PDA

View Full Version : Cooter tests Red and Yellow rear coils.



Cooter
04-27-2018, 12:01 PM
My 2014 (#24) came with the yellow rear coil and I thought it was a bit stiff, so I got a red one and tested them both side to side while they were off the shock. I was surprised by what I found, so I re-tested 2 more times and got repeatable results.

https://farm1.staticflickr.com/958/26872749327_87c22b5739_k.jpg

https://farm1.staticflickr.com/907/41741160071_e200a9e1c9_k.jpg

Cooter
04-27-2018, 12:04 PM
Wire diameter .4240(Yellow) vs. .4440 (Red)
https://farm1.staticflickr.com/869/41741159731_bb83887d92_k.jpg (https://flic.kr/p/26AwmxM)IMG_0724 (https://flic.kr/p/26AwmxM) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickrhttps://farm1.staticflickr.com/981/27871942118_580ac9846a_k.jpg (https://flic.kr/p/JsWZmb)IMG_0725 (https://flic.kr/p/JsWZmb) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickr

Cooter
04-27-2018, 12:07 PM
The free height was 6.4" (yellow) and 7.25" (red)
https://farm1.staticflickr.com/863/27871941098_d91e467272_c.jpg (https://flic.kr/p/JsWZ3A)
https://farm1.staticflickr.com/944/41741160451_8c6efb9846_c.jpg (https://flic.kr/p/26AwmLc)IMG_0745 (https://flic.kr/p/26AwmLc) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickr
https://farm1.staticflickr.com/826/41700340062_0695c5ab82_c.jpg (https://flic.kr/p/26wV9ho)IMG_0744 (https://flic.kr/p/26wV9ho) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickr

Cooter
04-27-2018, 12:15 PM
The yellow weighed 1.85lbs and the red was 2.6lbs:
https://farm1.staticflickr.com/978/41741166461_e746b962ee_c.jpg (https://flic.kr/p/26AwoxP)IMG_0732 (https://flic.kr/p/26AwoxP) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickr
https://farm1.staticflickr.com/868/41741163741_e1307db4da_c.jpg (https://flic.kr/p/26AwnJV)IMG_0738 (https://flic.kr/p/26AwnJV) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickr

Cooter
04-27-2018, 12:17 PM
At exactly 1" of compression I got 475.5lbs for the red, and 496.5lbs for the yellow
https://farm1.staticflickr.com/906/41700344612_628718f313_c.jpg (https://flic.kr/p/26wVaCQ)IMG_0733 (https://flic.kr/p/26wVaCQ) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on FlickrIMG_0739 (https://flic.kr/p/26wV9UW) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickrr
https://farm1.staticflickr.com/978/41741162401_e3904c31a5_c.jpg (https://flic.kr/p/26AwnkP)IMG_0741 (https://flic.kr/p/26AwnkP) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickr
https://farm1.staticflickr.com/958/41700342182_4d3a3c7820_c.jpg (https://flic.kr/p/26wV9UW)IMG_0739 (https://flic.kr/p/26wV9UW) by Cooter! (https://www.flickr.com/photos/77190879@N05/), on Flickrhttps://farm1.staticflickr.com/964/41741164471_3a5a5dbd59_c.jpg (https://flic.kr/p/26AwnXv)

Cooter
04-27-2018, 12:25 PM
I thought there was supposed to be a much bigger spring rate difference than 20lbs?
I measured sag on the bike with both springs (220lbs rider weight) and couldn't measure a difference at the shock or at the tail.

Since there is an actual top and bottom to the coils as shown in the EBR tech video, I assume they are progressive, but I'll need to weld a jig together and get a higher capacity scale test the 2nd inch of travel.

Doug Porcaro
04-27-2018, 04:20 PM
Very interesting, thank you for your efforts

EBRRider
04-28-2018, 09:50 AM
Kool Facts Cooter. Great Job!!!!!!

Brian S
07-24-2018, 11:26 PM
Anyone mind if we revisit this thread for a couple clarifications?


I assume they are progressive, but I'll need to weld a jig together and get a higher capacity scale test the 2nd inch of travel.

Based on the pics, I believe the yellow spring is linear and the red spring is progressive. Even though the wire diameter is about 10% thicker, the SX appears to have 6 full coils vs 5 for the yellow RX spring. The initial spring rate should be lower having an extra coil. But as it compresses, the closely spaced coils come in contact, you get coil bind and it essentially becomes a 5 coil spring. Compressing further, the next coil binds and it effectively becomes a 3 coil spring. A linear rate spring will have even spacing between coils so no coil bind occurs until it's fully compressed.

