# suspension tuning books



## bluetree211 (Apr 19, 2004)

looking to upgrade the suspension in spring and I want to make well informed decisions both before and after the purchase. Any good books out there besides "tune to win"? I'm just looking for mid-level stuff, not engineering-degree-required reading

thanks


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## Pinecone (Apr 3, 2002)

BUNCHES. Do a search on Amazon. Everything except the ones published by SAE are mid-level suitable for actual people. The SAE ones are expensive, very in depth, but LOTS of great info.

I am not at home so I can't list he ones I have,but I have most of them.


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## ·clyde· (Dec 26, 2001)

Pinecone said:


> BUNCHES. Do a search on Amazon. Everything except the ones published by SAE are mid-level suitable for actual people. The SAE ones are expensive, very in depth, but LOTS of great info.
> 
> I am not at home so I can't list he ones I have,but I have most of them.


 Do you have SAE books in your library? Can I get a library card? :angel:


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## Pinecone (Apr 3, 2002)

NO, out of my price range and not enough time to read them (they are NOT quick reads).

I would love to add some. But a $100 book on tires is just a bit much.


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## ·clyde· (Dec 26, 2001)

Pinecone said:


> NO, out of my price range and not enough time to read them (they are NOT quick reads).
> 
> I would love to add some. But a $100 book on tires is just a bit much.


 Oh well. Learned one lesson today. Even if you think that your compression is set to something, don't believe it unless you check it...and maybe then have someone else confirm. It looks like I've run almost all season with the left front at full stiff and the right front at full soft.


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## bluetree211 (Apr 19, 2004)

Pinecone said:


> BUNCHES. Do a search on Amazon. Everything except the ones published by SAE are mid-level suitable for actual people. The SAE ones are expensive, very in depth, but LOTS of great info.
> 
> I am not at home so I can't list he ones I have,but I have most of them.


it seems like a lot of them were initially published in the 70's and 80's with minor updates in any recent editions, general complaints indicating that what applied back then doesn't always apply to current technology. Is there anything more recent? Im hoping to learn about the benefits of double vs single adjustable shocks, how to approach camber plates and control arms, pro/con comparisons of different mounts and bushings, tire size/pressure tuning, etc. I know its a lot of stuff that people on this board must know about, but Id like to read it in a book instead of getting bits and pieces of it from vague sources who may only use settings because of habit/word of mouth advice, "seat of the pants" comparisons, or "butt dyno" testing.


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## Mr Paddle.Shift (Dec 19, 2001)

bluetree211 said:


> Is there anything more recent?


Yes, most the publications are printed back in the 80s. Fact is "F=ma" hasn't changed for the last nearly 200 years. The spring-mass system is still the same all these years: ma=-kx + cv + F(ext).

If you want the most recent publications, SAE is the one place to look for. www.sae.org. I have been a long-time member and the abundance of information ifrom SAE is exhilarating. Having an engineering background will give you an edge to read some of the more technical articles, but at the end of the day suspension tuning boils down to simple geometric adjustments, kinematics and dynamics analysis. And it can't never leave out the infamous "F=ma".

Just for kicks, SAE has a 2-day class on racecar suspension setup, partnered with Panoz Racing School. Now that's something!


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## Nick325xiT 5spd (Dec 24, 2001)

Compression adjustment benefits (i.e. double adjustable shocks):
1) Customizable control of how the car reacts over bumps.
2) Street comfort as you can dial the shocks down for the street.

Camber plates:
There are two choices out there that seem to be worht anything: Ground Control and TC Kline. Take your pick. Now, if you're looking for how to set these, that's a matter of experiementation. I've ordered a MaxQData telemetry system and will be testing based on that.

Bushings and mounts, I can't over well enough, other than to say that spherical bearings can be awfully annoying on a street car.

Size and pressure tuning again is a lot of testing.


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## Mr Paddle.Shift (Dec 19, 2001)

Nick, 

Just to clarify something...doesn't double adjustability refers to compression AND rebound adjustability? Meaning that there are separate damping ratios for each compression and rebound.

Btw, MazQData looks like the way to go. I have been eyeing Race Technology's DL 1 unit. Ultra expensive though...


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## Nick325xiT 5spd (Dec 24, 2001)

Yes, but single adjustable shocks (in the context of Konis) are rebound only. PSS9s are irrelevant because they're a lousy option.


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## ·clyde· (Dec 26, 2001)

Mr Paddle.Shift said:


> Btw, MazQData looks like the way to go. I have been eyeing Race Technology's DL 1 unit. Ultra expensive though...


Compared to what else is out there, and what it's capable of, the DL1 doesn't seem terribly expensive at ~$900.

Edelbrock's QwikData (with road racer setup) is getting up there at well over $5k.


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## Pinecone (Apr 3, 2002)

bluetree211 said:


> it seems like a lot of them were initially published in the 70's and 80's with minor updates in any recent editions, general complaints indicating that what applied back then doesn't always apply to current technology. Is there anything more recent? Im hoping to learn about the benefits of double vs single adjustable shocks, how to approach camber plates and control arms, pro/con comparisons of different mounts and bushings, tire size/pressure tuning, etc. I know its a lot of stuff that people on this board must know about, but Id like to read it in a book instead of getting bits and pieces of it from vague sources who may only use settings because of habit/word of mouth advice, "seat of the pants" comparisons, or "butt dyno" testing.


