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Discussion Starter #1
sorry to be stupid, but i dont see how the suspension can affect how a motorcycle takes curves. i mean, the bike is leaning so what difference does it make how far the forks go down? i just dont see it...

so if it makes such a big difference, what should i set mine at to handle better? softer or harder? how much softer or harder? do i need to buy something or is the stock adjustment enough? thanks
 

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well basically it does the same thing when u r straight up & down.. keeps the wheels in contact w/the road.

it may not look like it & it may not be logical but the susupension still works leaned over.

there is so much to know & so many variables in sportbike suspension that it would take days to post about it.. here is a link that is not technical at all & should shed a little more light on the subject..

http://www.directparts.com/static/goose/suspension.htm
 

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dash said:
sorry to be stupid, but i dont see how the suspension can affect how a motorcycle takes curves. i mean, the bike is leaning so what difference does it make how far the forks go down? i just dont see it...

so if it makes such a big difference, what should i set mine at to handle better? softer or harder? how much softer or harder? do i need to buy something or is the stock adjustment enough? thanks
There are no stupid questions if you're asking to learn. Before you go out and spend a bunch of money, read all you can, talk to as many people "in the know" as possible. Information is (for the most part) free. Just keep an open mind, since every rider likes their suspension and uses it differently. Once you've learned as much as you can stand :D, then you'll have the information you need for suspension tuning. At that point, you can then introduce Mr. Hammer to Mr. Piggy.

SP, good URL. I'll have to bookmark it.
 

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NOT a stupid question!

This is a question that every serious tuner, engineer, racer asks. For every person you ask you'll get a slightly, sometimes very different answer.
Here is a quick idea of the issues.
Chassis geometry and suspension are two unique and distinct components of a motorcycles handling. In an ideal world, suspension wouldn't affect chassis geometry, nor the reverse. But that has always been the burning issue in bike design and set-up!
If everything would be smooth and flat, suspension would be undesirable, Thats why in F1, the smoothest tracks get the shortest travel suspension.
The rougher things get, the more travel you need to maintain a semblence of control at high speeds.
We need to keep the wheels on the ground, the chassis in a stable state, and keep the bike comfortable, therefore controllable.
Unfortunately, when wheels go through their suspension travel, all the careful calculated chassis numbers (Rake, trail, C. of G. to name a few) change. THIS IS NOT GOOD.:crying:
Suspension setup also effects feedback to the rider.

I hope this helps explain the importance of suspension and technical problems it creates.

Set up your suspension? Here are a few important basic points.

First and very important step, set the sag!
To do this right, you need 2 assistants. The burly one holds the rear of the bike, balanced upright, with you in your normal riding position. You may need a few attempts to get comfortable, it takes a bit of tutoring to get the assistant to only keep you from tipping and at the balance point, so that he hardly needs to apply pressure on the bike at all. When he's got that point sussed, "assistant 2" measures from the fork wiper to the bottom triple-tree, then measures up from the rear axle to a grab rail bolt or something. Now get off, and fully extend the suspension and let "assistant 2" re-measure, using the exact same reference points. Now subtract the smaller numbers from the larger. This gives you you your sag! This number should be between 1/4 to 1/3 (25 to33%) of your total travel. This should be a one-shot-deal unless you or the bike gains or loses weight!:D
Now check that your tire pressures are correct and go riding! Fiddle with your damping settings a couple of clicks at a time. A Couple of hints:
If you get a sharp jolt over lips/potholes, less compression damping.
Pogo ride/topping out, more rebound damping.
If a rapid succession of bumps makes things feel rougher/pumping down, less rebound.
If you are at the limits of adjustability in your quest for nirvana, use a heavier/lighter suspension fluid.

I hope this Helps out!;) Seasons greetings!
 

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Grok's summary is pretty good. From your location we probably ride the same roads. I have helped set up suspension on many bikes at TWO with the owners grinning big time afterward from teh results. Setting sag and rebound/compresion damping make a big difference. Hard to explain in a short note but there is a lot of magazine articles on how to do it. Basically it will get the attitude of the bike set so the geometry of the components is correct, rake & trail, swing arm angle and to allow the full use of your suspension travel and keep both front & rear working together. Picture this, what if you had no oil in the front forks and set up for a turn. The front end would dive big time then picture the rest. If you have never set up the suspension you probably do not know any different. Afterward in a lot of cases you will wonder how you could ever have ridden the old way.
Steve S.
 

