| Author | Message | ||
     M1combat |
I realized the other day that I have NO static sag on the rear of my XB12R. The rear is set to the fourth preload position, and there seems to be no static sag whatsoever... This seems weird to me. Anyone else notice this? edited by m1combat on March 16, 2004 | ||
| Aesquire |
You mean that your suspension is topped out while you are NOT on the bike? sounds normal. Sag is measured with your mass in a riding position. | ||
| Wyckedflesh |
As in when he gets on the bike the rear suspension doesn't move... | ||
| Kaese |
The sag is set to the rider's weight. Sag should be set at 1/4 to 3/4"s for the rear shock and also referred to as preload. I found some good settings listed on http://groups.msn.com/xb9r/20022003fireboltsuspensionsetup.msnw to be used as general guidelines and will get you in the ballpark. I took a suspension class and it is more involved than I thought. I would venture to say that 1/3 of accidents can be attributed to improper suspension settings. Think about it, what do you know about the settings. There are so many adjustments you can make. Preload, dampening and rebound for both wheels. Make sure you record what your setting were and what changes you made to improve your knowledge of your settings. edited by kaese on March 17, 2004 | ||
| M1combat |
No. Static sag. With me not on the bike. When I sit on it I certainly get a bit of rider sag. Problem is... It seems that my total sag = my rider sag. There's no static sag (just the bike). As I understand I should have about 10mm of static sag (no rider), and 15-25mm of rider sag (with rider and all gear) for a total of 25-35mm total sag. | ||
| M1combat |
Kaese - on a side note... Some cars have preload, bump and rebound compression (on a fast circuit AND a slow circuit), anti-sway bars, toe, camber, caster, ackerman, and a whole host of things that can be done with the geometry of the control arms to change camber, caster, toe and ackerman curves... F1 cars actually have a THIRD spring on each end (not to mention the control arms with no end links that can be constructed to flex at different rates), wings, brake balancing, differing sized rotors, a plethora of settings just in the differential for both the acceleration side and coast side, ride height (changeable at each corner) and MANY others... Sorry, I got sidetracked... Car suspension is very cool stuff and I'm just learning about bike suspension (tech info seems to be much harder to find...). Anyway, shouldn't I have some static sag? I'm only on the fourth preload detent. Why does ackerman come up as a mis-spelled word? | ||
| Kaese |
Ackerman is making the inside wheel turn sharper than the outside. Bump, I think, is the limit of the extension of the shock if up in the air, ie. wheelies. Toe is the angle of the front wheel pointing in or out. Castor is the angle, forward or back, the front wheel is projected. Aren't you glad a motorcycle doesn't have to deal with all those? edited by kaese on March 17, 2004 | ||
| M1combat |
Yes I am, but it seems to me that most of these are a factor on a bike, it's just dynamically controlled by the rider (making it more difficult to actually go fast...). Sorry, I just went off on a tangent. Didn't mean to sound pretentious  . | ||
| Kaese |
Suspension is important, and I think there are adjustments one can make depending on how rough the track is. The idea is to make the bike absorb all most all of the track irregularities. The same applies to street riding. Getting your settings right for your riding style is good thing. | ||
| Henrik |
Suspension setting terms: Preload is the amount of tension there is on the spring(s) with no load on the suspension component (shock or fork legs). It's not a distance measurement. Preload along with spring rate influences how your suspension is set up as far as static and rider sag. Sag is always calculated in relation to a measurement with the suspension completely topped out = no weight on the wheel in question. For instance: no load measurement - loaded measurement = sag. So your static sag becomes the difference between the fully extended measurement and the number you get with the bike vertical but no rider. Your rider sag becomes the difference between fully extended and the measurement with you on the bike, feet on the pegs, wearing all your gear (including your tank bag or whatever else you usually ride with) - yes, that requires 2 assistants I don't have my numbers with me, but a rider sag of 25 - 30 mm is pretty standard for the SV. Can't remember the static sag numbers, but they shouldn't be 0 mm. If you can't get the right combination of static and rider sag you may consider changing the spring rate. I realize the XB is a different animal, so don't hold me to the numbers, but the general gist of these definitions are ok. Henrik | ||
