Dumb question about sag

[DirtJunkie69]

11 minutes ago, kbro45 said:

You are measuring incorrectly.  Wth 20mm preload its not possibly that you have so much static sag.  How are you figuring 20mm preload? 

I'm measuring the exposed threads on top of the preload collar.

[kbro45]

15 minutes ago, jacob429 said:

I'm measuring the exposed threads on top of the preload collar.

well theres the issue.  you need to measure the length of the spring unloaded and then again with the collar screwed down.  so if the spring is 250mm, then you add preload and it measures 240mm, you have 10mm preload.

[MartyMOOSE]

You need to measure the spring free length with no preload on it, then measure it again once preloaded. Your figures make no sense 25mm pre load and 49mm static @ 160lbs, 25mm is a huge amount pf preload on any spring. 

MM 

[kbro45]

try this:  unwind the collar completely, then wind it down until it contacts the spring.  Then go 5 full turns.  Then posts your sag numbers.  At your weight that should put you in the ballpark.

[MartyMOOSE]

8 minutes ago, kbro45 said:

well theres the issue.  you need to measure the length of the spring unloaded and then again with the collar screwed down.  so if the spring is 250mm, then you add preload and it measures 240mm, you have 10mm preload.

Ha beat me to it ??

 

[FORMA MOTO]

59 minutes ago, kbro45 said:

You are confused about what a tolerance is.  If the spring was 10 percent off, it would be OUTSIDE of the tolerance.  No company would stay in business if they had a policy of shipping out springs that are 20 percent off.  Of course mistakes are made.  Racetech Faq says 5 percent is industry standard.  

I'm not confused. If it were 10% off, it would not be outside of tolerance unless the tolerance was stated to be +/- 9% of the stated measurement.  'At measure' is zero deviation. In tolerance is within the stated range. Out of tolerance is outside the stated range.

You have obviously never owned a Suzuki or a 90's Honda, where the springs were so cheap and progressive, no one knew how to rate them....so they just grabbed a number and used it. 

Ask any suspension shop that has tried different spring companies, and most will have a brand that they know measures accurately and within their stated tolerance. Diverse is the only company I have had experience with good tolerances, that is why I mentioned them. I have three Race Tech springs in my garage marked at 6.0, and they are closer to 5.5......because we meausured them after being unable to make the math and the sag measurements come together....

I don't want to derail this post about the OP's issues with sag, but he really needs to do some reading so he can wrap his head around it.

......and how do you get a 20mm compression and sill have a static sag of 50mm ??? Some one is not measuring correctly

 

[Piney Woods]

1 hour ago, kbro45 said:

well theres the issue.  you need to measure the length of the spring unloaded and then again with the collar screwed down.  so if the spring is 250mm, then you add preload and it measures 240mm, you have 10mm preload.

This! This! This! And yes, Race Tech claims to be within 5% tolerance. I have found mine to be very accurate. My oem Honda springs are very accurate also.

Edited October 20, 2017 by YHGEORGE

[LSHD]

Jake, we can set sag on Saturday in just a couple minutes. Also, if you are harsh on roots (square edges), you probably need to adjust low speed compression clickers softer (unless you are packing due to too much rebound).

[DirtJunkie69]

4 minutes ago, LSHD said:

Jake, we can set sag on Saturday in just a couple minutes. Also, if you are harsh on roots (square edges), you probably need to adjust low speed compression clickers softer (unless you are packing due to too much rebound).

Hey LSHD, you da man. I bet the stock clickers would be just fine once I get the sag set up. When kbro asked me how I was measuring, I actually started thinking about it and was almost too embarrassed to post the answer. Kind of figured it out when I answered it and realized how silly it sounded. Still not sure what the term packing means though.

[LSHD]

Packing is when your rebound doesn't have time to recover after a series of deflections. Bike starts to sit and then gets really harsh and bounces you around. Cure is less rebound damping, even though it seems like you need more.

[DirtJunkie69]

Makes perfect sense!

[ballisticexchris]

The numbers add up and it works. My Beta handles as good as most bikes out there. I do a lot of careful setup to get the suspension just right. 

3 hours ago, kbro45 said:

I have seen a number of foolish posts by Chris that demonstrate he struggles to understand preload and sag.  

 

My information comes from actual careful measuring and testing. Just making a typed statement of someone leaving a “number of foolish posts”. 

3 hours ago, jacob429 said:

Why would a longer spring take more preload if it's the same rate?

If you have to springs the same rate and one is longer than the other it takes more preload to get the same sag and rate during travel out of the longer one. Please don’t mine or anyone else’s word for it. Measure and come up with your own conclusions.

Edited October 20, 2017 by ballisticexchris
Grammar

[weantright]

14 hours ago, jacob429 said:

Why would a longer spring take more preload if it's the same rate?

It won’t if the rate is correct. Rate is measured by force over dinstance and while Chris believes in what he is saying it’s not true.

