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TR2/3/3A minimum thickness for tr3 rotors
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HerronScott
Darth Vader
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The manual indicates to remove no more than .060" but doesn't give the original thickness. The TR4 manual indicates no thinner than .440".
Scott
Scott
sagebrushbob
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Minimum is 11mm or .433 in.
TR3driver
Great Pumpkin - R.I.P
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Where did you find that?
Yeh I just did not want to purchase new ones and find they were less than .5--- I am not sure, but I think they were originally .6 because back in the day the auto stores would comment on how think they were and how they did not have specs, but by just eyeballing them they would true they up. Moreover, most were surprised to find out they had disc brakes back in fifties. It is my understanding that Triumph was one of the first to use disc brakes. And again, I always worry about aftermarket parts. Heck I have half a mind to pay the shipping on Sagebrush’s and have them turned, but I am going to buy new because they look beefy.
CJD
Yoda
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It was interesting that the manual says the discs would not need to be faced in service. That had me wondering...till I remembered that all pads in the "old days" were organic. The fancy semi-metalics we use today (that are hard on the discs) didn't come till later. The organic pads coat the discs to prevent rusting, and they don't wear the discs much at all.
Steve, I may have a couple TR4 discs in my "Christmas" pile, free to a good home. Let me know if you are interested, and I'll take a good look at them to see what they're like.
Steve, I may have a couple TR4 discs in my "Christmas" pile, free to a good home. Let me know if you are interested, and I'll take a good look at them to see what they're like.
vivdownunder
Jedi Warrior
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Glenn's Triumph Repair and Tune-Up Guide of 1965 published in PA specifies TR discs may be machined to a thickness of 0.440" (11.18 mm). Maximum permissible run-out of the disc is 0.002" (0.05 mm)
Viv.
Viv.
sagebrushbob
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Tricky - it was stamped on the radius of the rotor.
TR3driver
Great Pumpkin - R.I.P
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Somewhat curious, since the TR4 manual says .440". The TR3 manual doesn't give a minimum thickness spec, but new rotors are .500" and the manual says to remove no more than .060".
HerronScott
Darth Vader
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Did the original rotors have the value stamped on them or is this something an aftermarket vendor has decided should be the minimum thickness?
Scott
Scott
TR3driver
Great Pumpkin - R.I.P
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None of the originals that I have seen have the thickness marked on them. So IMO the .433 figure is some aftermarket vendor's.
However, I've seen them worn well below that figure (presumably originals) and still working. A friend of mine was running rotors that couldn't have been more than 1/4" thick (lotta years ago), and said they worked fine for him. The TR3 brakes seem really big compared to the weight and power of the car, so I'm not sure why all that thickness is required. But IMO it's best to stick with the original recommendation.
(I also never turn them. If they don't run true, throw them out. A little bit of scoring won't hurt anything at all, bad scoring means throw them out.)
sagebrushbob
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If you subtract the two numbers above, you get 0.450 instead of 0.433.
Now that we have resolved this, I'm going to start counting the number of fairies dancing on the head of a cotter pin.
Now that we have resolved this, I'm going to start counting the number of fairies dancing on the head of a cotter pin.
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That made me laugh John, I am with Randall, I hardly ever get my rotors turned, and personally think the advice to do it everytime you do a brake job is propaganda from the aftermarket parts industry, as on new cars it won't take too many brake jobs before the say you need a new disk.
As far as the specs of how far you can turn them down, I have no idea, but I think the stock TR disks seem to be pretty substantial to me. Isn't the primary concern when you get them too thin warping?
As far as the specs of how far you can turn them down, I have no idea, but I think the stock TR disks seem to be pretty substantial to me. Isn't the primary concern when you get them too thin warping?