Required Guide Rail Clearance

[TAL]

Being many interpatations of wheel clearance on the rail, what is your requirements and what parts do you measure to inforce it?

When I (we) use the 1 3/4" rule I have always (regardless of the width of the body) checked to see if the inner running surface of the tire (tread) that rubs the rail is capable of providing at least a 1 3/4" clearance...

This is considering the 2 3/4" overall width of the car rule is also inforced...

The reason being is I have often found that some brands of pinewood derby cars don't cut their blocks on the 1 3/4" mark but in the enclosed rules of those kits state a 1 3/4" center rail rule...

What if a kid gets sanding happy or is useing a sander of some kind and takes off more than they should on the sides of the block...Are they to start all over, or add a spacer (bushing) to make up the difference???

Why not just pull the axle out slightly and stay within the 2 3/4" overall mark...

[SlartyBartFast]

Body can be narrow, but the wheels must be able to provide at least a 1 3/4" clearance (Explain what part of the wheel )

The explanation is simple. Put the car over a 1.75" x 3/8" board. The car must be able to roll.

Guide and bottom clearance checked.

[Pinewood Daddy]

Body can be narrow, but the wheels must be able to provide at least a 1 3/4" clearance (Explain what part of the wheel)

The explanation is simple. Put the car over a 1.75" x 3/8" board. The car must be able to roll.

Guide and bottom clearance checked.

Our District specs have a 1 3/4" dimension on both ends of the block and 3/8" clearance. But they are inspected by rolling the car on a simulated lane guide, 1 5/8" x 1/4". What's the sense of having specs if the cars aren't inspected to them??

[Mr. Slick]

Well here are the two sides of our coin.

The Rules:

DIMENSIONS: Car cannot be more than 2 3/4 inches wide. The maximum height is 3 ½ inches. Car cannot be more than 7 inches long. Since the starting pins are round, the minimum width of the front of the car is ½ inch. The front end may be no more than ¼ inch above the axle line. The car body must be at least 1 3/4 inches wide at the axles. It must clear the ground by at least 3/8 inch at the guide rail(s).

The Dimension Inspection Practices used:

Using the Go/No-Go gauge from MaxV/Lisano Enterprises verify that the car fits in the box.
IF the car is over the 3" height guide on the gauge, verify that the car will clear under the actual finish line. (Intent of rule is to avoid damage to finish line electronics.)
IF the car scrapes on the bottom verify that it does not scrape on the test section of the actual track.

So, the rules say the BODY at the axles must be 1.75" but all that is inspected is that the inside edge of the wheel tread is 1.75"

The rules say that the under body clearance must be 3/8" at the guide rails but we initially check that the entire under body clearance is 3/8" and only check to see if it clears the 3/8" at the guide rails if it fails the entire body height.

The goal is to allow as much as possible with out penalization of "slight" problems. The interpretation of the body width literally would mean there could be narrowing anyplace except at the axles so the overly enthusiastic sander would have problems. . .

[SlartyBartFast]

But they are inspected by rolling the car on a simulated lane guide, 1 5/8" x 1/4". What's the sense of having specs if the cars aren't inspected to them??

You know the answer. There's no sense at all.

Hate to say it, but I'd be tempted to do the following:

1 - Request the rules be changed.
2 - If the rules aren't changed, change the inspection.
3 - If the inspection is not changed, build two cars. First car to pass current inspect, second car to pass rules as written.

But perhaps that's a life lesson you don't want to teach your child...

[Pinewood Daddy]

[You know the answer. There's no sense at all.

Hate to say it, but I'd be tempted to do the following:

1 - Request the rules be changed.
2 - If the rules aren't changed, change the inspection.
3 - If the inspection is not changed, build two cars. First car to pass current inspect, second car to pass rules as written.

But perhaps that's a life lesson you don't want to teach your child...

I volunteered to help on the District Committee but we haven't had a meeting yet. There's a new Chairman this year. I discussed by email some changes I'd like to see. Hopefully we can clarify the rules without over complicating them.

Last year I questioned why our gages had a 1/4" high guide when the spec says 3/8". Even the gages at the District race were that way! Then they're nailing people for not having "4 on the floor"!! My pet peeve!! I hope to get that changed or added to the rules.

[Go Bubba Go]

Our Council and Pack rules state:

Track Clearance: The car must have an under-body and in-between-wheel clearance which will allow it to travel freely over a track lane strip which is 3/8 inches maximum in height and 1-3/4 inches maximum in width.

This clearance (as well as overall height and width) is inspected at Pack (and I believe at Council - don't recall 100%) by use of a go/no-go box with a rail over which the car is expected to move back and forth freely.

