Brakes - drums -> discs

craigs
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Brakes - drums -> discs

Post by craigs »

As with a lot of stuff this "has been tried before", but I wasn't around back then.

I was on my ass last weekend with my fancy adjuster tool in one hand, spinning the wheel with the other and a flashlight in my mouth and it hit me - wouldn't discs be much easier. With the recent shortage of brake shoes is it time to look at discs again? In my mind the perfect solution is a disc setup that uses the same beam, spindles, and wheels. Something like this seems like an off the shelf solution:

http://www.kustom1warehouse.net/Zero_of ... 05x205.htm

A better solution would be a cheap Wilwood caliper and cheap solid rotor, but that would take some designing and fitting to come up with a bracket. Anyone even close to interested in taking this on? Again, same beam, spindles, and wheels would be a must.

So why did discs get shot down last time?
Has anyone tried one of these kits on a vee?
Is it true they are heavier than our current setup and therefore would be a handicap? If yes, then why not let people run discs if it will hurt their times?
Has anyone come up with a Wilwood/cheap rotor solution?

Thanks,

Craig
tiagosantos
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Re: Brakes - drums -> discs

Post by tiagosantos »

:lol:

Best of luck.. I guess the disc brakes idea might get more traction every time someone comes up with it, but I don't think this time will be THE time yet.
MarkP-2
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Re: Brakes - drums -> discs

Post by MarkP-2 »

Craig,

I'm also tired of adjusting the damn drums all of the time and the older I get, the less patience I have for them! :lol:
Mark
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Re: Brakes - drums -> discs

Post by FV80 »

FWIW, I agree that "it's time" for us to allow disc brakes. Why don't one (or more) of you submit a request to the CRB and see if we can get it out for member input again. Maybe the results will be different this time. I do know of several people that have CHANGED their mind since the last time the membership was polled.

Steve, FV80

That kit that craig referenced looks pretty good... but I wonder if the parts are "up to the task" of full bore racing ? At least it would be using our current spindles, so likely it would be OK... hopefully. That's about the best deal I've seen on a front conversion kit. Last time I looked, the wide five versions were up in the 600 - 800 range.
The Racer's Wedge and now a Vortech, FV80
fvracer27
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Re: Brakes - drums -> discs

Post by fvracer27 »

Those kits are not even good for street cars. If kits like that are Allowed on our cars I will move on. A good kit is around $700- $800 but 90% of FV people won't spend that. Instead they will endanger themselves and others with cheap crap.

FST has disc brakes why mess is FV just move to FST


http://youtu.be/XJsOMuvpghI cheap junk

http://youtu.be/8uZI46iJ8WI
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AJP
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Re: Brakes - drums -> discs

Post by AJP »

I'm a bit wishy-washy on this subject but curious about what is "junk" about them. Is it the calipers? Rotors? Bracket? If the rotors are OK, would it be possible to use those only and come up with another caliper solution? How bad would it be to say rotors must be steel, non-vented, drilled etc while keeping calipers open? Would there be too much room for expensive fancy innovation?
It would be nice to try and logically discuss the possibilities and details and try to keep the broad statements to a minimum. Getting first hand data from someone that has recently tried/seen a kit such as this would be helpful.
If folks want to send me donations to my PayPal account I'll buy a set and do a report. Really.
Andy
BLS
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Re: Brakes - drums -> discs

Post by BLS »

I have the weight of standard drums w/bearings, backing plates, shoes, wheel cylinders, and lug nuts at just a bit under 20 pounds. The airkewld kit states 48 pounds. Unsprung weight, rotating mass, looks like a killer to me.
Barry
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fvracer27
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Re: Brakes - drums -> discs

Post by fvracer27 »

AJP wrote:I'm a bit wishy-washy on this subject but curious about what is "junk" about them. Is it the calipers? Rotors? Bracket? If the rotors are OK, would it be possible to use those only and come up with another caliper solution? How bad would it be to say rotors must be steel, non-vented, drilled etc while keeping calipers open? Would there be too much room for expensive fancy innovation?
It would be nice to try and logically discuss the possibilities and details and try to keep the broad statements to a minimum. Getting first hand data from someone that has recently tried/seen a kit such as this would be helpful.
If folks want to send me donations to my PayPal account I'll buy a set and do a report. Really.
Andy

