MG four six eight Bill Jacobson Wa state (324 posts) Registered: 10/23/2007 02:15AM Main British Car: 73 MGB Buick 215, Eaton/GM supercharger |
Brake bias calculator link.
While researching my brake upgrade I came across this handy dandy web site to calculate brake system bias. It's for 4 wheel disc set-ups, but it's kinda cool that you can plug in different caliper, rotor, pads, etc and see what effect it has on front to rear brake bias!
Bill [www.tceperformanceproducts.com] |
rficalora Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: Brake bias calculator link.
Cool. It should get you pretty close. It doesn't adjust for front/rear weight balance but with most of our cars being close to 50/50 I wouldn't expect that to matter much. From there you have to figure how much bias is changed with each click on your bias valve.
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MG four six eight Bill Jacobson Wa state (324 posts) Registered: 10/23/2007 02:15AM Main British Car: 73 MGB Buick 215, Eaton/GM supercharger |
Re: Brake bias calculator link.
Hi Jim
I installed a Fastcars front end, the wider one for flared fendered cars. It comes with Wilwood 4 pot (1.75" piston) calipers and 11.6" vented rotors. I'm in the process of shaving some unsprung weight off of the narrowed 8.75" Mopar rear end that I have been running for years. I switched to a custom length axle in the rear, to better match up with the front end and the more positive off-set wheels that I will be now using. Now I'm researching a rear disc set-up. I'll have to custom make some brackets due to the slightly longer axles, which should be kind of a fun project! I talked to Ted and he recommends a Wilwood 4 pot caliper (1.38" piston I think) for an ideal bias with the front and I may end up going that route. However I was kind of hoping to find a caliper that has an intragul e-brake and not have to mess with seperate e-brake calipers! According to the calculator the Wilwood 1.38" 4 pots would give me front bias of approx .627 with rear Wilwood 11.44" rotors. I can see where this would be just about ideal when factoring in some rear to front weight transfer during braking. I hoping that if I can find something in a OEM aluminum intragul caliper that is close to those numbers, that would work well! Bill |
mgb260 Jim Nichols Sequim,WA (2461 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Brake bias calculator link.
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rficalora Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: Brake bias calculator link.
Jim, I'm using the earlier Camaro calipers. I simply removed the big [ugly] round weights. The bracket is still there, but it isn't as bad as the weights. They aren't light though. Do you know if the RX7 ones have the same bolt spread & offset?
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mgb260 Jim Nichols Sequim,WA (2461 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Brake bias calculator link.
Rob, I don't have the calipers to measure but Robbie(Socorob) has the RX7 calipers and could give you the measurements.
Edited 1 time(s). Last edit at 10/18/2011 07:55PM by mgb260. |
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MG four six eight Bill Jacobson Wa state (324 posts) Registered: 10/23/2007 02:15AM Main British Car: 73 MGB Buick 215, Eaton/GM supercharger |
Re: Brake bias calculator link.
Jim
The Camaro calipers look like a good option. I found another website Edit: link no worky! ( will re-try latter LOL) The nice thing about the Centric site is that they show piston diameters along with the pic. There's over 3500 calipers to look at though!! Attached is some pics RX-7 = 35mm (1.38") piston, not sure if it's for non or vented rotors VW MkIV = 38 mm (1.49") piston non-vented rotors Audi TT = 41mm (1.61") appears to be non-vented judging by the gap in the mounting bracket RX-8 = 43mm piston, most likely vented rotors (caliper looks like it may be cast iron) RX-7 VW MK IV Audi TT RX-8 Edited 5 time(s). Last edit at 10/20/2011 02:15AM by MG four six eight. |
MG four six eight Bill Jacobson Wa state (324 posts) Registered: 10/23/2007 02:15AM Main British Car: 73 MGB Buick 215, Eaton/GM supercharger |
Re: Brake bias calculator link.
Here is another, Cobalt, Malibu, HHR These are for a solid rotor.
I'm kinda leaning towards using a solid rotor with aluminum hat for weight savings. ECS sells a VW MKIV upgrade kit that seems to be a decent price and includes hoses. Not sure if they are 38mm or 41mm though, I've heard reports that VW made that type of caliper in both sizes. [www.ecstuning.com] The 38mm piston size may be a little small when compared to the larger front Wilwoods Using a 11.44 rear rotor 35mm rear piston caliper = approx .746 front bias (1.38") 38mm rear piston caliper = approx .715 front bias (1.49") 40mm rear piston caliper = approx .707 front bias (1.59") 41mm rear piston caliper = approx .683 front bias (1.61") 44mm rear piston caliper = approx .646 front bias (1.75") 48mm rear piston caliper = approx .630 front bias (1.89") 35mm 4 pot rear caliper = approx .627 front bias (1.38") For comparison purposes Stock front MGB brakes and a 35mm rear piston on a 10" rear rotor calculates out to .702 front bias (depending on pad size used) Bill Edited 5 time(s). Last edit at 10/20/2011 02:06AM by MG four six eight. |
mgb260 Jim Nichols Sequim,WA (2461 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Brake bias calculator link.
