Mtn Cat gear down?
- Thread starter hansenmac
- Start date
First ride out I plan to check my sheave usage as I imagine there is some opportunity to drop it more for straight mtn riding. I believe the king cat lower drops it a tooth.
if the top speed on the trail is higher that the track speed while climbing then you should be able to gear down a bit because your not shifting all the way out while climbing. I love the sled and it climbs like crazy but was going to check my lower gear and thought if it needed a gear maybe there would be room to improve.
So what's the perceived advantage to making your clutches shift out all the way while climbing or under full load? In my mind the ideal shift point is when the clutches are at a 1:1 ratio since that is the point of max efficiency of the CVT system. If you're maintaining target RPM but not shifting to that point, then gearing down further is warranted. Being slightly under geared can give you a little extra consistency or cushion for conditions just like being a little under clutched. If you're significantly over shifting from that point you should be gearing up or you're leaving some performance on the table in other areas.
Has anyone measured shift marks on the primary AND secondary of the newer clutches to see where that 1:1 point is? With the large diameter of the helix in the secondary I wouldn't be surprised if it's not getting close to full shift of the secondary. Many have observed that they have quite a bit left on their primary. With the Team secondary diameter constraints and belt length I have doubts full primary shift is really possible. someone want to pull their clutch springs out, throw the belt on, and see for research purposes?
Has anyone measured shift marks on the primary AND secondary of the newer clutches to see where that 1:1 point is? With the large diameter of the helix in the secondary I wouldn't be surprised if it's not getting close to full shift of the secondary. Many have observed that they have quite a bit left on their primary. With the Team secondary diameter constraints and belt length I have doubts full primary shift is really possible. someone want to pull their clutch springs out, throw the belt on, and see for research purposes?
if track speed while climing is in the low 40's but top speed on the trail is 75 couldnt you gear the sled down a bit so maybe the top speed was 65 but have a better torque multiplication and pick up some track speed while climbing. you dont want to be geared too low and be at full shift out while climbing because maybe in sugar snow it will shift out more than in regualar snow. doesnt sound like many people have messed with the gearing on these though
Edit: that lowers the ratio from 2.63 to 2.77 save everyone the math.
Last edited:
Nope gearing down won't help as the clutch will simply upshift to compensate and your back to where you started. The possible increase in efficiency by getting closer to 1:1 will be to little to notice. The only real way to increase top speed going uphill or across the meadow is to increase HP. The upshift occurs because gearing down lowers the load feedback on the secondary when no real load has changed. The same effect occurs with a real load change occurs, as when you mentioned hitting sugar snow.
Don't get me wrong, I'm not against gearing down with proper clutching as I believe even though it won't change your top speed up the hill it will get to that speed quicker. It makes the sled noticeably snappier ( increased acceleration) which will get you higher up the hill before turning out and beating your buddy with stock gearing. Lower gearing is a huge benefit for boon docking in the trees as others have mentioned.
Cinno
Because the CVT overrides any small changes in chain case ratio you make. If you could somehow lock out the CTV from upshifting to its minimum ratio, you will over rev the motor and fall out of the motors power band.
Yep. Unless the gearing or clutching is considerably off for the conditions. There's a narrow target RPM for the engine so it's more or less fixed at a certain speed at WOT. It only has a certain amount of power and torque available at that RPM. If your gearing and clutching are close to start with at say 2.60 ratio and 1:1 shift, and you gear down to 2.80 that's a 7.7% change. Your clutches will shift out slightly further to 1.077:1 to run the same track speed.
Yes it does. A truck that is geared with a 4:10 rear end can tow a heavier load more easily than one that has a 3:55 rear end. Does it tow it faster? Maybe depending on how much power is available, transmission ratios, and peak torque RPM work out. The lower geared truck will be able to tow a heavier load though under the same conditions or accelerate the same load faster. There are always trade offs though. If the engine has enough power to pull a moderate load without much fuss there's little advantage to lower gearing. Someone that is towing heavy all the time might want the 4:10 at the expense of speed (or fuel mileage if they want to run higher rpm).
Translating that to sleds if someone is a larger rider (like me) tipping the scales at 300lb with a big 162X3" track they might benefit from lower gearing than someone that is 150lb on a 153X2.6". Different loading requirements but the same engine and power available. Elevation can also play into this as you lose power as you go up. Someone riding 10,000' and above all the time could use lower gearing than someone riding 3,000' because there is not as much power available to them so they need the extra mechanical advantage to pull the same load. Probably why guys that ride higher seem to be dropping the helixes back to 45 from the stock 48s.
That has been my experience on my sled. I used to run 2.52 when I was running the 2.6" track and now I'm back to 2.60 ratio after switching to a 3". That's with my 300lb self on a 900 big bore riding 9-10K. If I was riding 6-9K I might have stuck with the 2.52. The 2.60 ratio was giving me just a little more consistency in my RPM testing back to back on the same day and a little better pull out of downhill J-hooks. Didn't notice a difference in track speed up the hill.
Also, I'm not saying there aren't benefits to re-gearing sleds. People with 2012, 2013, or 2016 Limiteds can tell you there are times when re-gearing is warranted!
i will be sticking with the stock gearing. Cant wait to get out and ride. this sled is the best thing ive ever ridden and its outclimbed 2 different 850 skidoos and one was a 174 with helium hood and gear down kit. needless to say the doo owner was a bit disappointed. havent ridden with any 850 polaris yet so i wont talk any smack.
I have a lead on some 20/49 gears and chain for $100. would be going from stock 2.63 to 2.45 be a good try? seems gearing up is going to help a bit
Ur welcome to try it, i can tell u from experience, i wouldn't do that unless ur looking to travel 80mph or faster on the trail. That is the only place i seen an improvement. 2.45 creates a bit more belt heat in deep snow.
Sent it
It is a increase with track speed in the fluff- 80 MPH on the trail doesn't impress me at all .
What experience would you be willing to share? / and why you have reservations.
I can clutch for belt heat
I am far from a clutch expert. I buy kits and put them as the manufacturer recommends. If i have issues, i contact the manufacturer and have them give me things to change.
That being said, my 2014 seized a roller at 900mi. I put the 2016 team primary on at that time with MDS. At 1,200mi i put a 3in claw (kept 8tooth drivers)and changed the gearing to hyvo 20/49(only option on the shelf at the time). Been a belt eater ever since. Belt eater, as in pulling strings at 250-300mi. Belt temps are 170-200° cruising around. Climbing gets it to 220° quick, deep snow flat ground, I'll see 230° if im breaking trail. My 18 and 19 are so much better on The bottom end, i know a lot of that has to do with the Ctech vs Zuk but the gearing and clutch just feel much better on the bottom. My 14 feels good mid to top end. Definitely pulls harder on the trail at 60+mph.
Sent it
Similar threads
