| Author | Message | ||
     Diablobrian |
Shawn Higbee wrote a great article explaining the operation of suspension and adapting it to the roads you ride on. This is great stuff. I can't quote it because the whole thing is great and builds on itself to explain the mechanics of how your suspension works. If you don't get Fuell go visit your local Buell dealership and pick up the new issue when they get it in. Plus our own Mutation is profiled in this issue! Good show Anthony! | ||
| Etennuly |
Just got it in the mail. That is the most helpful article I've seen on Buell suspension settings. The book is the place to start, this article is the instructions for what to do next.  | ||
| Bomber |
it's a great piece -- it is so very rare for someone of great skill to be able to explain the concepts and application that clearly -- I wish I had access to the information when I started messing with suspension -- gave ma a couple of new ways to look at things . . . . THANKS MR HIGBEE! | ||
| Dtx |
That was a great article. I actually had some questions about suspension settings that I have been wondering about and his article answers them. Good job and thanks! | ||
| Mortarmanmike120 |
Hey guys. I don't get Fuell. Is it like a free newsletter or something? Or was it something you got from BRAG? Thanks. | ||
| Dano_12s |
Great read.Would sure like to see Shawn on an XBRR in '07 if Buell would approve. | ||
| Jimidan |
Shawn is racer, not an engineer, so it is much easier for him to express himself in terms that non-engineers can understand. I can remember him doing an article on set up for Battle2Win also. Very interesting. BTW, who is still getting the Fuell magazine? I am a BRAG member in good standing (whatever that means for a defunct organization) and I haven't received mine. jimidan | ||
| Diablobrian |
Michael, Fuell was a Brag thing, but your local Buell dealer should also receive a stack of the mags for distribution. Don't be afraid to ask about them. Be persistent because most people at the dealership will have NO IDEA what you are talking about! I'm not sure when it kicks in, but soon all Buell owners (in the US) will be able to get Fuell if they register with Buell.com in the owners section. | ||
| Jlnance |
Jimidan - I got mine yesterday. Others got theirs last week. Yours is probably on the way. | ||
| Slaughter |
You guys are killing me here. My PO Box is 45 freaking minutes away from me - and I hadn't planned the trip down there just yet. | ||
| Debueller |
Great article. I'm going to have to read it more than once to absorb it all. Alot of very well written info. | ||
| M1combat |
Dangit... I don't get Fuell any more and the nearest dealer that will do anything other than pitch them in the trash is two hours away... | ||
| Blake |
Don, you have email, with some attachments.  | ||
| Mikexlr650 |
can someone scan the article in? i don't get fuell either. mike | ||
| Captpete |
This needs to be in the KV, Blake! What's the holdup? | ||
| Diablobrian |
It belongs to Fuell and Shawn Higbee. It would be nice to have their permission to put it up on BadWeB. | ||
| Blake |
Frankly I didn't find the article that helpful. | ||
| Tx05xb12s |
Anyone know of a contact with Buell for getting a copy of this article? I am a BRAG member with paid dues and have not received my copy of FUELL in about six months. I am always looking for ways to improve my suspension setup and would probably benefit from this article. If someone would be willing to make a copy and mail it to me, I'd be glad to pay all expenses. Send me an IM. | ||
| Diablobrian |
I thought it was the best explanation in lay-man's terms I have seen. For non-engineers and people that have no experience it will be a godsend. | ||
| M1combat |
It was a good writeup on the basics. It's is indeed very difficult to explain to someone how to setup suspension. The best thing is to ride a bike that's setup "decently" for your riding style and then try to make your bike feel like that. There are certainly baseline things to start with (Static and rider sag, damping that works alright, etc...) but to try to explain how something should feel is just too subjective. Like I said though... It's a very good article on the basics. It's always good to read an article that's both well written and directly relates to the vehicle you're using. There is one thing that I learned (confirmed anyway). Buell did indeed take advantage of the low un-sprung mass in the front with their valving. The front end actually feels "supple" for a reason . Now... Anyone know exactly what I mean by supple? Exactly... Therein lies the problem with trying to explain how to setup a motorcycle . The best thing (as the article eludes to) is to learn exactly how suspension works and why, then do a LOT (read - TOO MUCH) thinking about what you want YOURS to do, and then set about making it do just that. It's more like playing a guitar. You have a song in your head and a guitar in your hands... No one on the earth can explain to you how to play your song. Only how to use the instrument . Learn to play . | ||
| Diablobrian |
Nice analogy M1 | ||
| Jlnance |
Since we are talking about suspensions ... Why wouldn't someone want compression and rebound damping to be equal? Anyone know the logic there? | ||
| Blake |
Why do you imagine you would want it to be equal? First try to imagine the loading that each damper must endure/support under worst case compression versus worst case rebound. Can you see that the rebound damper(s) must resist only suspension spring force while the compression dampers must resist massive (in comparison) inertial forces via sharp step-like inputs (sharp bump akin to hitting a curb or mongo speed bump)? Which damper needs to be more robust? | ||
| Jlnance |
Why do you imagine you would want it to be equal? My thought is that if they are not equal, and you are on a long patch of rough pavement, the forks will eventually end up fully compressed or fully extended. Can you see that the rebound damper(s) must resist only suspension spring force while the compression dampers must resist massive (in comparison) inertial forces via sharp step-like inputs? I had to think about that for a second In the extream, yes I can see that. If you hit a big hole, the tire may not be in contact with the road while it falls in. If you hit a big bump, the tire will always be in contact with the road. I was assuming the suspension was designed to keep the wheel in contact with the road, in which case the forces would be the same magnitude. If thats not the case, then yes, I can see why they would be different. | ||
