New to the Game

[Chris Stevenson]

This is our second year participating. I geeked out trying learn everything I could before our first build last year. My son is competitive by nature and he wanted a trophy. It was a good way to show him how knowledge and hard work can lead to positive results.

We built a 3-wheel rail runner. Got it very close to 5 oz. I only had a food scale that went to whole grams and 1/8 oz. so I wasn't sure of the exact weight, but the car was around 1/8 oz. under going into check in. Weighed the car on the official scale and plopped 2 1/16 oz. tungsten cylinders on the scale to get it closer to full weight. I didn't actually see the final weight, but the race director nodded and told me it was good to go so I secured the weights with two dots of super glue and handed it in. Right at 1" COG in front of rear axle. Extended wheel base with axles at 5/8" from each end of the car. Canted rear axles; bent front axle. Used "stock" axles and wheels purchased at Hobby Lobby. Removed burs and polished the axles extensively. Bent them ourselves (more on that later). Smoothed tread surface with fine sandpaper. Coned hubs, trued bore using Hobby Lobby tools. Polished bores using paste polish and pipe cleaner in kit also purchased from Hobby Lobby. Had no idea how we were going to do. My son placed 3rd in his pack with an average run time of 2.62 over 8 total runs. Best run was 2.60. Here are a couple of photos of last year's car:



This year's race is on Sunday Feb. 9th and we started a lot earlier on the build. Last year we started running out of time and got in a rush so we messed up the finish on the car because the paint and clear coat were not fully dry when we were installing the axles and graphiting. I read up even more for this year and realized there were a lot of things to improve on from last year's car. I ordered aftermarket axles and wheels. The wheels are BSA Ultralite from Pinewood Pro. Stated weight is 2.2g. Also ordered pre-bent front and rear axles from Pinewood Pro. I used a Hobby Lobby tool to bend the axles last year - the one where you bang it lightly with a hammer. Well, I dang near sheared the axles in half using that tool. I still used them, figuring that the sheared area was going to be inside the body and not touching anything. But they were waaaaay more angled than 2.5 and 1.5 degrees. Looking back it was so bad that it's kind of laughable. That's why I thought it better to order the axles pre-bent this time. Knowing what I know now, ordering pre-bent axles was probably a mistake. I thought they were fully polished from the vendor, but not so. I was still able to polish the bent axles even though they were wobbly when spinning, but I'd probably drill angled holes using one of the available jigs and use straight axles next time. I assume that the axles I bought are larger diameter than "stock" axles, but I'm not certain of this. Polished the bores on the lighter wheels with same past polish on pipe cleaner. Burnished all surfaces that could touch with graphite. COG is 5/8". Weight will be right at 5 oz. I ordered a new scale that goes to hundredths and will leave a little weight to add on race day in case the scales are slightly different. Same extended wheel base. Got the body slick, with a better finish than last year (I know that finish may be secondary to serious racers, but my son likes painting and wants his car to look good too). Tuned the car last weekend to get 4" of steer over 4'. Ran it on a 6' board against last year's car. 2020 car has an inch or so on the 2019 car over that distance. This is all imprecise, I know, but it appears to start faster, at least. I'm hoping for times in the 2.50-2.55 range this year. We'll see. Here are a couple of photos of this year's car:

 

[Loud2ns]

This is our second year participating. I geeked out trying learn everything I could before our first build last year. My son is competitive by nature and he wanted a trophy. It was a good way to show him how knowledge and hard work can lead to positive results.

We built a 3-wheel rail runner. Got it very close to 5 oz. I only had a food scale that went to whole grams and 1/8 oz. so I wasn't sure of the exact weight, but the car was around 1/8 oz. under going into check in. Weighed the car on the official scale and plopped 2 1/16 oz. tungsten cylinders on the scale to get it closer to full weight. I didn't actually see the final weight, but the race director nodded and told me it was good to go so I secured the weights with two dots of super glue and handed it in. Right at 1" COG in front of rear axle. Extended wheel base with axles at 5/8" from each end of the car. Canted rear axles; bent front axle. Used "stock" axles and wheels purchased at Hobby Lobby. Removed burs and polished the axles extensively. Bent them ourselves (more on that later). Smoothed tread surface with fine sandpaper. Coned hubs, trued bore using Hobby Lobby tools. Polished bores using paste polish and pipe cleaner in kit also purchased from Hobby Lobby. Had no idea how we were going to do. My son placed 3rd in his pack with an average run time of 2.62 over 8 total runs. Best run was 2.60. Here are a couple of photos of last year's car:

