Front axle vs. Rear axle weight distro against rear axle weight balancing...

[Speedy]

Hey guys!

Got an important question here. My boys and I are newbies to the forum here and we have only two years under our belts (including this year) with PWD racing (besides when I placed 1st in my Pack race as a cub scout a few decades ago with totally different rules, car parts etc.).

Last year my oldest son placed 1st in his previous Pack race and made it to the top ten at the District race. This year in his new pack our competition was very competitive and we barely made it to District placing 3rd overall. I tried to help our son make his car a rail runner but we didn't get the rail running effect working for the this year's Pack race due to last minute tinkering issues with the wheels vs. axles (long story). However, we now have the car set up as a genuine 3-wheeling rail runner and that's fine and dandy now and should help us better with our time at District.

THE QUESTION:
However, we're wondering, if our weight distro between the front axle vs. the rear axle needs tweeked a bit and how should the rear weight proportion be adjusted around the 'REAR' axle? Currently our weight is 18 +/- grams on the front axle vs. 125 +/- grams in the rear (+/- due to how our scale rounds up/down).

Should we put as much weight BEHIND the rear axle or should we go by DD4H's recommendation of putting only about 1.8 grams or so of weight behind the rear axle and then put the rest forward - which will make our front-end weight increase above the existing 18 gram front end axle weight Should this 1.8 gram max weight distro behind the rear axle be done w/o knowing how our car is set up form-wise based on how we chiseled up the block?

We've learned over time it's best to have a light front end weight between 12-16 grams (is this correct or just hear-say). Our weight distro over the 'front axle' will greatly increase if we move some of the (18) 1/4" cubes of tungsten (90 grams) forward of the rear axle. At the moment we only have (2) cubes of tungsten forward of our 'rear axle' (vs. the 18 aft of the rear axle) and do not want to increase the 'front axle weight' (to rear axle weight ratio) any more than necessary assuming we may lose some kinetic energy in the straight-away. What to do here w/o testing and knowing what's what?

Thanks, Speedy

 

[5KidsRacing]

What is your wheelbase? Standard slot location?

 

[Speedy]

Oh! Yes, wheel base is standard for BSA rules etc..

My main concern here is moving the weights from the rear side of the back axle car forward of the axle. Thus, increasing my front axle weight and moving the COG forward as well.

- Thx!

 

[Hogans Racing]

On my kid's scout cars with standard wheelbase, I run 3 rows of 4, 1/4" tung. cubes behind rear axle and the rest in front. I have also done 2 rows of 5 behind rear axle both with good results. I don't get to technical about individual wheel weight and COM. I put it together and let it rip! My son hasn't lost a scout race in two years.

 

[5KidsRacing]

With a standard WB car I would put less than 2 ounces behind the rear axle.... so like 1.8 what DD4H said or 10 cubes like Hogan said.... With a fully extended car I would stuff it full with 2 ounces, but the short WB is harder to control and putting a full 2 ounces or more behind the rear axle is tough to control and often makes for a slower car....

 

[Speedy]

Thanks guys! We'll re-distro the rear axle area weights and see how that pans out for us come the District race. We were trying for a lighter front end over last year's 33 gram front axle weight. I think with this new car we're gonna end up at about 23-24 grams at the front axle weight, after, we shift some of our rear butt-end axle weight forward of the back axle. So, of the 18 cubes in the back I'll move six or so forward of the rear axle and that will give us (8) cubes forward of the rear axle.

Thanks! I appreciate all your advices! If anyone has anymore tips let us know - ok? We'll be tinkering and tuning the car this evening while we watch another episode of 'Speed Racer' - LOL!

 

[Speedy]

One other thing here...

DFW weighing or not?:
Where and how much extra weight should we go on the DFW or should we simply make our weights balanced - to the middle of the car? I've heard two ways of doing this and I'm scratching my head wondering which direction to go? I've heard extra weight on the DFW side and then I've also heard put the extra weight opposite of the DFW??? Ready to flip a coin here and see what happens - but I don't want to mess things up like I did a few weeks ago and put too much weight in the wrong spots making our car perform lesser because we're not sure where to put it correctly?

LUBE issues?:
! Also got concerns about how to get the graphite loaded up for a longer lasting lube job. Last race my son ran he beat out a kid in his den race placing second only to be beat by the same kid in the winner's final race bracket? I know after he raced 16 times we were pretty much running on fumes graphite-wise, but how can we make it to over 10-14 races for District and be sure we don't slow down due to lubing issues? Of course, nobody is supposed to use anythig but graphite in our Pack/District but I suspected some may be using oil or an alternative lube that's working better and lasting longer.

 

[Obsessedderbydad]

If you stick to the graphite only rules the only thing you can do is burnish the graphite into the wheel bore. Re-apply graphite, and spin the wheels to work the graphite in. I was able to have my best runs with DD4H graphite runs 9-12. typically your best runs are runs 2-7 and you see time changes after 10 runs. Running 16 times is going to be hard to have graphite, but with proper bore prep you should be OK. Just make sure if you add graphite to your wheels to spin the wheels a few times or your times will be slower for a couple runs.

As far as weight goes, I always leaned on more weight on DFW side. Theory is there, the more weight on that side will ease the DFW into the rail rather than if you had weight opposite on the NDFW side, you'd have to put more steer than you normally would to get into the rail to counter the weight on the NDFW side. I could be wrong, but thats my thinking.