| Bomber |
Kaese what kind of class? from whom? where? how muck? deatails, man, details | ||
| M1combat |
Read "Total Control" by Lee Parks and the "Twist of the Wrist" series by Kieth Code. | ||
| Bomber |
M1 -- yessir, both good reads, and I learned alot . . .. . also see Nick Ienatch's (sp?) new book . . . . a class, however, sounds very intriguing . . . . I find I learn bunches during the Q&A sessions, cuz others ask questions that don't occur to me (not difficult, as I have a tendency to develop tunnel vision and hear/read things that I'm focused on, while other, perhaps more valuable data goes whipping on by at a high rate of knots) | ||
| Henrik |
Max at Traxxion has a suspension seminar on DVD now. Haven't seen it myself, but read a good review on an SV board. Lots of good, basic information and how-to leading up to the more intricate details. Henrik | ||
| Blake |
Having to increase preload to achieve proper rider sag that then results in zero static sag is an indication that the spring rate is not optimally stiff. I max out the preload for my Cyclone's rear shock to achieve the rider sag that I want; always end up with zero static sag. For the typical street rider, static sag is not near so important as rider sag. Get the rider sag set within spec and you will likely be happy and fine. If you want optimum suspension performance, sure, go to a stiffer spring(s) that will allow you to back off the preload and achieve some measurable static sag. Also take note of stiction. When measuring static sag do it two ways and compare the difference. First work the suspension and slowly let it come up to equilibrium from being compressed; measure the sag at that point. Then work the suspension and let it come down to equilibrium from being extended; measure the sag at that point. The difference between the two sag measurements is the stiction. Large stiction values are undesirable and indicate excessive friction in the suspension component being measured. Henrik, do you recall what Traxxion says is too much stiction? I seem to recall that Max says that anything more than 5mm (~3/16"  indicates a problem? To clarify, the rear sag measurements that are typically discussed in the industry are for for actual rear axle travel. Measuring sag directly at the rear shock will yield much different, significantly smaller numbers, usually close to a factor of 1/2 or so versus sag as measured at the rear axle. | ||
| Henrik |
Stiction; don't recall the actual number, but I'd be unhappy with more than 5 mm. If you don't dial out all the damping prior to doing the "bounce and measure" you'll end up with more stiction in your measurement. For your sag measurement, add the two numbers you get (lift & settle + push & settle) and divide by 2. Oh, and remember to keep notes on your settings so you can get back to where you were. Henrik | ||
| M1combat |
Sooo, If I end up with 25mm total sag and NO static sag... am I in grave danger or is it just not optimal? edited by m1combat on March 18, 2004 | ||
| Henrik |
Just not optimal. I think you by total mean Rider Sag = 25 mm, Static Sag = 0 mm - so I'd dial out some preload until I got 30 mm of Rider Sag and see how that felt. A friend of mine, who races vintage bikes (and really like to talk and explain ), claims that proper suspension set-up will do more for your lap times - and/or general cornering comfort - than anything else we buy for our bikes. In other words; the $5-800 we'd easily spend on a pipe, filter and ECM, would be much better spent on a quality shock and front end rework to make it fit you perfectly. At least if you are looking to go faster where I think it's most fun - in the corners. Well worth getting someone experienced to help with the set-up and dial-in recommendations. Marcus comes to mind. Henrik edited by Henrik on March 18, 2004 | ||
| Marcus_mcbain |
