mm 0.8-0.83C 4-dot (#358316) front, 82mm 0.68-0.7C 3-dot (#358343) rear. Stiffer springs suit high grip and big jumps; softer springs add grip on slick or bumpy tracks.
What diff fluid does the XRAY XB8 '25 come with?
The kit diff fluid is 10,000 cst front, 7,000 cst center, 3,000 cst rear. Thicker front adds steering on power; thicker center sends more drive rearward; thicker rear stabilizes the car under throttle.
Setup Help
All 1/8 Off-Road Cars →
Free to start · iOS & Android
Setup App & Race Log
Your XRAY XB8 '25 is in the RC Setup App
Save every setup change you make to your XRAY XB8 '25, get AI tuning answers for that exact car, and log your races — at the track or back in the pits.
- Setup Tracking
- AI Mechanic answers
- Find & Share Setups
- Race Log
- Gear Ratio Calculator
- Free to use
