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Stock gearing for the Schumacher CAT L1, with common pinions and their ratios.
| Pinion | Spur ÷ pinion | FDR |
|---|---|---|
| 16T | 5.19 | 12.71 |
| 17T | 4.88 | 11.96 |
| 18T | 4.61 | 11.30 |
| 19T | 4.37 | 10.70 |
| 20T | 4.15 | 10.17 |
| 21T | 3.95 | 9.68 |
| 22T | 3.77 | 9.24 |
| 23T | 3.61 | 8.84 |
| 24T | 3.46 | 8.47 |
| 25T | 3.32 | 8.13 |
| 26T | 3.19 | 7.82 |
| 27T | 3.07 | 7.53 |
| 28T | 2.96 | 7.26 |
Shaded rows are the pinions most 1/10 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 Schumacher CAT L1, with the range racers in the class run.
Get a recommendation →Shop pinion gears at AMain →It depends on your motor and the track. In the 1/10 4WD buggy class, racers gear by final drive ratio: 6T and below near 10.66, 7.5–8.5T near 10.00, 13.5T near 7.95. On the CAT L1's stock 83T spur that is about 19T for 6T and below, 20T for 7.5–8.5T, 26T for 13.5T. Tight tracks gear down, open tracks gear up. For a starting pinion matched to your motor, use the So Dialed Pinion Recommender with the CAT L1 selected.
The CAT L1 has an internal ratio of 2.45:1. Final drive ratio = spur ÷ pinion × 2.45. With the stock 83T spur, a 16T pinion gives an FDR of 12.71 and a 28T gives 7.26.
83 teeth. Changing the spur moves every pinion's ratio at once; most racers leave the spur and tune with the pinion.
Kit shock setup. Part numbers link to AMain.
Out of the box the CAT L1 runs 550 cst front, 400 cst rear (CORE oil), on 2 x 1.6mm - Black (#U7086) front, 3 x 1.6mm - Black (#U4701) 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.
The kit springs are CORE Blue (#CR182) front, CORE Green (#CR186) rear. Stiffer springs suit high grip and big jumps; softer springs add grip on slick or bumpy tracks.
The kit diff fluid is 12,000 cst front, 12,000 cst rear. Thicker front adds steering on power; thicker center sends more drive rearward; thicker rear stabilizes the car under throttle.
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