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Discussion Starter #6
Re: NOT a stupid question!

Grok said:
, "assistant 2" measures from the fork wiper to the bottom triple-tree, then measures up from the rear axle to a grab rail bolt or something. Now get off, and fully extend the suspension and let "assistant 2" re-measure, using the exact same reference points. Now subtract the smaller numbers from the larger. This gives you you your sag! This number should be between 1/4 to 1/3 (25 to33%) of your total travel. This should be a one-shot-deal unless you or the bike gains or loses weight!:D
Now check that your tire pressures are correct and go riding! Fiddle with your damping settings a couple of clicks at a time. A Couple of hints:
If you get a sharp jolt over lips/potholes, less compression damping.
Pogo ride/topping out, more rebound damping.
If a rapid succession of bumps makes things feel rougher/pumping down, less rebound.
If you are at the limits of adjustability in your quest for nirvana, use a heavier/lighter suspension fluid.

I hope this Helps out!;) Seasons greetings!
so whats the fork wiper and bottom triple tree? also, once i get my sag, you say it should be 25-33% of my total travel, whats total travel? one other thing, is the damping setting the things that are adjustable on my bike, like the turny things at the tops of the hadlebars and the one at the rear of the bike? i dont think i understand
 

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Dash, I would find the "total travel" numbers for your machine from the dealer, these numbers represent the total distance the suspension allows wheel to move. May as well ask those other questions while your there at your friendly dealers.
Sounds like you need a "mentor" to help with some of these basics. A knowledgeable biker-buddy can save you a lot of grief. Be sure to listen well and don't ask the same questions over and over. This will insure his/her help will continue. ;)
There is always a forum like this too!:D But words, (in my case particularly!) often come up short in these more involved technical matters.:eek:
Keep on asking questions.:)
 

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Discussion Starter #8
k, ive got my owners manual here just reading about how to adjust suspension and stuff. theres a spring preload adjuster and rebound damping adjuster for each of the front and rear. also the rear has a compression damping adjuster. the manual says for all of these that i should turn them to "Soft for a light load and smooth road conditions" or to "Hard for a firmer ride and rough road conditions." i read the article posted earlier in this discussion and what i got from it was that for a more performance setting it would be set at towards Hard so as to stand up to the pressure put on the bike in corners. but im not riding on anything real bumpy! cuz thats what the owners manual told me to do.

i guess my question is should the settings be set harder or softer for better performance in corners, not track but canyon roads, etc. i dont care a bit about comfort on the highway cuz i dont ride there. ive read so much on this lately that it seems like everything is contradictiong everything else...
 

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Good reading...

Dash (and others),

Here's an awesome book on... well, performance tuning, written by Kenvin Cameron, for non-rocket scientists. It helped me understand a lot of things about overall performance tuning. It's only like $15, or just pick one up from your local motorcycle shop (most carry it, in the Bay Area, CA anyway).

http://www.amazon.com/exec/obidos/ASIN/0760302294/107-3204927-1246935
 

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Discussion Starter #10
ok i think i understand everything now, i just dont know where to measure the front sag. you told me where but i dont know where those places are.
 

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Dude, suspension has EVERTHING to do with the ride.You ever drive a car with bad shocks and worn out springs? And then fix them and drive again? Feels like 2 different cars.
One exercise for you to understand what is going on is to set it up, doesn't have to be set correctly, and go ride. Nothing hard, but go ride a bit with some braking and turns. Then change the front/rear/or both. And not just a little, change it a lot. Go ride again, see how the bike feels. I assure you, you will feel a difference. That is just to prove it to yourself that it will make a difference. Then combine what these guys are telling you as far as what the "optimum" settings are and you think feels comfortable.
When I went to the Gap in Sept, my bike was set up for riding in FL. The first day of riding ended, and I HAD to change the suspension to what felt better for the roads I was on. You will learn with experiance what works for you and your style, and what works on the roads you are on.

Good luck, cause there is no one answer.
 

