[Mike_B]

I've seen some rumors flying around on here about which spring has a heavier rate, which brand and what machines need spring adapters. I've seen rumors elsewhere that the springs are the exact same thing, produced in the same plant, with different colors.

I reached out to Highlifter via email and asked them what their spring rates are for a set that fits a 2020 850 Premium. I asked where the spring adapters are required, and why.
The general sales manager replied to me.
HL "Our app needs updating. You will need this kit. We add 50lbs. of extra capacity over stock springs."
ME "Are the adapters needed for front, rear, or both?"
HL "One kit is required for each front or rear spring kit."

I was surprised to hear that they are recommending the adapters for both front, and rear shocks on the 850. There is much talk here about front spring adapters required on the 850. I've never heard rears are required.
It would have been nice to have actual spring rate values.

I reached out to EPI via email and asked them if their springs are heavier or lighter the HL, why their springs do not require spacers when others do, and if there is any truth to the rumor that EPI and HL products are the same thing, different color.

EPI: I don’t know the highlifter rates. Our front id 252 lbs per inch and rear is 150 lbs per inch. Most all of our springs are black, we have a few models available in red also. I’m guessing the require an adapter is because they are trying to make an older spring fit. ours are built based on the stock springs just 20-25% stiffer. hope that helps.

My curiosity is not satisfied!
I would like to do a comparison of the HL springs vs the EPI springs.

Hypothesis: HL Springs have a higher rate than EPI Springs.

Purpose: To provide information for those that wish to purchase. I don't think that having a lighter, or heavier rate is good or bad. It is up to the consumer to decide what suits their needs best. Most folks would probably be fine with the stock spring rates if they didn't end up squatting so soon.

Testing procedure:
Step 1. Spring rate test: I don't own am official spring testing machine. However, I do own a hydraulic press, a tape measure, and a scale. The idea would be to place the scale on the press, the spring on the scale, and use the press to compress the spring. Take measurements on spring height with a ruler and take weight readings on the scale. Disregard the first inch of compression. Take readings on the 1st, and 2nd inch of compression and do the math. Readings would be taken on OEM, EPI, and HL springs, front and rear.

Step 2. Physical examination of OEM, EPI, and HL springs, front and rear. Coil OD measured, coil count, length, and ID measurements. Compare ID measurements to shock OD.

Step 3. Spring fit up to shock. Show how each spring fits on the shock body and verify whether or not a spring adapter is required.

Step 4. Ground clearance on machine. Install each set of springs on the vehicle and measure ground clearance. A spot on the machine will be marked, a spot on the floor, and tire pressures monitored to assure consistency.

I plan to reach out to both EPI and HL again to see if they would be interested in supporting this test by providing the products. It would be great to see them both get involved. I don't have high hopes as it seems everyone is focused on SXS sales and support these days.

 

[Gmartino100]

Sprotsman and I have had many a conversations on this topic. The EPI’s are sold individually and they spec 252# for front springs and 150# for rear. HL claims 100# additional rate over stock if all 4 springs are changed, which is 25# per spring or 50# per set as they told you. Stock spring rates on the 850 are 180# front and 120# rear. Based on this, EPI are stiffer.

 

[bp405]

I can tell you this I put the highlifters on the 570 and the EPI's on the 800. G and I have discussed this before as you have found out Mike there are no numbers from highlifter to compare. Now my 570 and 800 take the exact same spring in both the highlifter and EPI version. So I am comparing apples to apples when I say the high lifter spring is much more heavy duty than EPI spring. It has more coils and it has thicker coils. The high lifters also are a progressive spring whereas the EPI is not. I will say this that the highlifter spring does take away that plush ride that Polaris is known for. The highlifter springs produce a much harsher ride than the EPIs. Now that's good and bad depending on what you're looking for. I was looking for heavier payload for the second passenger, more ground clearance, and less bottoming out when riding by myself in a spirited manner. Another positive of the highlifter spring is it also corners very well over OEM. I can't say anything bad about the EPI's other than launching off of water dams the machine would bottom out. All in all the EPI's are well balanced both for comfort and getting after it on the trail.

 

[Gmartino100]

That may be the case for the 570 springs, but the literature states differently for the 850’s. I have a set of 850 rear EPI’s that I haven’t installed yet. I’d be willing to count coils, height and thickness to compare to HL’s. What do you mean by progressive spring rate?

 

[Mike_B]

I've reached out to both vendors to see if they would be willing to donate parts to the comparison. I'll report back with their responses. I don't think there will be a winner or loser here. It all depends on what you are looking for as a rider. Either one is a great upgrade over OEM.

After hammering on my 570 a few years, the rear wheels looked like they were ready to fall off. Even with no load on it, the rear wheels looked like this /-----\. I installed some aftermarket springs and it instantly corrected the issue. They greatly reduced body roll. I can execute corners with extreme prejudice and not feel like I'm going to roll over. I do have to add a bit more body english to transfer weight in certain situations. Its not an issue, just had to adjust the way I ride a bit. I would not describe the ride as harsh. It is definitely more firm. I find it easier to go faster with the HD springs. On a side note, my ground clearance was definitely increased! I did not measure it with the worn out, stock springs. But, with true 26" tires (Bearclaw HTR) and HD springs, I'm sitting at 12" on a 570.

