Yes, in fact changing the 2nd gear pinion from 22t to 23t made the last little bit of difference to reach 50mph. However, gearing options are limited on this car (I'm already using a 16t 1st gear pinion "borrowed" from the R40 to get better acceleration at low speed), so there was no sense re-gearing if I couldn't at least get close to 50mph through engine tuning. 48mph was just close enough that re-gearing could bridge the gap.

Now that I know 50mph is possible with this specific engine in this specific car, I've replaced both spur gears with 47/41t instead of the 49/43t I was using before, which means I can go back to using the original pinion gears (because they're purple, and that matters to me) while maintaining the same top speed. In fact, it may be about 0.2mph faster in 2nd gear with the original pinion and the smaller spur, compared to the larger pinion and the original spur. Basically I'll know if that worked in real life because I'll see 50mph on the GPS more consistently than I did during the previous test. (my GPS doesn't measure tenths of an MPH, which is annoying -- or at least it doesn't display that info for me to see.)

Sure, using a race engine was always the easy option. But squeezing every last bit of performance out of this RTR engine, while keeping the convenience of the pullstarter, was more of a challenge. I have almost 40 RCs now, so I need to work on finding challenges that don't involve spending money. I have enough RC loans to pay off already, and I have plenty of spare parts stocked up for the .12R SS in case I destroy something.