| Author | Message | ||
     Daveinm |
I searched a bit and didn't find any threads that defined and explained suspension and what different settings will do. I'm usually not good at searching forums though. I'm not talking about what the suspension setting should be set to, just explanations on what adjusting each setting will do and how it will affect the way the bike handles. I saw the post from earlier about sag... http://www.badweatherbikers.com/buell/messages/32777/56872.html?1084239706. It had a link in it to some articles off another site. I think this is the link to the suspension articles... http://www.roadracinghelp.com/technical_articles_menu.htm. I read through those and don't really see what I need answered. This inquiry is mainly stemming from a high-speed wobble I've been trying to work out of the bike. There was a thread about two weeks ago about it... http://www.badweatherbikers.com/buell/messages/32777/55981.html?1083202898 I have found a suspension setup that seems to have fixed the wobble. I need to run it a bit more and make sure. The current setup is: Fork - 3.5 lines on preload - 1 turn on the rebound - 1 turn on the compression Rear - 6th notch for preload - 1 turn on the rebound - 1 turn on the compression I'm 6'0", 220 lbs., semi-agressive rider. Obviously, the setup is a bit different than what the book says it should be at my weight. It feels pretty stable with the above setup, but it's a bit bouncy. I think I like the way it is set up right now, but I definitely need to test it out more. So here are the brunt of the questions... What does the preload do and how does it affect the handling when it is set tighter(less lines/notches) or looser(more lines/notches)? What does the rebound do and how does it affect the handling when it is set tighter(less turns) or looser(more turns)? What does the compression do and how does it affect the handling when it is set tighter(less turns) or looser(more turns)? How will certain settings affect other settings? i.e. How does adjusting the compression higher than the rebound affect the handling? How do different setups on the front and rear affect each other? i.e. What happens if the front is set loose and the rear is set tight? I think that's pretty much it. I know it will take some time to explain, so thanks in advance. Please post back if you need any clarification. Dave | ||
| M1combat |
Uhhh, I'm still learning bike setup but I think that could exacerbate a medium speed, corner exit, on the throttle tank slapper. I think it could also be very bad if you were to enter a turn on the brakes with too little damping. I think that also it would make throttle changes during mid corner (especially with the torque of an XB) very un settling to the bike. A book I read once ("Total Control" by Lee Parks) said that an important part of riding safely and fast is to be SMOOTH!!! I know this to be true in a car and can only assume that it holds true on a bike as well. I think with that much preload and what would seem to be VERY little damping and 220# up top you would get very quick weight transfer. Any time weight transfers front to rear or vice versa on a bike you change your suspension geometry. I think that touching the brakes mid corner (not a good practice anyway but sometimes necessary on a road to avoid stuff) with a very underdamped setup could be bad. I think the settings in the book should work quite well. As far as a wobble - Have you tried different tires? What type of tire is on the bike now? How about pressure changes? I weigh 215# with gear and the book setup and get only a slight shimmy at about 80-100. That was on the stock Dunlops. I switched to Metzeler Sportecs and I am pretty sure it has gone away. | ||
| Henrik |
Dave: a quick Google search for "suspension tuning motorcycle" yields lots of info. Check here, about mid page, for 15 - 20 suspension tuning links. Henrik | ||
| Zip |
Daveinm-these are some very good Questions. I've often wanted to know my self. please report back if you come up with any good answers !!! | ||
| Daveinm |
M1: I've tried everything. New tires...Pirelli Diablos, got them rebalanced after they were mounted and it was still wobbling, correct tire pressures....nothing was working. I spent half a day at the Harley dealer in Stuart, FL. They seem to be good guys...more interested in me being happy with the bike than the sale. I rode a new demo and didn't feel it. Went out for rides with them. They don't feel it when they ride it, but they saw it when I was riding it and agree that it is there. After looking through everything, and not feeling it themselves, they said I should play with the suspension and keep test riding it and to come back if I can't get it figured out. I didn't really want to get back into that with this thread. I see sites on suspension everywhere. I haven't found anything that goes into detail about compression and rebound. Most of them just say compression is how fast/slow it compresses and rebound is how fast/slow it rebound. Rocket Science!!! Nobody seems to go into the details of how they affect the handling of the bike with tighter or looser settings. That's more what I'm looking for. | ||
| Daveinm |
Henrik: Thanks for the link. I read through the first few. Skimmed through them is more like it. I still didn't see exactly what I'm asking. I'm gonna go through them all later. Gotta get some work done at the moment. | ||
| Marcus_mcbain |
Most "wobbles" have more to do with geometry than the actual suspension "setup". Every question is addressed in the list of tech articles on my website. Most folks try to "drop" the front end on the Buell and this is a no-no. There is little rake/trail to begin with. Most "wobbles" are preceeded by a new tire type or "I dropped (lowered) the front end to get it to turn quicker". If you solve a "wobble" by changing preload, more than likely you actually affected the geometry by over adjusting the springs. Good Luck, Marcus | ||
| M1combat |