 

[Speedy]

Thanks for the follow up and advice! It was a veteran guy who's ranked in the mid-TOP-FIFTY racers in the country that gave me the advice to put the extra weight on the NDFW side of the car. My initial thoughts were to put the weight on the DFW side like you mention. I'm not sure why he felt it better to put the extra weight opposite of the DFW - but that's what he said, even after I asked for confirmation myself wondering if he flip-flopped in communicating things by chance. But he did say put the extra weight on the other side of the DFW. Maybe he felt the DFW would not put as much pressure on the rail by doing so and lessening the friction while running the rail? I can only guess here what was on his mind. Regardless, he's been winning races by doing so too!

One last question before we begin putting the graphite into our wheels and start spinning....

- has anyone ever heard of "Dri-Slide" multi-purpose lubricant (it's a form of liquid graphite)? Has anybody heard of guys having any luck with that stuff? A guy from our local Auto-body and paint shop suggested it to me yesterday while I was in there getting some 3000 grit sand paper etc. for polishing the axles. He said, "That's what we used to use some 20-years ago and it worked great!"

...now I'm beginning to split hairs I think - LOL! /images/boards/smilies/smile.gif

 

[Obsessedderbydad]

DD4H graphite... that's all you'll need. Now you'll need to do something about where the wheel can contact the body of the car. Either use sally hansen teflon tuff nail polish, monokote, washers (if allowed) or rub graphite real well in that area.

 

[5KidsRacing]

As far as weight placement and DFW or NDFW side placement people have found speed both ways, but everybody builds and tunes a little different so there is no one correct method. In my opinion the safe method is to lean towards having more weight towards the DFW axle side... once you get that mastered and you are up to speed then start messing with other things. You really have to have a track, a good skill set and experience to go off the proven path. Racing scouts once or twice a year you can win big by just sticking to the basics.

I have Dri-Slide.... was slower than the methods you will read here using a waxed bore, burnishing and a good graphite....

 

[Speedy]

Think I'll use the 'Dri-Slide' I got for my mower's linkage then - LOL!

...ALSO, how to post some pics here? Are the newbies allowed to post pics? I noticed I can only post a link for submitting a pic for now. Is this all you can do as a new guy in the forum?

P.s. - I like my new alias pic - thanks!!! That's perfect!

 

[Speedy]

[video]http://youtu.be/DvwhIStnDw8[/video]

....this is how our car is gonna run!

 

[Obsessedderbydad]

So your car is going to start off doing a doughnut then jump the track?

To post pictures go to an image hosting site, upload the picture, take the link they give you and post that for the link when you click the image icon in a thread

 

[Speedy]

LOL! Naw, it's simply gonna go fast like the car in YouTube video! Actually, it looks kinda like Speed's MACH VI car in that video! I just don't have experience with host pic sites etc. to post a pic - bummer!

 

[HMH Racing]

Pledge on the axles will also help.

 

[Speedy]

Thanks all!

Our district race was yesterday. Our son had the '4th' fastest PWD car per the timed averages and made it to the 'Top 16' in the finals. Last year we placed in the 'Top ten' finalists and our car was 5th overall.

SO, this year we bumped ourselves up another notch for a 4th fastest car in this year's district finals. Our car ran well over 16 races and I know the graphite was gone in the last few legs of the race. So, I guess it's fair game in the end as everyone is running on fumes lubrication-wise in their last few heats. I'm gonna experiment more on "dry lubes" and see what alternative lubes we can use. Because it's obvious some cars are remaining constant in their speeds while cars like my son's are slowing down near the end and losing speed. If we could have kept our speed up we'd have placed 2nd or 3rd overall. However, axles were running empty on lube after the 10th run or so and all we could do was coast down the track with friction increasing with each additional run.

 

[speed bump]

Thanks all!

Our district race was yesterday. Our son had the '4th' fastest PWD car per the timed averages and made it to the 'Top 16' in the finals. Last year we placed in the 'Top ten' finalists and our car was 5th overall.

SO, this year we bumped ourselves up another notch for a 4th fastest car in this year's district finals. Our car ran well over 16 races and I know the graphite was gone in the last few legs of the race. So, I guess it's fair game in the end as everyone is running on fumes lubrication-wise in their last few heats. I'm gonna experiment more on "dry lubes" and see what alternative lubes we can use. Because it's obvious some cars are remaining constant in their speeds while cars like my son's are slowing down near the end and losing speed. If we could have kept our speed up we'd have placed 2nd or 3rd overall. However, axles were running empty on lube after the 10th run or so and all we could do was coast down the track with friction increasing with each additional run.

.

Do u use red rocket and burnish graphite in the wheel bores? Wheel bore prep is key to longer runs. Steering of car is next. More steer = more friction.

 

[Speedy]

We used "Monkey Dust" Premium Graphite and did burnish the graphite into the wheel bores etc.. However, after so many runs I believe the graphite had ran it's course for the most part. On the races where we tied (on more than one occasion) with the other car we had to run additional heats up to 5-6 runs total.

The more I think of it, I think we ran over 20 races overall. Don't think graphite can last so long? I did discover later that "dry lubes are acceptable" and that opens up a whole new ballgame understanding of what can be used vs. the initial rules we were given that said "graphite only." I'm thinking we may have ran against some oil or other alternative lubricated cars because some of 'em simply kept their best times from beginning to end. Can graphite do that after 20 some races???

It was fun to watch the kids race 'em! Of course, near the end there was the 'agony of defeat'
and some were crying it off. My son ended his final heat with a smile and shook hands with the kid who beat him. They had to run extra heats because they tied on their 2nd race. It's amazing to see them tie down to a 1000th of a second!

 

[ngyoung]

I see a lot of people refer to using the Red Rocket bore polish then burnishing. Are you starting with the Red Rocket and skipping the Zero friction #1 polish or is that step just implied?