Disc-brake steel?

[Warr]

I spend a little time with brakes, and as a result I get to see a few... I've yet to find anyone that was satisfied with the Waihi made ones. That's not to say that they don't satisfy some people, naturally I only see complaints or problems that need fixing, but still, you can draw tentative conclusions.

Jot me down in the "Unsatisfied Customer" coloumn

His own statement when you buy is that they will not stand up to hard riding but are perfect for commuting. So he states what he sells and the limitations of them - thats a fair deal.

If I had known that I wouldnt have a set of useless fronts in my garage now !

[Ocean1]

See Skunk's recent thread on discs.

"Disc brake discs are commonly manufactured out of a material called grey iron. The SAE maintains a specification for the manufacture of grey iron for various applications. For normal car and light truck applications, the SAE specification is J431 G3000 (superseded to G10).."

Warning: Bike disks are NOT made out of grey iron (or SG iron), they are a specific carbon steel. Iron's claim to fame (and the reason it's used for common cage duties) is that it's thermally stable (not overly subject to heat stress cracks) and structurally ridged. But it's brittle, and not very strong. If you made iron disks to the same dimensions as your originals they would be seriously structurally under-designed.

It's probably quite possible to source an equivalent steel to the OE disks (if you can identify it correctly) and a matter of a few minutes to draw and laser cut them. The issue of hardening is really only a problem on surfaces which will contact the pads (vent holes) and these can be post-drilled. For most disk designs I've seen the cut disk could then be finished on a surface grinder. Easy, if you can identify the correct alloy. If someone does that and delivers it here I'd be happy to make a set for someone to evaluate.

[Animal]

...if you can identify the correct alloy.

I did. It wasn't easy, as the OE Manufacturers don't like to share proprietary information - selfish bastards!
It's certainly not Unobtainium, but exotic enough to make it impossible to buy locally, yet still prohibitively expensive to buy less than a couple of sheets at a time. Not too bad if I wanted to go into volume production.
After I'd added the costs of importing a suitable piece, getting it profile cut, finished and fitted with OEM floating buttons, it wasn't worth pursuing.

[Ocean1]

I did. It wasn't easy, as the OEM manufacturers don't like to share proprietary information - selfish bastards!
It's certainly not Unobtainium, but exotic enough to make it impossible to buy locally, yet still prohibitively expensive to buy less than a couple of sheets at a time. Not too bad if I wanted to go into volume production.
After I'd added the costs of importing a suitable piece, getting it profile cut, finished and fitted with OEM floating buttons, it wasn't worth pursuing.

Oh I'm an expert at getting around such obstructive practices.
But you're right, a one-off would be worthwhile only if you considered it research for a more concerted attack on the local market. I mean, sheesh, $1500 bucks for what cost mebe $25 to manufacture and $75 to stock? You'd be putting $1K in your pocket by the time you made your 10th set...

[imdying]

But you're right, a one-off would be worthwhile only if you considered it research for a more concerted attack on the local market. I mean, sheesh, $1500 bucks for what cost mebe $25 to manufacture and $75 to stock? You'd be putting $1K in your pocket by the time you made your 10th set...

If you're in manufacturing, you'll know why that is an unrealistic outcome that you've described. A disc is fairly useless without a centre and the mounting buttons for starters. $1500 would be close to the upper limit of a set of 3 OEM discs and pads. A single top of the line Brembo HP disc would cost approximately $800 here, complete with mounts and buttons.

[marty]

have you seen this place? are the RF900 brakes compatible with anything else?

http://stores.ebay.com/pacific-power...91964QQfrsrcZ1

[McJim]

A single top of the line Brembo HP disc would cost approximately $800 here, complete with mounts and buttons.

I'm gonna stick to engine braking only from now on.

[imdying]

I'm gonna stick to engine braking only from now on.

That's a top of the line race bike disc backed by a warranty and having been through rigorous testing. For a disc that you can use in those sort of circumstances with that degree of confidence in the reliability of the product, that's not bad money.

[Skunk]

I got a disc made to a one off pattern. I don't know what the material is (I left that to a trusted engineer friend).

Don't panic! It's on my bucket (AX100) and is a 300mm jobby. I expect it to warp...

[Animal]

Oh I'm an expert at getting around such obstructive practices.
But you're right, a one-off would be worthwhile only if you considered it research for a more concerted attack on the local market. I mean, sheesh, $1500 bucks for what cost mebe $25 to manufacture and $75 to stock? You'd be putting $1K in your pocket by the time you made your 10th set...

In my experience, $25 wouldn't cover the setup cost on a CNC mill, never mind the time to carve out the surplus material inside the disc blank, the button holes, the cross-drilling, the chamfered edges... Even if the blank was profiled through laser or water-jet, there is still a huge amount of finishing involved.

