Car track widths

[gordon]

Guys,

First if all, this topic excludes open-wheeled cars. Also, for those not aware of its meaning, the word "track" in the context of a car's specifications means the width from the centerline of the left tyre contact patch to the centerline of the right tyre contact patch. The front and rear track on a car can be the same or different.

In keeping with the idea of having our cars look as realistic as is practical, I've been thinking of something for some time and would like to mention it here. We've all probably got at least one car where the tyres protrude beyond the widest point of the fender. Sometimes the chassis, motor or rear axle configuration makes it difficult or even impossible to avoid this. Other times, we may have intentionally set the car up this way to make the track as wide as possible. Unfortunately this can be taken to a point where the car no longer looks realistic. It may also give the car an unfair advantage against other cars that maintain their correct track appearance. For example, I can put extra-wide axles, wheels and tyres on my very narrow Ferrari 275 P so that it takes up almost 50% of the Scalextric Sport track width (78 mm). To my knowledge FRC has no rule preventing this.

So here are my suggestions:

1. We can add the following to the General section of the class rules: "Unless contradicted by the rules of a specific class, any single tyre may not extend beyond bodywork by more than 2 mm when viewed from above." This is the equivalent of 6.4 cm or 2.5 inches in 1/1 scale, which I think is reasonable and not overdoing it.
2. If necessary, in specific classes we can have a maximum track allowance (these could be different for each class/era). This way, even extremely wide cars would still be limited by the maximum allowed track. This will also prevent someone adding fender flares which, with the 2 mm allowance, still take the car to a ridiculous width.

I did some research into the following Vintage Sports cars' 1/1 track measurements and then divided them by 32 to give the 1/32 equivalents in mm. Here they are:

Rear Track in 1/32 scale, based on actual car rear track:

• Ferrari 275 P - 42mm
  Cobra Daytona - 42mm
  Porsche 914 - 43mm
  Cobra Roadster - 44mm
  Chaparral 2 - 44mm
  Corvette Grand Sport - 45mm
  Ford GT40 - 45mm
  Pantera - 46mm
  Corvette L88 - 47mm
  Alfa Romeo 33/3 - 47mm

I then measured the rear track on all my running Vintage Sports cars, with these results:

• Ferrari 275 P - 43mm
  Cobra Roadster - 46mm
  Chaparral 2 - 47mm
  Ford GT Mk IV - 48mm
  Cobra Daytona - 48mm
  Ferrari 312 - 52mm
  Alfa 33/3 - 52mm
  Ford GT40 - 52mm
  Lola T70 - 53mm

Almost all of these cars have their wheels covered by the fenders and the others protrude no more than 2 mm.

Based on all the above data, if we decide to have a maximum allowed track in our Vintage Sports class for example, we could use the widest measurement above, 53mm (please let me know if you have a Vintage Sports car whose tyres do not protrude more than 2 mm but has a wider track measurement than this).

Here are two pics of my Cobra Daytona, the first taken from above, the second from below.



The rear tyres extend exactly 2 mm beyond the widest point of the fenders and the car does not look ridiculous (in my opinion).



Here's the reason the rear tyres couldn't fit entirely within the fenders. You'll notice that the right rear wheel is directly against the Motor pod bearing. The only way to get it further in is to use a hub-less wheel or narrower wheels and tyres, neither of which I had at the time.

So, what do you think of my suggestions?

[obrie]

I agree that we need to “regulate” the track width and I am guilty of having a car or two with wide track. Some cars can, some can’t. I will do a survey of my garage and see what the situation is. However, I will say that we will have to keep in mind that the track of a particular car say the BMW E30, varies between the manufacturers. So if we agree on a width for the wider car then by right the narrower car can also use that width even if it looks ridiculous! So looks can not be the yard stick, I think that this can become a bothersome rule if we overdo the looks aspect, as important as it is, and not set a limit that is class decided or just the limit the Scalextric Sport track can handle. Lots of room for discussion here!

[steveaca]

Sounds reasonable to me Gordon. I checked my Cheetah and the track is just about 53 mm although the outside edges of the tyres are just about flush with the rear fenders. As O'Brie says however, there is room for discussion here.
Steve

[gordon]

When checking track, remember that it's from the centre of the contact patches, not the outer edges of the tyres. All the measurements shown above are done this way.

[gordon]

Here are how some slot car club/association rules from around the world deal with this topic. Maybe we can get some ideas from here.

• DISCA (Digital Slot Car Association):
  7.2. The maximum allowed track width is as follows; 7.2.1. LM P1 cars 2014-present 62.5mm
  7.2.2. All other cars 64.0mm
  7.3. When viewed from above, tyre edges must be contained within the widest point of the wheel arch.
  
  The Hobby Shop:
  Wheels/tires must be within body unless stock on car.
  
  British Slot Car Racing Association:
  11. No part of the motor, chassis, gears or tyres shall be visible when viewed from above or through the windscreen or windows.
  
  United Slot Racers Association:
  8. No cutting into top of body or fenders allowed. No part of the chassis or tires may be visible when viewed from above. Maximum of 1/8 inch (3.175 mm) of tire may be visible as viewed from above.
  
