Dutch84

Hello I am just wondering anyone knows the biggest brake kit I can use with factory A-Molds? I really like them and don’t want to go to a larger size rim so hopefully someone can chime in. Thanks for all of the input.

93Rubie

13" is about as big a rotor that will fit. C5 brakes MIGHT fit. J55 on C4's will obviously fit. Some aftermarket will fit. C6Z06 brakes will NOT fit.

PAINTER MAN

I have A molds with C5 brakes.

WVZR-1

OP - you mentioned 'factory A-Molds' and your avatar/user ID might suggest an '84 so I believe it needs mentioned if your question is regarding 'factory' or if you're interested in maybe 'REPLICA' 5-spokes? Wheel offset has much to do with any brake option a person considers. Diameter ain't the only restriction.

Dutch84

i have oem zr1 a molds and yes they are on my 84’. I am looking into ordering a full set of Wilwood brakes front and rear however I am just making sure not to order the wrong size for the fronts. They come in 13” and 14”. So from what I am getting the 13” will be my best choice to stay with the 17” wheels. Offset isn’t to concerning to me because I run spacers with ARP wheel studs.

Dutch84

The fronts are using 1” spacers and the rears use 1 1/4” spaces once the flares are installed. My biggest concern is stopping once I swap in my LS3 376/525.

WVZR-1

The 11" @36 less spacers I'd think should do well on an '84 rear and 'no flares' maybe!! The fronts you'll have no issues except that I'd think the caliper mounting hardware even for Wilwood would require the 12mm bores of the spindle mounts be modified. That Joby I believe mentions NOT being a problem.

Interesting build! Rear axle ratio and what trans?

Dutch84

i have 87’ front spindles with new bearings and ARP studs ready to go👍👍 Thank you for the reply very helpful.

Dutch84

SST tremec TKX 3.73 rear gears.

AZSP33D

I have an 86 with the OEM ZR1 A-Molds (11x17X36 Japan - 6mm spacers in front) on all 4s, and Wilwoods on all 4's... the 13 (12.88) Superlite 6R/4R Wilwoods front and rear.

Not sure if 14's fit or not, but certainly a lot of room with the 13's so they might... now Wilwood says you need 18" wheels for the 14's so I never tried. However, they are heavy rotors so with the increase in unsprung weight, the 14's are probably an extra 3-4 lbs per wheel, keep that in mind. Got rid of the OEM e-brake to save about 6 lbs per wheel in the rear (use a different park and e-brake system but that's a whole 'nother story). Brakes work great with Polimatrix B pads (budget an extra $250 for better pads)... tried the Polimatrix A pads in front but they produce about 2-3 lbs of dust per mile and not so nice to modulate. I have the Rippy bias spring and it has a little bit too much rear bias now with R comp tires, so also budget for a proportioning valve unless you keep the lame rear pads the kit comes with.

vetteLT193

A question you should really consider is how long will you really keep the 17's? I say this because tires are getting unobtainable. I just bought a set for my 96 and now I am kinda regretting not just getting new wheels and storing the 17's for the next few years. They are so rare TireRack called me to explain they had none of the fronts in stock but they were getting 6 total tires in the front size (in several weeks) and he suggested I stay in line because I'd never get a matching set of anything else if I didn't get the tires I ordered. The standard C4 sizes are more available now with other brands but with less and less on the road it just seems like a matter of time. FWIW the only matching set I could find were Michelin PS2's at around $400 a tire.

So I just bring that up because if you end up with 18's then you may as well get the big brakes.

Dutch84

thank you I totally appreciate your input!! It’s very helpful. Thank you.

Dutch84

I really know where your coming from!! I had a hard time finding my fronts as well. The 275’s were tough to find and the 315’s not so bad but ya they are getting scarce but I really like the look. I have considered going to 18’s and getting custom widths and offsets but forgeline wheels are stupid expensive lol.

vetteLT193

315s come only in drag radials now. I had to bump to 335. I wanted 285 for the fronts to help balance things bit those were also unavailable

I'm thinking those c8 wheels to see of the guy can make them fit a C4, only 2k. https://www.aerolarri.com/samurai.html

MatthewMiller

That's not true. 315/35/17s come in several road race and autocross tires and there are several street tire options. The two main street tire options are the Nitto 555 G2 and the Mickey Thompson Street Comp. Neither is stellar compared to today's best, but I'd probably choose the M/T for street use.

If those are made to fit a C8, then they have the wrong bolt pattern and I would recommend against trying to make them fit. Also, if the center bore size is made hubcentric to a C8, it will be more than 3mm too small to fit over the hub pilot of a C4. Of course, you can't tell any of that from their crappy website because they don't list any specs. They won't even tell you what the offsets are! I'd stay away - they don't want customers who need to know specs to do "off-label" fitments. If you want a wheel with a clean five-spoke design, check out the Forgestar CF5. They make those in the proper 5x120.65 bolt pattern, and they make a wide range of sizes and offsets.

AZSP33D

Lot more 275 options than 315 options for sure...

315/35R17 half dozen or more tires available
Nitto (numerous)
Toyo (numerous)
Hoosier (numerous)
Mediocre or better 200TW autocross street tire - none

275/40R17 -- two dozen or more tires available
Firestone Indy 500
Kumho (numerous)
Sumitomo (numerous)
Falken (numerous)
Toyo (numerous)
Michelin (numerous)
Hoosier (numerous)
Continental Sport Contact
Mediocre or better 200TW autocross street tire - Falken Azenis RT660

Biggest issue is in Bold

AZSP33D

Amolds 11x17x36 with Willwood 12.88 Forged Narrow Superlight 6R/4R

MatthewMiller

In general I agree with everything you wrote. I would add the Mickey Thompson Street Comp to the list of true street tires, though. It's effectively the old Cooper RS3-S from about 9-10 years ago. It's going to be a lot better than the Nitto 555 G2 or Toyo Extensa, which are the only the other true street tires I know of in this size (those companies' other offerings are drag/track tires).

lgaff

Im modifying a c5/c6 caliper adapter bracket and going to run Wilwood SLC56 Calipers with C5 Rotors

Dutch84

I was able to find that Toyo r888r’s were available. Pretty much a summer/nice weather tire but they are good tires. But no one really has anything these days.