Miata hard top rule?

[rhygin]

I am in the process of trying to prepare a 1995 miata for ITA next year. Asside from now needing a new transmission and engine and cage... I have a question about the top required. my car has a hard top from the previous owner, but my sense is that it is not a factory top because the mounting bolt holes are different.

In the 2007 Improved Touring section of the GCR... (8.f) there is nothing that dictates a factory hard top as far as I can tell whereas in the spec miata section there is an explicity rule that says you need a factory hard top.

So.. mine is heavier than stock and I figured out how to mount it with AL plates that I made... is there any reason why I cannot use this one legally? I am looking to not incur costs that I do not need to incur (getting tight already) but do not want to be illegal with what I (very newbie) am considering a "replacement part... from sourcces other than the manufacturer." The specs are prolly not 100% exact (worse in my case... weight) and is made of the same materials.

Thoughts?

Thanks,
Brad

[johnny yanez]

i believe the ita rule on the miata states you do not have to have a top but if you have a top you have to bolt it likea spec miata rule, it does not state that it has to be a factory oem top like spec miata. There are some tops that are made by other sources that are lighter and look the same as the factory top,,
I run a 85 miata also with ITA rules

[Andy Bettencourt]

Guys - if you are going to replace a factory piece, it needs to be of similar dimension and function - including weight. Under the above logic, you could make a carbon-fiber HT and bolt it on in the stock location...that just ain't legal. GCR Page 294 - first paragraph.

[ddewhurst]

Brad, the following comment is for grins & NOT aimed towards you.

Is there a rule within the ITCS which allows use of a top in an ITA Miata with the soft top or hard top ? They are both removable convertible tops.

[jjjanos]

Guys - if you are going to replace a factory piece, it needs to be of similar dimension and function - including weight. Under the above logic, you could make a carbon-fiber HT and bolt it on in the stock location...that just ain't legal. GCR Page 294 - first paragraph.
[/b]

Yep, but GCR Page 294 isn't relevant, IMO. The spec line says "Detachable hardtop may be installed." It doesn't say "FACTORY detachable hardtop may be installed."

[Knestis]

...but the bigger presumption is that we will use OE parts unless otherwise specifically authorized. Andy's right on here.

K

[Greg Amy]

...but the bigger presumption is that we will use OE parts unless otherwise specifically authorized.[/b]

I disagree, Prof. With the addition of the "replacement part... from sources other than the manufacturer" that Brad mentions, that presumption is lost.

*WE* (you, I, and Andy) may presume that, because that's where we came from (for the young'uns, used to be we had to use factory replacement parts only). But if you read that rule fresh with 'aftermarket parts' in mind then at best we presume nothing and remain agnostic about the source; at worst we presume the opposite, that folks will tend to gravitate towards aftermarket parts because they may be cheaper and more easily obtained.

We don't require factory fenders, hoods, and door panels; why would we require factory hard tops?

Andy is correct in that the 'aftermarket rule' does specify "exact equivalent" (though we do need some reasonable flexibility there, given the aftermarket suppliers can't be expected to use the factory tools and material suppliers) but our buddy jjjanos is correct in that the rules do not require a factory hardtop... - GA

[Knestis]

Sorry - yes, Greg is right. (On the same point that I've ignored twice in the last couple weeks.)

There is a specific authorization to use equivalent parts (or whatever the language is). I was focusing on Andy's use of "...similar dimension and function - including weight" as defining what is allowable under that provision.

Kirk (who's used a six-pack of aftermarket front fenders on the Golf, not all of which were purchased by Mr. Amy)

:P

[ddewhurst]

Sorry about that. When all else fails READ the spec line.

I am in total agrement with jjjanos, "Detachable hardtop may be installed."

[Andy Bettencourt]

I think we now all agree that an aftermarket hardtop can be used. The comment then needs to be adressed by Yanez Racing about anything 'lighter' than stock.

I still say aftermarket OK in IT but anything lighter is a no-no.

[rhygin]

Great discussion here... I will weigh the top and let everyone know what the deal is. Totally agree that a light weight and "flimsy" top that is not a "faithful" replication of the factory unit is not in the spirit of an equivalent replacement part.

On the specmiata forum... there has been some chatter about the SnugTop (guess that is what I have)... it appears to be heavier, but i will check. Looks like 40 - 48lbs is the factory weight from what I have been able to gather on specmiata.com and miata.net

I will be able to pull the top and such this weekend...

Thanks,
Brad

[loudes13]

I think we now all agree that an aftermarket hardtop can be used. The comment then needs to be adressed by Yanez Racing about anything 'lighter' than stock.

I still say aftermarket OK in IT but anything lighter is a no-no.
[/b]

that logic means heavier is illegal also.

protest yourself and find out...

[rhygin]

Loudes13...
Being new here... how should I react to the last post in this string... I am not even sure what it means or what I should take away. LMK.

Thanks,
Brad

[Greg Amy]

...how should I react to the last post in this string...[/b]

Don't.

You'll find an eclectic bunch of folks in this forum. You'll find rules nerds like me and the Prof who will take apart every rule to its nth degree, and others that take a "devil may care" attitude. None, for the most part, harbor ill will.

Technically to the rules, any part that does not EXACTLY conform to the original manufacturer's part - or allowances in the rules - is illegal. Thus, Loudes is correct: a part that is heavier than stock is technically illegal.

However, there's also a "spirit" to the rules that most of us try to cling to; we only use the technical part of the rules to support it. Thus, yes, a heavier hard top is illegal, but in reality as long as your replacement part meets the "spirit" of the rules and does not present a performance advantage above the stock hard top, I really, really don't think anyone's going to give you significant grief over it. Sure, they could protest you, but I doubt it'll happen (that's one of them thar things we call a "weenie protest").

On the other hand, a heavier top can be a significant performance DISadvantage, so you might see about finding a factory one and selling your aftermarket one... - GA

[JeffYoung]

And for God's sake man, get a sail.

[ltblouis]

Guys I have a question and maybe Miata guys can answer it,
why do you even run a hard top??? do hard top gives an advantage over not having one ???

[Knestis]

Aero drag is way higher without it. I think Jeff has actually run the TR with and without and can share his results...?

K

[ltblouis]

Aero drag make sense but having 50 or 60 lbs on the highest point of the car is bad to.

[Andy Bettencourt]

It's certainly a give and take. I have heard that as some tracks eliminating the HT will knock 10mph off your top speed (Texas I think). We have 2 tracks here in the NE that I would like to test without it but it's such a pain to take it on and off along with another 40-ish pounds of ballast to go in, it's just a pain to make happen.

[Z3_GoCar]

Aero drag make sense but having 50 or 60 lbs on the highest point of the car is bad to.
[/b]

Like most things, it's not an easy answer. At some tracks it's a break even proposition, the hard tops adds to top speed but takes corner speed in the slow section. At others it's a definant advantage. Here in So-Cal it's an advantage no matter which track we run same thing at Thunder Hill, any of the Roval tracks, Road Atlanta, and VIR. Then there's the safety aspect. I'd have hated to have done my roll in the soft silty soil with out the hard top, even if it only scratched the top and the bars are a pinch point so I have arm restraints. Then back to speed, believe me when you get passed at the end of the straight because there's no more top end speed, then once passed you pick up 5-10mph, you'll realize the value of better aero.

James