| Slaughter |
I think you'd want the RATE of damping to be similar - just not the ACTUAL damping. ("RATE" isn't an exact description but bear with me) That is kinda/sorta done by the internals anyways. A half turn in or out for compression or rebound damping has a similar response in terms of the CHANGE in damping. You don't have to think: "geez, lemme see... the response in compression needs to be about 8.7 times the response in rebound" Nope - if you need a slight change in response, an 1/8 - 1/4 turn will do it. HUGE change - a full turn will do it. | ||
| M1combat |
The bump damping needs to dissipate all (no more, no less) of the energy that is imparted to the suspension by a bump. It must do it in exactly the amount of time that the bump is busy imparting energy. You could actually attain this if all of the bumps you encountered were exactly the same size and shape, and you were always traveling at the same speed... "Theoretically" the chassis should never move. It will . The bump has imparted energy. That energy is now stored by the spring. The rebound damping needs to help dissipate this energy as quickly as possible without allowing any to be imparted into the chassis. The values need to be different because of a few reasons... One is that the leading and trailing edge of bumps are generally different shapes. Another is that the ground is imparting energy in one direction and the spring is exerting energy in the other. Another is that at the top (where the wheel must be slowed, stopped and then sent back down) the wheel is controlled by a spring and at the bottom it's controlled by the location of the ground and a much stiffer spring (the tire). | ||
| M1combat |
"My thought is that if they are not equal, and you are on a long patch of rough pavement, the forks will eventually end up fully compressed or fully extended. " You are correct except that ... The more compressed they get the more tension there is in the spring to counteract the bump damping, the more extended they get the less there is to act against the rebound damping . Then there's this stuff called gravity . You are somewhat correct though, and the phenomenon you are talking about is called suspension jacking. That said... there's another form of suspension jacking that allows F1 cars to have a COG that's actually BELOW the pavement . Several feet below no less . Did you know that there are seven adjustable springs at each end of an F1 car? Only three dampers though . | ||
| Jlnance |
Did you know that there are seven adjustable springs at each end of an F1 car? I had no idea. I'm sure thats fun to adjust. | ||
| M1combat |
They mount the entire suspension system (sort of...) on it's own suspension system so that if both tires move up and down (line perpendicular to the direction of travel, changes in downforce, gusts of wind, brakes, gas, gear changes in a straight line, etc) that uses one shock absorber, and if one wheel moves relative to the other, it also has it's own shock absorber that controls it's movement independently of the other (like a conventional setup). The other four springs are the two tires and the control arms. There are no ball joints or other "hinging" mechanisms related to the control arms. It's one big structure. They tune that spring by changing the way they wrap the carbon fiber to create the control arm structure . The reason that they don't use ball joints or anything comparable is to reduce stiction . Many (if not all) of the teams use Ohlins or Penske dampers. Neat things those F1 cars . | ||
| Blake |
"My thought is that if they are not equal, and you are on a long patch of rough pavement, the forks will eventually end up fully compressed or fully extended." The spring prevents that. Also, the force imparted to the suspension resulting from the mass of the motorcycle/rider when hitting a bump can be orders of magnitude greater than the force the spring excerts in rebounding. Thus, the compression damper must be able to handle much greater energy input compared to the rebound damper. "I was assuming the suspension was designed to keep the wheel in contact with the road, in which case the forces would be the same magnitude. If thats not the case, then yes, I can see why they would be different." The suspension is indeed meant to keep the tire on the road. But the compression and rebound forces, an dmost importantly their energies are not equal. Let's look at each phase separately. In rebound the suspension has been compressed and is trying to return to equilibrium. The only force available to aid this extension is that imparted by the spring. Imagine if you will a motorcycle suspended in mid-air with the front suspension fully compressed and tied in place. Now cut the ties downs. The springs are generating the only force acting to extend the suspension. No imagine the same bike suspende mid-air but this time with the suspension resting at equilibrium, no tie-downs or anything. Now say that we drop the bike three feet to the floor so that it lands upright on it's wheels and with a rider mounted aboard. How much force/energy was imparted to the dampers in that case? The same amount as if only the springs were acting on the dampers? No, a LOT more. This holds true for a bike traveling at high speed that hits a sever bump. The suspension is subjected to a horrendous (compared to rebounding) compression energy, a near spike or step input, meaning that the suspension went from equilibrium to max compression force loading almost instantaneusly. Steve Slaugter hit on an interesting point. He's a wicked sharp engineer in case you didn't know. Damping velocity and damping energy are two different things. I'm focusing on the energy side of the issue, how much energy a compression versus rebound damper must be able to absorb. Maybe that is not what you are talking about? , say |
