zero index birdcage

[brett4]

what is the benefit of running zero index birdcage plates?

[RaceEngineer]

what is the benefit of running zero index birdcage plates?As you index, the suspension gets stiffer and stiffer until it is almost locked up. Remember when guys used to hit a hole on the straight and bounce 3 times? Fast cars don't do that now. Second reason, what goes up must come down. When it unindexes, the shock mount is moving away from the load as the car settles down on entry. The shock and spring is not holding the car up, as their job requires.

[DJ16]

Race engineer,
Would mind sharing your thoughts on best amount of indexing if any on the right rear of most cars? I'm liking no indexing on LR. Do we need to index into or out of RR ? Or go with none and work with springs?
Thanks

[grt74]

Race engineer,
Would mind sharing your thoughts on best amount of indexing if any on the right rear of most cars? I'm liking no indexing on LR. Do we need to index into or out of RR ? Or go with none and work with springs?
Thanks

if you don't want indexing, just bolt the bottom of the shock to the top of the tube, lr, i could see that working, rr you'll get beat by some sharp people, unless you carry several rr shock/spring setups

[Jking24]

I think people get a little too caught up in this "how we race now vs. The old school way. The bars still work just the same as they always did and the objective is still the same. Every thing is a give and take situation it may be good for one reason but bad in another way. If your not changing bar position then the index ratio is constant so no consistency loss or question marks marks their. It's also something that can easily be measured so it's not a "un known". The principal of smashing springs is not to eliminate all the geometry in the car but to be able to tune on it in a dynamic state where it is used most. Sorry i just don't understand alot of the ideology that comes up with "we don't race that way anymore" mindset

[RaceEngineer]

I think people get a little too caught up in this "how we race now vs. The old school way. The bars still work just the same as they always did and the objective is still the same. Every thing is a give and take situation it may be good for one reason but bad in another way. If your not changing bar position then the index ratio is constant so no consistency loss or question marks marks their. It's also something that can easily be measured so it's not a "un known". The principal of smashing springs is not to eliminate all the geometry in the car but to be able to tune on it in a dynamic state where it is used most. Sorry i just don't understand alot of the ideology that comes up with "we don't race that way anymore" mindset

The bars still work the same. We just know better than to put the LR top bar down to 3.5" from axle centerline now. A birdcage anywhere near cam over is a killer of speed. We also understand that unhike on corner entry kills corner speed. We now know that corner speed beats drag racing as well. 20 years ago, no one thought those things.

[RaceEngineer]

Race engineer,
Would mind sharing your thoughts on best amount of indexing if any on the right rear of most cars? I'm liking no indexing on LR. Do we need to index into or out of RR ? Or go with none and work with springs?
Thanks

I don't know that there is a best amount. You just need to get the dynamic load curve that works for you.

[Jking24]

The bars still work the same. We just know better than to put the LR top bar down to 3.5" from axle centerline now. A birdcage anywhere near cam over is a killer of speed. We also understand that unhike on corner entry kills corner speed. We now know that corner speed beats drag racing as well. 20 years ago, no one thought those things.i agree completely. This one just struck a nerve because while helping someone over the weekend with an older car. A bar change was suggested and the reply was not that he thought it didn't work that way but that it wouldn't have the desired effect because we don't race that way now so it wouldn't have the same effect.

[cjsracing]

i agree completely. This one just struck a nerve because while helping someone over the weekend with an older car. A bar change was suggested and the reply was not that he thought it didn't work that way but that it wouldn't have the desired effect because we don't race that way now so it wouldn't have the same effect.

My go to adjustment in 2014 and 2015 for a slick track feature was to crank turns into the LR and get a high bite number. That car was so good in the slick.

If I try that now the car doesn't turn and I'd get lapped twice in a 25 lap feature.

[King1]

My go to adjustment in 2014 and 2015 for a slick track feature was to crank turns into the LR and get a high bite number. That car was so good in the slick.

