Wilwood LD20 Aluminum Replacement

[SteveG]

Did you use the ST version of the calipers?

I talked this question over with a Wilwood engineer before buying a set of WLD20s for my Swift DB2 and to paraphrase what he told me; typically purpose built road racing cars (open wheel and sports racers) don't need the ST pistons because the calipers and regular pistons cool enough on straights so the heat transfer to the brake fluid is minimal. He did provide a couple of caveats, ST pistons should be used if the car is "under braked" I.E. too much weight and/or speed for the rotor/caliper size or has closed wheels with little or no cooling. He closed out by saying that the WLD20s are intended as replacements for a steel LD20 and if the LD20s didn't boil the brake fluid the standard WLD20s wouldn't either.

Steve

[145inmy73]

Does anyone run LD19 on all 4 corners? My 32F Crossle came with 4 LD19’s and I read the trend is to run 20’s up front, then 19’s in the rear. Any pros or cons to either method? I know the bores are different sizes, 20’s being bigger. Just don’t want to run something because that’s the way it came. I want to know why. Thanks

[Garey Guzman]

Does anyone run LD19 on all 4 corners? My 32F Crossle came with 4 LD19’s and I read the trend is to run 20’s up front, then 19’s in the rear. Any pros or cons to either method? I know the bores are different sizes, 20’s being bigger. Just don’t want to run something because that’s the way it came. I want to know why. Thanks

I run LD19s all around on my DB6

[TimH]

My Crossle' 30F came with LD19 rear and massive LD15 front. I changed to LD19 front with no regrets except to need even more lead elsewhere in the car.

Later addition: We're talking DOT radial tires, so it doesn't take much brake power to exceed the tire capability.

[DaveW]

Does anyone run LD19 on all 4 corners? My 32F Crossle came with 4 LD19’s and I read the trend is to run 20’s up front, then 19’s in the rear. Any pros or cons to either method? I know the bores are different sizes, 20’s being bigger. Just don’t want to run something because that’s the way it came. I want to know why. Thanks

IMO, whether you want to run LD20 size (1.75" piston & larger, thicker pads) front and the smaller LD19 (1.625" piston & smaller, thinner pads) on the rear depends on 3 things:
1. If you are having excessive wear or fade on the front then the '20's in front would be better.
2. If you are having brake balance issues, i.e., having to run a LOT of front bias on the bias bar, then putting the LD20 size in front will help that.
3. All of this depends on whether the larger LD20 caliper fits (wheel interference, etc.).

In aluminum, the weight difference will be minimal.

[reidhazelton]

IMO, whether you want to run LD20 size (1.75" piston & larger, thicker pads) front and the smaller LD19 (1.625" piston & smaller, thinner pads) on the rear depends on 3 things:
1. If you are having excessive wear or fade on the front then the '20's in front would be better.
2. If you are having brake balance issues, i.e., having to run a LOT of front bias on the bias bar, then putting the LD20 size in front will help that.
3. All of this depends on whether the larger LD20 caliper fits (wheel interference, etc.).

In aluminum, the weight difference will be minimal.

What Dave said.

This is the brake caliper setup I have on my 92. I had 19's on the front, but with the drilled rotors a set of pads was good for about 2 sessions. The 20s still wear pretty quick because of the rotors but it works better. LD20 front, LD19 rear if you have to use iron steel calipers, or the Alcon if you can use aluminum. I really like the Alcons on a small hp formula car.

[924RACR]

My SE1 (then DSR, now P2) came with 19's all around; bumped up to 20's up front, and have had a bit of a tough time getting the wear rate in the back (with the 19's) to balance out to a reasonable rate. Was easy to get cooling up front to get decent pad wear, but think I finally have gotten the rears to a reasonable point.

So yeah, what Dave said...

But being that you're still FF spec, I'd suspect you'd be fine as-is, just a question of lining selection...

[DaveW]

FYI, on my Zetec F2000 I'm using Alcon LD20 clones (CAL7940P10, 1.75" dia pistons) on the front, and Alcon CRR300/10-35 (1.375" dia pistons) on the rear. Both setups use the same DO44 size pads. The last time I ran, this gave almost perfect brake balance with the balance bar centered and 5/8" dia MC pistons front, rear, & clutch.

Wear using Carbotech XP20 pads is slightly greater in the front, but easily manageable by swapping pads around between weekends.

[problemchild]

I have stopped running LD-19s on my FF cars for economic reasons. With alloy calipers, there is no real weight penalty, so you get better braking (in theory) but the LD20 pads last 3X or 4X as long. They are bigger but also thicker, so I very quickly cover the slight increase in cost of the initial purchase. This may not be relevant if you are running slow for several events per year, but if you are running hard for a dozen, the cost becomes a factor. The really good drivers seem to be able to get the best out of the bigger brakes too.

[DaveW]

... LD20 pads last 3X or 4X as long. They are bigger but also thicker...

FWIW, LD20 pads are also bigger than the D044's that I have to run in the Alcons.