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Ez way to measure sag and suspension glossary

1. Get a zip tie..
2. Put it around the fork slider. (The little tube that slides in and out of the bigger tube)
3. Push it all the way up against the fork seal. (The black rubber seal where the tubes slide in and out of each other)
4. Use the aforementioned method to balance yourself on the bike (i.e. someone to hold the back)
5. Get off (I know simple one, but some people...)
6. Measure the distance from the seal to the zip tie (it slid down the slider as your weight compressed the suspension)

---===BAM, you now have static sag measurement===---

7. CAREFULLY cut the zip tie off, being excruciatingly careful NOT TO NICK OR GOUGE THE FORK SLIDER...*

Walla, no measuring gymnastics.


*I am not responsible, nor can be held liable for nicked or gouged fork sliders due to this method of sag measurement.


This same method can be used to determine how much suspension you are using, by putting on the zip tie, going for a ride, riding at your usual pace. When you get back, the zip tie will be at the lowest point your suspension traveled during the ride. If it is within an inch or so from the bottom, you are excessively compressing the suspension while you ride, if not bottoming it on the bump stops. You need to add some spring preload and compression damping..

Glossary:

Compression damping:
Compression is when you push down on the front end, and the fork slider moves into the tube (it *compresses*..ahhhh) Compression damping controls how easily this happens. More damping will make it harder to push the tube in, less will make it easier. You ask, "Why do I need that"? Lets say you go over your average bump in the road. If your compression damping is to soft, after the wheel passes over the crest of the bump it keeps rising, thus loosing contact with the road (a serious detriment to traction). If you have too much compression damping, your wheel isn't able to rise fast enough to ride over the bump, and the suspension cant absorb the impact, so transmits it to the frame, motor, you, back wheel, reverberates, etc,.. Eventually it gets back to the road through the front wheel (again a serious detriment to traction)..

Rebound Damping:
The opposite of compression damping, rebound damping is how fast the fork slider comes back out of the tube after it is compressed (it *rebounds*..ahhh again). More rebound damping will cause the fork to extend slower, less..faster. Again you may ask, " Why do I need that too?” Lets go bask to our bump in the road example again. You have you compression damping set just right now, so no problems there. The wheel crests the bump and you have too little rebound damping. The fork starts to rebound while the wheel is still over the bump causing the front end to rise slightly, causing all those nicely calculated figures mentioned earlier (rake, trail, etc..) to go out the window (once again, a detriment to traction). Too much rebound damping and the wheel wont be able to fall fast enough to follow the bump, and will "float" as we call it, causing it to loose contact with the ground momentarily (you guessed it, loss of traction again).

Spring Preload:
There are springs in the forks, and around the back shock. These springs support the all the weight above them, the frame, engine, you. Every thing but the tires, wheels, brakes disks, calipers, sprocket, etc.. This is known as sprung weight. The springs control the over all feel of the ride, soft or hard, and control the first inch and a half or so of suspension travel. More spring preload will compress the spring more, making the ride a little harder, whereas less makes it softer. That’s why you crank up the preload when you have a fat chick on the pillion (not a problem for me, as I have a "no fat chicks" sticker promptly displayed on my bike). More preload will help control more weight, and harden the ride a little, less for less weight and a softer ride.

There you have it. If I have confused any of you, then go have a beer, smoke a cigarette, and don't worry about it.

Keep it safe, Rubber side down.

Mark
 

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Discussion Starter #13
Mongrel Racing said:
Ok your Honda F3 has 5.1" of travel on the front. Using 30% would be about 1.5" so set the front sag between 1.25" - 1.5"

On the rear you have 4.7" of travel using 25% is about 1.2", so try setting the rear with 1" - 1.25"

Next set your compression and rebound setting at the middle of the range. Ride the bike, now you need to find a source such as Basic Suspension setup read it and try and figure out how the bike is reacting and adjust the suspension accordingly. Remember only make one adjustment at a time, and then ride the bike. It is a long process and requires you to take notes and be good at identifying what is going. The other option is to set the suspension according to the owner?s manual
Mongrel, just wondering where you got this info about my bikes total travel? i would like to help my friend set up his 01 r6.
 

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Discussion Starter #15
thanks

just wanted to say thanks to Mongrel, Mark, DaDuck, SpeedPhreak, Grok, and ssalber for your help and stuff. i havent been able to do anything to my bike yet but look at it cuz its so cold, but by spring ill have new tires and confidence in my suspension. thanks youenz
dash
 
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