I have not seen any binding issues with the go/no-go box at Council, but at Pack our previous Pack Chairman would take any cars that bound on the box and check them on the actual track. If they moved freely on the actual track, he would pass them along regardless of their binding on the go/no-go box.

[Darin McGrew]

Our rule is that the car must fit the track. Anyone who just builds the car with the block provided should end up with a car that fits the track. All the dimensions we provide are considered guidelines to help those who "think outside the block" build an unusual car that will still fit the track. For testing guide rail clearance, we have a section of our old track (our new track was built to the same dimensions) available on registration night.

[Pinewood Daddy]

Our rule is that the car must fit the track. Anyone who just builds the car with the block provided should end up with a car that fits the track. All the dimensions we provide are considered guidelines to help those who "think outside the block" build an unusual car that will still fit the track. For testing guide rail clearance, we have a section of our old track (our new track was built to the same dimensions) available on registration night.

Yes!! All the car has to do is fit the track. That's all our gages do is simulate the track. The dimensions are just guidelines. We need to change to rules to reflect that.

[SlartyBartFast]

Yes!! All the car has to do is fit the track. That's all our gages do is simulate the track. The dimensions are just guidelines. We need to change to rules to reflect that.

RUBBISH!

If your track needs different clearances, and the cars will not be used on any other track, by all means change the rules to reflect your track clearances.

But, once set, they are RULES. It's what stops arguments about how close a fit is "good enough". A car either makes it through inspection or it doesn't.

Or do you consider the 5 oz weight limit a "guideline" as well?

Designing to the strict minimum the track will allow has advantages. Just as more weight does.

If the car is going to race on other tracks, the racers MUST be made aware of whether they break the clearance rules. Whether or not they are allowed to race.

At least save the organizers of the other race the hassle of putting up with arguments/whining of "but I raced it at the last race!".

[Pinewood Daddy]

Yes!! All the car has to do is fit the track. That's all our gages do is simulate the track. The dimensions are just guidelines. We need to change to rules to reflect that.

RUBBISH!

If your track needs different clearances, and the cars will not be used on any other track, by all means change the rules to reflect your track clearances.

But, once set, they are RULES. It's what stops arguments about how close a fit is "good enough". A car either makes it through inspection or it doesn't.

Or do you consider the 5 oz weight limit a "guideline" as well?

Designing to the strict minimum the track will allow has advantages. Just as more weight does.

If the car is going to race on other tracks, the racers MUST be made aware of whether they break the clearance rules. Whether or not they are allowed to race.

At least save the organizers of the other race the hassle of putting up with arguments/whining of "but I raced it at the last race!".

My point was our Pack and District don't inspect all of the rules, they check for flat BSA wheels, axle points, weigh, put the car in the box and run it over a lane guide. If they're not going to inspect most of the rules, then they should be noted as a guideline or removed. The "hard" rules should be noted as such. I assume the 1/4" x 1 5/8" lane guide is universal so a car that fits on our track should fit on any track with a lane guide.

[SlartyBartFast]

My point was our Pack and District don't inspect all of the rules, they check for flat BSA wheels, axle points, weigh, put the car in the box and run it over a lane guide. If they're not going to inspect most of the rules, then they should be noted as a guideline or removed. The "hard" rules should be noted as such. I assume the 1/4" x 1 5/8" lane guide is universal so a car that fits on our track should fit on any track with a lane guide.

Actually, you DO have a hard rule. At least for inspection. The car must roll over the 1/4" x 1 5/8" lane guide.

Problem is that the clearance reduces as the car travels the transition curve. So, a car could pass the lane guide inspection and bottom out on the track.

The cars must have enough clearance for the thickest part of the guide/ tallest protrusion/tightest curve.

The only thing likely to be universal is that a car built to 3/8" clearance should be able to freely run on any track built to accepted standards.

[Darin McGrew]

If the car is going to race on other tracks, the racers MUST be made aware of whether they break the clearance rules.

Sure. And the years when we've had a regional derby, we've let everyone know what the regional derby's dimension requirements are, so those who are interested in attending the regional derby can design their cars with those requirements in mind. But for our derby, our rules require only that the cars fit our track.

Well, that isn't the only thing our rules require. They also limit the weight to 5.0oz (142g), and they limit construction techniques in certain ways. But as far as car dimensions go, they require only that the cars fit our track.

[Pinewood Daddy]

I would like to see our rules changed from 1 3/4" across the block to 1 3/4" between the inner edge wheels. That is a functional requirement.

I think the inspection blocks should be changed from a 1/4" x 1 5/8" rail to a 3/8" x 1 3/4" rail.

[TAL]

The official State of Oklahoma PineWood Derby took place April 7, 2007.

What is the next step for the winner? We do not want to miss an opportunity, yet I am not finding any official next step?

You'll probably find more information on that Topic in the General car/truck racer topics...