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We just found out that 87-89 NA wheels (15) fit TT cal

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  • We just found out that 87-89 NA wheels (15) fit TT cal

    I dont know if this has been posted anywhere but Casner and I just found out that on my car, 85 turbo with 88 turbo hubs and stock 88 turbo rotors, that his 88 NA wheels (yes the 15" wheels) fit over the 90TT aluminum caliper (for 30mm rotor) and bolt up just fine with no rubbing. The only thing I can confirm is the 87-89 NA wheels. I dont know about the other stock 15" z wheels.

    Also, the 90 TT calipers (ones for 30mm rotors) do not fit center over the stock 88t rotor (24mm). It appears as though the 88t rotor needs to move out 2mm or the caliper needs to move in 2mm. You cant really put washers behind the rotor to bring it out (just a bad idea) so I would think you would have to take off some material from the caliper to move it in. Then you could later put washers on it to move it back out if need be.

    Also why do people say you can use the TT calipers on the stock 87-89 turbo 11" rotors and hubs with the stock 87-89 turbo wheels, but if you try to switch to the actual 30mm twin turbo rotor that that same wheel wont fit? I can only assume that the TT rotor would push the wheel FURTHER from the caliper. I dont understand how this could be a problem. And now you would have the correct rotor for the caliper.

    Will somone please explain what it is that I am failing to see as to why it wont work?
    85 Z31 6.0 LSX turbo 766whp/792wtq
    04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

  • #2
    I sold my 87na rims to someone with an s14 w/z32 brakes..... they rubbed slightly, possible your pads are worn sufficiently for the caliper to be inward that little bit

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    • #3
      G-E wrote: I sold my 87na rims to someone with an s14 w/z32 brakes..... they rubbed slightly, possible your pads are worn sufficiently for the caliper to be inward that little bit
      This is with no pads in the caliper. Just bolted up the caliper over the rotor and then bolted on the wheel. The pads wouldnt make the caliper sit in eithier direction more than the other. Meaning the caliper is not self centering like the z31 calipers. So pads would make no difference.
      85 Z31 6.0 LSX turbo 766whp/792wtq
      04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

      Comment


      • #4
        Re: We just found out that 87-89 NA wheels (15&#34 fit TT

        SATAN wrote: Also why do people say you can use the TT calipers on the stock 87-89 turbo 11" rotors and hubs with the stock 87-89 turbo wheels, but if you try to switch to the actual 30mm twin turbo rotor that that same wheel wont fit? I can only assume that the TT rotor would push the wheel FURTHER from the caliper. I dont understand how this could be a problem. And now you would have the correct rotor for the caliper.
        I've never heard that.

        The TT rotor would not move the wheel, it has a different thickness and hat height so the center of the rotor is less centered than with 87-89T rotors and needs the spacer. I think I measured about 1mm back when I checked it, but a whole 2mm is still less than an issue that requires spacing the caliper for use with 87-89T rotors... IMO at least.

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        • #5
          The " moving the wheel out further" was just a guess as to what I could only imagine was going to happen. Just thought maybe the rotor hat was thicker.

          So then you are saying that the TT rotor sits to the outside of the car where as the 88T rotor sits to the inside of the car? How much further does the rotor sit to the outside. I stuck my finger behind the fins on the wheel (between the caliper and the wheel) and estimated about 10m of clearance. This is just an estimate but I cant see the caliper needing to go out 10mm to be centered on the TT rotor could it??? :?

          I'm gonna do some searching to see what I can find as far as how far you have to space the caliper to use the TT rotor. I dont want to go and buy the thicker TT rotors and then not be able to use them. I just think the thicker 30mm rotor would be better as far as not heating up as fast and not cooling down TOO fast to create a warp as easily.
          85 Z31 6.0 LSX turbo 766whp/792wtq
          04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

          Comment


          • #6
            I have been running z32 calipers with z32 rotors for the last 6 years with no problems. I don't drive a lot of miles on the z and have not yet needed to replace the pads. I did not use any spacer as I was concerned that without exact measures it would be more problematic. The only thing I watch for is that the outside piston does not over-extend, and so far that has not even come close. As for wheel offset, I really cannot speak to whether the hats bring the wheels out more or not. I never even thought about it.

            Without spacers you are looking at having to replace your pads more often. I hope I am not missing the point here. I think that's it.
            "If you don't hold it....you don't own it"

            Comment


            • #7
              DrewZee87T wrote: I have been running z32 calipers with z32 rotors for the last 6 years with no problems. I don't drive a lot of miles on the z and have not yet needed to replace the pads. I did not use any spacer as I was concerned that without exact measures it would be more problematic. The only thing I watch for is that the outside piston does not over-extend, and so far that has not even come close. As for wheel offset, I really cannot speak to whether the hats bring the wheels out more or not. I never even thought about it.

              Without spacers you are looking at having to replace your pads more often. I hope I am not missing the point here. I think that's it.
              So then you run the stock wheels on your TT calipers? I wouldnt think there would be ANY concern if you were running the TT calipers AND the rotors to match them. I guess I dont understand why you would be concerned of the out side piston over extending. If you are using the TT rotor (30mm) then it should be centered perfectly, right?

