Switch from 16 to 15's?

[Pistolmiller]

A few questions...

2002 BBK Bil. shocks etc....

16" stock rims.

Is it worth it to switch to lighter 15" rims? I ran on the stock rims w/ 205/45-16's last year, but want a dedicated track combo.

If stick with 16's, bigger tire like 225/50?

Last question...

The car has 16K on it. I want to upgrade to Koni's. Replace the springs at the same time? Will the "old" springs affect the performance of the new shocks?

Thanks for the info!!!

[Brian]

For a dedicated track combo a 15x7 will serve you nicely and give you many choices on tires from every major brand and including long time Miata track day favorites like TOYO RA1... All our 15x7s will fit your car with the exception of the Enkei RP-F1. Take a look at our Team Dynamics wheels in particular...a very popular and inexpensive track day Miata wheel.

If you stick with 16s you do NOT want 225/50/16 which would be way too tall. There are not a lot of good track tire sizes in 16s which is one of the reasons you see so many Miata drivers on 15s for track days.

You can run the KONI shocks with stock springs...won't hurt the shocks. Most folks upgrade to a little stiffer spring for a little more performance and the labor is the same whether changing shocks only...or shocks and springs.

[Pistolmiller]

Yes, I know that there are but a few "track tires" in the 16 size. But as far as performance, does a 205/45 16 perform as well as a 215/45 15?

I have been reading all of the discussions on this and I am still confused. Is it a matter of convienience to go to 15's? I can see that with the limited amount of tires for the 16's. But am I losing something by switching?

[Brian]

Nope, I would expect the 215/45/15 on a light 15x7 to beat the 205/45/16 on your factory 16 inch rim. It is not an apples to apples comparison. IF we had just 205s in 15 inch against 205s in 16 inch and the rims weighed the same then the choice would be 16 inch for the slightly shorter sidewall and sharper turn-in. But when we consider all the options in 15 inch...and the generally lighter weight of those options, then it becomes clear why so many go 15 inch.

For example, with a 15x7 you can run 205/50/15 for your first set of track tires (our recommendation would be this size in TOYO RA1) and then jump to as much as a 225/45/15 on that same rim later after you have more track experience. Most of the major players now make a 225/45/15 so you have choices.

In 16 inch it was the case until very recently that you had NO choices in true R compounds that gave you 225s in a proper diameter. Avon recently started making their Tech R in a 225/40/16 which makes a interesting choice when mounted on our Enkei RP-F1 16x8 (which fit your car in this size). That would give you slightly better sidewall response when compared with a 15 inch combo but the cost is higher and if you don't like that R compound you would be stuck running street tires instead. If you were thinking of running street tires on track days anyway...I suggest that if you are going to bother owning a dedicated set of track wheels (which I consistently recommend for track day enthusiasts) you might as well load them with R compounds like the RA1 which can be driven to and from events and which will be MUCH FASTER than street tires.

[Pistolmiller]

As always you are the KING OF INFO! Thanks for all the help, that explained what I needed explained...

[na6cguy]

205/50/15 all the way