Bob C
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| posted on 8/9/05 at 08:25 PM |
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Looking good for lower unsprung weight..
Thought I'd post a piccy of my front uprights; I'm keen to get as low unsprung weight as I can without spending silly money. The wilwood
caliper shown is only 1.4lbs weight. The lash-up pictured will be modified, different bolts & the wheel side bracket plate increased to 4mm steel-
this was lashed up to check dimensions - fits the wheel perfect so I'm feeling smug! The upright is off an mx5 & I'll use the old mx5
14" wheels as they're nice & light too.
I want cast iron non-vented discs (264mm) on alloy bells but it's proving a bit hard to get suitable discs at a sensible price (APracing do
'em but want £80 EACH - +VAT!!!!!!) I'm starting to think along the lines of buying ordinary bog std discs & machining the middle out
(£10 a pair......) Anyone tell me a good reason why not? I've been put off the idea of making 'em out of steel plate - not a good friction
material apparently..
cheers
Bob
 
Rescued attachment frupcal.jpg
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NS Dev
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| posted on 8/9/05 at 08:33 PM |
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std (cast iron, steel is indeed no good!)discs with the middles mcahined out works fine mate!
You might need to give them a skim after in case they move a tad but just check the runout, you may be ok.
A mate did this using Mazda RX7 4 pot alloy calipers and some big Jag solid discs on a fwd escort hillclimb car, worked a treat.
Just watch the costs, I assume you can do all the machining, else the AP price will seem ok!
AP are not a rip off, they just charge a fair price for a good product.
DIY discs are fine though!
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Bob C
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| posted on 8/9/05 at 08:39 PM |
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Those RX7 alloy 4pots are lovely things aren't they - SO light! I remember trying to get them to fit in my V8 mx5 (without success)
OK I'm round at the motor factors tomorrow lunchtime checkin out the disc catalogs...
CHeers
Bob
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Hellfire
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| posted on 8/9/05 at 11:23 PM |
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Just went outside into the garage to click 'post reply' on the other screen  to answer this thread....
Why not use bike disc's? I've never machined those but I don't believe they are cast iron - I reckon they are High Speed Steel -
anyone in the know? If they are HSS - just buy some blanks and make them this way... just a thought!
I'm gonna find out what they r made from now... curious 
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Peteff
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| posted on 9/9/05 at 12:27 AM |
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Bike disks might be stainless. Mine were stood 7 years and never rusted. They use sintered pads which will improve the friction coefficient.
yours, Pete
I went into the RSPCA office the other day. It was so small you could hardly swing a cat in there.
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NS Dev
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| posted on 9/9/05 at 11:20 AM |
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quote:
Originally posted by Bob C
Those RX7 alloy 4pots are lovely things aren't they - SO light! I remember trying to get them to fit in my V8 mx5 (without success)
OK I'm round at the motor factors tomorrow lunchtime checkin out the disc catalogs...
CHeers
Bob
V8 Mx5!!!
Now there's a thing. I have thought about doing one of those a few times, or at least putting a v6 in if not going the whole
hog.................you don't know if the mazda 2.5 v6 fits the std mx5 gearbox do you?
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Bob C
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| posted on 9/9/05 at 12:10 PM |
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The mazda (probe?) V6 problem, I think, is that the engine suffers catastrophic oil surge/starvation when installed north/south and upright - I think
this was done in america somewhere & took quite a lot of engineering. RV8 is cool - weight same but lower down, only problem exhaust
routeing....
Back on topic, just bought a pair of ford discs for £27 - now to take 'em home & convert 'em into scrap . . . . .
cheers
Bob
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chrisf
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| posted on 9/9/05 at 01:00 PM |
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Hi Bob:
This looks very good. Do keep us posted to you progress.
--Chris
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NS Dev
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| posted on 9/9/05 at 01:12 PM |
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have you seen this alternative from Stuart Taylors??
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britishtrident
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| posted on 9/9/05 at 02:31 PM |
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It might be easier trying to find a 10.25" disk that fits over the hub wheel pcd top hat style rather than use a mounting bell.
The unsprung weight might be slightly higher but it is simpler -- less to go wrong.
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Rorty
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| posted on 10/9/05 at 03:36 AM |
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Bike discs are usually cast steel or stainless steel.
I've made discs from cast steel, cast iron and aluminium all work well, but you need to match pad material to disc material for best results.
Cheers, Rorty.
"Faster than a speeding Pullet".
PLEASE DON'T U2U ME IF YOU WANT A QUICK RESPONSE. TRY EMAILING ME INSTEAD!
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Bob C
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| posted on 10/9/05 at 11:18 AM |
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Cheers guys,
OK reasons why I did it that way (I'm not saying these are good reasons . . just my prejudices!) - Alloy mounting bells save weight and allow
me to customise exactly for wheel stud PCD and diam, flange diameter and disc offset: the probability of finding something right is a disc catalog is
very low (my estimate is a probablity of 0:1) Space is tight in a 14" rim so I don't have a lot of room for manoevre! I must say I
hadn't considered the bike brake route & the weight thing is appealing: downsides I'd say are hose connection sticking out (you can
see it on NSdev's picture) and heat capacity of the discs; they're physically smaller (less weight) than a car disc so a single heavy stop
will generate a correspondigly bigger thermal shock. This energy is 1/2mv2 so if you reckon a bike is 1/2 a locost which is 1/2 a car weight,
I'll get half the delta T expected by a car disc, but 2x the delta T expected by a bike disc. I know that's not completely fair 'cos
bikes are engineered for higher speed & better continuous disc cooling.
Finally I bought a lathe so I'm determined to use it!!!! BTW that HE30 alloy for the disc bells is lovely stuff to machine.
cheers
Bob
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alistairolsen
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| posted on 1/4/08 at 09:55 PM |
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quote:
Originally posted by Rorty
Bike discs are usually cast steel or stainless steel.
I've made discs from cast steel, cast iron and aluminium all work well, but you need to match pad material to disc material for best results.
Aluminium brake disks? How does that work then?
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MikeRJ
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| posted on 1/4/08 at 10:25 PM |
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quote:
Originally posted by alistairolsen
Aluminium brake disks? How does that work then?
Very well providing you use the correct alloy and pads. The S1 Lotus Elise had alloy disks, though they changed to iron when the company that made
them closed down.
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Fred W B
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| posted on 2/4/08 at 05:47 AM |
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Im giving bike discs a try - see
HERE
got them for peanuts from a bike breakers
Cheers
Fred W B
[Edited on 2/4/08 by Fred W B]
You can do it quickly. You can do it cheap. You can do it right. – Pick any two.
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alistairolsen
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| posted on 2/4/08 at 10:09 AM |
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never realised that! take it youre quite limited on pad choice?
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MikeRJ
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| posted on 2/4/08 at 08:01 PM |
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quote:
Originally posted by alistairolsen
never realised that! take it youre quite limited on pad choice?
Yes, have to be the correct pads. The Elise disks were actually a composite alloy based material, google for "Metal Matrix Composite".
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