Well another year is in the books. We had our fastest car ever thanks to the folks on this forum.
This was our 6th year (2nd scout) and we did our very best to economize our efforts and focus on the things that we know work. Our pack has a decent set of rules but the district is pretty strict so we build for the tighter rules (stock wheelbase, graphite only). We really just don’t want to build two cars. We ran a 3-wheel rail rider as we have for the past few years. The body was a slim wedge. To make life a little easier, we switched from the block to the silver bullet pro. I hadn’t done this in the past because I thought the #43 bit needed for the jig would leave the BSA axles too loose in the holes. Turns out that was a non-issue. The axles were snug and remained stable even through the stop section of our pack track, which I often liken to a mad max film. We sanded the kit axles to 2000grit. No mods to the wheels are allowed in our pack race so we tried a bunch and settled on the 3 that were the most stable.
On pack race day we were disappointed to see the car’s rear end wiggle all the way down the track. That hadn’t happened to us in years. 4” in 4’ had always been enough. Ended up second in the pack with a time 0.05 slower than our last car which won the pack and district. The car took second in the pack. For context, 1st and 3rd ran thee wheels with no steering and stock axle slots. Not a good day : |
We considered filling and re-drilling for the rear axles before the district race, but chose not to for fear the fill material would bias re-drill. Instead we pulled the rear wheels and measured the diameter of the rear axles at their widest and thinnest and reinstalled them making sure they were oriented to achieve the most contact between the bottom of the axles and wheel bores. Not sure why we always overlooked this step but I think it may have helped eliminate the wiggles for the district race. We also changed the steering to ~8” in 4’. I’ve always read that more steer is better than the wiggles. We don’t have a test track so we figured more is better.
Looking for one last thing to try, we finally took the time to polish and wax the wheel bores. Another step I regret skipping all these years. It was so simple. We used micro gloss followed by derby worx wax (it was the only thing we had on hand). We will likely shop for something better next year.
Today at the district race the car ran a 2.97X on three of the six runs on a 42’ best track. Aggregate time was 2.99X (our first sub-3 second car). I couldn’t believe how much the additional steps helped. The car took first against a weak field, but we were most proud of the times.
Thanks to everyone who takes the time to share what they know here on the forum. We couldn’t have done it without you.
This was our 6th year (2nd scout) and we did our very best to economize our efforts and focus on the things that we know work. Our pack has a decent set of rules but the district is pretty strict so we build for the tighter rules (stock wheelbase, graphite only). We really just don’t want to build two cars. We ran a 3-wheel rail rider as we have for the past few years. The body was a slim wedge. To make life a little easier, we switched from the block to the silver bullet pro. I hadn’t done this in the past because I thought the #43 bit needed for the jig would leave the BSA axles too loose in the holes. Turns out that was a non-issue. The axles were snug and remained stable even through the stop section of our pack track, which I often liken to a mad max film. We sanded the kit axles to 2000grit. No mods to the wheels are allowed in our pack race so we tried a bunch and settled on the 3 that were the most stable.
On pack race day we were disappointed to see the car’s rear end wiggle all the way down the track. That hadn’t happened to us in years. 4” in 4’ had always been enough. Ended up second in the pack with a time 0.05 slower than our last car which won the pack and district. The car took second in the pack. For context, 1st and 3rd ran thee wheels with no steering and stock axle slots. Not a good day : |
We considered filling and re-drilling for the rear axles before the district race, but chose not to for fear the fill material would bias re-drill. Instead we pulled the rear wheels and measured the diameter of the rear axles at their widest and thinnest and reinstalled them making sure they were oriented to achieve the most contact between the bottom of the axles and wheel bores. Not sure why we always overlooked this step but I think it may have helped eliminate the wiggles for the district race. We also changed the steering to ~8” in 4’. I’ve always read that more steer is better than the wiggles. We don’t have a test track so we figured more is better.
Looking for one last thing to try, we finally took the time to polish and wax the wheel bores. Another step I regret skipping all these years. It was so simple. We used micro gloss followed by derby worx wax (it was the only thing we had on hand). We will likely shop for something better next year.
Today at the district race the car ran a 2.97X on three of the six runs on a 42’ best track. Aggregate time was 2.99X (our first sub-3 second car). I couldn’t believe how much the additional steps helped. The car took first against a weak field, but we were most proud of the times.
Thanks to everyone who takes the time to share what they know here on the forum. We couldn’t have done it without you.
Nice job in troubleshooting the issues. You helped the kids learn that things don't always go well, but if you are persistent that you can do better! 
