4 wheel tuning

Kurtis Long

Pinewood Ninja
Jan 26, 2019
31
6
8
41
Owosso Michigan
So the rules for my sons district race are all four wheels must touch the ground. Would you try to drill the non Drive front wheel a couple thousandths up just to keep the axle pressure off it then wile still keeping it on the ground? Then drill the DFW flat but angle it towards the rail a little? Rules for this race also say all wheels should be flat on the ground so no angles in the rear axles and no sanding, beveling, tapering, wavering, narrowing, or lightening of wheels. Lol
 
I'm definitely not an expert, so take my advice for what it is. Would love to hear an expert opinion.

Answering because you're rules are very strict and similar to my pack rules, so I can share my experience. I would try to have the non dominant front wheel a shade higher. Float it so it turns when you roll the car, but spins when on the ground and you roll it. Basically you are wanting it to roll when you roll the car, but just barely touch. I did this by putting a piece of floral wire under the non dominant front wheel axle. I've also had luck with inserting both wheels, and bend the non dominant front wheel upward a bit till it barely touches, then gluing it in. If you can drill it, that works too. In the past, I've used a drill bit on it's side sitting in the slot to kind of shave off a bit of wood and also used a small file to shave a little of the wood from the slot to make it sit up higher. But go slow and be careful. Don't want to do TOO much. I can imagine drill this would be hard, but you may have an awesome set up and the skill to do this. I couldn't do it. Just play around with it til it float and glue it down so it won't move.

Unless you have an awesome jig, or again, have an awesome set up and the skill to do it, I wouldn't recommend drilling the dominant front wheel. You are going to have to make sure you are exact. I'm not sure the exact angle, someone would know better than me, but you basically want 4 inches of drift over 4 feet, whatever angle gives it to you. A much simpler answer is to bend the angle if allowed. This will make it easy to adjust to the proper drift. I've also had luck finding imperfect bent axles stock, and experimenting with different block to get one crooked enough to drift on it's own! It's possible. But if you can bend the axles, do that, you'll save yourself a lot of time.

Even with canting or bending the axles, I think you should be OK. The small angle you have to achieve isn't going to be significant enough that the wheel won't sit flat. Again, not an expert, so if someone knows different, please chime in. Usually the inspection process is pretty lax and done by volunteers, so even if you don't have them sitting flat, they over look it. If they see anything, most likely they will think its how the wheel is inserted in the axle slot and/or the slot itself. I've seen slots like this! Non are perfectly straight. By no means, am I condoning cheating, you just have to take what you're rules give you. If you can cant the wheels and have them basically flat and touching the ground, I'd say go for it. Almost positive it won't be a problem. Again, you can do this with bending the axles if allowed, which will allow you to control the steer of the rear and keep them off the rail.

I'd also suggesting shaving 1/32 off the front dominant wheel side. It will keep the wheels off the rail and give you less of a chance to lose speed. If you rules day it has to be 1 3/4 wide, simply add it to the other side. Boom,, 1 3/4 car with a shaved dominant wheel side!

Our pack doesn't allow bent axles. Our district does.

In summary, shave 1/32 off dominant side, move it to the other side. Float front non dominant wheel so it is just touching but rolls on a hard surface. Bend the front dominant wheel axle and adjust to drift 4 inches over 4 feet. Bend the back axles and adjust so they won't touch the railing, if you aren't comfortable doing that, straight up and down will probably work with the front shaved. You'll have to check the drift again and most likely adjust since adjusting the back wheels. Additionally, I'd place the Center of Gravity somewhere around .75 inches in front of the axles. Aggressive but not too aggressive for scout cars. Just make sure your axle prep is good and the wheels are decent.

And of course, if you DO have a great jig and/or the skill and tools to do it by drill, by all means, go for it! Either way, I'm sure you will kick names and take butt...or something.
 
I can’t stand when packs try and make a race fair for everyone and take away the science of it and limit kids. So annoying.
Seconded. They are trying to even the field. But it doesn't matter. The same kids will win with strict rules that allow no creativity and learning or more lax rules that encourage effort and learning.
 
Should add, with our Pack, the rules are strict. The District level is less strict, meaning our cars won't be competitive unless we alter or build a new car. It's just a disservice, not a way to even the field.
 
