# Why are there options for different sizes of NA and NB Little Big Brake Kits? Which size should I get?

> NA and NB Miatas had different size rotors throughout the years, and the short version is that we designed the kits around those stock sizes. The stock...

Source: https://help.flyinmiata.com/en_us/why-are-there-options-for-different-rotor-sizes-which-size-should-i-get-HyQ7zafCI

Last updated: 2022-05-27T23:20:10.939Z

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NA and NB Miatas had different size rotors throughout the years, and the short version is that we designed the kits around those stock sizes.  The stock sizes aren't literally 9", 10", and 11", but they're close enough that we round to those sizes for simplicity.  And don't ask us why Mazda decided to make it complicated and offer two brake options in 2001 and 2002 - if you're not sure, whip out your trusty tape measure and find out which size your Miata has. 

1.  1990-93 Miatas have 9" rotors
2.  1994-02 (non-Sport) have 10" rotors
3.  2001-05 (Sport) have 11" rotors

  

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## What size should I get for my brake kit?

  

The cheapest and easiest option is to select the same rotor size that your car originally came equipped with from the factory (except for the 9" kit, more on that later).  If your rotors are in good shape, you could even reuse them for some of [our Little Big Brake Kits](https://www.flyinmiata.com/default/flyin-miata-four-wheel-little-big-brake-kit.html).  There are some things to bear in mind, though: 

The smaller the rotor, the lighter the rotor, and the lighter the brakes are overall (unsprung weight).  The flip side is that larger rotors have more leverage (more slowing potential for a given type of pad and force on that pad) and more thermal mass (less likely to overheat and fade).  For autocross, you'll probably want a smaller kit.  Any of these sizes should be good enough for street use, so fitment with your wheels will be the most critical factor.  You'll want the bigger kits for track use/road courses and might even consider [our Big Brake Kits](https://www.flyinmiata.com/default/flyin-miata-big-brake-kit-for-na-nb.html) instead for even greater stopping power.

The (NLA) 9" kit is quite tricky to fit.  This is a counter-intuitive statement for most people; "The smaller rotor is harder to fit into place?"  Yup.  The new Wilwood Powerlite caliper is significantly wider than the stock caliper (on the outside/side that faces the wheel), and most brake clearance issues happen where the wider caliper face is closest to the backside of the spokes, not at the barrel of the wheel.  Since the rotor is small, the caliper is close to the wheel hub (where wheel spokes are typically the closest to the brakes), so you'll likely need wheel spacers or a specific wheel with very curved spokes.  The smaller rotors and LBBKs are more likely to not fit than fit.  This is the main reason why we no longer offer 9" LBBKs and stick with just the 10" and 11" options.

If you get new rotors that match the LBBK option you want, you can put any size kit on any car (NA and NB only, of course).  If you're stepping up to a larger rotor than what your Miata came with from the factory, you may need to bend/trim your dust shields to fit the larger rotors (more info about this in our installation instructions).  You _**always**_ need to use our brake kit fitment templates to check for wheel clearance, though - aside from the (NLA) 9" kit, either our 10" or our 11" LBBK will fit with most wheels, but not all.