If I try that now the car doesn't turn and I'd get lapped twice in a 25 lap feature.

Yea I used to be the same way. Now days all I mess with is LF droop, LR droop, packers, rear end lead, and spring rubbers. A lot less work that's for sure.

[Kromulous]

I guess it cant hurt to ask, but would you comment on your LF and LR Droop changes? What impact etc.

[Jking24]

I think a lot of you missed the point .I was referring specifically to a bar angle change. It still does the same thing that it always did. Some changes have less or minimal effect because of the fact that we maintain attitude better now and there is less movement in certain Corners than there used to be

[Jking24]

My main point was I see a lot of people outsmarting themselves chasing load numbers Etc the mechanics of the racecar haven't changed fundamentals of it are the same we just go about achieving what we need a different way now if you understand a lot of this stuff you can look back at your old setups and kind of start to understand why you had to do certain things because of what we know now and how those changes affected other corners

[RaceEngineer]

My main point was I see a lot of people outsmarting themselves chasing load numbers Etc the mechanics of the racecar haven't changed fundamentals of it are the same we just go about achieving what we need a different way now if you understand a lot of this stuff you can look back at your old setups and kind of start to understand why you had to do certain things because of what we know now and how those changes affected other corners

I agree with that 100%

[fastford]

i agree also jking , one thing i guess you could say theses " new " set ups has done is cause you to change or redesign the chassis , especially the front end.......

[King1]

My main point was I see a lot of people outsmarting themselves chasing load numbers Etc the mechanics of the racecar haven't changed fundamentals of it are the same we just go about achieving what we need a different way now if you understand a lot of this stuff you can look back at your old setups and kind of start to understand why you had to do certain things because of what we know now and how those changes affected other corners

I hear what you're saying. I think we're all smarter than we used to be and take a piece to the track that is a little more dialed in than it used to be.

I drop the LF out a little more if I need the RR to do a little more work in the center

And i take LR droop out just to control roll steer a little better.

I hadn't tried it til the guy I get info from tested with me once. I went from cranking wedge in a car and rolling the tool box out, to making small adjustments and not working near as hard. But that's why I source my info because I'm simply not smart enough nor do I have the time or resources to test or make educated guesses.

[Kromulous]

Thanks King1, i was thinking along the same lines with LF and LR, but i always like to check my thoughts about what affects what.

Anyway, i agree with the small adjustments. I am in the process of learning spring rubbers etc, and after sitting with my spring smasher and adding in and taking out rubbers and packers you can make some big changes, and with minimal work. After this last couple weeks where i dialed the car completely out, i am going to change my approach, to small adjustments etc.

[Nesmith14b]

@RaceEngineer. Why do you suppose a nearly cammed over birdcage kills speed? On the LR, the solution might be to raise the lower bar on the frame, or lengthen the lower, or index the birdcage back at ride height, to decrease upper bar angle at full droop. But what do those changes accomplish?

[RaceEngineer]

@RaceEngineer. Why do you suppose a nearly cammed over birdcage kills speed? On the LR, the solution might be to raise the lower bar on the frame, or lengthen the lower, or index the birdcage back at ride height, to decrease upper bar angle at full droop. But what do those changes accomplish?

The system has little to no compliance. The spring cannot function. The shock cannot function. That is bad for maintaining traction over bumps. You can rock the cage back to compensate.

[Nesmith14b]

Thanks. Now you have me thinking... :)

[brett4]

what would your guys opinion be on just moving the left rear lower bar forward on zero index plate and leaving the top bar alone??? so on the birdcage with the car on the ground to top bar would be at 12 o'clock and the bottom would be at 7 o'clock.

[Kromulous]

I believe it would almost index away from the spring, the further it traveled down, it would be a small amount, maybe even zero indexing. If the bars are perfectly parallel, i think it would index away from the spring.

[brett4]

I agree just wondering all your opinions..

[ukydude]

It would not index away from the spring. Moving the bottom rod forward and keeping it the same distance from axle centerline will not change indexing all that much but it will change how much load that bar carries and how the car lifts and falls.