As has been said, the basics are the same. Specifics are too car dependant to have books about them.

DA versus SA, more adjustable parameters, triple even more so. It can also mean you can get LOST in teh settings and chase your tail around and around trying to get back to where you started.

Camber plates and controls arms - camber plates allow adjustment of stativc camber, see above. Control arms do get into som eintereresting things (if your competition class allows changes) but that all comes back to camber gain and roll center, which hasn't changed in a long time.

Different mounts and bushings, the stiffist you can stand or are legal are the best for best ahndling. But for a street driven car, the trade off is comfort. Basics haven't changed, what is available for YOUR car is again a very narrow subject.

Tires and tire pressures, test, test, and after that, test some more. Read the threads here, tire pressure is an art and science. A lot is in reading your tires. But the basics of what does what when you change it hasn't changed in a long time.

Now there are always new wrinkles, that may or may not work in a particular situation. Take the racers, running no rear bar with a very stiff front bar. Common logic says that creates a lot of understeer, but in certain cars no understeer and better power absorbtion on corner exit. Again very car specific, and based on race cars runningVERY stiff springs in general.

Bottom line, you have to get a grounding in teh fundamentals before you can get out of the box (have to know what and where the box is). And those "old" texts are where you find that.


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## Mr Paddle.Shift (Dec 19, 2001)

Nick325xiT 5spd said:


> Yes, but single adjustable shocks (in the context of Konis) are rebound only. PSS9s are irrelevant because they're a lousy option.


So does KW V2. Single ad with rebound only.

Some strong statement there about PSS9, Nick. :eeps: I don't suppose you have a similar comment about supercharged BMWs? Whatever turns you on. Yes they have prog springs. Yes, they adjust only one damping ratio as opposed to two. No, it's not race worthy. Still, they got me erected on the tracks. No complains.


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## Mr Paddle.Shift (Dec 19, 2001)

·clyde· said:


> Compared to what else is out there, and what it's capable of, the DL1 doesn't seem terribly expensive at ~$900.
> 
> Edelbrock's QwikData (with road racer setup) is getting up there at well over $5k.


I am aware of the more expensive setup. Just that I would love try out a DL 1 or at least see one in action before putting some money down. Actually, I am applying for a distributorship. We will see what happens.


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## Pinecone (Apr 3, 2002)

Mr Paddle.Shift said:


> So does KW V2. Single ad with rebound only.
> 
> Some strong statement there about PSS9, Nick. :eeps: I don't suppose you have a similar comment about supercharged BMWs? Whatever turns you on. Yes they have prog springs. Yes, they adjust only one damping ratio as opposed to two. No, it's not race worthy. Still, they got me erected on the tracks. No complains.


Actually PSS(s adjust both rebound and compression, but they are adjusted togther. Versus typical DA shocks where each can be adjusted separately.

The springs on the PSS9s are too soft for the car. Both Ground Control (Eibach) and Turner (H&R) do conversions to replace the springs with better ones. But to spend more for them than a basic coil over setup from either vendor, then spend even more to put decent springs on them is kind of nuts.


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## Nick325xiT 5spd (Dec 24, 2001)

Mr Paddle.Shift said:


> So does KW V2. Single ad with rebound only.
> 
> Some strong statement there about PSS9, Nick. :eeps: I don't suppose you have a similar comment about supercharged BMWs? Whatever turns you on. Yes they have prog springs. Yes, they adjust only one damping ratio as opposed to two. No, it's not race worthy. Still, they got me erected on the tracks. No complains.


No, I don't have any prblem with an FI Bimmer. I've been giving serious thought to building one as a track car.

I dislike the PSS9s because of the following reasons:

1) Tire clearance.
2) No separate adjustment. This is stupid. They adjust BOTH compression AND rebound at the same time. That's worse than rebound only.
3) Excessive cost for crappy components.
4) Wimpy springs.

Any questions?


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## Mr Paddle.Shift (Dec 19, 2001)

Pinecone said:


> Actually PSS(s adjust both rebound and compression, but they are adjusted togther. Versus typical DA shocks where each can be adjusted separately.


I know. Want the accompany equation for that? This shows a DA setup. For PSS9, C_comp is C_reb and d cancels out. This of course is the most basic linear system. One can take into account the spring/damp characteristics of the wheel + tire. That should make this a two mass/two spring/two dampers system.


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## Mr Paddle.Shift (Dec 19, 2001)

I follow and respect the opinions, fellas. It's been a long time since I write the word "stupid" and now I understand how much a word like that hurts. I'd like to hear a scientific explanation as to why adjusting one damping ratio is undesirable. No, calling it "stupid" doesn't count. 