That’s what’s frustration. Your pack is basically holding you back from districts unless you make a new car. Very unfair for the kids. I talked with our pack master, and we modified the rules so it was fair for everyone. I did a seminar for everyone so I could explain why the rules were the way they were and how to make your car faster.
 
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That’s what’s frustration. Your pack is basically holding you back from districts unless you make a new car. Very unfair for the kids. I talked with our pack master, and we modified the rules so it was fair for everyone. I did a seminar for everyone so I could explain why the rules were the way they were and how to make your car faster.
That's great! I will bring that up to our pack. Our district is still strict, requires 4 wheels touching, but less strict about bending axles and canting the wheels. So why not just go with there rules for our pack? Strict enough to keep the races close, but won't kill our winner's chances at district.

Sure, for districts you could build a whole new car or alter your car, but then you don't know what you have with no chance to test before the race and requires more time and money. It's a crap shoot. So you are almost forced to stay with what you have. Our pack obviously never does good at the district level.
 
4 on the floor is silly to me. Don’t teach your kids about friction and it’s so simple to do. I would build 2 cars. Even if you can’t test it, cant’d wheels and bent DFW is faster than non. What you can try is build that second car and ask if you can test and tune after the race. People knew I raced in leagues and always want to race after the race to see if they could beat me. I used that time to fine tune my kids car since we used our track for the district race.
 
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4 on the floor is silly to me. Don’t teach your kids about friction and it’s so simple to do. I would build 2 cars. Even if you can’t test it, cant’d wheels and bent DFW is faster than non. What you can try is build that second car and ask if you can test and tune after the race. People knew I raced in leagues and always want to race after the race to see if they could beat me. I used that time to fine tune my kids car since we used our track for the district race.
Way ahead of you, we built 4 cars for the kids, two for pack and two for districts ahead of time so we could test on tech day lol. It was the only solution.
 
Wow thank you all for your help and thoughts. I will get to work on this stuff. Our pack rules are pretty open. Wheels have to say BSA but you could cut them. Pretty loose rules. This district race is crazy to me. I get the intent but jeez. Our counsel race has some pretty good rules. 2.5 gram wheels. Only allowed to square them up. BSA axles. So kinda in between our pack and district races. Thanks again!
 
I can’t stand when packs try and make a race fair for everyone and take away the science of it and limit kids. So annoying.
THIS!! THREE TIMES THIS!!! We're supposed to be teaching these kids the value and benefit of hard work, but don't want them to get any advantage for it? Come on. I've yet to see a scout race other than the big national ones like Mid-America and Northern Star Council that can make a decent set of rules....because doing so TAKES HARD WORK!
But the rules you race in are there and everyone should follow...that doesn't mean you have to shove 4 nails in a block of wood and call it a day.
4 wheel touchers are very difficult to build for kids...because 3 points define a plane, not 4. If your kid has the ability to lift a NDFW by a thousandth or two. Good for him. The problem is that it might not help much.
No canting makes tuning the car way difficult, because the normal method of bending and K-grooving the DFW axle isn't going to work now, your very likely to introduce cant. CAN you dill the axle toed...you can in hopes that you get it just right. If I remember correctly, there IS a drill fixture out there made for the NYC race that does this... BUT a flat wheel turning the car with 3 other flat wheels is going to be dragging those other three along the track. That's not good, but probably better than sloshing back and forth down the track...I'd be pretty confident in that as long as you toe lightly. What about angling the car body? If you angle the DFW side of the car body by ~1/16 inch, and drill straight against that there would naturally be some toe to that wheel...and you don't have to bend an axle to do it.
It's hard to tell you all the tricks you can leverage without the run set...even then, some of those are going to be interpretation.
In my experience, a 4 wheel touching race means at inspection, the judge is going to put his hand on your car and roll it on a "flat" surface like a table. If all 4 wheels roll, your good. That leaves a little room to have one wheel not completely touching because of the pressure the judge applies during check in. Is that 64th of an inch enough to keep the wheel from spinning when you race? Maybe. You can't intentionally cant the rear wheels, but you CAN select the axles with the worst runout and turn them to your advantage. This might not be enough to get the wheels to migrate, but you can also drill with a little toe in the rear as well.
I think I would make that trade...a little dragging of the wheels for a straight wobble free run every time.
 
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