View attachment 1534 View attachment 1535

This year's race is on Sunday Feb. 9th and we started a lot earlier on the build. Last year we started running out of time and got in a rush so we messed up the finish on the car because the paint and clear coat were not fully dry when we were installing the axles and graphiting. I read up even more for this year and realized there were a lot of things to improve on from last year's car. I ordered aftermarket axles and wheels. The wheels are BSA Ultralite from Pinewood Pro. Stated weight is 2.2g. Also ordered pre-bent front and rear axles from Pinewood Pro. I used a Hobby Lobby tool to bend the axles last year - the one where you bang it lightly with a hammer. Well, I dang near sheared the axles in half using that tool. I still used them, figuring that the sheared area was going to be inside the body and not touching anything. But they were waaaaay more angled than 2.5 and 1.5 degrees. Looking back it was so bad that it's kind of laughable. That's why I thought it better to order the axles pre-bent this time. Knowing what I know now, ordering pre-bent axles was probably a mistake. I thought they were fully polished from the vendor, but not so. I was still able to polish the bent axles even though they were wobbly when spinning, but I'd probably drill angled holes using one of the available jigs and use straight axles next time. I assume that the axles I bought are larger diameter than "stock" axles, but I'm not certain of this. Polished the bores on the lighter wheels with same past polish on pipe cleaner. Burnished all surfaces that could touch with graphite. COG is 5/8". Weight will be right at 5 oz. I ordered a new scale that goes to hundredths and will leave a little weight to add on race day in case the scales are slightly different. Same extended wheel base. Got the body slick, with a better finish than last year (I know that finish may be secondary to serious racers, but my son likes painting and wants his car to look good too). Tuned the car last weekend to get 4" of steer over 4'. Ran it on a 6' board against last year's car. 2020 car has an inch or so on the 2019 car over that distance. This is all imprecise, I know, but it appears to start faster, at least. I'm hoping for times in the 2.50-2.55 range this year. We'll see. Here are a couple of photos of this year's car:

View attachment 1537 View attachment 1538

Good luck!

 

[Kurtis Long]

Looks like you’re going in the right direction! You’re in the right place to be as fast as anyone. I frequently dig through old posts on here trying to learn more. Tons to read.

 

[Prozach2]

This is our second year participating. I geeked out trying learn everything I could before our first build last year. My son is competitive by nature and he wanted a trophy. It was a good way to show him how knowledge and hard work can lead to positive results.

We built a 3-wheel rail runner. Got it very close to 5 oz. I only had a food scale that went to whole grams and 1/8 oz. so I wasn't sure of the exact weight, but the car was around 1/8 oz. under going into check in. Weighed the car on the official scale and plopped 2 1/16 oz. tungsten cylinders on the scale to get it closer to full weight. I didn't actually see the final weight, but the race director nodded and told me it was good to go so I secured the weights with two dots of super glue and handed it in. Right at 1" COG in front of rear axle. Extended wheel base with axles at 5/8" from each end of the car. Canted rear axles; bent front axle. Used "stock" axles and wheels purchased at Hobby Lobby. Removed burs and polished the axles extensively. Bent them ourselves (more on that later). Smoothed tread surface with fine sandpaper. Coned hubs, trued bore using Hobby Lobby tools. Polished bores using paste polish and pipe cleaner in kit also purchased from Hobby Lobby. Had no idea how we were going to do. My son placed 3rd in his pack with an average run time of 2.62 over 8 total runs. Best run was 2.60. Here are a couple of photos of last year's car:

View attachment 1534 View attachment 1535

This year's race is on Sunday Feb. 9th and we started a lot earlier on the build. Last year we started running out of time and got in a rush so we messed up the finish on the car because the paint and clear coat were not fully dry when we were installing the axles and graphiting. I read up even more for this year and realized there were a lot of things to improve on from last year's car. I ordered aftermarket axles and wheels. The wheels are BSA Ultralite from Pinewood Pro. Stated weight is 2.2g. Also ordered pre-bent front and rear axles from Pinewood Pro. I used a Hobby Lobby tool to bend the axles last year - the one where you bang it lightly with a hammer. Well, I dang near sheared the axles in half using that tool. I still used them, figuring that the sheared area was going to be inside the body and not touching anything. But they were waaaaay more angled than 2.5 and 1.5 degrees. Looking back it was so bad that it's kind of laughable. That's why I thought it better to order the axles pre-bent this time. Knowing what I know now, ordering pre-bent axles was probably a mistake. I thought they were fully polished from the vendor, but not so. I was still able to polish the bent axles even though they were wobbly when spinning, but I'd probably drill angled holes using one of the available jigs and use straight axles next time. I assume that the axles I bought are larger diameter than "stock" axles, but I'm not certain of this. Polished the bores on the lighter wheels with same past polish on pipe cleaner. Burnished all surfaces that could touch with graphite. COG is 5/8". Weight will be right at 5 oz. I ordered a new scale that goes to hundredths and will leave a little weight to add on race day in case the scales are slightly different. Same extended wheel base. Got the body slick, with a better finish than last year (I know that finish may be secondary to serious racers, but my son likes painting and wants his car to look good too). Tuned the car last weekend to get 4" of steer over 4'. Ran it on a 6' board against last year's car. 2020 car has an inch or so on the 2019 car over that distance. This is all imprecise, I know, but it appears to start faster, at least. I'm hoping for times in the 2.50-2.55 range this year. We'll see. Here are a couple of photos of this year's car:

View attachment 1537 View attachment 1538

I understand the struggle. My son and I got hooked around the same time as you. Best of luck this year!

