Length of car past the front wheels

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Crazylegsiraq
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Length of car past the front wheels

Post by Crazylegsiraq » Mon Feb 20, 2017 11:31 am

I'm thinking of cutting off the back of our BSA block in order to gain as much length as possible past the front wheels. If I do this, what, if any, issues can I anticipate dealing with throughout the rest of the build process?

The rules in our district and pack say no longer than 7 inches. So is trying to "Win by a nose" creating more problems in the rear of the car?

I intend to leave about 3/8 - 1/2 inch of body behind the rear wheels. Any opinions or suggestions are appreciated. Especially if any of you out there have tried this.



Speedster
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Re: Length of car past the front wheels

Post by Speedster » Mon Feb 20, 2017 12:07 pm

Hello, Fellow Buckeye. Welcome to Derbytalk
Your car will still be 7". What you are doing is shifting the wheelbase. This will move the COM a little higher up the arc.
I'm assuming you are using the long end for the front. You can only cut off 5/16" if you're really careful. The wheels cannot extend past the rear of the car because the car will then be longer than 7". You will still have room for 2 rows of 6 - 1/4" tungsten cubes. I'm assuming you are building a 1/4" high car that will look like a Hershey Bar. On extended wheelbase cars the rear axle holes are drilled 5/8" from the rear of the car. The long nose will clear the Best track curve OK. Maximum Velocity did a test on this and the improvement was so small it's not worth the effort. I use to do it regularly but we either won or lost by a much greater margin and I stopped doing it. If you are a beginner it is far better to concentrate on other things such as wheel and axle prep, weight placement, tuning, 3 wheelers if allowed, rail riding, etc.
Have lots of Fun.



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Re: Length of car past the front wheels

Post by Crazylegsiraq » Mon Feb 20, 2017 3:43 pm

Thanks for getting back to me. And good looking out on those rear wheels! Haha. In our Dist., no wheel base change is allowed and we must use axle slots on the block.

However, axles may only be polished and burrs/crimp marks removed. I'm interested in cambering wheels for rail riding but am weary of drilling the correct angles into the block. I believe the track is short (40ft or less?). Is or are there methods of drilling these angles properly to achieve this?

Thanks again for your or anyone's advice.



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Re: Length of car past the front wheels

Post by Speedster » Mon Feb 20, 2017 6:31 pm

You can't drill holes if you must use slots. Or can you? Theres's lots of tools that will help you drill holes but let's go without doing any drilling. The reason the rear wheels have Negative camber is to get the wheel to ride on the nail head which will be the widest from the guide strip. However, if you put the rear axles in perfectly straight, preferably using the Derbyworx tool, for some reason the back wheels will still migrate to the axle heads while moving the car forward and backward. Hopefully the rules allow you to run on 3 wheels. Now on to the Dominant Front Wheel. You need a bent nail preferably bent 1 1/2 degrees and then Put Positive Camber and toe-in on the wheel so the car will drift 2" in 4'. If you have a track you're in luck. Take it to the track and find the fastest time.

Tell us about yourself. Have you been building cars for awhile? Is this your 1st car?



Crazylegsiraq
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Re: Length of car past the front wheels

Post by Crazylegsiraq » Mon Feb 20, 2017 9:28 pm

Thanks again for the response. I'll need to look up the difference between camber and tow in mean to understand better.

And to answer about myself, no, this isn't my first derby. I am a father of 4, and had my oldest son go through 4 derbies. However, my last car was built 4 years ago, and the 3 cars built by my oldest and I, were all more for looks rather than speed. With him, I found that anytime I would begin to even try and research speed tips, tricks, etc., he would either lose interest in the concept or not put forth the effort or patience needed to be successful. So design and paint were always the focus. So there was always this cool looking car rattling down the track... In last place.

My new scout, on the other hand, as we spoke about designs and looked at other designs on line would always question the design with," Does it go fast?" So I think with this boy, I have a new creative direction to go in. Speed!

But as I've researched the last week, I started seeing more and more differing opinions as to the "best practice" for this tip or that technique. So as I run into a couple of derby threads, this has seamed like a great place to start and have discussions that I hope I can translate into some good father/son moments learning more about science, physics, and creation together.



Speedster
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Re: Length of car past the front wheels

Post by Speedster » Tue Feb 21, 2017 5:05 am

I have your answer. Your son will enjoy it too because its got 300 How-to-Photos.

"Build a Winning Pinewood Derby Car", by Troy Thorne, 2013 Edition. Fox Chapel Publishing, $9.99.

Once you and he read it you will have the basics. There is also a search function on Derbytalk where I'm sure there is an answer to any question you might have. That's not to suggest you should not ask questions. If you are in a Super hurry for the book, email me. I can get one to you faster than the publishing company. I stock them because I offer them for sale at our workshops. I can't find these at Hobby Lobby or Michaels anymore. I had to get them from Fox Chapel.
Best
Bill Klingler



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Length of car past the front wheels

Post by whodathunkit » Tue Feb 21, 2017 7:37 am

There latest book out is called
Fast & Furious speed tips and tricks.
By David Meade, Troy Thorne,
And other derby experts.
There is also lots of info and car patterns to chose from in this one.