Andy the calipers flex so much the pedal feels soft. There are tons and tons of threads on this in the VW bug world and those guys use them occasionally on the street not to the extremes as we do. The Airkewld kits Seem to be the best but adding a ton of weight.
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craigs
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Re: Brakes - drums -> discs

Post by craigs »

Hi Barry:

Is the weight a reason to not allow it? If it is a penalty to run them why not allow the heavy disc package and let the racers decide?

I assume 4.5" wide or smooth wheels are legal. Same thinking - if it is a penalty to run them why not allow people?

Craig
BLS
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Re: Brakes - drums -> discs

Post by BLS »

Craig,

Sorry if it seemed I was against the use of discs. I'm not. The Airkewld kit states an app weight. There are some other higher quality kits, CSP (german) makes one but I don't know the weight. I think it is time to find a good kit or parts and allow them. I certainly would not add 28 pounds of unsprung weight per side to do it.

Regards,
Barry
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Re: Brakes - drums -> discs

Post by tiagosantos »

I'm glad we seem to have a couple more people interested or at least willing to talk about disc brakes.. I actually think the idea of allowing a kit at a substantial weight penalty would be great. Those of really are tired of dealing with drums would get their chance, but those who have figured out how to optimize their braking with drums, could keep them with no performance disadvantage. The weight penalty could be adjusted as needed after a couple of seasons of comparisons to equalize performance. But I feel it's important that there is no discernible performance advantage to a disc brake conversion. It should be allowed for the maintenance and availability advantages..

The airkewld kits do seem nice, but I wonder if they have to be that expensive. If the problem with the cheaper kit is the caliper (and it does seem pretty horrible!) I'd be tempted to try and buy the kit without calipers and caliper brackets and machining an adapter for a cheap pair of wilwood calipers.
BLS
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Re: Brakes - drums -> discs

Post by BLS »

I think a correction is in order. I went back to the Airkewld site. I believe the total weight of the kit, both sides is 48 pounds. I thought it seemed too high for one side :shock:

That would appear to be a penalty of 4-6 pounds per side, depending upon the accuracy of my weight for the drum components. Still a substantial increase in unsprung weight...
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Stan
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Re: Brakes - drums -> discs

Post by Stan »

I bought a complete disc-to-disc ball joint beam this past weekend, with which I'm planning to build a VSR. I haven't taken it apart yet, but I'm guessing it's heavier than a drum brake setup.
SR Racing
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Re: Brakes - drums -> discs

Post by SR Racing »

While discs may be in FV's future, I sure wouldn't go to the KustomWarehouse solution. A non VW solution with minimal supplier(s) for how long?
The only sensible way is to go with a VW solution. (BJ Beam and VW/Ghia brakes and rotors.) Some fab work, but less $, plenty of availability now and into the future, with many years of track testing. How long will good link pin beams be available? You will still be using the same long narrow heavily cantileaved axles and breaking them even more often. The VW setup uses a short, much stronger stub axle. You will never break one and they are plentiful and available cheap and new. The KustomWarehouse solution would be a step backward in safety, reliability and price.

Front discs are a big step and I am not sure FV should even consider it, but if so... don't go that route.
craigs
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Re: Brakes - drums -> discs

Post by craigs »

I believe the ball joint beam is too radical of a change for most FV drivers. I also feel that the only disc solution that has a chance of passing right now is a front conversion that uses a Wilwood caliper and a two piece rotor all on the current beam, spindles, wheels, etc...I am no rules person but we could even specify the model caliper and rotor material.

