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Discussion Starter #1
My main ? is how is ride height related to setting sag. It seems like it wouldn't matter. My current understanding is you set sag with preload and then use ride height to make the bike turn turn faster/slower. After riding around on the stock shock for the past 35+K miles, I decided that it was time for a serious upgrade. I installed an Ohlins shock over the w/e and put about 200 miles on it. I was trying to hit the ill maintained back roads. Well, it worked better than the stocker (duh), but wasn't quite what I expected....The bike was hard as a rock over major bumps (bouncing me off my seat). It was better than stock in bumpy corners ridden aggressively, but I think there's more. I'm now deep in the black art of suspension tuning and I need help.

I got home and reset everything to Ohlins' reccommendations last night. My dealer had said he "had it close" for me. As it turns out the shock had been set for very little compression and similarly little rebound with 19 mm of preload. Now, Ohlins reccommends 12mm of preload and 14 (out from closed?)on compression and rebound as a base-line on the SV . Once I got the compression and rebound back to 14 (without yet touching preload because the dealer said it would take the spring a while to settle), I couldn't even compress the shock when I bounced on the bike (140lbs of bounce). However, after I backed off the preload to 12 mm (12 lines showing), the same compression and rebound settings yielded a much different result. I can now get the shock to easily compress. I haven't ridden it since I made the changes, but I suspect that the ride will be a tad plusher since the shock looks like it may work (rather than just the spring). Any tuning pros with suggestions? Also, can I set the sag now or should I wait for the spring to "break in."
 

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You should really take it somewhere that really knows how to set up suspensions. If you had it done at a shop, and they didn't have you get on the bike and bounce it up and down with you on it, and then with you off it, and measure both loaded and un loaded sag, IMPO, I don't think they are doing it right.

I just took mine to a shop that I had it done a while ago. The first time I had it set up, it was a world of difference from stock, and now I brought it back, cause my riding style has gotten more agressive, and I wanted quicker turn in. We made more adjustments, and it again, it feels much better....almost the turn in of my GSXR, just with the added SV weight factor.
 

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Ignore whatever Ohlins tells you about preload. Have a buddy help you set the sag yourself. You want 30mm of rider sag. If you have the right spring rate, ideally you'll come out with around 10mm of free sag.

Sag is ride height. If you have 5mm less sag it will have the same effect on sharpening steering as adding 5mm of ride height. BUT, sag is different because it keeps the suspension in the proper range. You want about 30mm with you sitting on it because that is roughly 1/3 of the suspension travel, so that the suspension can compress for acceleration and bumps but also has room to extend, say under braking or over dips. So, ideally you get the sag in the right range and then you use the ride height adjuster for changes. If you use sag to make major changes in geometry you are compromising the suspension's range.

If you couldn't get the shock to compress while bouncing on it, you most probably had it preloaded so much that it wouldn't move (zero sag).
 

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Discussion Starter #4
Thanks guys, very helpful both.

As for the shop. I just bought it from them. I installed the shock myself for the added reward (well, that, and "saving" $90 from install made spending so much on the shock more palatable to my wife). But, he told me it was close.

Anyway, the shock looked the same length when I installed it with 19 lines showing, so I suspect that it is shorter now that I reduced sag my 7mm (is that right?).

I'll check free sag by myself next time I have a chance and see where it ends up. Assuming the correct spring (which it should be because I ordered it according to my weight) should I get free sag in the ballpark by setting the preload and then static sag (me on it) will also be close?
 

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Nimbus said:
Anyway, the shock looked the same length when I installed it with 19 lines showing, so I suspect that it is shorter now that I reduced sag my 7mm (is that right?).
Yes if it sags more the ride height is lowered.

Nimbus said:
I'll check free sag by myself next time I have a chance and see where it ends up.  Assuming the correct spring (which it should be because I ordered it according to my weight) should I get free sag in the ballpark by setting the preload and then static sag (me on it) will also be close?
That worked for me, but Ohlins reportedly has a habit of shipping out the stock spring rate.

Edit: what does it say on the spring? The rate is usually on there somewhere in newton/mm.
 

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Ditto every bit of NoSquids excellent advice and explanation.
To include Öhlins very possibly supplying with the wrong spring, despite it allegedly being set up right for you. I do a lot of tuning and some sales of Öhlins, mostly on BMWs, and this happens all the time. And being that we're both lighter than average, it affects us significantly.

So, as NoSquid said, what is the spring rate printed on the spring.
It's not worth proceeding until you know that. But if you're totally topped
and have no motion when bouncing, then it is severely off. Likely indicating both rate and preload too high.

Also, the Öhlins, though very nice, tend towards pretty heavy high speed compression damping. Couple that with too much spring, and it may indeed feel very harsh.

Also, terminology varies, even among experts (I've had formal engineering courses in this, plus seminars from Foale and RaceTech) but generally, free and static sag are the same thing (how much the suspension compresses just under the bike's weight. The sag with you on it too is variously called rider/race/laden/total sag.

I prefer the method/check already described by no-squid.
Adjust laden sag to your preference (I like 35mm street and 30mm track or aggressive street) via preload. Then check your freesag. Anything from about 5-20 is borderline acceptable, but if you get 10-15 free/static sag, then your rate is about right. I'm very happy with an initial spring setup when it gives me sag numbers of 12 and 32mm. A few mm eitehr way is just quibbling, and you can then go up or down a rate depending on personal preference and how the bike is handling.

So, set your total sag to about 30mm and see if your free sag isn't about 10mm.
If so, you're OK. You could in that event, drop a spring rate for more comfort, but the harshness normally comes from severely mischosen rates, or much more often, too much high speed compression damping.

let us know your rate (from the numbers stamped on the spring) and your sag numbers. I bet we can get you set up well.
 
