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| GT disk pads and New Rotors. https://www.bellett.net/forums/viewtopic.php?f=35&t=1801 |
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| Author: | JT191 [ Mon Mar 05, 2012 11:06 pm ] |
| Post subject: | Re: GT disk pads and New Rotors. |
gt orphanage wrote: Maybe jt191 could see if bills isuzu can produce the rotors as a bulk deal as someone has done the tooling and hard yards this is So if bills isuzu can supply a bulk order maybe they are affordable and they can recoupe there efforts and money. I paid a little over one thousand US dollars for my rotors in 2008. In case anyone has not been paying attention, everything has gotten a little more expensive since then (like steel and iron), and all I can comment on is what the price was four years ago. The material is an iron alloy, not steel, and it's more expensive than steel. And the weight of the piece the disk was cut out of was three or four times the weight of the end product. The metal is sold by weight. It's many times more money for the little length of round bar of metal to cut the rotor out of, than it would cost for a common mass produced disk from the auto parts store. They did say that they could do more for about $30 less in labor costs, since they now had all the manufacturing steps worked out with the first pair. You can chuckle about that, I did when I heard it. I have a little experience with metal casting that relates to the conversation. I had a small bracket, that I wanted to slightly change the design of, and have a small production run made, cast in steel. It was going to be $2,000-3,000 to digital scan the bracket into the computer and make a positive plug. Then it was going to be $2,000 setup and tooling and attach the plug to a board, and the material (steel) would be $30 per piece produced. Excluding the scanning cost, it was going to be $130-160 per bracket for a run of 20. With the scanning cost, $260+ each. And this was not a finished product. I quickly learned that any and all critical surfaces (mounting faces, flats, where ever it fit against something else) would still have to be machined. And, the outer eighth or quarter inch of material on the surface of the casting is not as clean and pure as the material inside. The face of a rotor where the pad rests and presses against to slow the car down, that surface would have to be machined also, to take the crust off the outside. If it has to be balanced because it spins around in a circle, all surfaces would have to be machined to make sure any and all irregularities are removed. Threaded holes would still need to be drilled and tapped. Non-threaded holes would still need to be drilled. Casting doesn't mean that you pump out a finished product in one step and it's done. Casting reduces material cost because the entire thing isn't cut out of a solid, and it's down to the last steps of machining without wasting all that time removing huge amounts of material. But every single piece still has to be machined. The costs mentioned were for a smaller piece and in steel, not a fancy iron alloy like would be needed for a brake rotor. And the material did not have to be checked for metallurgy like a rotor would have to be checked, to make sure the casting cured correctly. It's a simpler shape, so there might not be much cost for just machining a plug by hand, instead of scanning and producing it with a CNC machine. But as a price example, I don't think a price of $130 each + the cost of turning, drilling, and tapping per each rotor, is what people are thinking of when they talk about a "bulk discount". If you want to get down into the price range of mass produced rotors from the auto parts store, then bulk discount means 2,000+ quantities. By the way, when the guy puts a note next to the picture saying it's not for sale, it doesn't mean he won't sell it. It means he won't listen to complaints about how much he's willing to sell it for. |
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| Author: | Glenn [ Mon Mar 05, 2012 11:11 pm ] |
| Post subject: | Re: GT disk pads and New Rotors. |
this is stalled as I have no dimensions of the rotor glenn |
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| Author: | JT191 [ Tue Mar 06, 2012 1:12 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
Glenn wrote: this is stalled as I have no dimensions of the rotor The dimensions used on my rotors were from rotors used long past their minimum thickness. Quite a bit of guessing was involved, and the most important dimensions of offset and thickness were slightly wrong guesses. If I could actually get the parts to rebuild the calipers, they would have to be shimmed to fit the rotor. No one's fault, I remember asking here for dimensions and coming up blank too. |
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| Author: | Glenn [ Tue Mar 06, 2012 4:25 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
Its a problem alright as I doubt there are published specs for this stuff. I might contact Brett R. who has 2 brand new ones i have made before and run over them with calipers. Still a risk as they were patterned off a fairly good but worn original rotor. glenn |
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| Author: | PR91 [ Wed Mar 07, 2012 12:41 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
i spoke to Craig about this and he's happy to use the almost new rotors on his rally car as a sizing unit. according to my paperwork here, GT rotors are 238mm in diameter with a 13mm thick pad surface. until we get one to really measure tho, i don't have any further measurements relating to offset, hub face, mounting hole PCD, etc. |
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| Author: | Glenn [ Wed Mar 07, 2012 2:01 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
Hi Brett, are you sure about the 13mm? I always thought it was 10mm with a min of 7mm Glenn |
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| Author: | PR91 [ Wed Mar 07, 2012 2:24 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
yep, sorry Glenn. that should be 238mm dia, 10mm thick. when reviewing the numbers i read another number wrong! cheers. |
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| Author: | Glenn [ Wed Mar 07, 2012 2:26 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
OK Brett. Brett R has 2. I might call him and see if he can lend one. g |
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| Author: | 67GT [ Sun Mar 11, 2012 9:27 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
I have a workshop manual at work, that may be of some assistance. I will check tomorrow. I too would be interested in at least one set, maybe two, depending on cost. |
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| Author: | 67GT [ Mon Mar 26, 2012 10:07 am ] |
| Post subject: | Re: GT disk pads and New Rotors. |
unfortunately the manuals I have dont give any data on the disc brakes. Every thing else but that. sorry |
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