Is there actually opposition to allowing a quality disc setup that is heavier than the current drum setup? The one from Air Kewld seems to tick all the right boxes - Wilwood, made in the US, and two piece rotors. It's is also a few pounds heavier than the current setup so if someone does want to run it it shouldn't be a super advantage.
BLS
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Re: Brakes - drums -> discs

Post by BLS »

There may be some issues with the increased weight of the airkewld: Shocks possibly need to be revalved due to the unsprung weight increase. Increased rotating mass will effect accel/decel rates. The most worrisome to me, how does the increased weight effect the spindles? While fine for a street car, our spindles are way overstressed and prone to breakage already. The Porsche 356A used the same spindle diameters but was marginal. The 356B increased spindle diameter (from 25mm to 30mm IIRC) to handle the increased loading.

A lot of 356 guys scoff at replacing the drums with discs. Purists, yes. But they also swear there is no performance advantage to the discs over a properly set up drum system.

Jim may have it correct in his post above, if you want to go to discs it's probably best to go to the BJ beam. I do not see that it changes the character of the FV class. Some cars will be easier than others to adapt and while discs are probably not a real performance advantage over properly set up drums, a BJ beam makes setting caster/camber much easier. It is heavier. I'm willing to bet a good link pin / drum brake FV will not be faster with a BJ front. Going to rear discs is much easier, no real change required.
Barry
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jferreira
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Re: Brakes - drums -> disc's

Post by jferreira »

Oh boy .....John the new guy here, who just so happens to have a bit of experience as I design, manufacture, install for superkarts. Hats (carriers), rotors, brackets and even our own special pads.
FYI, for purposes of "flexing" the brackets are tig welded to the "strengthened" spindles. (more on that latter)

The problem:
  • the brakes are a PITA because of the need for constant adjustment (agreed)
    we can't get "performance" shoes (even though some say they are not needed)
Do drum brakes have enough stopping power? Yes they do. If you can lock up the wheels, then you have enough power.

I am NOT too thrilled about what I see being offered. First, Wildwood brakes are best mounted at 12:00 O-clock. Especially the single piston, single pin arrangement. Otherwise you can get puck twist and puck drag. 2nd, the first thing you do, is replace the square cut O-Ring, with a round O-Ring so the pucks do not drag on the disk.
Maintenance: You WILL glaze both the rotor and the pads. After each weekend you will need to take a flap disk or something similar to remove the glazing.
Rotor material. In order of performance, carbon fiber (special), ceramic coated aluminum based, meehanite cast iron **, and steel. IF we were to allow disk brakes, I would STRONGLY urge that we allow only cast iron and steel, and single rotor and not dual wall. I use meehanite because of: almost no warpage, less fade vs steel, less glazing, better feel, and better grab. The specialty rotors of carbon and coated are way too $$$.

My other concern is spindle strength. Especially the spindle with the speedo cable hole (left spindle??) But if the FST guys do not have a problem, that risk may be minimal.

Also, the Wildwood shown is good, but that may be overkill. http://www.bicknellracingproducts.com/c ... ct&id=3201 unit would be better. Or the Bicknell or Bembro, which offer smaller units, would/may be better.
My opinion, we do not need them. We are trying to get people to join the FV class. Raising the cost would not help the situation. So, IF allowed, do NOT specify a caliper brand. What I do think we need is the availability of a performance brake shoe, and NOT at $200 a set.

Jim mentioned going to the newer VW beam and brake assembly. Not sure of the implications or cost of that solution.

I can bring a front and rear Wildwood brake assembly with brackets to the race next weekend at NHMS if anyone is interested.

John
BLS
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Re: Brakes - drums -> discs

Post by BLS »

But if the FST guys do not have a problem, that risk may be minimal.
John,

The FST cars use the BJ beam which has different spindles which are much stronger.
Barry
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Re: Brakes - drums -> discs

Post by Veefan »

If FV changed to the VW disk brake beam, wouldn't that also mean everyone switching to a different rim? Except for the aftermarket stuff, I'm not sure VW made a disk brake rotor for the 5 wide rims?
craigs
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Re: Brakes - drums -> discs

Post by craigs »

John (or anyone else)

Educate me - why do the spindles need to be stronger with disc brakes vs drums?

Also, if I buy the rotors do you think you could build a bracket and caliper setup that would work? I'm thinking about switching to discs for one of the NHMS regionals. After I run them they are available for any of you to try. I will be the guinea pig.

