Here is what I have been working on and all the information I have gathered. I am now into the testing phase as my researched has mostly been completed. Pictures will be added later showing heights and CV angles of the finalized shock/spring combination choices. I will update once I get more information to fill in the "?" blanks. If you happen to have or know that information already please feel free to fill it in and let me know. All my shock measurements were made from center eyelet to center eyelet.
My goal is to find replacement springs and shocks that provide added capacity and lack of bottoming. What I also wanted to accomplish was to get lift within specifications of the lift kits on the market. The one I used to compare it to was the StrongMade lift kit as that is what I had handy. The other requirements I had with replacing the shocks was to also have a more quality ride and longer suspension travel but all at a reasonable price.
I have been able to get the stock spring rates for the dual rate shocks. In finding this info, I noticed that the springs are not the problem in the stock suspension, the shocks are. They are sprung VERY heavy for a stock machine, heavier than most machine rear shocks are! The numbers that Honda gave me were in Newtons per MM of travel so all numbers I gave are rounded when converted to Pounds per Inch.
Pioneer Stock:
Front: 206-328 LB/Inch (36N/mm then 57.5N/mm) Progressive
Rear: 260 LB/Inch (45.6N per mm)
Stock front:
1.25" eyelet shocks, 5.25" shock shaft travel
Shock Length: 19.25" eye to eye extended, 14" eye to eye fully compressed
Weight of the machine on the shocks Resting Compressed 17" eye to eye
11.25" resting clearance to frame on 27" BigHorn tires & StrongMade lift installed
Stock rear:
1.5" eyelet, ?" shock shaft travel
Shock Length: 18.5" eye to eye extended, ?" eye to eye fully compressed
Weight of the machine on the shocks resting compressed with preload set highest 16.75 eye to eye
12.5" resting clearance to frame on 27" BigHorn tires, NO lift installed, again preload highest
Now came the hard part of finding shocks that would fit in the eyelets and provide lift similar to those already on the market. I looked at a few shock options, Can-Am Commander XT 2011-2015 models and Polaris RZRs. I settled on the Commander as the shock eyelets were proper width and the length of the shocks were spot on to match the StrongMade lift. They are also adjustable front and rear for preload and a much larger shock body than stock. Both front and rear shocks are nearly identical, I am assuming only the valving is different. The shocks are gas charged unlike stock Pioneer shocks which are not and do not rebound on their own. The shocks are longer but so is the shock travel. I should gain (a rough guess) 2" of front and rear suspension travel while not allowing bottoming or tire rub as they should not compress further than stock. They will provide a constant lift, unlike the StrongMade lift kit which doesn't do much for the front when there is weight on it, this is mostly due to the angle change when the lift is installed allowing for the wheels to put more leverage on the shocks causing a need for a heavier spring to avoid bottoming (which is the problem I had). Both stock and the Commander shocks have rubber bump stops on the shock shaft.
Commander Stock:
Front: 137-162.7 LB Progressive
Rear: 200 LB
The shock eyelets are 1.25" and 6" shock shaft travel
Both shocks are 20.1" eye to eye extended and 14.1" eye to eye fully compressed
I mounted the front shocks from the Commander, a 2013 XT, and found them to work great. Suspension travel was increased and they were smooth although a little soft for me. I did not notice any bottoming but I also did not get a chance to beat on them before deciding to go with a heavier spring. I compared them to aftermarket and stock Pioneer spring weights to find the ideal numbers and ordered what I thought would be the best combination of spring weights. It is not just the spring rate that needs to be calculated but also the overall usable spring. For example, if a stock Pioneer had 5" of shock travel and the Commander has 6", you have gained 1" of shock travel. If the spring is 200 LB then you gain that much in overall spring during full compression. Therefore, in theory, you could use a lighter spring while retaining the overall spring weight and get a softer ride. I tried to stay stock or higher but you could also play around with the rates yourself. The numbers I put were approximate total weights using shock shaft travel. With progressive springs I split shock travel length in half per rate (this is clearly an approximation and could be way off). The rear shock travel length of the Pioneer is still unknown and I just made the assumption it is the same as the front for now.
Pioneer Stock with 5.25" travel:
Front: 206-328 LB (total pounds 1402)
Rear: 260 LB (total pounds 1365)
Pioneer Fox shocks with 5.25" travel:
Front: 225 LB (total pounds 1181)
Rear: 300-350 LB Progressive (total pounds 1706)
Commander stock with 6" travel:
Front: 137-162.7 LB (total pounds 899)
Rear: 200 LB (total pounds 1200)
Commander Superatv springs:
Available in weights of up to 175LB (front)
and up to 225LB rear (total pounds of the 225 springs: 1350)
EPI/QuadBoss springs go up to 250LB rear or 1500 total pounds
Commander HighLifter springs:
Front: 165-180 LB (total pounds 1035)
Rear: 260-310 LB Progressive (total pounds 1710)
For 2.25" ID springs, such as those on the Commander, the highest seems to be around 250 LB/Inch. Rear Commander springs can reportedly be used on the front Commander shocks. You can use 2.5" springs with adapters for a higher spring rate but that is an added cost and I don't feel it is necessary.
The setup I chose to use and what I have on order are the EPI or QuadBoss (appear the same, they are probably cheaper Chinese steel) 250 LB springs which I will put on the front. I think you could use 225 LB springs without issue as well but for the same price I found some 250 LB springs and decided why not? The rear I chose to use were the HighLifter springs which were similar to stock initial weights and then moved up 50 LB as they are progressive. My goal is to turn the preload down in the rear to soften the ride without sacrificing weight carrying capacity. I included the Fox shock rates as a comparison. I think their shocks are much stronger than stock and provide good valving allowing them to keep a total overall lower rate than that of the stock Pioneer. I split the difference when settling on the 250 LB springs which overall will have a higher total weight than stock but the average spring rate, (again assuming a progressive spring being 50% of each weight) still being lower than stock.
I will report back on my findings with photos of the springs, CV angles, height measurements and a real world usage report. I have done a lot of research here in springs and shocks to find the best combination. For those of you who don't care about going cheap and want a good quality shock such as from Fox and want longer suspension travel, this information is also for you. Now you can lift your Pioneer by using quality shocks. How? Buy the Fox shocks (or your aftermarket preference) for a Commander!