I hadn't really seen any correct answers, so here is some info. 1) Stock bikes - Generally, all rules are out the window. The only time I actually obey static/rider/total sag protocol is usually with a rider in the 150lbs. range. Most street bikes are terribly undersprung. 2) In the absence of proper springs, set your total sag to 37mm. Don't use the 100.00 part of the fork (springs) to tune, use those dials on the 900.00 part of the fork to control your suspension. Here are some good articles that will help you understand the principles a little better from www.roadracinghelp.com http://www.roadracinghelp.com/TechArticle/February/February-Tech.pdf http://www.roadracinghelp.com/TechArticle/Tech803.htm Oh yeah, if you want your suspension on your XB optimized, I can handle that. Most have seen this, but I will post it again. http://www.roadracinghelp.com/TechArticle/January/Main.htm I am writing an article on how to set sag this month for the CMRA newsletter and will post a link when it is published. Thanks, Marcus | ||
| Kaese |
Ok Bomber, here is the scoop on the Suspension Clinic I attended. The good news is that it is free and is conducted by a suspension tuner. The bad news it that is in Redwood City, CA. Here is the link with everything DocWong Offers: http://www.docwong.com/st-clinc/index.htm | ||
| Bomber |
Thank you sir! hmmmm . . . .wonder if I've got enough Freckie Flier points saved up! | ||
| Marcus_mcbain |
Last thing. If you find a website that posts "generic" numbers for your suspension...RUN AWAY. It is a dangerous thing these guys do. I have found numbers actually work good less than 10% of the time. I have had many customer come to me after crashing their bikes when they just setup their bikes with Publication X numbers. They confidently go down the road and WHAM, they crash. This is why this is dangerous stuff. 1) When tightening up a fork cap, a 1/16th of a turn difference of when I tighten the cap will cause the adjusters to be a 1/4 turn off from where I started. If there is a 1/2 turn difference, then the adjuster is over a turn off from spec. 2) Every mm of variance on the preload spacers makes 1.25mm of sag difference. I understand that it is hard to know what to do when you first start approaching suspension. I have sincerely done my best to provide as much free ACCURATE information as possible. I put it out there so you don't screw yourself like I did my first 5 or so years of riding. I kinda get on soapbox on this subject as I see so many shops and individuals ripping people off because it is easy to be a self pronounced "expert" when you talking to someone who doesn't know the subject in the first place. Lastly, this is a hobby for most everyone. It is fun to be your own suspension guy or have your buddy that knows a little more than you, twist knobs. At the same time, we are riding motorcycles that easily go fast enough to kill the rider in just moments if the wrong decision is made or the equipment does not perform properly. Just keep that in mind. Marcus McBain | ||
| Kaese |
Marcus, do you happen to know the shock travel on the Stock Showa rear for the XB9R? I asked the question and someone had quoted the rear swing arm travel was at the ratio of 1.85 and the shock travel was 70mm. I couldn't find any suspension specs anywhere. I used 129mm for preload. Think I am using the correct numbers? Thanks | ||
| M1combat |
The sag measurement you stated up there... that is good for an XBXR I assume, and should that be front and rear? Also, where should the forks be in the triple tree? I am thinking (wild guess here...) that at 37mm total sag on the front and rear I should hold a level to the bottom of the exhaust and adjust the front forks until it's level??? I'll be seeing you some time this summer in Colorado or New Mexico to setup my bike and I may send you my forks beforehand to have you work on them (it all depends on if I can get the money together). Thanks in advance. If you think any of the answers are giving away too much of your secrets don't worry about it. I understand you are running a business. | ||
| Marcus_mcbain |
Kaese - If I told you anything I would be lying as I have not paid attention to it, becuase I haven't seen it come up as an issue. The one item I did look at in the Showa OEM shocks is if they had a bumper inside. (They Don't). I wanted to remove it if it did to get an extry 15mm of ride height. M1 - It depends on the tire. Don't drop the front end. Although the trail is short stock, the lack of any rear ride height prohibits raising the front to gain trail, unless you want it to be a true Harley chopper  Marcus edited by Marcus McBain on March 18, 2004 | ||
| Aesquire |
Thanks! I've never had any static sag, when my bike was setup with aprox the right rider sag. I mass over 200lbs though. Diet, & stiffer springs, got it. | ||
| Marcus_mcbain |
Really, you want to put on a Penske if you are going to ride the bike regularly on back roads/track days. I sell the shock for about 849.00. Let me know if you need this, Marcus McBain www.roadracinghelp.com |
