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sorkyah

Suspension for NEWBS

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sorkyah
I am an automotive technician. I know about cars, specifically Chrysler. Suspension however is a dept in which I'm lacking knowledge. I know that suspension increases ride comfort, I know that alignment angles can wreak havoc on a vehicle's drive-train if left unchecked, BUT I don't know the performance side. Performance auto, and Motorcycle suspension, measurements, terminology, and adjustment are foreign to me, and quite possible foreign to the new riders out there as well. 
 
I've seen a few videos but nothing really goes into detail regarding what each measurement/item does what compounds on what, how adjusting one will adjust the other.
 
For the fork cartridges @pattonme installed, I used a video on YouTube that described what I should be feeling and what I shouldn't, when setting them up. It didn't describe what forces were acting or reacting, why turning an adjuster 1/4turn helped.
 
Matt, @gregjet
You guys know your stuff, care to help out a NEWB?
There's more out there, I just don't know who you are.(sorry in advance, hopefully you'll get dragged in here to sound off too)
 
I want to learn about Moto-suspension and how/why it works, what makes it tick as it were.
any help you guys can give... I'd greatly appreciate  and I'm sure the other new riders out there will too
 
 

sorry for being long winded in this

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ATGATT... ATTATT, two acronyms I live by.
 

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JanM
I would recommend doing some reading or further youtube-watching; eg. the Suspension for Mortals videos by Traxxion Dynamics are available from their youtube channel - see them sequentially...
 

 
I also recommend reading the Suspension Bible by Racetech for more technical info on how parts work.
 
This should provide a good solid base understanding - the info in above is to an extent opinionated, but not necessarily wrong - there are however several different solution and choices available.
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sorkyah
I would recommend doing some reading or further youtube-watching; eg. the Suspension for Mortals videos by Traxxion Dynamics are available from their youtube channel - see them sequentially... 
 
I also recommend reading the Suspension Bible by Racetech for more technical info on how parts work.
 
This should provide a good solid base understanding - the info in above is to an extent opinionated, but not necessarily wrong - there are however several different solution and choices available.
my google-fu is horrible... i didnt see this one during my searches
thnx dude
 

ATGATT... ATTATT, two acronyms I live by.
 

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pattonme
I'm not lazy, honest! But the Motorcycle Suspension Bible is a very easy read and a good primer. Though it's a little vague on specifics.
 
I guess what I'll do is reference the "what's wrong with the FZ09" thread I've got going separately with the damping curves to get into some more practical application thereof.
 

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gregjet
The biggie here is feel as much as raw tech data. Two similiar riders may want a totally different feel to feel confident ( and sometimes wrongly but that is another story). Some things are relatively immutable and suspension goes in concert with frame geometry JUST FOR A START. Motorcycle ( and similiarly bicycle) geometry/handling is substantially different from 4 wheel as what you are trying to achieve, and what you are trying to control, are not really the same. So first forget pretty much what you know about 4 wheel and start from scratch. Some of it will reconverge and those bits will be easier to assimilate. It's not a "dark art" but it IS complex( in the proper meaning of the word) and very technical and requires real understanding of each concept and how it relates to other concepts. Don't skim it. Having said all that it is still very much an evolving area much behind automotive engineering still at present.
Basically listen to Pattonme and a few others here. And follow motoGP tech stuff. They talk about stuff that helps get your head around a lot of things.
We are all still learning , as I am sure even Pattonme will reinforce.
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Go forth and modify my son...go forth and modify...

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Mr.Puss
My complete and utter lack of knowledge/experience in MC suspension 'know how' is what is preventing me from purchasing a new setup. I wouldnt know decent suspension if it slapped me in the face, nor would I know how to set it, or if its even set to a safe or proper configuration. Calling me a 'Newb' is being generous.
 
Basically....hats off to @sorkyah for getting this post rolling, and also to those who have pointed me in the right direction to help me learn a thing or two. I have a lot of research to do.
 
 
 

Crush your enemies. See them driven before you. Hear the lamentations of their women.

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pattonme
it wasn't a slight, @frabus . We just missed it. Welcome and hopefully you'll enjoy the conversation.
 
@mrpuss , if the suspension is hitting you in the face, you either "landed" a triple wrong, or you're doing something very unconventional with your suspension parts. ;)
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sorkyah
 
 

The biggie here is feel as much as raw tech data. Two similiar riders may want a totally different feel to feel confident ( and sometimes wrongly but that is another story). Some things are relatively immutable and suspension goes in concert with frame geometry JUST FOR A START. Motorcycle ( and similiarly bicycle) geometry/handling is substantially different from 4 wheel as what you are trying to achieve, and what you are trying to control, are not really the same. So first forget pretty much what you know about 4 wheel and start from scratch. Some of it will reconverge and those bits will be easier to assimilate. It's not a "dark art" but it IS complex( in the proper meaning of the word) and very technical and requires real understanding of each concept and how it relates to other concepts. Don't skim it. Having said all that it is still very much an evolving area much behind automotive engineering still at present. Basically listen to Pattonme and a few others here. And follow motoGP tech stuff. They talk about stuff that helps get your head around a lot of things.
We are all still learning , as I am sure even Pattonme will reinforce.
 
i watched through the first 6 of the traxxion videos linked above while between classes today
 
Alot of what he says make sense as i can relate it to a 4wheel setup
it seems caster(rake/trail relation) is critical... as is sag, and low speed rebound adjustment(?compression)
 

I posted about this topic a while back but didnt get much interest.  
http://fz07.org/thread/3836/suspension-noobs
Sorry dude... i looked and saw a bunch of pattonme's threads... didnt see yours

ATGATT... ATTATT, two acronyms I live by.
 