I read somewhere the 2014 (yellow) rear spring should be 550lbs/in. The 2015 (red) rear spring is supposed to be 475lbs/in. But if the spring isn't linear that number won't remain a constant.

Cooter
07-25-2018, 07:51 PM
I don't believe there is a difference in RX and SX coils like you say, and the wire diameter is only a 2% difference, not 10%. There is not nearly enough travel on this shock to get into coil bind. Which would be very bad anyway.

Progressive coils can be made by varying the coils wire diameter, root diameter or winding rate. It happens, but rarely is a coil made to operate with coil binding as a calculation, because coil bind will kill a coil in short order.
One exception is the "3rd rate coil" on a very long travel coil-over shock. But that can work because they are built to sit at coil-bind and only extend when coils are at free height (shock extension) so all the coils are kept in position on their seats. They are not used to support weight.

I also read those rate numbers for these coils and thats what drove me to test them. My findings didn't support that rumor but who knows? I do know that a 75lb difference in coil rate would make the sag-height measurably different and that didn't happen either.

Initially I thought they were slightly progressive simply because they do have a top and bottom direction of install. I now believe that is not the case for two reasons.
1) There isn't enough travel in this application to make a progessively wound coil to get through its transition period.
2) The spring rate I found is written as a single rate (same as you did). Not as 225/500lb like a progressive coil would be written.

I'm still curious, and would still like a MUCH softer spring for me, even at 220lbs. Still tuning compression rates though. We'll see:)

konarider94
07-26-2018, 09:11 AM
Not sure where you got a 2% difference Cooter. Its almost 5% bigger diameter but that translates to almost 10% bigger cross section area which is what you need to consider for comparing the strength of one to another.

Why are you so focused on the spring for riding comfort or stiffness as you call it? Have you measured the amount of rear sag you have? You should be in the 20-25mm range. What have you done with the compression clickers? They will have a much bigger impact on dynamic stiffness. I cant believe that EBR got it that wrong on spring rate especially since I am just over the 200lb mark as well.

from the owners manual
"Ride Quality Enhancement1. The stock settings are designed to offer sufficientchassis control, but some may choose to enhance ridecomfort over rougher road conditions or for long rides.Reducing the compression damping will allow the suspensionto move more freely reducing road input to the rider. Adjust suspension for rider weight. See OPERATINGRECOMMENDATIONS, Suggested Suspension Settings, Table17, as the starting point.2. Increase ride quality by reducing front and rearcompression damping by turning adjuster counterclockwisefrom 1/2 to 1 1/2 turns.3. If additional ride quality is desired, reduce frontpreload by turning adjuster counterclockwise one turn.4. If maximum ride quality is desired, decrease frontrebound damping 1 turn and rear rebound by ½ turn."

Brian S
07-26-2018, 12:15 PM
Not sure where you got a 2% difference Cooter. Its almost 5% bigger diameter but that translates to almost 10% bigger cross section area which is what you need to consider for comparing the strength of one to another

Ya beat me too it. Here's the math I used originally.

The wire diameters are .424 & .444
I got 4.7% for the difference
.424 x 1.047 = .4439


2% would only be .424 x 1.02 = .432


But for comparison I used the cross sectional area of the wire as mentioned...not diameter.
P x R2
3.14 x .212 x .212 = .141
3.14 x .222 x .222 = .158
I said about 10% thicker (in terms of mass) for the estimate.
Didn't think I was gonna get called on it...should have said 12%
.141 x 1.12 = .1579


I was focusing on the measurements in the pics but I just realized the spring tested was not the same red spring in the first 2 images. I thought the shock was taken from the bike and the spring was removed from the shock so it could be tested.

The red spring in the first 2 was progressive. Coil bind is by design but it's not a problem because it only happens one at a time.

The 2 tested appear to be linear. 12% increase in mass doesn't explain the weight difference though. The only way the red spring could weigh that much more is if it had more coils. 6 coils should weigh 20% more than 5. That also would explain why the red spring is softer rate wise.

Cooter
07-26-2018, 07:23 PM
Kona, don't forget that setting up motorcycle suspension for the load being carried is only the starting point. Most people stop there, but there are a multitude of factors that dictate shock damping, including personal preference. I have been unable to adjust the rear of the bike to my liking with the speeds and the roads that I travel. i.e. With the rear preload low and the shock as compliant as I can make it the rear still skips over imperfections in a corner and oversteers. I have tried stiffer settings as well. I have new Q3+ on it. I have adjusted the front and rear almost weekly for 6000 miles and have concluded I want a lighter spring rate. Then I can begin to adjust the rear shock back to mid settings instead of compensating for what I believe is a coil stiffer than I like. Not to mention the kidney killing freeway expansion joints. I should be able to drop compression and raise rebound to smooth that out but no joy:(

Brian S: 2%-4.7% whatever, Thanks for the math, but we aren't calculating coil rate here, we have that already so it's a pointless... point? haha. I measured the wire diameter as accurately as I could but did not do it correct enough to argue percentages. Coil wire is not even round (a by product of making a coil) so I would need to measure its oval-ish shape and average it. I also did not take into account the possible powerdercoating thickness difference between the two coils. There are only 2 coils. I only had one red and one yellow coil. Perhaps the pic is upside down? I wouldn't throw a 3rd leg into this (poorly done:wave:) experiment.