My thought is that allowing discs wouldn't increase the cost of entry in FV. Discs, as has been discussed, are heavier and would make the car slower so a driver should choose drums. If discs are allowed I would be selling 5 - 6 drums, a few sets of used carbotech shoes, and two sets of brand new carbotech shoes. Shoot if discs are legalized I will give my drums away to a new competitor.

Again, the only way I think this works - same spindles, beam, and wheels and a specified rotor material.

Thanks,

Craig
BLS
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Re: Brakes - drums -> discs

Post by BLS »

Educate me - why do the spindles need to be stronger with disc brakes vs drums?
My guess is the incresed weight will put a bit more stress on the spindles. The side loading/bending force will not change. Just a guess, but since we are marginal anyway, the increased mass of the Airkewld disc brake may be a tipping point. Or, I could be completely wrong. Or there may be lighter systems available.

IIRC, Stevan Davis mentioned somewhere that he tested discs - quite a while ago I believe. You might want to contact Stevan for his thoughts.
Barry
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Re: Brakes - drums -> discs

Post by fvracer27 »

Barry I agree 100%
John F I also agree 100%
John S yes you also are 100% correct as you know from experience from converting to FST. beam mounting is different, different rims and correct me if I'm wrong will also require body mods on some cars to run a BJ beam.

My thinking is if your going to do it just build a FST and leave FV alone

FV guys are like this :oops: and the FST guys are like this :mrgreen: reading this thread.
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Re: Brakes - drums -> discs

Post by tiagosantos »

I'd love to run the ball joint beam, but that introduces a few other advantages.. I doubt that would ever "fly". The ease of adjusting camber alone would be a pretty significant improvement, I think! Edit: I *think* there are wide 5 rotors for the ball joint beam as well, aftermarket of course. There are also 4-bolt, 4-1/2" wide steel rims that would fit out tires with the stock vw rotors. But I agree that the BJ beam might be too big of a change.

I like Craig's idea.. Allow a specific caliper (wilwood single piston or something similarly cheap) and rotor, and let people either buy a kit that includes those, or make their own adapter. Mandate a weight penalty (1050lbs minimum if using disc brakes?) and see how things turn out. The reason I feel the caliper should be somewhat restricted is you can bet someone will spend a grand on a set of calipers (whether they are an advantage or not..) and cause an uproar :)

In my opinion, and based on how older threads about disc brakes have turned out, we would have to pretty much guarantee that they wouldn't be an advantage. Do we need better brakes? I don't think so.. But I feel if I must spend almost $200 on a set of shoes to be "at the front", I'd rather spend a one time lump sum and get rid of the damn shoes for good. I agree that raising the cost of entry into the class isn't a good thing, which is why these shouldn't be perceived as a must have. Again, the weight penalty should help with that. On the other hand, the $$$$ brake shoes are a definite advantage and end up being a significant expense if you race enough weekends over a season, but no one seems to care about that, so I dunno.

Lastly, on spindle strength.. I can't say if disc brakes would be an extra strain on the spindles, personally I wouldn't want my brakes to be any "grabbier" than with carbotech shoes, but there may be other forces involved that I'm not visualizing. I run the spindle spacers between the bearings though and have stopped worrying about broken spindles :) highly recommended whichever brakes you happen to be using ;)
SR Racing
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Re: Brakes - drums -> discs

Post by SR Racing »

Wrong path. You are pushing $800+ (without a beam) to put on an out of production beam with weak axles and terrible geometry. The VW BJ beam parts for spindle to spindle is under $500 and that INCLUDES a beam with needle bearings. Neither will ever happen due to the lack of consensus. Stay with drums.
Bill_Bonow
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Re: Brakes - drums -> discs

Post by Bill_Bonow »

fvracer27 wrote:My thinking is if your going to do it just build a FST and leave FV alone
Speaking as a 20 year guy in FV and 10 year guy in FST, Mark's statement is spot on. There is no good "partial" anything. Either take the plunge or don't. FV's best path is to stay the course.
Bill Bonow
" I love Formula Vees, they're delicious!"
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