zep Posted November 16, 2011 Share Posted November 16, 2011 I've been offered some R32 GTR calipers cheap. Research tells me that the rotor diameter is exactly the same as my current VT Commodore setup (296mm) but the thickness is 4mm different (GTR: 32mm, VT: 28mm). I assume the GTR 4-pots are about a million times better than the 2-pot Commo things. The question is, are my rotors too thin to use these brakes? I've heard 1-2mm is okay but 4mm might not be. Cheers Quote Link to comment Share on other sites More sharing options...
sheepers Posted November 16, 2011 Share Posted November 16, 2011 i think the min thickness is 30. however the R33 GTST rotors are 296 x 28 so if you run a pair of these calipers (i have a spare pair that ill sell you if you want) you'll be laughing. Quote Link to comment Share on other sites More sharing options...
zep Posted November 16, 2011 Author Share Posted November 16, 2011 Damn. Unfortunately the deal is the R32 calipers, so may as well stick with what I've got for now... they do work. Quote Link to comment Share on other sites More sharing options...
glen Posted November 16, 2011 Share Posted November 16, 2011 Guessing, but as that would be a difference of 2mm per brake pad i'd have thought it would make f. all difference. ? Quote Link to comment Share on other sites More sharing options...
fuel Posted November 16, 2011 Share Posted November 16, 2011 ^^ yeah until both brake pads wear down and the piston pops out further than it ever has before. Luckily those pads are held in by cotter pins so wont be slipping out in a hurry. Not a high chance of being a problem but still a possibility. Quote Link to comment Share on other sites More sharing options...
zep Posted November 16, 2011 Author Share Posted November 16, 2011 So you're saying....? Quote Link to comment Share on other sites More sharing options...
DJZ Posted November 16, 2011 Share Posted November 16, 2011 I'm not sure whether the calipers are much different to the R33 GTS-25t calipers. I was using R32 GTS-t calipers on my car with AU Falcon rotors which were 28mm thick rather than 30mm for the Skyline. Now I'm using R32 GTR rotors with R33 calipers, so the rotor is actually 2mm bigger than what the caliper is supposed to be for but it doesn't rub. Quote Link to comment Share on other sites More sharing options...
sheepers Posted November 16, 2011 Share Posted November 16, 2011 you could get away with it but you will just have to keep an eye on your pad wear and make a call on how far you want to push it. you could measure it all up on the bench first if you want, maybe there is enough spare travel in the piston to take up the extra 2mm a side. up to you really. Quote Link to comment Share on other sites More sharing options...
mikuni Posted November 16, 2011 Share Posted November 16, 2011 Markku or Touge need to chime in here with pics of the Trueno after the brake pad/s fell out. I'd say if theres any doubt where brakes are concerned, don't go there. Quote Link to comment Share on other sites More sharing options...
zep Posted November 16, 2011 Author Share Posted November 16, 2011 I think I'll measure it up like Sheepers said and see how it looks. Will make a decision based on that. Quote Link to comment Share on other sites More sharing options...
fuel Posted November 16, 2011 Share Posted November 16, 2011 Markku or Touge need to chime in here with pics of the Trueno after the brake pad/s fell out. I'd say if theres any doubt where brakes are concerned, don't go there. Yeah that's what I was concerned about but the calipers on that AE101 are just the typical sliding type where the pad seat on the edges move as the brake pad wears down, whereas the GTR brakes like most 4 pot calipers are fixed seating with pins going through holes in the brake pads - they probably wouldn't fall out but the piston would be extending further than it would usually. Although Nissan probably thought of this and made the one caliper which suits both widths of rotors. Quote Link to comment Share on other sites More sharing options...
sheepers Posted November 16, 2011 Share Posted November 16, 2011 thinking about it, if the difference between "functioning normally" and "piston coming out and jamming the pad into the rotor" was 2mm past normal extent of ware, then shit would be hitting the fan on a regular basis for most road users. the piles of rotors that have been driven around with steel on steel action at Stirling brake and clutch are large and many. lots of then are way past 2mm of degradation. i reckon it will be sweet. Quote Link to comment Share on other sites More sharing options...
tortron Posted November 16, 2011 Share Posted November 16, 2011 spin up some longer pistons out of brass stock? Quote Link to comment Share on other sites More sharing options...
mikuni Posted November 16, 2011 Share Posted November 16, 2011 I think I'll measure it up like Sheepers said and see how it looks. Will make a decision based on that. As Sheepers alludes to, if the pistons aren't over extended with pads in there that are worn to only the thickness of the backing plates, then there is no chance of failure. Obviously you won't let it get to this stage on purpose, but the fact that the car see's the track some times means sudden massive wear on brake pads is possible. Quote Link to comment Share on other sites More sharing options...
SloNLo Posted November 17, 2011 Share Posted November 17, 2011 could just run a 2mm spacer behind each pad. pins will hold in place and add grease to stop any chatter sounds Quote Link to comment Share on other sites More sharing options...
zep Posted November 17, 2011 Author Share Posted November 17, 2011 Interesting debate. I had a chat with Tony Lynch about it and his recommendation was not to risk it, but said that I could come up and see him and he could sort something out. Reckons he could source appropriate discs for under $100! Quote Link to comment Share on other sites More sharing options...
DJZ Posted November 17, 2011 Share Posted November 17, 2011 You could take the calipers apart and have 2mm machined off each face? Probably not worth the hassle but that's what I suspect they do in the factory to accomodate the different rotor widths. Quote Link to comment Share on other sites More sharing options...
zep Posted November 17, 2011 Author Share Posted November 17, 2011 It's a thinner rotor though, so unless I'm not thinking about this correctly, it would make it worse. Quote Link to comment Share on other sites More sharing options...
DJZ Posted November 17, 2011 Share Posted November 17, 2011 Machining material off the mating surfaces in the middle of the caliper would bring the two halves closer together in other words they'd be narrower in the middle. Quote Link to comment Share on other sites More sharing options...
Roman Posted November 17, 2011 Share Posted November 17, 2011 I had a pair of gtr calipers, the issue was that they are so freaken wide that wouldnt even fit between strut and wheel. Quote Link to comment Share on other sites More sharing options...
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