[Kromulous]

Ok, more or less loading? and how so on the lifting and falling?

Interested in this, something i have never done before.

[billetbirdcage]

Ok, more or less loading? and how so on the lifting and falling?

Interested in this, something i have never done before.

Too lazy to figure out just moving the lower bar only but this will give you an idea:

if you take a std cage set up with 25* LRU and 9* LRL and let it travel till the upper bar reaches 45.7* and compare that to the bars moved 1" each forward/backwards the difference isn't much (granted drawn in CAD and only looking at the LR cage movement not the whole rear end movement which will be exaggerated at the LR wheel):

Both set to 45.7* of LRU bar angle at drop

STD: 4.89" of drop at cage
2.587" of Steer
12.384 degrees of index

Bars moved 1 back and 1 forward: 4.999" of drop
2.646 of steer
11.356 degrees of index

Difference of .060 drop and .100 steer.

[powerslide]

what would your guys opinion be on just moving the left rear lower bar forward on zero index plate and leaving the top bar alone??? so on the birdcage with the car on the ground to top bar would be at 12 o'clock and the bottom would be at 7 o'clock.

Could you create similar effect by indexing the birdcage back instead of forward?

[ukydude]

If you want to alter indexing you need to work on your combination of upper and lower bar angles/lengths. Placement on the birdcage has more to do with load and timing. Moving the top back and bottom forward have different effects and both have advantages and disadvantages. I can tell you exactly how and why but I would suggest just trying out different configurations. Something that looks great on paper might be excellent for driver A but terrible for driver B. And yes you can index the cage back and that will have a similar effect of moving top back and bottom forward but now you have altered the shock mount location and the spring's input/resistance will also be altered.

[Kromulous]

More steer, and less indexing, might be worthwhile. I have run the top bar back 1" but not the bottom bar.

[7uptruckracer]

So I see these “zero Index” cages they almost look like the old school where we had a few series of holes. Is that how to zero index? Which some say here is good or bad or run longer upper bars and shorter lowers if we have the corresponding holes on the 4 link brackets? I’m trying to do this on a mod ALSO SECONDLY is it true if you run the zero index being CAM over isn’t a problem you have guys running much steeper angle in the LRU?

[billetbirdcage]

No idea who came up with the name but it's a horrible name. They still index, but just can't over center nowhere near as easy unless you change bar angles/lengthen chain.

Again the name is misleading, the cage still indexes. Should be called "no over center cage"

[7uptruckracer]

Just birdcage plates with another row of holes? Or are we just running longer bars and a different series of bracket holes? I’ve seen the plates with top holes behind center and bottom holes ahead of center.


No idea who came up with the name but it's a horrible name. They still index, but just can't over center nowhere near as easy unless you change bar angles/lengthen chain.

Again the name is misleading, the cage still indexes. Should be called "no over center cage"

[billetbirdcage]

Yes, top bar back on cage and bottom bar forward on cage. Then you either have to move bars on frame the same amount or change lengths if you don't have holes there. Typically you will move on frame and not change bar lengths but you can and people do but your changing a lot more doing that. The bar length change is typically done because guys don't have replaceable 4 link brackets or holes to allow the bar to just be moved.

[Punisher88]

If you did have to lengthen the bar in the top, I would assume moving it closer to center of the axle would help negate the effects of the longer bar..

[ukydude]

No idea who came up with the name but it's a horrible name. They still index, but just can't over center nowhere near as easy unless you change bar angles/lengthen chain.

Again the name is misleading, the cage still indexes. Should be called "no over center cage"

Exactly!!!!!

[sam73]

My car has a 20in ride height# and 23 3/8 droop# on the LR. What if without any loss of droop height, you could keep the spring at the 20in RH and at full droop spring centers would be 21in? It was mentioned what goes up must come down. Kinda wonder about the going down part.

