Wheel and Tyre Fitment: Legalities
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Legalities
04.05
| 00:00 | Now, that we're all on the same page and have a solid understanding of wheels and all the relevant terms, it's time to discuss the legalities around them. |
| 00:08 | Unfortunately or fortunately, depending on how you look at it, we can't just run whatever fitment we want, and this isn't just limited by clearance and performance metrics, but in some cases by law as well. |
| 00:21 | Let's first discuss streetcars intended for use on public roads. |
| 00:26 | And to be clear, I won't be covering an exhausted list of all the rules and regulations here, that's just not realistic, as this is going to largely depend on where you live and how draconian the local laws are. |
| 00:39 | Some countries or states are going to be stricter than others, so it's up to you to do the research and understand what you can and can't do before making any commitments. |
| 00:49 | Remember, these laws are usually made in the interest of safety and to avoid people making modifications without considering all the factors and risks. |
| 00:59 | Naturally, since you've taken this course, you'd have considered all the possible implications of the change, and any compromises made will not be at the expense of safety. |
| 01:08 | So, sometimes the laws can seem unnecessary, unreasonable and annoying, but it's still not worth the risk of breaking them. |
| 01:16 | If you're not already familiar with any of these laws, then you might be wondering what all of this is even about, so let's cover a few examples to clear things up. |
| 01:26 | Here in New Zealand, many modifications are illegal unless they've been certified by the LVVTA, which is the Low Volume Vehicle Technical Association. |
| 01:36 | In which case it's up to the certifier to determine what's suitable and what isn't. |
| 01:41 | For example, the offset must be no more than 35% of the total wheel width, positive or negative, and if it is, axle and hub components from a vehicle that's substantially heavier must be used, or alternatively, a fully floating hub and axle assembly needs to be installed. |
| 02:00 | This 35% includes the use of a spacer, and the maximum spacer size that can be used is 20mm, which also involves a long list of other requirements depending on the type of wheel that's being used and its manufacturing method. |
| 02:16 | Alongside wheels, the maximum camber can only be plus or minus half a degree from the manufacturer's quoted factory spec. |
| 02:24 | Which means that we can't just run excessive negative camber to get our wheels to fit if they aren't the right size. |
| 02:31 | Likewise there are rules around how the wheel and tyre can't extend beyond the guard, as well as the tyre size relative to the wheel width to avoid excessive stretch. |
| 02:40 | In some cases an authority card can be issued for dual purpose vehicles, also used in motorsport, which comes with some other conditions. |
| 02:48 | Remember, these are the laws in New Zealand and are just being used to demonstrate what may need to be considered. |
| 02:55 | This will almost certainly be different to your country so make sure that you check for yourself. |
| 03:01 | On that note, and moving on to racecars, if the vehicle will solely be used for motorsport and not used on public roads, then these laws mean very little. |
| 03:10 | But that's not to say that we can just do whatever we want. |
| 03:14 | Some race circuits will also have their own rules around fitment, like those around tread exposure that we just discussed, open wheel cars being the exception here of course. |
| 03:23 | The final say on the matter really comes down to the tech inspector in any case. |
| 03:28 | Besides this, the likes of spec racing classes will almost always have rules stating the size of wheel and tyre that cars must run. |
| 03:37 | So, naturally these need to be followed if you want to compete. |
| 03:41 | In the end, remember that it's your responsibility to check with your local road authority or motorsport governing body to ensure that your modifications fit within the technical regulation guidelines. |
| 03:52 | If you're at all unsure about the suitability of your wheel and tyre fitment for either road or motorsport use, be sure to consult a suitably qualified engineer. |