I like this! I'll geek out on suspension all day, thank guys:pimp:

LeesEBR
07-27-2018, 11:25 AM
it's a pointless... point? haha.
moot point

I'm finding all this interesting. I want a yellow spring for the color, but like the softness of the red.

MakingPAIN
07-27-2018, 02:21 PM
Paint yours red lol...

hey cooter what are you running for setting on the red spring?? I can’t remember mine off the top of my head but I have mine pretty close to a comfortable setting for road use. you may ride harder than me. And we have a lot less curves to carve in AZ than Cali. I am 165 lbs soaking wet haha so mine may be way different than yours to start with

you seem into suspension set ups and would like your opinion if anything at all. Thanks in advance if you post back.

Why?because I just wing it and hope I feel it getting better under my butt.

Brian S
07-27-2018, 02:44 PM
I'm finding all this interesting. I want a yellow spring for the color, but like the softness of the red.

I'm glad you chimed in because I read your thread about lowering the bike. I want to do the same and didn't think anyone reached a conclusion yet.

In my first post I said 10% and was told I'm wrong. 4.7% is only half of the calculation. Konarider94 said 10% as well. I showed the work so forum readers understand we didn't pull the numbers out of thin air. If the math is wrong I want someone to correct me.

Cooter, could you double check the free height of the yellow spring? It may be a bit longer than 6.4".

konarider94
07-27-2018, 03:28 PM
In my first post I said 10% and was told I'm wrong. 4.7% is only half of the calculation. Konarider94 said 10% as well. I showed the work so forum readers understand we didn't pull the numbers out of thin air. If the math is wrong I want someone to correct me.


The larger area is 0.1548 so I think you missed a digit when rounding. Should be .155 and you get a 9.7% larger area. I was going to let it go but you literally asked.

Brian S
07-27-2018, 04:36 PM
The larger area is 0.1548 so I think you missed a digit when rounding. Should be .155 and you get a 9.7% larger area. I was going to let it go but you literally asked.

Thanks, I may have done it correctly the first time a few days ago but didn't write anything down because like I said....didn't think I was going to get called out on it. My concern about the red spring is the free length. The range of the stock shock is between 6.125 and 6.5 if I measured accurately. The scale shows the red to be a bit softer but if the free length is 7.25, wouldn't that add a lot more pre-load than a shorter spring? It feels like we're comparing apples to bananas here if we don't take the installed height into consideration. I have some general knowledge about the automotive industry but haven't worked on bikes very much.

Cooter
07-27-2018, 09:15 PM
Motorcycle and car springs work the same:). But decimals aside (.3%? really?), we have the answer already, as tested. No need to calculate anything.

With no pre-load adjustment, the sag height of the rear with either coil installed... Is the same (I don't have a laser....) If you want to lower the bike, that is an entirely different (and huge) can of worms. Miniscually lower free height with a barely measurable increase in spring rate aside, they are virtually identical. I firmly believe MFG tolerance could be the reason for the small measurement differences.

Cooter
07-27-2018, 09:21 PM
Hey Pain, I'll check my chart when I get home and let you know. My short-term memory is wack:lol:

Rb70383
11-18-2018, 03:51 PM
Old thread but does anyone have a black spring to test? Curious if the Black lightning was firmer since it was lowered?
https://www.ebay.com/itm/EBR-Motorcycle-REAR-SHOCK-SPRING-SHOWA-RACE-525-LB-IN-K0424E-08AZ-Rev-A1/202346315483

Cooter
11-20-2018, 03:20 AM
The link says it's 525.

Rb70383
11-21-2018, 04:34 AM
Goes complete opposite for the "softer" SX spring, however reduced suspension travel.

EBRRider
11-21-2018, 08:47 AM
Stay with ur red one at 475 lbs

Rb70383
11-28-2018, 06:40 AM
Stay with ur red one at 475 lbs

Tis my plan. just curious.

EBRRider
11-28-2018, 10:33 AM
Tis my plan. just curious.

I had my suspension tweaked at the Thunder hill track by a pro, he said it was way to soft he set it up for my weight and riding style.