The trick to grip is to make the suspension (and namely the tire) conform to bumps. The tire will ride up the bump when you hit it. The bump/compression damping will attempt to transmit that energy to the frame. The lower it is, the easier the tire will travel upwards, HOWEVER, you don't want it too light because then the tire will continue it's upward travel after it leaves the bump. This is bad. Now, for the rebound damping. Once the tire crosses the crest of the bump (with correct preload and compression damping) it will begin to fall. The trick with rebound damping is to make sure that the tire can fall fast enough so that it doesn't lose contact with the road. If it is too stiff, the chassis will fall with it. If it is too light, you could get a bit of a secondary movement in the wheel as the tire compresses and then rebounds (keep in mind that the tire is an undamped spring for all intents and purposes). Now for preload. If you have too much preload, the bike will act a bit like it is overdamped. It will move the bike upwards too far on the face of the bump. At that point the suspension will need to extend a long ways to keep the tire on the ground. This changes suspension geometry (and on a bike - steering geometry). If you have too little preload then you won't have enough travel in the compression direction AND your weight transfer will have a greater effect in the balance of the motorcycle. Spring pre-load really ought to be set to attain the proper sag measurements. At our weight we can't exactly achieve this correctly w/o stiffer springs. I have heard that it is "ok" to have too little static sag but try to go for the proper amount of rider sag anyway. After that, you should be able to find damper settings that work for you. Also... I think someone posted a link to some different setups at some point. Maybe do a search here. I know this doesn't answer your question really but as far as coming up with a setup that's good for you I think safety should be of the highest concern. Too much weight transfer in a corner leads to changes in steering/suspension geometry and can lead to things like tank slappers. That said though, I think it's over damping that leads to low sides/high sides (that and too much speed). | ||
| M1combat |
By the way... What's the front ride height set to? I STRONGLY only recommend the factory setting there. | ||
| Henrik |
Dave; there was at least one of those links that had lists of what too much or too little of one or the other felt like. About half the links are dead, unfortunately. I've come across that list before, where the links were good. But at least it's a place to start. Being that you're referring to a high speed wobble - and I'm guessing straight line?? - issue, I'd be thinking steering head bearings, tires and rider input before anything else. Can you be more specific about how it feels? High or low frequency? Does it feel like it's coming from the front or the rear? Does it get progressively worse with higher speeds, or is it constant within a speed range? Will it change if you change riding position - weight forward/weight towards the rear? Any change if you change your grip on the bars? etc. etc. Henrik | ||
| Daveinm |
}Can you be more specific about how it feels? High or low frequency? Does it feel like it's coming from the front or the rear? Does it get progressively worse with higher speeds, or is it constant within a speed range? Will it change if you change riding position - weight forward/weight towards the rear? Any change if you change your grip on the bars? etc. etc. The wobble feels like it's coming from the front. It's definitely not from wind. It happens sporadically...mainly 80 mph +++. I haven't taken it past 110 mph. I don't know what you mean by high or low frequency. It does seem to get progressively worse with higher speeds. It comes and goes though, I was just cruisin down the highway at 90 mph with not wobble at all. It does change when the riding position changes. If I lean over the air box and put my head towards the front, it will almost always start the wobble. If I shift my ••• towards the back of the seat, it will almost wobble. If I sit up straight with my arms straight, it will wobble. If I tighten my grip and move my hand towards the inside of the grips, it seems to be a bit better, but it will still wobble. I changed the stock tires out for pirelli diablos a few weeks ago when I began working on fixing the problem. The stock tires were almost done with anyway. Besides, I figured it would be one less variable in the equation. What gets me is the guys at the Harley dealership rode it and they say they don't feel it. They definitely acknowledge that it's there cause they saw it from behind when they went out for a ride with me. They all weigh 60 to 80 lbs less than me though. I'm gonna check out the front ride height to see if that as another cause. | ||
| M1combat |
My apologies... I'm a dingbat. I just took a look at my service manual and I realized you are probably referring to your damper setting like the book does. Turns out from maximum. Sorry, your setup probably isn't as horribly underdamped as I suspected. After looking at the book though, I see you have set it up to be a little softer at the rear. I believe that would tend to set the weight back a little and change the attitude of the bike towards pointing upwards at the front. Your comment about the certainty of the wobble while leaned over the front would seem to indicate that your slightly less preloaded spring should help. I could be remembering this incorrectly (and I don't have a book to look to) but I think I have heard that too weak of a spring on the rear will cause a "wallowing" or "squirmy" feeling from the rear of the bike while exiting a corner on the throttle. | ||
| Bomber |
so would too little rear-preload . . .. . M1's right on, I'm thinkin (although I'm a tuber rider, the same theory applies) and, hey, we're all dingbats | ||
| Glitch |
we're all dingbats  | ||
| M1combat |