 

[bp405]

Granite each model specific spring is going to be a little bit different. it's not a progressive spring rate it's a progressive spring. A progressive spring provides essentially two spring rates within a one piece coil. This picture is a good example. This is a job I'm doing on a 2020 canned ham 850 XT with 300 mi on it. Stop springs just aren't cutting it. As you can see on the highlifters on the right the top of the spring is the progressive part as the turns in the coils gets more numerous.

 

[Sprotsman]

So OE 570 springs are:
Fronts-90/Rears-100
HL HD says they add “about 100 lbs. So if you add 25 lbs. to each you’d get:
Fronts-115/Rears-125

EPI 570 springs are:
Fronts-120/Rears-120
————————
850 Springs OEM:
Fronts-180/Rears-120
Adding 100 lbs. for HL HD
Fronts-205/Rears-145

EPI:
Fronts-252/Rears-150

The numbers for the 570 seem more realistic. The 850 numbers go haywire! Front OE the EPI fronts supposedly jump 72 lbs.!!!!! So on paper EPI says theirs are higher but most feedback says the opposite.

Could be misprint on EPI 850 numbers. Also, can’t discount bp405’s real world observations, compared to what a website says! Mike it would be interesting for you to get some side by side comparison’s.

 

[Mike_B]

Highlifter says they will "Get back to me ASAP"
I'm hoping they decide to participate. I'd be excited to do this test!

 

[Mike_B]

So I got some official feed back from EPI. See below:

From EPI Director of Sales, "we sell a ton of these springs every year and don’t have any call backs on them not performing as expected. Our spring engineer is top notch and very familiar with OEM spring designs so we are very confident that what we offer works and fits as it should. Also, I can tell that our springs are different than HL ones, not just a different color. Ours are made here in the Midwest with our own design from our spring engineer, who also engineers our clutch springs. I am not sure how HL comes up with their fitments or rates.

On that front spring for the 850’s, I saw some questions on why our rate is 252 lb/in. To answer that, Polaris played with several different springs rates over the years on these machines and if memory serves me correctly they ranged from 180 to 210 on the OEM side. We made the decision to use the 210 as the one to base from, so our 252 rate is at our minimum increase of 20%. I believe the OEM spring # on the 210 lb. rate is 7043713, the 180 lb rate is 7043708. So yes, on the ones with the 180 rate OEM springs, ours would be more like 40% stiffer rate. We would rather have it little too stiff than not stiff enough since most of the time the guys using these are using them in a work type application where load capacity is important (along with ride height, like with a plow mounted). Hope this helps answer your questions."

I've got a set of EPI springs on order.

Haven't had any additional correspondence with HL since they said they will get right back to me.

I plan to provide the data listed in the first post for EPI and OEM springs. Would be nice to get some HL ones here too.

 

[Gmartino100]

So based on the information provided by EPI, their springs are in fact stiffer. Now maybe HL is being conservative with their 100lb increase overall or maybe 100lb additional load capacity doesn’t translate to 25lb/in additional spring rate.

 

[Sprotsman]

Had the same thought G! It’s strange cause it seems like everyone always said HL was stiffer. Maybe they don’t say specifically as to not scare away prospective buyers!

 

[Mike_B]

I've had the EPI springs sitting here for a bit. High Lifter declined to participate. Finally got a chance to play in the garage this weekend.
So, my "test" is stock vs EPI.
I'm part cave man so my methods may be considered crude.
Here is what happened.

Step 1. Spring Rate Test:

I put a piece of steel on my bench vise. I put a scale on top of it. I put a small plate on scale. A spring on the plate. A plate on top of the spring, and compressed away.
A real spring rate tester compresses the spring 1" and then starts the test procedure from there. The second inch of compression is usually where the measurement is taken.
Due to what I had available that did not work for me. What I did was load each spring with 100LBS of pressure. I measured the spring at that point.
Then, I cranked the pressure up to 300LBS and measured again.
I used some basic math to come up with the rate.

IE, If my measurements are 100LBS = 9 11/16" spring length and 300LBS=8 7/8"; THEN 200LBS= 13/16" of compression
13/16"= 0.8125

0.8125 = 200
1 = X You need to cross multiply, then divide to get the answer. 200 x 1=200.

200/0.8215= 246LBS

I tested each spring at least 2 times. I recorded and averaged the tests.

Step 2. Physical Comparison

I took physical measurements of all springs. Overall length, number of coils (not counting the "seat" on each end), Outside Diameter, and Wire diameter. Actual spring diameter can be achieved mathematically by subtracting 1 wire diameter from O.D.

Step 3. Spring fit up to shock/are adapters required.

The EPI springs fit the shock body and adjuster just as well as OEM. No need for adapters.

Step 4. Ground clearance on machine. Install each set of springs on the vehicle and measure ground clearance. A spot on the machine will be marked, a spot on the floor, and tire pressures monitored to assure consistency.

The EPI springs added 1" of ground clearance. This machine only has a couple hundred miles on it and the OEM springs were still pretty tight/no signs of sagging.

Results are listed in the chart.
I've included photos of the test procedure, spring removal, ground clearance measurements, etc..

 

[Mike_B]

Some more photos. Could only add 10 at a time

 

[bp405]

Mike post a pic of one of each of the front and rear EPI springs if you would.

 

[Sprotsman]

Yeah, I’m a bit confused looking at them side by side at least for my 570 the Highlifter HD’s wire diameter is much more noticeably thicker. Also, advertised OEM 2020 850 rates are 180# fronts and 120# for rears.