13 hours ago, kbro45 said:

I had to stop after you claimed the typical tolerance is 20 percent.  So I order a 5.0 and I might get a 6.0 ?  Thats ridiculous.  5 percent is more of the normal tolerance.  

While 20% seem a stretch, tuners I have worked with all measure the spring for length, rate and diameters when choosing. Most see just over 10% with certain brands while the better ones are Cannon and WP. 

[basalt]

16 hours ago, ballisticexchris said:

The numbers add up and it works. My Beta handles as good as most bikes out there. I do a lot of careful setup to get the suspension just right. 

My information comes from actual careful measuring and testing. Just making a typed statement of someone leaving a “number of foolish posts”. 

If you have to springs the same rate and one is longer than the other it takes more preload to get the same sag and rate during travel out of the longer one. Please don’t mine or anyone else’s word for it. Measure and come up with your own conclusions.

Spring force is F=kx where k is the spring rate, and x is the distance displaced. IE, length of the spring is irrelevant.

 

See Hooke's Law.

Edited October 20, 2017 by basalt

[basalt]

And while I don't want to jump into the tolerance pissing match, I think tolerance, out of tolerance, and quality control are getting confused with each other.

[Piney Woods]

Eibach is another brand that claims a very close rate. But I did have one of their fork springs break once, never did understand that.

[ballisticexchris]

1 hour ago, YHGEORGE said:

Eibach is another brand that claims a very close rate. But I did have one of their fork springs break once, never did understand that.

 

20 hours ago, YHGEORGE said:

This! This! This! And yes, Race Tech claims to be within 5% tolerance. I have found mine to be very accurate. My oem Honda springs are very accurate also.

Since around the year 2000 I have been using nothing but Race Tech springs. I too have found the rates are very accurate. I have them measure the rate at the shop as well as my local suspension tuner. They always match up to what's marked on the spring. 

While suspension is a very subjective topic, it's important to test and see how it works. I always try show the measurements and do a lot of testing with different settings. Just wait until you bag up one of these beasts and have to get it to work good with the same springs on a 350lb vs 270lb bike.

The best suspension purchase I ever got for my Beta is the quick adjuster. And also going out to the desert and testing all kinds of different clicker and preload adjustments.

It's really too bad that some guys come on here and give out such misinformation with nothing to back up their claims. Lots of laughable statements like "it wont work", "Chris making foolish posts", and my all time stupid favorite quoting "Hooke's law" (this one always seems to make it into suspension threads). 

 

 

Edited October 20, 2017 by ballisticexchris

[Piney Woods]

All I know for sure is that you guys with a bazillion miles of open land to ride are very fortunate.

[ballisticexchris]

12 minutes ago, YHGEORGE said:

All I know for sure is that you guys with a bazillion miles of open land to ride are very fortunate.

You got that right! I’m very grateful to live here on CA. It’s prety much open off road riding everywhere right out my door! 

[MartyMOOSE]

On 19/10/2017 at 8:59 AM, jacob429 said:

Hey guys, I have been thoroughly enjoying my 2018 300rr but have 2 issues with it. First, I really love the suspension in most of my riding and haven't touched the clickers, I have never had a bike track so well through the whoops. However at my first hare scramble, I got myself pretty wore out on the last lap and did a lot of sitting in terrain that got really chopped up and absolutely infested with roots. The shock was harsh in the roots, sitting or standing but painful when sitting. I recently set the sag to 105mm (from 90mm) to help in sandy corners. I'm wondering if maybe I'm not even measuring sag correctly because I'm 159lbs without gear and seem to have the preload collar wound down a lot, it was almost at the bottom out of the box and has been backed off a few turns to get the 105mm rider sag (still at least 15-20mm preload). I have a helper measure with a measuring tape on the left side of the bike, from the bottom of the axle nut to a point on the fender straight above it. I have looked at the manual and I seem to be doing it right but it doesn't make sense to me to have it wound down so much at my weight. So I wonder if the harshness is due to the excessive preload, or do I have too much sag and riding too low in the stroke?

 

The other thing is the bike seems to get hot. Just about any time I do a hill climb or slow hard terrain, the idle seems to climb a lot and I often hear a ticking noise at idle like a plug knock and it's kind of unnerving so I usually ride faster terrain to cool it off, I haven't boiled it over yet. *Edit: i should note that this can happen after just one or two climbs after riding fast terrain, doesnt seem to take much for it to happen.* I did increase the fuel/float level a bit so it's near stock, thinking it was getting fuel starved (the dealer lowers the floats a bit due to customer feedback about the bike pissing fuel a lot on side stand etc) but I don't think that has had any noticeable effect. I heard about bad head o-rings allowing pressures to expand in the rads and causing problems like leaky tstats, and I have seen a mysterious puddle under the bike in the garage once but couldn't track it down to anythinf. Thoughts?

To the op download this PDF and read it and use it http://www.teknikmotorsport.com/Offroad-MX-Enduro-SX-Motorcycle-Suspension-Tuning