After some thought... I think that using a setup that is over sprung (or over preloaded) up front may cause the front tire to have less overall grip than it would if the setup were balanced. This could indicate a slightly higher tendency to low side due to front end wash-out. It doesn't seem to me that the amount of variance you have would be TOO much though... But what do I know? It seems that you would have two options... What you did or raising the front ride height a smidgeon. Of the two I think I would go with the suspension adjustment unless that caused a mushy feeling coming out of a corner then I would set the rear back to stock and raise the front a little but I certainly don't recommend that you do that. | ||
| Marcus_mcbain |
Hey guys. I don't mean to sound bad, but many times I listen to some really "incorrect" stuff. I have not seen too much in this thread that is true or helpful. I know guys mean well, but it is a lot of bad (dangerous) information here. Again, sorry for being forward on this subject. One of the specific items. Anyone that knows the Cartridge on the XB's knows they are crude and not very "exact". There is no "universal" damping rate because the cartridge is of such low overall quality, it is not possible. This is true for almost any fork (to a lesser degree on better quality forks). So if anyone tells you, "you should set your preload to...and your compression to....and your rebound to..." then you should politely walk away and realize the quality of content in any future mechanical conversations. Marcus McBain | ||
| Henrik |
. So if anyone tells you, "you should set your preload to... Don't know anything about the cartridge, but Marcus, are you saying that the springs are of such varying rate/quality that you can't even compare preload settings?? Henrik | ||
| Marcus_mcbain |
Most OEM springs vary by .05kg or more than specified manufacturing specs. Additionally, the wire that is used in most OEM springs is crap. This means that your XB (Or another bike for that matter) can have the springs lose accuracy of rating within 2000 miles (Depends on rider weight, practices, etc.). I mentioned it in this months tech article on my site. Basically, just set your total sag on both ends of the motorcycle to 35mm (front and rear respectively) if your are "big guy" (Over 200lbs.) if you are doing two-up riding a lot, turn the rear spring to maximum tension on the XB's as they are woefully undersprung for anything over 200lbs. | ||
| Two_buells |
Dave, try this link http://home.att.net/~mikey394/XB9RSuspensionsettings.jpg | ||
| M1combat |
Marcus - In case you were directing that first comment at me I don't seem to remember making any recommendations. I didn't take offense though as I'm the first to admit that I don't know a lot about suspension (on a bike) but it's the most intriguing subject involved with bikes if you ask me. As far as being forward - Thank you. I don't think I made any recommendations but if the bad information you are referring to is mine please set me straight. Will having a setup that is over sprung in the front/under sprung in the back not lead to less grip at the front in mid corner high lean angles? Are there glaring problems with the facts in my second post? I assure you if there are I won't be upset. You know a good deal more about this subject than I do and I'm very interested in learning. If running a lower rear preload seems to solve a problem with a high speed wobble would it not be a correct assumption that raising the front ride height would have a similar effect but w/o the side effect of lowering the rear? Anyway, I'm just glad we have people here like you who can set the record straight when people like me are trying to offer insight but not getting it quite right. I would appreciate it if you could point out where I'm not quite right though. Only for the sake of learning. | ||
| Daveinm |
I just got back from a test ride with my suspension set according to the chart is the link Two_buells posted. Fork - 3.5 lines on preload - 1.25 turn on the rebound - 1 turn on the compression Rear - 7th notch for preload - half a turn on the rebound - half a turn on the compression Firstly, I can't believe how much those minor adjustments affected the handling. I didn't adjust anything more than .5 turns (See my first post for my previous settings). It handled great around town on all the twisting streets. I need to take it out during the day and push it a little harder...I don't see very well at night...contacts or glasses. Besides, there are animals and sprinklers to worry about around here. I took it on the highway. It feels good, but I'm still getting the wobble. It feels like it's less intense though. However, it was really windy. I need to take it for another test run tomorrow. | ||
| Marcus_mcbain |
Hey M1, I tried typing a post to respond, but am way tired and am headed to PPIR tomorrow. Sorry, Marcus | ||
| M1combat |
No problem Marcus. | ||
| Easyflier |
I think even Marcus would agree that the Xb is very sensitive to suspension setup. Marcus, what have you got to say about the Hyperpro products? Do you carry them? | ||
| Baybueller |
When I first ran my 9S above 80 mph I noticed a front end shimmy. Turned out to be transmission from from my arms. loose thin leather jacket sleeves flapping in the wind. | ||
| Daveinm |
Yeah, it's definitely not from that. It's a much more intense wobble than feedback from arms catching wind. I just got "Total Control" by Lee Parks based on the post by Wordshop1 http://www.badweatherbikers.com/buell/messages/32777/57511.html?1084418787 It has charts in it showing what different dampening settings do and how they affect the handling. I'll scan them in and upload them to this thread later today or tomorrow. | ||
| Daveinm |
Here are the charts I talked about from "Total Control." They show answers to some of the questions from my first post on this thread.   | ||
| Kevyn |
Traxxion Dynamics--Suspension For Mortals DVD will walk you through an entire suspension set up as well as explain with drawings and components what's going on. Easy to watch. Starts with the basic terminology and works from there to the track and street. |
