Disc brake interchange info.

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Blue
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Disc brake interchange info.

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Dave-R
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Post by Dave-R »

I have posted that link many times so it is good someone made it a sticky at long last. ;)
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MrNorm
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Post by MrNorm »

Dave wrote:I have posted that link many times so it is good someone made it a sticky at long last. ;)
Ditto - everyone should read it! Just as there are classic Mopars this is a classic Mopar tech article by the E-booger himself - I've still got the original magazine with it from the late eighties!
Actually IIRC E-Berg first wrote the article when he worked for HPM magazine (if anyone remembers that). Steve Dulcich from Mopar Action soon wrote another article about using the F/M/J spindles which were more plentiful but slightly taller. Then E-Berg got his 'panties in a wad' (to use the vernacular :D ) and stated in print that the Dulcich article was dangerous and should not be used. Thus started a debate/Bananarama! contest that has lasted 20 years or more!!!!
I'll spare you the pros and cons though happy to elaborate if so desired!
Everyone has waded in, even Bill Reilly (BB Dart, Alterkation) took some measurements to show they were OK, but the debate continues!!

A year or two later E-Berg went to Mopar Action and wrote an updated article which is what you see posted (did not alter his view on the taller spindles).
One of the most useful swaps, all using stock Mopar parts. E-Bergs Green Brick is a shining example of what could be achieved with this 'Mopar had it right' approach! :thumbright:
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Post by Dave-R »

The taller spindles cause camber changes with suspension movement.

Now this can be a good thing or a bad thing depending on the car and how well it is set up for cornering.

With body roll and fairly soft suspension (typical stock yank) it is probably a good thing as it helps keep the tyres planted.

On a car with stiffer suspension that handles well on corners you probably don't want the wheels moving in and out at the top and bottom all the time. It causes toe changes and possibly a bit of bump steer too?

Anyway. Chysler suspension/steering engineers thought it was a bad idea. Which is why the suspension is carefully designed not to do that.
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Post by MrNorm »

Dave, Bill Reilly took a load of bump steer measurements a few years ago and showed it was fine. They are probably still on his website. Some people even prefer using them to get a bit more camber.

Arguments used against them are mainly limited to "might overstress the upper ball joint" (NFW), "might overstress the brake hose" (doubtful - but always check your brake hose when making any mods, it's easy to eyeball), and "Chrysler did not do it and they knew what they were doing!". as you repeat above.

Well, Chrysler did not do lots of things that we do, for lots of reasons. Certainly they were designing for use with bias ply tyres, and average 100K user etc. They did not fit fibreglass bumpers, Caltracs, 11.75 brakes to E-Bodies, etc, but there are good reasons for all of them in the right place.
I am a card-carrying member of the "Chrysler got it pretty right" club, I maintain that the Green Brick is an awesome example of what using their basic designs could achieve, but even that had lots of stock parts in non-stock applications.
My 2c - I wouldn't hesitate to use the taller spindles if I couldn't get the stock height ones. (Actually now you can get the forged 2" drop spindles I'd probably do that instead!)
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Post by Dave-R »

Well I only have a basic knowledge of suspension geometry but I do know that if a wheel moves in an arc, rather than a vertical movement, the tie rod will have to change length a lot more. Of course it cannot change length so surely it must pull the steering (if just one wheel) or pull the wheels in at the rear (producing toe out).

Now if during cornering the wheels go toe out but it stays toe in on a straight line then that would actually be a great benefit to cornering and stability too.

So I am not completely against the taller spindles and in fact these days I am leaning towards their benefits... ;)
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Post by MrNorm »

There you are, I found the info on BBD...
http://www.bigblockdart.com/techpages/spindles.shtml
Bit more toe-in on extension, slightly higher roll centre, but increased camber is good:
Conclusion - "Overall, using the B-spindle will result in geometry changes that are unnoticeable with all but the most aggressive drivers running against a stopwatch. Even at that, there's a good argument that the increased camber gain will have a positive impact on cornering while the increased toe-in through extension will go undetected"

There is lots more debate if you do search on Moparts, both E-Berg and Dulcich have waded in, I hugely respect them both, but many people have done this and reported no real issues, and the Reilly measurements carried the day for me
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Post by AllKiller »

1973 C body spindles are almost an Inch taller....73 a one year only option.
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Post by AllKiller »

:read2:
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Post by sublimemike »

What's the latest with disc brake upgrades from stock 10" front discs on 15" wheels ebodys? Ade has 11 3/4 discs with 2 pot calipers made up from sourcing a variety of parts. Killer Steve has the the Viper set up for around £900 ish?? with some mods to make fit. Strange do a light weight kit drilled & slotted for about $700 but I think its just for racing?? Wilwood do 11" rotors drilled & slotted with 4 pot calipers around $700 in different colours. Also Wilwood do a 12" rotor big brake but its for 16" plus wheels that I wouldn't want. Master Power in the sticky do upgrades but they look to have been surpassed by others and I could get more for my $ going elsewhere. A friend is going to the states in May and I've bribed him to use most of my baggage weight allowance. Thanks all
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Re: Disc brake interchange info.

Post by MilesnMiles »

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Blue
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Re: Disc brake interchange info.

Post by Blue »

The doctor diff kit is probably the best deal for improved braking while retaining 15” wheels. The Strange set up is the lightest which I find perfectly adequate on the street. The best set up is very much dependent on your driving style, if you go into corners fast and brake late you need large diameter discs. The Viper conversion is pretty much dead in the water these days due to the lack of availability of calipers at a sensible price.
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Blue
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Re: Disc brake interchange info.

Post by Blue »

Another benefit of the Strange set up is you can use drum spindles for maximum weight loss. Then you can sell your existing disc set up complete to recoup some money. I have a pair of drum spindles spare if anyone wants to go down that route.
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