[EACIII]

How do the Wilwood LD20s compare to size to the old iron LD20's? Tried to find drawing on the Wilwood site last year and came up with nothing. Maybe I should check again.

The ICP while iron are light and much smaller then the iron LD20. Clearance issues on the Bowman.

Ed

[CGOffroad]

Tried to find drawing on the Wilwood site last year and came up with nothing. Maybe I should check again.

Try the link below. It should take you to the Wilwood page about the LD-20. On this page, you will find a couple of links to downloadable PDF's. In one of the these PDF"s is a schematic.

If the link doesn't work, go on Wilwood site and search for part number: 120-14375

https://www.wilwood.com/Search/PartNoSearch?q=120-14375

[145inmy73]

That is really good insight on caliper balancing and reasons why. Do the 19 sized calipers fade quicker because of the pad size, getting hotter quicker? Also, I wouldn’t of guessed the drilled rotors increase pad wear significantly. Is there a minimum rotor thickness to keep in mind? Seems new rotors come pretty thin to start, .250” at times. My drilled rotors are .350” F .250” R. And need turning, for clean up only. It was mentioned a few times, not sure if the thread want to go this direction, but pad selection with these caliper sizes would be a fun topic. I have used Performance Friction Carbon PFC pads with good results. Consistent. Come in fast. Smooth. I haven’t tried others so all I have to go off of.

[145inmy73]

Did everyone else already know that if you run LD20 or LD19 sytle pads, you need to run different diameter rotors? I didn't until today. The diameter is still up for debate. 10" for LD20, 9" for LD19, right?

[DaveW]

Did everyone else already know that if you run LD20 or LD19 sytle pads, you need to run different diameter rotors? I didn't until today. The diameter is still up for debate. 10" for LD20, 9" for LD19, right?

The different disk diameter is related to the pad and caliper shape which are made to follow the circumference of the rotor. IMO, within reason, one can get away with a different rotor other than the 9" one the LD19 was designed for. You just have to make sure the rotor and the caliper don't interfere on the OD, and that the pad doesn't hang very far over the edge of the rotor. So getting everything to fit is a little more critical, but I'd think you could make it work fine with a 10" rotor.

[R. Pare]

When using the same mounting layout, the LD20 uses a 1/4" larger diameter rotor than the LD19.

That said, there are lots of cars (FCs) running 10"x3/8 front rotors with ld20s, and 10x1/4 rear rotors with LD19s, so 10" rotors generally have no problem working with LD19 calipers.

[Joefisherff]

So the Alcon FF LD20 replacements are $450 and the Wilwood are $200, is the price difference justified?

[hdsporty1988]

So the Alcon FF LD20 replacements are $450 and the Wilwood are $200, is the price difference justified?

I ran the Alcons on my 86 Reynard and liked them. After buying my 94 Van Diemen the Wildwoods had come out so I decided to buy them and have been happy with them also. I would say save the $.

[Captain]

Has anyone had fitment issues?

LD19 on the rear of a 94/95 VD. It doesn't look like much, but the rotor hat bolts hit the caliper.

Thinking about increasing the chamfer on the caliper a bit.

LD20 on the front fit great.

[t walgamuth]

You might be able to help it by shimming the caliper out 1/16 or so. Champhering should work too but be careful with it.

[kea]

Has anyone had fitment issues?

LD19 on the rear of a 94/95 VD. It doesn't look like much, but the rotor hat bolts hit the caliper.

Thinking about increasing the chamfer on the caliper a bit.

LD20 on the front fit great.

The steel LD-19 calipers were often ground a small amount to clear such issues. Thus,do the same on those alloy ones.

[Rick Kirchner]

When I first got my 94 VD it had 20's front, 19's rear, and no hitting issues, but given the tolerances on these things it doesn't surprise me. Are your uprights sort-faced where the calipers bolt on? Easy for the supplier to miss that finishing step. Same with the ICPs. But when I went to Alcons the backing plates nicked the hat a bit on the rears and I now grind the plates down a bit. I had to do that on the 20's to get a smooth fit anyway.

Incidentally, the sharp edge left by the spot facing can generate a crack in the upright.

[Captain]

I ended up grinding them down. No big deal, given they are aluminum, just something I was nervous of doing to brand new parts.

Besides finding rubber in the brake fluid last year, this was certainly worth doing. I also discovered the caliper mounting threads on the upright had failed on one front and 1 rear....i don't want to think about what would happen if one of the bolts came out. Ended up having to put in some inserts.

Hoping to finish the install this weekend with fresh new lines! Its a brand new car!

[Rick Kirchner]

I've done multiple inserts as well. Also - you might have to put stacks of washers under the legs to center up the caliper.

I had to machine a flat on one lower leg. I bought an upright from VD when they went out of business and guess what - the toe-link pickup point was lower than the ones on my 94, and the aluminum caliper ears are thicker than the steel ones - so interference.

Guess they moved the points around year to year and between FF and FC and all the other specialty cars they made over the years. Who knows what the part was actually for. All the rest of the points were the same.