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yea,keep waiting for spring to settle ;D
what year is your sv and what numbers are stamped on spring?
 

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Discussion Starter #8
Wow, that's a ton of great info. I'll have to check on the spring rate tonight after work(I hadn't thought to look when I got it home). I think I said this earlier, but after I backed off the preload to what Ohlins recommends as a baseline the bike was much, much more compliant (sitting in the garage). As it sits now, the bike seems softer than with the stock shock.
 

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Discussion Starter #9
TWF said:
yea,keep waiting for spring to settle   ;D
I assume you are being sarcastic?

The bike is a '99 Naked and I'll get the spring rate tonight after work. Maybe I'll be able to balance myself and the bike on the wall and have my wife do the sag measurements.
 

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You can safely assume that to have been sarcasm. Modern springs will settle little if any over any sort of reasonable timeframe. I wouldn't count on more than 2mm, if ANY.

What you have to be careful of in any tuning and setup work, be it carbs, injection, forks, or shocks, is the placebo effect. We tend to make observations in accordance with our expectations.

i.e. if we think that backing off of preload makes the shock feel softer, then we observe just that.

In reality, except for the special case of preload being so heavy the bike is topped, that does not happen. lowering preload does NOT affect plushness. Period. That is not the way springs work.

I encourage you to keep working on the setup. There's some good folks here that will help you and you'll learn a ton and have a better bike. Just keep and open mind and down let yourself believe a sugar pill is making you better. :)

Do let us know your rate along with the preload and sag
 

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Discussion Starter #12
Here's what's printed on the Spring:

O1091 29/90 LO95

I have no idea what that means. I think I go about 63.5 kilos (135 lbs).
 
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Nimbus said:
Here's what's printed on the Spring:

O1091 29/90 LO95

I have no idea what that means. I think I go about 63.5 kilos (135 lbs).
514# spring.same as stock.
you need stiffer spring even tough you dont weight much :).600# spring is what I would use in your place.
 

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Discussion Starter #14
Wonderful. I suppose that will make my sag numbers off. I can't check even free sag yet as my car's current flat tire is requiring the use of my jackstands :'( And my wife is off doing Mary Kay stuff so I have no measurer anyway. :-\

So, is the 514# spring even close? I was planning on making this my track bike someday. Currently it lives its life as a hard ridden street bike.
 
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Nimbus said:
So, is the 514# spring even close? I was planning on making this my track bike someday. Currently it lives its life as a hard ridden street bike.
about 4 sizes off.most racers use 650# one.for your weight 600 or 625 would work.
I use 675 or 700 for my 200#.and my bike is at least 70 pounds lighter than your.
 

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Wow, 514#. Light. The shop should have asked you what your weight was before they ordered it for you.

Problem with too light a spring is that your rider and static sag values will not both be in their proper respective ranges. Set the preload for correct rider sag, and you will have too little (if any) static sag. Set the preload for correct static sag, and you will have too much rider sag. The correct spring will put both numbers in the correct range.
 

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Discussion Starter #17
I weigh 140lbs, and the shop knows that (he asked). He knows how I ride (as he has seen my tires, ground pegs sans feelers, and knee sliders). I'm seriously hoping the sag numbers are correct. I won't know until tomorrow when my dad gets here and we can measure. I will be so utterly pissed if I have to take the stupid shock back off the bike so he can fix his mistake. I bought from him as opposed to SV Race Shop because he is the "local dealer" and he assured me that he would be building the shock himself to fit me. He also told me specifically that he would have the right spring whereas if I bought elsewhere I may not end up with the proper rate. I guess we shall see, eh? Maybe the sag numbers by some small miracle are correct. Thanks so much for all the help everybody. I'll keep you posted.
 

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Hi all,

What I don't get here, is that the sag numbers I get are a good deal different from what some of you (TWF et all) must see.

I don't recall my exact numbers, but they were on the order of static 10mm and race 30-35, which is normally about what I like. I too weigh about 145 and manage to get those numbers with a spring a bit under 500lb

For you light guys running 600lb or more springs, what kind of static sag are you running?
I'd think quite a bit to keep preload light enough to get race/rider sag right.

I understand all you're saying about setup, and agree, but I end up with significantly different rates to get reasonable sag numbers.

I'd like to see some guys chime in with some 4-point data sets
Rider Weight, Spring Rate, Static Sag, Race sag.


thanks
roger
 
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rogsvr said:
Hi all,

What I don't get here, is that the sag numbers I get are a good deal different from what some of you (TWF et all) must see.
thanks
roger
what year bike and what shock.
 

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I've set up several with the circa '98 SRAD showa shocks.
99 and 00 1st gen models with riders on the light side. 140-155 lb
As said, that's given me sags of 10-ish/30-ish, with decent compliance and control.
I've had to make only minor shock valving mods, but that's probably down to having
springs that are only moderately stiffer than those shock bodies were equipped with.
I'm sure it's a whole different valving game when you throw on a spring that is 50-100% stiffer than original. But that's another topic.

I have to assume there's a whole in my knowledge specific to these SVs and or their linkage and/or their linkage in concert with the non-stock shocks, as I've never had trouble setting up many other bikes for myself or customers. Yet here, I'm seeing obviously suspension-savvy guys draw a different conclusion.

Makes me want to doublecheck myself and/or seek a bit of education/correction.

I'd be glad for any such insight, and thrilled to see a few examples of what others are getting for both sag numbers, along with thier weights and rates.

thanks in advance.
 
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