  Way2Fast Slot Car Model Racing Rules:
  Cars must retain original track or wheelbase and wheels must not protrude beyond the body when viewed from above (SCX Rally and certain SCX class cars are a noted exception).
  
  Classic Slot Car Racing Association:
  The chassis, wheels and tyres, motor and all running gear must not be visible from above or through the cockpit opening, cabin area or engine bay unless that which can be seen represents parts of the real car.
  
  Four Lane Black Top:
  Tyres may not project beyond body when car is at rest on level track.
  
  Viking Scalextric and Slot Car Club:
  3.4.1 Rear Axle Assembly width: This rule exists to stop wheel hubs and tyres from protruding unrealistically outside of the body work of a slot car.
  The distance a wheel hub can protrude outside of the top edge of the wheel arch as viewed from above is zero. This rule applies to the HUB and NOT the TYRE. The tyre can protrude but must still fit the hub properly. The tyre protrusion will normally be in respect of its natural bulging – not extra tread on the track!
  
  Austin Slot Car Club:
  Wheel/tire must not we visible outside wheel-well/fender when viewed from above.
  
  Canberra Slotcar Club:
  10. Wheels – Wheels must not protrude outside the bodywork unless box standard.
  
  Gateway Slot Racing Association:
  2. Chassis width maximum of 2.52”. 1/24 max. width is 3.252” Body must cover the entire chassis when viewed directly from above. May be visible through openings in body where they existed on the full size car being represented. See Special Classes for their exceptions. Under certain circumstances, Production Class chassis may need to be trimmed or cut to allow wheels to be moved in, to not exceed maximum allowable width, and/or not protrude from beneath the body.
  
  Barn Burners Slot Car Club
  Tires must fit within body limits. Tires must be covered by the body as viewed from directly above the car. This does not apply to open wheeled cars.
  
  NJ Metro Slotcars:
  5. No wheel/tire must not extend beyond body's wheel well by more than .040".
  
  New Zealand Slot Car Association:
  1.1 - Width - Wheels and tyres must fit into the original arches looking from above.
  
  Bury St Edmunds Slot Car Club:
  7. Closed wheel cars must not have wheels and tyres visible from above.

[steveaca]

I like the idea of maintaining a certain amount of realism in the cars' appearance but, as Gordon said earlier, sometimes absolute realism is not possible or practical. We know that some classes allow no body modification while others allow some modification, eg. fitment of wheel arch extensions (flares). I would suggest something like this:

Subject to all other applicable rules for the particular class:
-Where no flares are fitted, outside edge of wheel should extend no further than ... mm. (2 ?)beyond wheel arch.
-Where flares are fitted, wheels must not extend beyond beyond edge of flare.
-Flares, where fitted must not extend more than .... mm. (3 ?) beyond door panel of front door.

I'd like to hear the thoughts of others on this topic.
Steve

[gordon]

Not bad suggestions Steve. What about where cars come already flared, like the Gp 5 ones (Zakspeed Capri, BMW, etc.). Some of those flares are pretty wide.

Also, I still feel we need a maximum track width limit, either overall or varying by class.

This topic takes me back to my earliest writing of slot car regs when I was about 14 years old. I remember recognising the need to limit how far out of the fenders tyres should be and setting it at 1/8"

[steveaca]

Hi Gordon,
in the case of cars that come with extra wide flares, it would be unreasonable to ask owners to reduce the width of the flares. Maybe what could be done is to leave the flares alone but restrict extension of wheels to the same limit (3 mm. ?) beyond width of car at front door panel.
I think that at 14 years old, you were pretty much on the ball. 1/8" is just about 3 mm. !
I'm still thinking about the maximum track width .

[Luke]

... my earliest writing of slot car regs when I was about 14 years old.

You doing this since then Gordon

Thinking back (and that’s 41 years ago) when I was 14 years - a Sunday could have fall on a Monday.

In essence what you doing here today is just for the sake of practice ...

Must compliment you for all these forum efforts

Luke

[gordon]

Hi Gordon,
in the case of cars that come with extra wide flares, it would be unreasonable to ask owners to reduce the width of the flares.

Agreed.

Maybe what could be done is to leave the flares alone but restrict extension of wheels to the same limit (3 mm. ?) beyond width of car at front door panel.

I think that cars at 1/32 scale which come with big flares should be allowed to have their wheels/tyres use the full width of the flares (as the real car would have done), but maybe not extend beyond them. Of course we'll then need a definition of what "big flares" constitutes, which is another complication and complications are not good.

I think that at 14 years old, you were pretty much on the ball. 1/8" is just about 3 mm. !

I really wish I could find these old documents somewhere.

I'm still thinking about the maximum track width .

Well a simple solution is probably what I initially proposed:

• Set a reasonable limit on how far any tyre may extend beyond the fender in any class, flared or not (e.g. 2 to 3mm. This works out to 6.4cm/2.5" to 9.6cm/3.8" on a 1/1 car).
• Set a maximum track width. This can be by class or a single figure for all classes. Although it somewhat complicates things, I prefer the former since real (1/1) cars from different eras and different classes generally have different maximum widths.

So, maybe we're making progress with this ongoing discussion! (O'Brie, we need your further input.)