Big Wheels < Small Wheels

The e21 has 13's, but the brakes(the vented discs at that) are garbage. It needs better ones.

I loved my Miata on 13" e21 basketweaves and 205/60/13 R-comps. So damn fun and looked great. I'll have to dig up the other pictures of fitment. Very 'flush' and aggressive.

EDIT: found some on m.net! http://forum.miata.net/vb/showpost.php?p=1938758&postcount=324

Is this a K-car thing?

Ive only had one k-car with 13" wheel brakes and it wouldnt go fast enough to matter before i upgraded (both brakes and power). When i got that one it topped out about 90 mph. Now it has 11+" discs in the front, 10+ in the back, weighs a bit less, and would probably do 150-160 last time i had it going.. Ive never driven a k-car truly fast on 13" wheel brakes.

But there are some cars that come with 13" wheels and tiny brakes that will go 120+. Probably faster than the speed rating of any 13" street tire you can still get.

My magnum has 12+" brakes and they're still undersized. I dont think you can even bolt a 16" wheel to it. Id rather have bigger brakes AND bigger wheels.

I think it depends on the weight of the car. Magnums are made from lead, right?

I had a 14:1 compression Corolla with 13 inch slicks and solid disk brakes. Worked fine. I'm guessing the 1400 lb fighting weight had something to do with that, though.

Yeah, the magnum weighs 3800 lbs.

I drove my Insight from San Antonio to Austin and all over Austin and back to San Antonio last saturday. Somewhere in all that, i picked up some warped rotors. OH berkeleyING JOY. I never even went over 90 mph. That's an 1800 lb car with vented disc brakes that fit under 13" wheels.

Guess which cars DONT have warped rotors in my fleet? Other than the magnum, NONE of my other cars have warped rotors! All of them have more brakes per weight, proportionally, many of them due to upgrades i did. A car has to be so ridiculously light and kindly driven for brakes that fit under 13s to be worth a crap. Even 1800 lbs and 60 hp is enough to find the failings of tiny brakes with some mildly agressive driving. Im guessing what's happening here is that most of the 13" wheel cars that yall are thinking about or owning have way more power and are more enthusiast-oriented than my stock hybrid, but when it comes down to it yall just dont drive em hard enough to notice how much tiny brakes suck.

What pads are you running on all of these cars (and are they bedded properly)? Something tells me its E36 M3ty pads more than it is brakes that are too small. Tons of cars with tiny brakes stand up to 12-24hour LeChump races without much trouble.

Parts store pads. The same pads that have no issues on the street with all my other cars. I dont drive on track, and id rather not buy expensive pads for E36 M3 rotors when i can probably upgrade the rotor size out of the junkyard for the same money, and run cheap pads with no issues forevermore. After all, i already put 15" wheels on my 13" wheel brakes and im not going back. I have NO reason to stick with tiny rotors that cant even handle my STREET driving.

As for the 13" wheels and brakes: a common Datsun 1200, 510 & others suspension upgrade is 280ZX struts and many of us use 13" wheels. Mine is strictly a track car, as is typically of someone who races small bore cars I routinely preload the throttle while trailing the brakes heading down into corners, it's great for lap times but hard on brakes. A 280ZX weighs 1000lbs more than a 1200 so naturally I do not have any issues with brakes, fading or warpage.

Same deal with our D-Sports Racer, 13" wheels with uprights that were VW rabbit/scirocco. The car would pull 3G's on the brakes. The discs were stock VW items with wilwood dynalight calipers...........nothing fancy. OK yeah it was a 900lb car but the point being is getting proper proper parts.

Most road cars with 13" wheels have brakes that weren't meant for repeated hard use. The rims don't provided adequate cooling, or the pad compounds were not designed for this. We can't be critical about a part that was never intended for this use, it's like complaining about the gas mileage of your Hemi Cuda or body roll on a Camry.

Back to the 1200 I race, when we first put it on track we'd use either Repco or Ferodo pads, the stopping power was decent, no fade or problems with rotors, and they were fine for a car that only had 70 horsepower.

Very often what get described as warpage is actually build up on the rotors, you get same stuttering.

Finally there are plenty of small cars with 13" with decent brakes, I seem to recall driving a couple of student Fiats at track days that held up well.

       Tom

Vigo wrote: Parts store pads. The same pads that have no issues on the street with all my other cars. I dont drive on track, and id rather not buy expensive pads for E36 M3 rotors when i can probably upgrade the rotor size out of the junkyard for the same money, and run cheap pads with no issues forevermore. After all, i already put 15" wheels on my 13" wheel brakes and im not going back. I have NO reason to stick with tiny rotors that cant even handle my STREET driving.

Methinks you have some good local roads