Suspension

[manxman]

I have a 2014 RT. and trying to determine the spring rate per pound on the rear replacement shock. The spring that came with the shock is too soft and I have a replacement spring which is too harsh, 500 pounds per square inch. My self and rider combined wt.is 300#. without taking into consideration the wt. of the rear half of machine, what should I determine the wt. to be riding two up all the time? thanks for any input.......

 

[KX5062]

Are you factoring in the air bag, which is a designed spring helper and ride leveler?

 

[manxman]

Are you factoring in the air bag, which is a designed spring helper and ride leveler?

No, just the spring rate for the shock, the air bag I assume takes care of the machines wt.

 

[PMK]

I do not know the rate of the oem spring.

Springs are rated in pounds per inch of travel or kg/cm. If the stock spring has been removed, either estimate the rate using one of the many spring rate calculators, or better still, see if there is a local motorcycle or car race shop with a suspension spring tester.

On the stock RT, later models do not have adjustable preload. So if the spring you installed is longer the springs preload is increased. Added preload, combined with a higher spring rate will combine to possibly be to firm, even if the springs rate is correct.

Spring rate + spring force under preload determines net force but does not change spring rate.

 

[Arion]

I can't answer your question but I couldn't help but notice that you're "Manxman." Are you from the Isle of Man or do you have heritage with the island? As you can see, my avatar is the three legs of Man crest. My ancestors come from the Isle and I've been fortunate enough to visit five times now since my first and second Manx Grand Prix adventures in 1969 and 10970. Sometimes my curiosity gets the best of me.

 

[KX5062]

No, just the spring rate for the shock, the air bag I assume takes care of the machines wt.

Actually, it does not. The spring and airbag work together and how they figure this out is unknown to me. You can tell this is the case by measuring the ride height when the airbag is properly inflated and then remeasuring after letting all of the air out of the airbag and compare these figures.

 

[PMK]

Actually, it does not. The spring and airbag work together and how they figure this out is unknown to me. You can tell this is the case by measuring the ride height when the airbag is properly inflated and then remeasuring after letting all of the air out of the airbag and compare these figures.

Yes, the coil spring is suplemented by the air spring for a combined total spring force.

The air spring also is a progressive rate, with variable force based on pressure. The coil spring is most likely linear, or not progressive, meaning it retains a constant rate until coilbound.

If the weight of the rider, or combined weight of both rider and passenger is overpowering the coil spring and air spring, yes a new coil spring with firmer rate can be swapped in.

Depending upon the severity of overloading the spring, possibly the rate of the coil spring remains acceptable, but a preload increase is needed.

Choosing a correct spring is correctly addressing all parameters. Spring diameter, spring free length, spring rate, type of end, and if progressive or linear.

All the best with getting it sorted out.

Also, what is the rider or rider and passenger combined weight?

 

[Snowbelt Spyder]

I have a 2014 RT. and trying to determine the spring rate per pound on the rear replacement shock. The spring that came with the shock is too soft and I have a replacement spring which is too harsh, 500 pounds per square inch. My self and rider combined wt.is 300#. without taking into consideration the wt. of the rear half of machine, what should I determine the wt. to be riding two up all the time? thanks for any input.......

Unless there's a typo here, a lot of us wish that our combined weight of rider and passenger was only 300#. So, if you believe that the coil spring is too soft because you are bottoming out or some other issue is happening, then I think this is more likely an air suspension problem and not a coil spring too soft problem. As already stated, the two springs together form the rear suspension system. From the standpoint that the air spring can reduce sag, it effectively acts as an overall preload adjustment. Since it gets firmer with higher pressure, it also effectively can act as a change in overall spring rate of the rear suspension. So, curious as too why you think your OEM spring is too soft and what kind of air pressure your system is maintaining in the air spring.

 

[manxman]

Yes, the coil spring is suplemented by the air spring for a combined total spring force.

The air spring also is a progressive rate, with variable force based on pressure. The coil spring is most likely linear, or not progressive, meaning it retains a constant rate until coilbound.

If the weight of the rider, or combined weight of both rider and passenger is overpowering the coil spring and air spring, yes a new coil spring with firmer rate can be swapped in.

Depending upon the severity of overloading the spring, possibly the rate of the coil spring remains acceptable, but a preload increase is needed.

Choosing a correct spring is correctly addressing all parameters. Spring diameter, spring free length, spring rate, type of end, and if progressive or linear.

All the best with getting it sorted out.

Also, what is the rider or rider and passenger combined weight?

Combined wt. #300 plus a few oddments. I have an Elka. rear shock which was sent with a weak spring. They sent me another spring which is #500 per in. This is too much, I am in the process of sending the spring back and have the option of selecting several springs, I was thinking of getting #375 hoping to strike a happy medium.

 

[manxman]

Unless there's a typo here, a lot of us wish that our combined weight of rider and passenger was only 300#. So, if you believe that the coil spring is too soft because you are bottoming out or some other issue is happening, then I think this is more likely an air suspension problem and not a coil spring too soft problem. As already stated, the two springs together form the rear suspension system. From the standpoint that the air spring can reduce sag, it effectively acts as an overall preload adjustment. Since it gets firmer with higher pressure, it also effectively can act as a change in overall spring rate of the rear suspension. So, curious as too why you think your OEM spring is too soft and what kind of air pressure your system is maintaining in the air spring.

