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87 GTA- Thinking about new rotors- Any new deveopments?

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Old May 9, 2026 | 08:31 PM
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Car: 1987 GTA
Engine: 5.7L tpi
87 GTA- Thinking about new rotors- Any new deveopments?

Car has stock brakes. In the process of replacing the MC. and the lines. Pulled the rotors and they could use a refresh but they're so tiny! I've got the 16 gold lace rims that I'd like to keep. The calipers appear to be new.

I think I read that I can swap in the 12" C4 (maybe 13" ) rotors and be fine with it? Not sure if I misread or if there are any new developments in brake set ups. Maybe something slightly larger that will clear the 16's?

Trying to keep it budget friendly with a light upgrade if possible.
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Old May 10, 2026 | 04:50 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

You can't simply bolt on bigger rotors unfortunately. This post has some great info, a long with the rest of the thread.

https://www.thirdgen.org/forums/brak...m_content=post
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Old May 10, 2026 | 08:48 AM
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Car: 82 TA
Engine: Zz430 clone w a torquestorm blower
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Axle/Gears: Ford 9 w 4.11
Re: 87 GTA- Thinking about new rotors- Any new deveopments?

I think both baer and wilwood make kits that will fit under 16 in wheels. All of the upgrades will require spindle modification. Its not hard or expensive. The stock brakes are pitiful. Especially if you have a faster car. I think you have lots of options. You can also look at hawks and big brake upgrade. There are kits for better 4th gen caliper/rotor upgrades. You can use your stock MC and just swap the front components. The car will be much safer.
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Old May 11, 2026 | 07:37 AM
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Car: 1991 Trans Am
Engine: L31, LT4 hot cam
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

agree the later 4th gen ("LS1") conversion is something a hobbyist could do (I did) with the turned down rotors and brackets from bigbrakeupgrade.com - i.e. modifying your spindles and sourcing the calipers and 4th gen rotors locally

Not cutting edge, but good bang per buck and serviceability

I went with C5 calipers and had to do some minor clearancing to the calipers and thin wheelspacers for the 16" mesh wheels to clear. Been absolutely fine for the 5 or so years I've had them

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Old May 11, 2026 | 07:43 AM
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Car: 1987 GTA
Engine: 5.7L tpi
Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Do you recall the width of the spacer and the length of the studs? I like to make sure I have lots of stud engagement.

Wonder the the ls1 caliper is that much different than the C5?
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Old May 11, 2026 | 09:35 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Originally Posted by Boostmaster
but they're so tiny....
brakes are built to how you drive.
are you autocrossing?
are you drag racing?
are you just cruisin the local hang out?

most pople put big brakes on their cars for looks only. Its their money to do with as they please, but not needed.
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Old May 11, 2026 | 09:42 AM
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Car: 1987 GTA
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

^^ Agreed. For now, we've decided to stay stock while we finish the rest of the car. We just cruise around mostly, but I do like to stop when I need to. I think I can do the upgrade to the LS1 12" rotors relatively cheap enough but that will be a project for another day.


Thanks for everyone for the suggestions and info!
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Old May 11, 2026 | 11:09 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Originally Posted by Boostmaster
^^ Agreed. For now, we've decided to stay stock while we finish the rest of the car. We just cruise around mostly, but I do like to stop when I need to. I think I can do the upgrade to the LS1 12" rotors relatively cheap enough but that will be a project for another day.


Thanks for everyone for the suggestions and info!
100% same boat here. It'll happen some day
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Old May 26, 2026 | 07:17 PM
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Car: 1987 GTA
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Anyone have the part numbers for the correct wheel bearings for the LS1 brakes? I keep finding 3rd gen. Want to make sure I can find he correct ones.
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Old May 26, 2026 | 07:51 PM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Originally Posted by Boostmaster
Anyone have the part numbers for the correct wheel bearings for the LS1 brakes? I keep finding 3rd gen. Want to make sure I can find he correct ones.
Which hubs? Sounds like these use the stock 3rd gen bearings because (if I'm reading this correctly) the hubs are cut out from the stock 3rd gen rotors

https://bigbrakeupgrade.com/product/...nversion-hubs/
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Old May 27, 2026 | 06:14 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

^^Correct. Just confirmed with Scott at Big Brakes.... It did not even occur to me.
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Old May 27, 2026 | 08:05 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

If you're ordering up a new set of rotors to cut down into hubs, you might want to consider getting a set of the 1LE front rotors (Performance Package on RockAuto). Same inner diameter for the bearings for the spindle, but larger outer diameter for the hub itself. Back when Scott was still making the billet conversion hubs, they all came standard with the 1LE bearings, nice upgrade... I was lucky enough to snag the last set from him a couple years ago, shame he isn't still making the billet hubs, but I'd imagine the demand wasn't high enough to justify the cost.

I DO see that the iron conversion hubs from Scott use the standard rotors though, not sure why the 1LE size isn't available..... there might be something different about the rotor hat with the factory 1LE rotors? Worth giving Scott another call if you had any interest in the bigger bearings, he'll have an answer for you.
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Old May 27, 2026 | 08:16 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Just a heads up, kore3 makes aluminum hubs for this application. They're awesome. They have 1le bearings also.




Last edited by Firechicken82; May 27, 2026 at 02:12 PM.
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Old May 27, 2026 | 11:07 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Originally Posted by Firechicken82
Just a heads up, kore3 makes aluminum hubs for this application. They're awesome. They have 1le brarings also.
YES!
Those are my personal favorite option! Love them on my Car!

Otherwise BBU still offers the 1LE size Outer Bearing: Hyperlink

All these Hubs really benefit from the DRP Bearing Spacer!!!

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Old May 27, 2026 | 11:08 AM
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Re: 87 GTA- Thinking about new rotors- Any new deveopments?

Originally Posted by LLCooLM495
If you're ordering up a new set of rotors to cut down into hubs, you might want to consider getting a set of the 1LE front rotors (Performance Package on RockAuto). Same inner diameter for the bearings for the spindle, but larger outer diameter for the hub itself. Back when Scott was still making the billet conversion hubs, they all came standard with the 1LE bearings, nice upgrade... I was lucky enough to snag the last set from him a couple years ago, shame he isn't still making the billet hubs, but I'd imagine the demand wasn't high enough to justify the cost.

I DO see that the iron conversion hubs from Scott use the standard rotors though, not sure why the 1LE size isn't available..... there might be something different about the rotor hat with the factory 1LE rotors? Worth giving Scott another call if you had any interest in the bigger bearings, he'll have an answer for you.
They have the 1LE option still available but it's way more money and they are made to order.
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