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tanner68
Total Control by Lee Parks covers suspension more thoroughly than the other books in the category (Twist of the Wrist/Code, Sport Riding Technique /Ienatsch, Hough's books.) And he recommends that suspension book mentioned above. 
 
 
 
 

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norwest
My recommendation when receiving any suspension component and after installing it is go ride it, Do NOT touch the screws or dials as there is a reason it is set the way it is from the company or suspension tuner. More often then not what happens is the rider whom is happy to have adjustability will go crazy with the screwdriver and never pay attention to what the baseline was set at.
 
Also after taking that initial ride and if you want to know what should or should not be happening with the suspension contact your suspension tuner and ask questions, They should be able to explain what they did and listen to your concerns and give you a direction to go to change it for you and your riding style.
 
A very good article on motorcycle suspension tuning is located Here
 
Terry
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pattonme
I ship forks with the comp all the way open (3 turns) and rebound at ~1.5 turns out. While I agree with NorWest where it relates to shocks, forks can and should be adjusted 'some' when mounted.
 
1) adjust preload to get proper sag - don't even leave the garage without this being done.
2) adjust fork rebound so it's as fast as possible without more than 1 hop
3) confirm shock rebound ~matches front in speed. If it's sloooow then take up to a turn off but probably should call your shock guy and definitely check to see that you don't have any binding in the linkage
4) bounce as hard as you can on the bike and (a spotter helps) confirm everything moves reasonably easily
5) find notebook and pen and document ALL settings as clicks/turns from CW *lightly* seated
6) test ride
 
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pattonme
So here's some fork damping curves for the FZ09. Since all damping is done by just one leg, I doubled up the GSXR and Forks-by-Matt curves.
 
The thin+thick line pairs show the base valve's contribution to compression damping and then when you add the restrictive orifice mid-valve. On the Matris thread I had a similar looking graph where I showed how the mid-valve basically took things vertical.
 
The FJ09 base valve isn't that bad if they had simply changed out the mid-valve piston for any of the non-restrictive models in the KYB catalog.
 
fz09%20vs%20fj09%20-%20force.gif
 
The ~50in/sec range is what people attribute to "feel" or "stability under braking". There's a sharp point in the Forks-by-Matt curve (RaceTech's likewise) because my shim stack is preloaded.
 
I drew the orange dashed line to show that Yamaha added ~25% more damping to the base valve between the FZ and FJ.
 
For reference, a 1" bump hit at 70mph is 250in/sec of shaft rate.
street-17f.png
 
 
Below we see the difference the needle can make between wide open (U.wo) and fully closed (U.clsd) for rebound. Someone on the FZ09 board posted that his tuner had remarked there was f-all adjustment on the FZ09's rebound needle. And indeed we can see that is definitely the case. 
 
fz09%20vs%20fj09%20-%20rebound%20force.gif
 
Unlike the Comp graph, the FbM and GSXR lines aren't doubled. I ran the "single-leg doing all rebound" simulation using FbM as the "perfect" curve and that's represented as 'Double Spring'.
 
We see that the FZ09 when fully closed barely handles what the GSXR does at typical openings (not graphed), despite needing to handle twice as much spring. Colossal screw up by Yamaha/KYB.
 
Conversely the FJ09 brackets the 'Double' so needle adjustments will achieve the desired behavior. I graphed the Andreani kit's range.
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norwest
I ship forks with the comp all the way open (3 turns) and rebound at ~1.5 turns out. While I agree with NorWest where it relates to shocks, forks can and should be adjusted 'some' when mounted. 
1) adjust preload to get proper sag - don't even leave the garage without this being done.
2) adjust fork rebound so it's as fast as possible without more than 1 hop
3) confirm shock rebound ~matches front in speed. If it's sloooow then take up to a turn off but probably should call your shock guy and definitely check to see that you don't have any binding in the linkage
4) bounce as hard as you can on the bike and (a spotter helps) confirm everything moves reasonably easily
5) find notebook and pen and document ALL settings as clicks/turns from CW *lightly* seated
6) test ride

I guess we differ in opinions on this one then. 
1) The suspension tech doing the job should know what spring rate and what preload for a given rider weight, back in my Race Tech days we would setup the suspensions in the shop and we would check after for the correct sag and we were normally within 2mm of being where we wanted to be. Not that I have anything against the rider checking but I can't tell you how many hours I had spent on the phone explaining to customers how to check sag. I have heard all sorts of crazy numbers.
 