The spring was too soft on the replacement shock. Bottom out. I do not have a compressor on board, have to increase settings manually. I run between 50-60 psi as I ride two up all the time. So I am looking for a higher rat spring to correct the bottoming. Tried a #500 per in. but it is too much. Thinking of #350 per in.

 

[Snowbelt Spyder]

Combined wt. #300 plus a few oddments. I have an Elka. rear shock which was sent with a weak spring. They sent me another spring which is #500 per in. This is too much, I am in the process of sending the spring back and have the option of selecting several springs, I was thinking of getting #375 hoping to strike a happy medium.

The spring was too soft on the replacement shock. Bottom out. I do not have a compressor on board, have to increase settings manually. I run between 50-60 psi as I ride two up all the time. So I am looking for a higher rat spring to correct the bottoming. Tried a #500 per in. but it is too much. Thinking of #350 per in.

Apologize - I missed the part about it being a replacement shock. Understanding now that it is an Elka shock, and puzzled that they don’t already have it nailed down as to what spring you need. They know how much the machine weighs and you supply the rider weight to them. I thought they were the experts on things like that. What was the rating of the spring that was too soft? With that info maybe someone can help you pick the correct spring.

 

[spyderyderjim]

The spring was too soft on the replacement shock. Bottom out. I do not have a compressor on board, have to increase settings manually. I run between 50-60 psi as I ride two up all the time. So I am looking for a higher rat spring to correct the bottoming. Tried a #500 per in. but it is too much. Thinking of #350 per in.

(I believe stock rear BRP RT shock spring is 360#).
Do you have dual springs on rear RT Elka shock? Which spring did you replace with the 500# spring, the short 3 3/4" spring or the 5" long spring?
If you have a 8" long single spring of 500#, it should be correct for weight you stated, you can let air out or down to about 20# in air bladder to see if 500# spring works ok without air assist bladder on your RT. (my new rear Elka F3 shock came with dual springs that were way too soft also).
On my 2015 F3S Spyder I ran a rear Elka stage 2 shock with single spring 8" long x 2 1/4" ID Eibach 650# spring (but I don't have a air bladder assist on my F3), (for about 2 years), I weigh 170#.
I now run a Fox Podium RC2 rear remote reservoir shock with dampening adjustments, Eibach 525# single 8" long spring, 1" preload, that works great.
Hope this helps.
(you can pm me if need more spring # info; I bought several different # Eibach 8" single springs before getting where I was comfy on F3 rear shock).
Jim

 

[PMK]

Combined wt. #300 plus a few oddments. I have an Elka. rear shock which was sent with a weak spring. They sent me another spring which is #500 per in. This is too much, I am in the process of sending the spring back and have the option of selecting several springs, I was thinking of getting #375 hoping to strike a happy medium.

With that said, and you confirmed the 300 pounds is the combuned rider weight, plus reading you have replaced the oem rear shock with an ELKA, this will not be a popular comment, but I say let ELKA do the work they supposedly do with their statement of setting up for each rider.

If you had a race bike, I would understand the need to test various springs, but for a Spyder RT series and the amount that ELKA makes you spend for a shock, it should work properly, at least regarding spring rate, right out of the box.

If the stock spring has been removed and is in hand at the moment, let ELKA pay the overnight shipping on their FedEx account to get that oem spring to them. Let them test it, and then let them provide the proper spring, which, in my opinion, based on your claimed weight, should be a stock rate.

Essentially, it sounds as if ELKA has a test rider paying them to sort out their product.

Dead serious, all the best with it.

 

[manxman]

Apologize - I missed the part about it being a replacement shock. Understanding now that it is an Elka shock, and puzzled that they don’t already have it nailed down as to what spring you need. They know how much the machine weighs and you supply the rider weight to them. I thought they were the experts on things like that. What was the rating of the spring that was too soft? With that info maybe someone can help you pick the correct spring.

The spring that came with the shock was #200-225. I received a #500 per in. and that its too hard. I have an option of getting a # 3.50 hundred pounds per inch or a #3.75 hundred per inch. ..

 

[manxman]

With that said, and you confirmed the 300 pounds is the combuned rider weight, plus reading you have replaced the oem rear shock with an ELKA, this will not be a popular comment, but I say let ELKA do the work they supposedly do with their statement of setting up for each rider.

If you had a race bike, I would understand the need to test various springs, but for a Spyder RT series and the amount that ELKA makes you spend for a shock, it should work properly, at least regarding spring rate, right out of the box.

If the stock spring has been removed and is in hand at the moment, let ELKA pay the overnight shipping on their FedEx account to get that oem spring to them. Let them test it, and then let them provide the proper spring, which, in my opinion, based on your claimed weight, should be a stock rate.

Essentially, it sounds as if ELKA has a test rider paying them to sort out their product.

Dead serious, all the best with it.

Elka is doing what it takes and are very good about it. I am sending back the heavy spring and they are taking care of all. Very good service they have given me.....