1441 replies to this topic

[tonyp]

Tech like we do now front and rear tires supporting the car and .055" clearance for the whole chassis. Simple, easy, and nothing to talk about on the blog. LOL...

[gascarnut]

Larry - you win.

I had a small bet going with myself whether it would be you or Rick that would be the first to react to that!

Ron, unless the tech block has the same braid depression as the track, Tony's suggestion makes more sense - sorry!

[gascarnut]

I dunno if I will come to Columbus now... knowing that there's this African-American guy waiting to "deal" with me... LOL!!

According to the D3 guys, I'm the "Colorado Cowboy" now - check the photos from the last race!

[Ron Hershman]

Ron, unless the tech block has the same braid depression as the track, Tony's suggestion makes more sense - sorry!

No problem with that... that was my intention.

[Cheater]

To put this discussion in this thread to bed, interested parties should know that the IRRA board will be revisiting chassis to track clearance, how it's defined, and how it's measured.

If and when change in the clearance parameter is made, it will be announced here on Slotblog.

[Cheater]

One more point: this thread was meant to act as a reference, where questions would be posted and answered. Obviously, it hasn't exactly worked out that way, as there is more discussion than anything else.

Prodded by a suggestion sent via PM, I'm going to split this thread in two: one will be "IRRA Rules Questions & Answers" and the other will be "IRRA Rules Comments & Discussion", which will actually be this thread retitled. The former will be locked and only IRRA board members will be able to post there. The latter will be open to all, and is where the questions eventually answered in the other thread should be posted.

And, as will be noticed, IRRA racing now has its own forum, separate from the General Retro Racing and D3 Retro Racing forums.

[Jay Guard]

Sorry Guys:

Geeeesh... For the life of me I just can't understand what is so difficult to understand about this "clearance thing". .015" at the front of the chassis and .050" at the rear and a straight line in between. Personally I would be embarrassed to admit that I couldn't understand or reasonably check a geometric principle as basic as this. Two pieces of wire and a straight edge just doesn't seem all that technologically advanced to me!

Or as Greg Wells might have said: Are we trying hard to fix a problem that doesn't even exist?

[NJ Racer]

For all you USRA knockers, how do you think wing car chassis clearance is teched based on USRA National rules...

[TSR]

NASCAR templates?

[Ron Hershman]

For all you USRA knockers, how do you think wing car chassis clearance is teched based on USRA National rules...

A piece of .063" wire about 6 or so inches long. They shove that sucker in from the rear of the car all the way to the front.

If nothing touches or rubs... no problem. If they feel friction or something else, they take a closer look and usually send you back to your pit box to make corrections.

[Ron Hershman]

Geeeesh... For the life of me I just can't understand what is so difficult to understand about this "clearance thing". .015" at the front of the chassis and .050" at the rear and a straight line in between. Personally I would be embarrassed to admit that I couldn't understand or reasonably check a geometric principle as basic as this. Two pieces of wire and a straight edge just doesn't seem all that technologically advanced to me!

Or as Greg Wells might have said: Are we trying hard to fix a problem that doesn't even exist?

Here is what is so difficult... we see pictures of cars that have weight added to the bottom of them. Now if your motor bracket had to clear by .050" then the rear of the pans directly across from the motor bracket SHOULD TOO!!! Now if you add weight to the bottom of the pan that had .050" clearance without the weight, then the weight cannot clear by the .050" that is required. This is another way of getting around "Z-Bend" main rails that you brought up awhile back and we made a rule about it.

This angular plane thing is crazy. How much clearance should a chassis/main rails/drop arm/pans have if you measure one inch back from the center of the guide??? Can anyone know the correct amount? Is there a tech tool or wire of proper dimension to check this? NOPE.

I have heard some raceway owners complain that we don't have .063" at the rear and all around. .050" all around with the front wheels touching stops any thing from hanging from the bottom of the car/chassis without much modification having to be made to current chassis/cars.

[Dominator]

I have recently built a Can-Am car but not raced it yet. So my question is how much tire is actually worn off the rear during the race? Where these motors have "low horsepower" they shouldn't be spinning the tires much but then again the cars are heavy. If the tires, depending on treated or not, I would assume they would be wearing about .035" for nontreated and about .022" for treated. This of course referring to the rear tires.

What if .047" clearance was used all around? This would make the cars easier to drive (especially for newbies) and better racing all around. Assuming my estimates are correct if you started off with .047" clearance you should still have approximately .030" clearance at the end of the race which still leaves plenty of room between the chassis and track surface without the track owner being worried about the track being damaged.

Ultimately it is still the track owner's call on clearance. The .050" clearance is an interesting clearance measurement that I assumed was designed to help the cars handle better as already mentioned, "the old cars" had 1/16" clearance. I think if anything was going to change, the .047" would be best as someone has already said the front end is the easiest to change on a chassis and the rear is essentially there (alright it is .003" off but who cares with a car weighing in at 100+grams).