[MasterSbilt_Racer]

My car has a 20in ride height# and 23 3/8 droop# on the LR. What if without any loss of droop height, you could keep the spring at the 20in RH and at full droop spring centers would be 21in? It was mentioned what goes up must come down. Kinda wonder about the going down part.

Not possible and be within the rules. Air shocks are popular because what you are asking can't be done.

[PayinDaPurse]

I’m a little Confused when guys are running this “zero index”? Is this the new normal setup or is there a track condition that would make you go to “zero index”.

I don’t have this option on my cages, should I update them to the brackets that allow the “zero index”?

Thanks

[Jking24]

Dont get to caught up in it. With the added droop and the increased rf travel the lr suspension is in danger if flipping the birdcage or over centering. When you get near this condition the lr suspension goes ridged ie. No shock and spring. When you have no shock and spring in play you have no control over what's happening on that corner (bad). Yes you need to look closely at your lr bar angles in full droop. No you don't necessarily need some magic bird cage

[MasterSbilt_Racer]

There is speed to be had by getting your spoiler in the air. There is speed to be had not rotating your cage too far. Take those 2 facts and sharpen your pencil.

[Krooser]

So what birdcages are the ones to have to get a good start on the season? Right now I have an ancient pair of steel cages from the mid 90's for my '03 MB. I have the Mastersbilt 2019 raised front x-member, raised right frame rail and new four bar brackets.

https://www.flickr.com/photos/151953470@N05/49611840642/in/dateposted-public/

https://www.flickr.com/photos/151953470@N05/49612858551/in/dateposted-public/

https://www.flickr.com/photos/151953470@N05/49612858111/in/dateposted-public/

[Jking24]

So what birdcages are the ones to have to get a good start on the season? Right now I have an ancient pair of steel cages from the mid 90's for my '03 MB. I have the Mastersbilt 2019 raised front x-member, raised right frame rail and new four bar brackets.https://www.flickr.com/photos/151953470@N05/49611840642/in/dateposted-public/https://www.flickr.com/photos/151953470@N05/49612858551/in/dateposted-public/https://www.flickr.com/photos/151953470@N05/49612858111/in/dateposted-public/ I don't know what is the current go to cage for masterbilts but most stuff doesn't need a whole new cage usually their is a different plate available at least on the single shear stuff. I think the most important thing in your scenario is to get something that has bearings in it and not teflon

[Krooser]

Mine do not have bearings and I've been told that may not be a bad thing.

I could fab a bolt or weld on piece to create my own zero index cage...

[Jking24]

Mine do not have bearings and I've been told that may not be a bad thing.I could fab a bolt or weld on piece to create my own zero index cage...I don't have any real information(testing) to prove otherwise. Seems to me when we had lined cages with grease they worked well as long as they were kept clean witch in my experience was allot more of a pia then spinning them every week or two.

[fastford]

the first bearing cages that cam out did not have as good of bearings as is available now , the newer bearings are sealed better and require less maintaince , we have some older cages were running on a car now with newer bearings that work just fine , krooser , i know your a budget racer like me so you might find some older one,s at a bargain and upgrade the bearings , i have a pt number some where for a very good bearing that could be purchased threw motion industries , if i can find it , i will send you a pm.....one other thing i have herd of , but dont know for sure , but you may can have your teflon cages bored out to use a bearing , if the cage tube is thick enough...

[Jking24]

the first bearing cages that cam out did not have as good of bearings as is available now , the newer bearings are sealed better and require less maintaince , we have some older cages were running on a car now with newer bearings that work just fine , krooser , i know your a budget racer like me so you might find some older one,s at a bargain and upgrade the bearings , i have a pt number some where for a very good bearing that could be purchased threw motion industries , if i can find it , i will send you a pm.....one other thing i have herd of , but dont know for sure , but you may can have your teflon cages bored out to use a bearing , if the cage tube is thick enough...I would also be interested in that part number

[fastford]

i will be back at shop monday and will try and dig it up....