I track about 5 weekends a year. The car is still a daily driver to get to work, buy grocery and stuff like that. Having progressive springs is justifiable. Like I said, it's not race worthy but good for the majority of us who has this as a daily driver. Not that I doubt Turner's or GC's tuning capability. Suspension tuning is a black art. Everyone knows that. Choosing the right spring and damping rates also depends on the equipment weight distribution, tires, wheel rotational inertia, control/trailing arm material dynamics and the list goes on. I picked PSS9 based on reviews from folks who have tracked in them, similar pricing to GC + lack of customer service from GC which really annoyed me, tested and proven to work with Alpina's very conservative wheels without need for spacers. 

Bottomline is no single suspension package sold over the phone/internet/counter is a near perfect setup for any car. But different drivers prefer different packages for different driving environments and different bizarre reasons. One ought to respect that. Who knows I might upgrade in the next coming year. For now, PSS9 will do just fine.


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## bluetree211 (Apr 19, 2004)

I didn't mean to open the can of worms, but I guess putting a thread titled "suspension" in the motorsport forum will do that. As far as books go (my initial question) I'm gonna finish Tune to win and then maybe try the "speed secrets" series. For specific suspension questions, I'll field those with GC/Turner/TCKline people over the phone, they should know what they're doing because they sell this stuff. Hopefully they will point me in the smart direction and not the expensive one. I really just want to make my car handle better, for mostly autocross but increasing track usage as well.


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## ·clyde· (Dec 26, 2001)

Mr Paddle.Shift said:


> I'd like to hear a scientific explanation as to why adjusting one damping ratio is undesirable. No, calling it "stupid" doesn't count.


If you need a scientific explanation, I can't really help you out there. The simple layman's explanation is that rebound and bump control two different things. In a practical application, bump controls the upward movement of unsprung weight while rebound is used to control the car's rate of roll (and to a lesser extent when you're prevented from changing springs, pitch). Said another way, bump helps the car deal with the surface and rebound helps the car deal with the driver.

Imagine a course with a couple of severe mid-turn bumpy sections. You may be best off by setting the compression to a very soft setting. Now imagine the same course after the track is resurfaced. You can now run much higher compression settings without the car skating around over the bumps. Bumpy or smooth, though, you may want to use the same rebound settings. Even if you want to change them, it's unlikely that you would want to change them to the same extent as the compression settings.


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## BMWRacerITS (Mar 17, 2004)

·clyde· said:


> If you need a scientific explanation, I can't really help you out there. The simple layman's explanation is that rebound and bump control two different things. In a practical application, bump controls the upward movement of unsprung weight while rebound is used to control the car's rate of roll (and to a lesser extent when you're prevented from changing springs, pitch).


EDIT: Oops...I read your post wrong, see posts below.

As for the original question, for a VERY technical suspension tuning book, you can try Milliken and Milliken, "Race Car Vehicle Dynamics". :thumbup: It's very deep but well worth a read once you get past the "easy" stuff.


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## Pinecone (Apr 3, 2002)

BMWRacerITS said:


> I believe you have those two sorta mixed up. Bump controls the compression of the spring, rebound controls the extension of the spring. More advanced dampers not only control both, but often control high and low speed bump. I'm not so sure how rebound could control the rate of roll.
> 
> For a VERY technical suspension tuning book, you can try Milliken and Milliken, "Race Car Vehicle Dynamics". :thumbup:


Upward movement of the UNSPRING weight is compression of the spring. 

I never said it was stupid, that was someone else.  My probelm with them is that they cost more money, but have several compromises in adjustability and springs. More moeny for something that doesn't work as well. :dunno:

MANY people run GC coil over systems on the street with a compromise spring that does a better job than the PSS9 springs, street and track. Several people who have PSS9 systems to do a bit or tracking find that hte combination is undersprung and over damped for the springs. Neither of these is a good thing.

The separate adjustment of the compression na rebound effects different parts of the handling. Of the two, reboun is more important (re: single adjustable shocks), but for the best ability to tune requires the ability to adjust separately.

As for suspension tuing being a black art, only to those who don't test.


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## BMWRacerITS (Mar 17, 2004)

Pinecone said:


> Upward movement of the UNSPRING weight is compression of the spring.


Nevermind...totally read that wrong.


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## BMWRacerITS (Mar 17, 2004)

Pinecone said:


> As for suspension tuing being a black art, only to those who don't test.


Exactly. In fact, at this point you can even get quite close without testing. Using computer programs you can choose spring rates and then get damper valving fairly close before ever setting foot on the track.

Of course, under "stock" type rules, suspension tuning can be a bit more of a black art due to some of the extreme measures one must take to go fast due to the rules (i.e. extreme rebound valving that purposefully jacks the car down onto the bump stops for an stiffer spring rate).


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## Pinecone (Apr 3, 2002)

Yeah, rules can really mess things up. 

Andyes, the top teams are using simulations of tracks to get very close to suspension settings and gear ratios. And the differences from simulation and rel life probably have to do more with track surface roughness changes than anything else.


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## moks1983 (Nov 5, 2004)

*- Omg -*

I Think I Need To Find A New Task
N Maybe Create A New Book
Hehehehe................. Hmmmmm Self Publishing Will Be A Good Start....


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