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rficalora Rob Ficalora Willis, TX (2764 posts) Registered: 10/24/2007 02:46PM Main British Car: '76 MGB w/CB front, Sebring rear, early metal dash Ford 302 |
Re: Brake bias calculator link.
Watch the direction the e-brake pulls. On the B it's easier to route the cable if it pulls toward the middle of the car like the camaro or turbo rx7 ones than ones that pull north/south like the cobalt/hhr one above.
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MG four six eight Bill Jacobson Wa state (324 posts) Registered: 10/23/2007 02:15AM Main British Car: 73 MGB Buick 215, Eaton/GM supercharger |
Re: Brake bias calculator link.
Jim, I forgot about those older Subarus. I remember the first time that I saw one thinking "whats up with that" then I saw how small the rear brakes were and it made sense!
Rob, I can see where that would be an advantage for sure. Were you able to use a stock e-brake cable(s) with the Camaro calipers? How does the front to rear bias feel on your car when braking? Bill |
BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Brake bias calculator link.
That Subaru caliper looks very interesting. If it uses some method other than spinning the piston for retract and pad changes it might be a very good choice. Having to wrestle with a loose caliper, a badly fitting retract tool, a can of brake clean and an electric drill all at once underneath the car while the internals just spin instead of retracting the piston is, in my opinion, no way to go about freshening up the pads. And in the pits it would just be inexcusable. I still can't understand what made the car makers think they could foist that one on us, but they sure did do it and it seems to be the most common way.
JB |
ex-tyke Graham Creswick Chatham, Ontario, Canada (1165 posts) Registered: 10/25/2007 11:17AM Main British Car: 1976 MGB Ford 302 |
Re: Brake bias calculator link.
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mgb260 Jim Nichols Sequim,WA (2461 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Brake bias calculator link.
Subaru uses the threaded piston like 99 percent of rear disc brakes(Mazda uses an allen bolt) for self adjusting. Sometimes the pistons corrode or stick. If you can't turn it with the special socket or needle nose pliers or channel locks on the back of the piston you have to put the caliper on the bench and disassemble and clean. I had the Subaru DL and had no problem screwing the piston back. I think the rubber boot helps protect it. I think it would be an excellent choice for rear brakes if you have large front brakes, as the later vented one uses the same thickness rotor as the popular thinner aftermarket rotor and hat. The earlier one uses a solid disc. Centric makes ceramic pads and Hawk HPS pads are also available. This picture shows the adjuster notches in the piston.
Edited 3 time(s). Last edit at 10/21/2011 09:21PM by mgb260. |
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Brake bias calculator link.
Maybe that Mazda design would bear looking into. My wife had a Mitsu Eclipse with that sort of a design and the one time I changed pads on it, it was a breeze to retract and install new pads. But I've never seen another caliper with that design. Jim, if you could find that Mazda caliper and post it here that could be a benefit to anyone wanting to upgrade their rear brakes.
JB |
mgb260 Jim Nichols Sequim,WA (2461 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Brake bias calculator link.
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Brake bias calculator link.
As well as I can recall that looks like the Mitsu caliper I remember. Those would be good ones to keep in mind, as pad changes are dead easy, especially when compared to the other 99%. Pull the cover plug, insert allen wrench, retract piston, change pads. I don't think it can get any easier with an E-brake caliper.
JB |
mgb260 Jim Nichols Sequim,WA (2461 posts) Registered: 02/29/2008 08:29PM Main British Car: 1973 MGB roadster 260 Ford V8 |
Re: Brake bias calculator link.
I looked up Mitsubishi too. My kid has an 93 Eclipse but it had the piston type adjuster. Maybe you had an odd one or someone put a Mazda caliper on.
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BlownMGB-V8 Jim Blackwood 9406 Gunpowder Rd., Florence, KY 41042 (6468 posts) Registered: 10/23/2007 12:59PM Main British Car: 1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS |
Re: Brake bias calculator link.
Yeah it was really strange. I don't remember the year but I could ask Edith. She bought it new. The odd thing was that I looked it up and the part for it was shown as the other type. I had even gone to the junkyard and pulled a set only to discover much later that they were the wrong ones. It was pretty much a base line Eclipse with the itty bitty motor, (1300, 1500 or something like that, whatever the smallest one was.) but had nice interior and ran good. She bought it for the looks and the interior I think. But it came with those calipers. Same ears sticking out to the sides and all. Really easy to change pads. I remember thinking at the time that if this was the new design there was hope for e-brake calipers after all.
JB |