Might try looking on line or at target for it.

Sent from my iPhone using Tapatalk


What type of automobile can be spelled the same forwards & backwards?

Crazylegsiraq
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Re: Length of car past the front wheels

Post by Crazylegsiraq » Tue Feb 21, 2017 8:14 am

Thanks so much! Right now I'm just gonna keep strolling through this cool blog site. I really like reading about the trials and errors. My first boy always did well with design/paint. We usually placed at pack level and got to enjoy two trips to district events. One for design and one for paint.

But my 8yr old seems as if he's all about speed! Good news for me, as he has a 6yr old coming in next year that his mother and I swear that he's so OCD, he'll have me starting him on his car right after His older brother finishes the pack race this year.

Can't thank you all enough for this kind of site, and replies. I've been on so called "active" blogs for other topics and wait weeks and sometimes months for any type of replies. Lots of enthusiasm and good dads/moms on here.



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Re: Length of car past the front wheels

Post by Speedster » Tue Feb 21, 2017 10:05 am

OK, Buckeye, that was a really nice compliment. Thank you. I agree with you, the Derbytalk folks are the Greatest.
If you will email me your mailing address I will send you this book, no charge. Share it with your friends.
Happy Easter
Speedster



Crazylegsiraq
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Re: Length of car past the front wheels

Post by Crazylegsiraq » Tue Feb 21, 2017 12:13 pm

Holy Smokes! Super cool of you to offer this. You don't even know. Wow thanks again. For everything.



Crazylegsiraq
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Re: Length of car past the front wheels

Post by Crazylegsiraq » Tue Mar 14, 2017 7:54 am

So I have been in the book and Speedster sent me(Thanks a million by the way!), and after getting my boy into the power tools(polishing axles/wheels etc.), I debated inserting the axles prior to filling the slots provided with the 5min. epoxy after using the #44 bit in a drill jig found online.

So on the other body, I decided to not drill the slots and place axles until after it set up a day. Have any of you out there done either, or both, and if so, what was more successful? The jury is still out on this as we have two weeks before race day to find out. Initially, I'm thinking drilling after filling slots with epoxy would make for a tighter more accurate axle insertion.



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Re: Length of car past the front wheels

Post by Speedster » Tue Mar 14, 2017 8:56 am

Our rules state the wheels must be straight up and down and slots and axles must be visible.

This is what I do. I first use the Part # 5140 Pro-Body Tool and drill the rear slots with the # 44 drill bit the tool comes with.
When it's time to install the axles I use the # 5149 Pro-axle Guide and clamp it to the car. I remove the steel guide on the side of the tool and use a notched, plastic credit card for spacing between the car and wheel hub. The steel spacer on the tool can do a lot of damage to the wheel hub. I push the nails in with the drill press. If you don't have a drill press the #5150 Axle install support can make installing axles a lot easier. The rear wheels have (so far) migrated out to the axle heads both rolling the car forward and rearward. We are allowed to run on 3 wheels. We build - sort of - rail riders. Last Saturday at our District race it was obvious "wheels need to be straight up and down" was not enforced. If it doesn't weigh more than 5 ounces it will probably pass. Our dfw also sits straight up and down because of the clearance between the axle and bore even though it is set with 1 1/2 degrees of Positive Camber.
That's our build.



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Re: Length of car past the front wheels

Post by Crazylegsiraq » Tue Mar 14, 2017 9:12 am

Our rules allow rail rider. However they have rules on axles as being polished only. BUT, before I bend the axles straight(because they're all bent except for maybe 3 of them)5 out of 8 wobble like crazy in our press meaning they're bent out of the box, is it really gonna make a difference if I bend them to my liking? A couple of these things actually center on the outer most edge of the nail head. I just can't see them disqualifying a car knowing these nails don't come straight. Having a moral dilemma here as I don't wish to break the rules but I don't think that we have a snowball's chance unless I make some adjustments to these wobberjawed things. Any opinions on this are appreciated. I don't want my next trip to confession discussing Pinewood derby dos and don't Sto my priest! Hahaha.



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Re: Length of car past the front wheels

Post by Speedster » Tue Mar 14, 2017 2:49 pm

Get in your car and drive to Curtice, Ohio and I'll pick you up. My wife's going to West, Virginia for a few days on the 24th. I'll have a nail waiting for you and we'll run it down the track.



Crazylegsiraq
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Re: Length of car past the front wheels

Post by Crazylegsiraq » Tue Mar 14, 2017 3:49 pm

Speedster wrote:Get in your car and drive to Curtice, Ohio and I'll pick you up. My wife's going to West, Virginia for a few days on the 24th. I'll have a nail waiting for you and we'll run it down the track.

I've done some crazy stuff for my family Speedster! But driving over two hours for a straight nail? I may be better suited to invest that gas money and buy about 8 - 10 new BSA kits.



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