Where to put the wheels

[Newtoderby]

Hi gang,

Last year you all helped us to a 3rd locally and a 5th at district. So we are back at it and derby time is a couple weeks off. We have a question on where the wheels should be. My understanding is the wheels should be as close to front and back as possible, Our rules state wheels cant be sticking out in front or behind. So here is out questions. When measuring the COM the rear wheel would be about 7/8 of an inch to where the axle hole will be drilled. Making the rear tread about 3/8 inch from the back end. That placement gives us a COM of 5/8" The front wheel can be all the way forward. So is that ok or do I need to make the weight get further to the back and move the wheels back?

Also we grooved the axels. We have to use official boy scout axles but there is no rule you cant groove polish etc. we sanded up to 2500 and then used a piece of smooth leather to apply brasso to it.

Any other thoughts appreciated. Yes its three wheel one wheel up and yes we will bend the rear axles so they cant the right way. as well as the front too

We know there is a lot of competition. Just trying to improve from last year

Thanks

NewtoDerby and my Wolf scout

 

[Crash Enburn]

(Be prepared for a litany of "Don't bend the rear axles!")

You want your rear wheels as far back as they can go without sticking out past the end of the car. Most here drill their rears at 5/8" from the back. This lets you put more weight further back (higher from the bottom of the track, and thus more speed).

Regarding canting the rears:
Ideally, you would use the Silver Bullet. If you do not have access to one, you can replicate the angle drilling using a second wood block and a drill bit.

Line the block you're drilling carefully on another block, and clamp it on top. Take a drill bit, and tape it lengthwise at the top of the side of the lower block.

Drill Bit Size	Angle
1/16"	2.87°
5/64"	3.6°
3/32"	4.3°
7/64"	5°
1/8"	5.75°
9/64"	6.4°
5/32"	7.2°

From this post: http://www.pinewoodderbyonline.com/post/how-to-drill-axle-holes-without-the-silver-bullet-7141146?pid=1284841353#post1284838256

I'm suddenly full of doubt as to the angle you want as I am now using a Silver Bullet and the supplied pin. I believe that 3° is typical.

Everything else you listed there should work great for you in the scout races. /images/boards/smilies/thumb.gif

 

[Newtoderby]

Thanks Crash.

Only reason I was looking to bend the rear axles was because we don't have a silver bullet. I think I will go with that concept and drill the way you mentioned. I also wondered why I cant just adjust the drill press table to the proper angle and then drill?

We just finished up polishing axles. My scout did all the polishing himself. He is very pleased with himself and should be!!

I think we will remove the weight put some filler in to move it further to the rear. Thanks

Ross

 

[Guest]

...

 

[Kinser Racing]

Start here: http://www.pinewoodderbyonline.com/post/keys-to-win-from-the-pinewood-derby-king-5782181?pid=1272943640#post1272943640

and go here: http://5kidsracing.webs.com/

5kids is one of us and he promotes correct principles.

 

[Newtoderby]

Kinser...yep 5kids is the guide we are using. That is actually why we asked the question since the wheels on that one are not all the way to the back.

the stanpope page looks very useful

Thanks

 

[5KidsRacing]

Yeah I made that part of my site when our pack rules were standard wheelbase..... I think the other workshop page has examples of cars with extended wheel bases.

 

[Newtoderby]

Thanks 5 kid . we are going to move the weight back!!!''

 

[HMH Racing]

You can't go wrong with 5kids web site, excellent info. Start there and then ask questions and/or search the forums here. DD4H web site for supplies and you should be set.

 

[Newtoderby]

You guys really are the best. Last year when we knew nothing you steered us in the right direction and this year same thing. Thanks for the help. We got the weight out and moved it back. Next we drill the axle holes then some painting and we are lookin good!! This year is so much easier now that we are through the learning curve of last year'

 

[Obsessedderbydad]

Hi gang,

Last year you all helped us to a 3rd locally and a 5th at district. So we are back at it and derby time is a couple weeks off. We have a question on where the wheels should be. My understanding is the wheels should be as close to front and back as possible, Our rules state wheels cant be sticking out in front or behind. So here is out questions. We have a spot for out weight and poured in hot lead. when measuring the COM the rear wheel would be about 7/8 of an inch to where the axle hole will be drilled. Making the rear tread about 3/8 inch from the back end. That placement gives us a COM of 5/8" The front wheel can be all the way forward. So is that ok or do I need to make the weight get further to the back and move the wheels back?

Also we grooved the axels. We have to use official boy scout axles but there is no rule you cant groove polish etc. we sanded up to 2500 and then used a piece of smooth leather to apply brasso to it.

Any other thoughts appreciated. Yes its three wheel one wheel up and yes we will bend the rear axles so they cant the right way. as well as the front too

We know there is a lot of competition. Just trying to improve from last year

Thanks

NewtoDerby and my Wolf scout

I know I shouldn't have to tell you this, but BE CAREFUL doing this method. There's a ton of safer ways to do weight placement that are not hazardous to your health. PLEASE PLEASE PLEASE, if you do HAVE to do this, wear a mask and dont have your child be around for this. Other wise, just buy tungsten!

 

[NeedforSpeed]

Hey new to derby...I used to be a lead man myself. Tungsten is the way to go. More mass in less space. We were first place losers for two years until we found the 5kids manual and derbydads products. Follow the manual and spend the money on the axle polishing kit and the wheel bore prep kit. The silver bullet is awesome too. Use all that and you will put that pompous guy in his place.

 

[Newtoderby]

ODD. Don't worry I always be as safe as possible when doing that and the boy doesn't help. Also don't worry I am not melting it by any crazy method either. I just cant seem to bring myself to pop for the tungsten for the cost next year I may break down

 

[Bullet]

+1 on the 5Kids website...I used this as a guide when I started getting serious about the scout races...not that long ago, just last year! lol Full of great stuff...I see his stuff on a lot of the cars racing now./images/boards/smilies/thumb.gif

 

[Obsessedderbydad]

I never doubted that you werent safe, just wanted to post because there are safer methods now a days. Tungsten is the way to go. Worth every penny. I know its hard to drop money on it at first, but you really can't beat it.

 

[DEW36]

I never doubted that you werent safe, just wanted to post because there are safer methods now a days. Tungsten is the way to go. Worth every penny. I know its hard to drop money on it at first, but you really can't beat it.

+1

 

[Crash Enburn]

Unlike the lead, just don't seal the tungsten into the car. After the race, you can remove the tungsten and put it into a new car; so it's just an up-front cost that then becomes a zero-cost from here on out.

 

[HMH Racing]

Unlike the lead, just don't seal the tungsten into the car. After the race, you can remove the tungsten and put it into a new car; so it's just an up-front cost that then becomes a zero-cost from here on out.

+1 ... double sided tape in the weight pocket and HD packing or HVAC tape on the bottom. Just pop it out of the old car and into the new one. Because tungsten is denser it will allow for a more compact area for the weight. It is worth it in the long run.

 

[ngyoung]

I wrap my tungsten in aluminum tape then glue it in.