I must be doing something really wrong then, but the price to import the steel, the profile cutting, drilling and chamfering the holes and chamfering the contact surface circumference (on both sides), purchasing the buttons, and fitting the new discs to the original centres (using the buttons and a forming tool in a hydraulic press) made it completely unviable. I'd expect to make a huge investment in any prototype, and I am bloody tight with my costing, but I wouldn't anticipate seeing a profit for quite a long time. (This didn't even include my CAD time and programming my CNC mill.)

I'm probably missing a glaringly obvious point here, but how could you possibly do all that for $25? If your estimate is correct, then I'm sending ALL my manufacturing work to you from now on!

[Ocean1]

In my experience, $25 wouldn't cover the setup cost on a CNC mill, never mind the time to carve out the surplus material inside the disc blank, the button holes, the cross-drilling, the chamfered edges... Even if the blank was profiled through laser or water-jet, there is still a huge amount of finishing involved.

I must be doing something really wrong then, but the price to import the steel, the profile cutting, drilling and chamfering the holes and chamfering the contact surface circumference (on both sides), purchasing the buttons, and fitting the new discs to the original centres (using the buttons and a forming tool in a hydraulic press) made it completely unviable. I'd expect to make a huge investment in any prototype, and I am bloody tight with my costing, but I wouldn't anticipate seeing a profit for quite a long time. (This didn't even include my CAD time and programming my CNC mill.)

I'm probably missing a glaringly obvious point here, but how could you possibly do all that for $25? If your estimate is correct, then I'm sending ALL my manufacturing work to you from now on!

I wasn't suggesting you could make the complete assembly for $25, I was suggesting the OE supplier probably makes the bare disks for about that.

Hence the reference to the first being a lost-leader, pure R&D overhead.

[riffer]

have you seen this place? are the RF900 brakes compatible with anything else?

http://stores.ebay.com/pacific-power...91964QQfrsrcZ1

Yup. The RF900 shares the same front rotors as the following Suzuki models:

GS 500 EK/EL/EM/EN/EP/ER/ES
GS 500 ET/EV/EW/EX/EY/K1-K3
GS 500 FK4/FK5/FK6/FK7
GSF1200 Bandit 1995-2000
GSF 250 N/ZM/P/NP/ZP/R/NR Bandit (GJ74A)
GS 500 EK/EL/EM/EN/EP/ER/ES (GM51A)
GS 500 ET/EV/EW/EX/EY/K1/K2/K3
GS 500 FK4/K4/FK5/K5/FK6/K6/FK7/K7
GS 1200 SSK1/ZK1 (GV78A)
GSX 1200 FSW/FSX

and rear rotors with:

GSX 600 FJ Katana
GSF 600 Bandit ST/SV/SW
GSX 600 FK/FL/FM/FN/FP/FR/FT Katana
RF 600 RR/RS/RT/RV
GSX 750 FK/FL/FM/FN/FP/FR/FS/FT/FV Katana
GSX-R 1100 G/H/J
GSX-R 750 RG/G/H
GS 500 EK/EL/EM/EN/EP/ER/ES
GS 500 ET/EV/EW/EX/EY/K1-K3
GS 500 FK4/FK5/FK6/FK7
GSF 1200 SV/SW/SX
GSF 1200 SK1-SK5/K1-K3 Bandit
GSX-R 600 WN/WP
GSX-R 750 J/K/L/M/N/WP
GSX-R 750 WR/WS
GSX-R 1100 K/L/M/N
GSX-R 1100 WP/WR/WS/WT/WV/WW

[Mumbles]

Brought brand new disks through AFC Motorcycles here is Palmerston for the ZXR 750
2 Front
1x Rear (cant remember the exact cost but worked out good <$1500. I think it worked out about $400 for each disk + Pads)
Metalgear do export direct to NZ so can order online if you like.
http://metalgear.com.au/

Liked the fact that I got my complete old disks back (no swaps)

Sorry not sure if your after options to purchase or just going over the manufacturing options.

[pete376403]

My friend bought a wrecked BMW k100 some years back. It needed new disks. One if HIS friends worked in the toolroom at Mitsubishi (nee Todd) Motors in Porirua, where they had all sorts of large and fancy metalworking machinery. Two landrover flywheels (cast iron) were cut, turned and ground down to become BMW disks and they worked VERY well, far better than the original stainless ones, even in the wet. Only problem, if you could call it that, was that the disks would get a very light surface rust coat overnight, which would wipe off on the first brake application. Just like original Ducati GT750 / 900s.

[imdying]

That was a cunning plan