 

[Chris Stevenson]

Thanks for the encouragement. I realize that my post didn't really have a "question for the pros," but if any pros would like to weigh in on my process I'd be grateful for any feedback. There are a few things I know I can do to get faster:

1. Buy one of the jigs available for drilling axle holes. Probably the Silver Bullet from DD4H.
2. Use more extensive process and better products for polishing wheel bores. Probably the Black Ice kit from DD4H.
3. Use tungsten cube weights instead of the cylinders for more precise weight placement.
4. Use body style that allows to cut down on the amount of wood in the finished car and have more of the overall weight from added tungsten cubes.

Generally, just follow the process used by 5KidsRacing.

A couple of things I *might* do that would help:

1. Get a test track. This is a big commitment. I've read on this forum about people's wives starting the cars while sitting on the toilet because their track was set up through the house and taking their track on the road during work trips. Not sure I'm ready to get that crazy. I'm already getting some strange looks from my wife as it is. However, the pack leader who runs our race has asked someone to "store" the pack's track this year. Hmmm....
2. Need some tools I don't currently have. I don't have a small router. I don't have a drill press. Don't have a pin vise, pin gauges, measuring caliper, gap gauge set (I have one, but it's probably too thick.). I did just get a digital pocket scale that goes up to thousandths of an ounce though.

I know a lot of this is elementary to you guys who have been doing this at a high level for a long time. Any tips or recommendations appreciated. I do have a couple of specific questions:

1. What about air shields/fenders? I've seen them used on some cars and not others. I've watched some of the pro races on YouTube and they don't use them, but that might be because of class rules - not sure. The consensus seems to be that they do help a little. If so, why isn't everyone using them?
2. About the axle heads. I'm not seeing any recommendations to actually reduce the diameter of the axle head. I've read about coning it to reduce the surface area touching the wheel hub, but what about taking a file and just reducing he head way down? Seems like it would reduce some surface area and reduce friction. It's non-load bearing, so weight and load/friction wouldn't simply be redistributed.

 

[Prozach2]

I'm new at this just like you, so take what I say with a grain of salt. I followed the 5kidsracing template to the best of my ability... almost. We did the ladder body exactly like he said, and used tungsten cubes (two rows of 6 behind the axle and a row of 6 and a row of 5 in front of the axle). We also used the Silver Bullet Extreme. I even used the packaging labels like 5kids suggested. However, I did not bend the front axle or adjust the steer at all. Frankly, I just didn't know how to do it without a tuning board.

I learned the valuable lesson, "what you do wrong might matter more than what you do right." The cars were fast, but not nearly as fast as they should've been given the amount of time we put into everything else. They wobbled pretty violently going down the track. So, if you follow the 5kidsracing template, don't underestimate the importance of steer. It's counter productive to make a car that light and with that much weight in the back if you do not tune it properly.

 

[Chris Stevenson]

I'm new at this just like you, so take what I say with a grain of salt. I followed the 5kidsracing template to the best of my ability... almost. We did the ladder body exactly like he said, and used tungsten cubes (two rows of 6 behind the axle and a row of 6 and a row of 5 in front of the axle). We also used the Silver Bullet Extreme. I even used the packaging labels like 5kids suggested. However, I did not bend the front axle or adjust the steer at all. Frankly, I just didn't know how to do it without a tuning board.

I learned the valuable lesson, "what you do wrong might matter more than what you do right." The cars were fast, but not nearly as fast as they should've been given the amount of time we put into everything else. They wobbled pretty violently going down the track. So, if you follow the 5kidsracing template, don't underestimate the importance of steer. It's counter productive to make a car that light and with that much weight in the back if you do not tune it properly.

I know exactly what you are saying. I think we've been kind of lucky so far (with the ONE car we've built). We put steer on the car last year, with my severely flawed bent axles, but it worked out. The car ran very smoothly with no wobbles that I could detect from my vantage point. The car seemed to drop off in speed moreso that the other two cars that beat it, so there might have been something going on with not having enough graphite or not working it in properly beforehand. I was afraid of putting too much graphite because I'd read that could work against you. One thing I failed to do last year was cut down the DFW side by 1/16" to keep the rear wheel from rubbing the rail. But I don't think that hurt us because the rear wheels were canted so much that the wheels migrated out to the axle head and didn't come close to the rail. The too wide gap between the wheel and body also probably helped here too, ironically. Last year's car had fins that we built and glued on the rear of the car. We did it because it looked cool, but it created an unnecessary surface for the rear wheels to rub and there were signs that they actually did; again, because of the heavy canting of the rear wheels. Anyway, all lessons learned.

 

[Jupiter 2.9]

Hey guy, just some perspective from my point of view.
It's more about learning how to use the tools you have & the correct methods used in tuning a car.
Sounds like you both are headed in the right direction.
We built about 4 cars before we got one to runs straight then 4 more that speed changes were noticeable.
Then one day the next 3 cars all were running .97's.

The only magic tool or tip I have is repetition...Relax, build & learn it's the only way get faster.
All the information you pick up here is very valuable when applied correctly

Good luck @ the District & Counsel races
& welcome to the nut house.
David