Please view our recommended ratios when it comes to gearing your RC Car. We are NOT liable for any damages done to product from the result of over-gearing or under-gearing your car or any other negligible driving while using our product. If your gearing is not the same as our recommended ratios for Gears, Belts, and Motors we will not replace. We are ONLY liable for manufacture defects and possible damages made through shipping valid 90 days from date purchased. Only 1 warranty replacement valid per product.