[MSwiss]

Ron,

I think you're assuming the car is right at the minimum clearance and the weight is added after tech.

If it is, the car should be reteched.

[Larry Mattingly]

Larry - you win.

I had a small bet going with myself whether it would be you or Rick that would be the first to react to that!

Dennis,

Do I get a 'cut' of the winnings?...

LM

[Larry Mattingly]

NASCAR templates?

Now that was funny....

Good to see you still have your sense of humor.

I might be one of the few who appreciates pure sarcasm.

Hershman is good, but he is still young. Imagine what he will be like when he gets old and cranky...

Well, at least old...

LM

[NJ Racer]

Witty yes, but Ron obviously answered correctly.

[Ron Hershman]

Hey, I am getting older and crankier by the day.

[TSR]

I might be one of the few who appreciates pure sarcasm.

Hershman cannot compete against such obvious talent. Actually I am trying out for Leno next month.

[Rick]

.050" front to back, what a concept. Who'd a thunk it?

It would be so much easier to set up a car with the thing being on the guide than this mess now...

There is still hope for rational common sense in slot cars?

[jimht]

Whack-A-Mole...
as I said in the previous discussion, the clearance rule is badly written.
Question on updated chassis rules
No problems with "bowing" if there's a minimum clearance.
Also, be wary of rules written to "help" beginners (dimensions of less than 1/16" under the chassis)...such things always wind up helping the more serious.
Rules writers must not think as or of racers when they're writing technical rules...racers should only be considered in discussions of procedures.

[John Reimels]

When I orignally asked the question concerning the addition of lead to the bottom of a chassis I had no idea what a can of worms I was opening.

I think the chassis clearance as it is currently defined is perfectly clear and not very hard to inspect. There's growing interest up here in New England to start a racing series and utilizing the IRRA rules is an obvious choice. I'm all for the 0.015"/0.050" clearance with nothing hanging below the main frame rails.

Thanks,

[Pablo]

I like the slope effect of 015/050 because it offers legal ground effects. One interesting thing about the existing rules is, the further you extend your frame in front, the higher the area under the front axle must be. My point is, the way the rules are written, it is a self-limiting deal - if you extend that front way out there, the under axle area gets higher......the slope deal was a building challenge for me, and I learned from it.

050 size is weird, I don't know where guys are getting 050 wire, or plate or whatever....048 or 055 would be good because that size K & S wire is commonly found at local hobby shops...some of us don't live near raceways.....

radical change such as 063 flat would make many existing frames illegal and unable to comply without major rebuilds, however, slight changes to the front, eg. .015 to .047 would be easy to change by simply refloating the front axle assembly.....Of course I'm referring to my frames only, my point of view.....

Best suggestion: "Tony P : Tech like we do now front and rear tires supporting the car and .055" clearance for the whole chassis. Simple, easy" I like it. BUT, question, will my rear that currently clears 050 with .830 wheels be able to support 055 clearance with out of the bottle 13/16 wheels which usually measure .835? Do they sell 7/8 OD rears? I may need some for my frames......
The piano wire on my frames is rusting so fast, I will probably be rethinking my frames anyway, and starting all over again so I'm open for change. BUT, once I go to all bronze, all change must stop, as will the rust. Time will be frozen at that point, just kidding haha
Just my input and I will continue to build to IRRA specs regardless. The communication here is awesome. As dc-65x would say....ONWARD.......!!!!!!!!

[GTPJoe]

Pablo

McMaster Carr has wire in many sizes. In fact their .051 is really .0505 so pretty close to .050! I don't know why you'd need it.

I too like the sloping effect of the frame. But I like the way the SoCal guys do it with the .015 being measured under the front axle. So then I just set my jig wheels to give me at least .015 right there. It's easy to control clearance right there with bigger or smaller wheels.

With the IRRA measuring method I have to make a .015 shim and put it under the front most part of the chassis and then set my jig wheels up for that, if I still want to make it an angle down to the front as the lowest spot. Of course it looks like a lot of the chassis are level up front.

See ya!

[Hworth08]

050 size is weird, I don't know where guys are getting 050 wire, or plate or whatever....048 or 055 would be good because that size K & S wire is commonly found at local hobby shops...some of us don't live near raceways.....

Hi Pablo,

You can buy a feeler gage set at most any parts house. The set will have around 20 different indiviual blades, from .002 to maybe .028. Usually two or three different blades can be combined to give most any thickness. The better gage sets will be held together in a manner so it is easy to remove each blade for "combining" if a person is in a limited space.

The nice feeler gage set used to cost 3 or 4 dollars. Probably about the cost of a Falcon motor today.

[TSR]

Probably about the cost of a Falcon motor today.

At Falcon Discount-R-Us?