              So a recap, you are using TT calipers, TT rotors and stock z31 wheels?
              85 Z31 6.0 LSX turbo 766whp/792wtq
              04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

              Comment


              • #8
                Re: We just found out that 87-89 NA wheels (15&#34 fit TT

                Jason84NA2T wrote: The TT rotor would not move the wheel
                posted that on little sleep, yes I must have insomina induced amnesia, of course z32 are monoblock.... and they were the 86na rims we tried on the s14, the 87na went on a camry the next day heh

                the 86na now that I think about it had a gentler tapered "spokes" towards the hub where the 87's were sharper, the rubbing occured at the inner (towards spindle) edge of the caliper

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                • #9
                  sorry, my bad....I never ran them with stock wheels so I cannot speak to that...
                  "If you don't hold it....you don't own it"

                  Comment


                  • #10
                    G-E wrote: I sold my 87na rims to someone with an s14 w/z32 brakes..... they rubbed slightly, possible your pads are worn sufficiently for the caliper to be inward that little bit
                    Fixed caliper?

                    Terrible idea putting those wheels on...

                    Comment


                    • #11
                      as long as the rotor is proportionate (sp?) to the calipers, there should be no spacing required or problems with one side extending an extra mm ( although can't see why they would if the rotor is centered in the caliper ). and that's what satan was saying, with a fixed caliper, and my 15" wheels, there were no clearance issues. so the only question that needs a solid answer here is what do spacers have to do with the brake conversion? drew said he runs tt rotors and calipers, and satan's car has a very minimal off center condition with his z31 rotors. so, does the tt rotor (30mm for the 30mm caliper) center itself in the caliper when mounted on our cars?

                      Comment


                      • #12
                        It is a fixed caliper. The 87+ setup with slip on rotors that I am running does not perfectly center the rotor in the caliper - but it is a small difference. There is a small space that is off which is why some people advocate putting spacers in to push the caliper out a bit and thus center the rotor more exactly. The caliper is fixed, and the rotor is fixed, so the slack is taken up by the pistons. That means that you need to just keep an eye on your brakes (which you should do anyway as normal maintenance) to make sure you don't wear the outside pad to the point where the piston wants to overextend the caliper.

                        I have never heard of this happening, and I figure they put enough piston in the caliper to allow for a certain amount of overextension. So far, I have had no problems.

                        As to how this would impact your car if you were running 15" stock wheels, if they fit without the spacers, you should be good to go. If you put spacers in, they may not fit anymore.

                        The bigger question is what do you do when you have a flat front tire? That one I have not figured out yet. I am pretty sure the donut (and quite positive that the NOS bottle that sits where the donut used to live) won't fit. That's the biggest worry I have with TT brakes. What happens when I have bad tire luck. Right now the answer is a can of fixaflat and pray. Otherwise its call a truck and ask them to bring a wheel or tow you home.

                        Think that through on your next cross country journey, it might be a good idea to have a spare.....
                        "If you don't hold it....you don't own it"

                        Comment


                        • #13
                          DrewZee87T wrote: It is a fixed caliper. The 87+ setup with slip on rotors that I am running does not perfectly center the rotor in the caliper - but it is a small difference. There is a small space that is off which is why some people advocate putting spacers in to push the caliper out a bit and thus center the rotor more exactly. The caliper is fixed, and the rotor is fixed, so the slack is taken up by the pistons. That means that you need to just keep an eye on your brakes (which you should do anyway as normal maintenance) to make sure you don't wear the outside pad to the point where the piston wants to overextend the caliper.

                          I have never heard of this happening, and I figure they put enough piston in the caliper to allow for a certain amount of overextension. So far, I have had no problems.

                          As to how this would impact your car if you were running 15" stock wheels, if they fit without the spacers, you should be good to go. If you put spacers in, they may not fit anymore.

                          The bigger question is what do you do when you have a flat front tire? That one I have not figured out yet. I am pretty sure the donut (and quite positive that the NOS bottle that sits where the donut used to live) won't fit. That's the biggest worry I have with TT brakes. What happens when I have bad tire luck. Right now the answer is a can of fixaflat and pray. Otherwise its call a truck and ask them to bring a wheel or tow you home.

                          Think that through on your next cross country journey, it might be a good idea to have a spare.....
                          or get another easy to find z wheel?

                          Comment


                          • #14
                            Yes, a spare. Like one that you might pick off any z, etc. in a junkyard. I don't generally roll with a full sized spare bouncing around in the hatch, but for long trips it's a good idea. That's all.

                            "If you don't hold it....you don't own it"

                            Comment


                            • #15
                              Ok, I ground the calipers down on the back side 2mm exactly and now the calipers straddle the rotor PERFECTLY center. This way I dont even have to THINK obout if there would be a problem from one side of the caliper extending further than the other, or them balancing out on their own or what have you.

                              This way later, if I need to I can allways shim the caliper further out.
                              85 Z31 6.0 LSX turbo 766whp/792wtq
                              04 GTO, LS6, big cam, porting, N20... underway for summertime daily driver.

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