2) When setting rebound for the street I set it to go past static sag by 8mm and then settle at static sag much as shown in the image below highlighted by the red circle. For track use it should settle at static sag and not go the 8mm past static. In the image below you can see what the pogo effect looks like as it is starting to bounce although very slightly.
 
rebound.jpg
 
3) I agree a balanced bike is very important and may be just as important if not more so then having the damping spot on. During bike night setups while working at Race Tech we were not offered the luxury of revalving in the parking lots so we would deal with what we had. Even if the front was stiff and the rear soft we would match the two whether it be too soft or stiff and the rider would be amazed at the difference.
 
4) Also check to make sure that the bike is compressing and rebound evenly as that will create a balanced bike.
 
5) There is no harm in doing this but the suspension tuner should be supplying a setup sheet so you know where the baselines are at in case you get happy with the screwdriver and forget where you started.
 
6) The bike is going to feel different so don't just hop on and try and play Rossi, Take your time and get the feel of the bike and increase speed and corner speed incrementally until you know what the bike is going to do and how it goes into a corner.
 
As long as the suspension tech did their job properly you should have a bike with good feedback and handling without feeling harsh on rough roads.  
 

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Holderosa
I would recommend doing some reading or further youtube-watching; eg. the Suspension for Mortals videos by Traxxion Dynamics are available from their youtube channel - see them sequentially...
This is precisely what I needed to begin my understanding of the bike's suspension, fantastic post, thank you! 

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frabus
 

The biggie here is feel as much as raw tech data. Two similiar riders may want a totally different feel to feel confident ( and sometimes wrongly but that is another story). Some things are relatively immutable and suspension goes in concert with frame geometry JUST FOR A START. Motorcycle ( and similiarly bicycle) geometry/handling is substantially different from 4 wheel as what you are trying to achieve, and what you are trying to control, are not really the same. So first forget pretty much what you know about 4 wheel and start from scratch. Some of it will reconverge and those bits will be easier to assimilate. It's not a "dark art" but it IS complex( in the proper meaning of the word) and very technical and requires real understanding of each concept and how it relates to other concepts. Don't skim it. Having said all that it is still very much an evolving area much behind automotive engineering still at present. Basically listen to Pattonme and a few others here. And follow motoGP tech stuff. They talk about stuff that helps get your head around a lot of things.
We are all still learning , as I am sure even Pattonme will reinforce.
i watched through the first 6 of the traxxion videos linked above while between classes today 
Alot of what he says make sense as i can relate it to a 4wheel setup
it seems caster(rake/trail relation) is critical... as is sag, and low speed rebound adjustment(?compression)
 

I posted about this topic a while back but didnt get much interest.  
http://fz07.org/thread/3836/suspension-noobs
Sorry dude... i looked and saw a bunch of pattonme's threads... didnt see yours
 
 
No worries, Im glad the info is getting out there.
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gregjet
" watched through the first 6 of the traxxion videos linked above while between classes today"
Watch all of them. There are some gems all the way along.
 
 

Go forth and modify my son...go forth and modify...

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JanM
The great thing about the Traxxion videos is that Max McAllister shows how the bike moves and that they cover a lot of good things. For a more precise and thorough explanation on the tech stuff, please read the books. One word of caution - the videos were made a little over 10 years ago and since then topout springs with fairly long strokes are more common in stock forks and also in some shocks, take the info on setting up the bike only by working to get the sag numbers given as for bikes with no or very stiff and short stroke topout springs only. If you can't get the sag numbers inside the given values, it could be because of topout springs. Shouldn't be a problem for FZ-07's, though.
 
As for books to read, I would like to extend the reading list to include the two books by John Bradley "The Racing Motorcycle - a technical guide for constructors" vol.1 and vol.2 - but they are for the really nerdy.

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pattonme
Excellent video showing what insufficient flow and also insufficient highspeed response does to impact and road-holding.

 
nice background

 
And how even KTM engineers probably need to go re-read their fluid dynamics books

 
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travisaurusrex
I'm at a point where I want a suspension upgrade, but I don't feel that I know enough to make an informed decision on purchasing a shock. I'm not quite ready to cough up $1k+ for a multi-adjustable racing shock and I don't want anything that is preload adjustable only.
 
Most of the single-adjustable shocks say that they have a shared compression/rebound needle and preload adjustment (ex: Nitron). I've also seen some that offer only rebound adjustment and preload adjustment (ex: Bitubo). Does this translate into a noticeable difference to the rider?
 
Out of the shock options available to us, what factors truly influence the quality of the product?

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pattonme
Out of the shock options available to us, what factors truly influence the quality of the product?
Valving experience/simulation. Ohlins has been at this a very long time at all levels of street and competition. Some of the others, not so much. Piston design and mating up proper shim stack is more important than if it has 1 or 4 knobs to twiddle. 
Also getting it serviced locally is a factor. eg. Matris has no US-based service network AFAIK, not to say any competent suspension shop can't handle it just fine. Nitron has some coverage, Hyperpro/Wilburs only one or two outfits, K-tech has a few, and JRI/Penske/Ohlins are very easy to come by. (The JRI is basically a Penske clone)
 
Any ~$600 shock will stand you in good stead. Over that you're pretty much paying for extra features.
 
 

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