It is the new helix and "reverse" angle.
New ramp too....just waiting on it.
Its going to have to be something in the neighborhood with the shape of the 410/412/417 ramp to keep rpms “straight”.
What I don't get is....
*Arc area of contact of belt decreases as shift increases - The belt is clamped with less area.
*As helix angle increases belt clamp force decreases - The belt is clamped with less force.
What method of testing was done? What terrain did “they” test on to make a calibration determination to come up with those angles?
This is something I ran by owners who talked to me on the phone or by email.
I like to focus on "Snow depth" and not on elevation. I know elevation increases and power decreases but rather put a thinking cap on "snow depth" or "Snow load" - Neglect elevation. The reason I ask is that it is normal to observe that (snow load determines track speed), does not matter what elevation, you are in your own area and you observe your results. Whether you are are at sea level or 13000 feet, what track speed did you see and what is the highest track speed you have seen.
I have talked to guys who have run in jan/feb with (normal-to-see) track speeds from 28~35mph and rarely get over 38mph in snow on a climb with a stock 800R. [Washington/Wyoming/Montana]
I have talked to guys who have run in jan/feb with (normal-to-see) track speeds from 38~45mph and rarely get over 50mph in snow on a climb with a stock 800R. [Golden/Revelstoke/Maine/Newfoundland]
I have talked to guys who have run in jan/feb with (normal-to-see) track speeds from 45~55mph and think it's impossible to get over 60mph track speed on a climb with a stock 800R. [Alaska/BC/Maine/Sweden/Norway]
Alright...set all opinions aside and answer...[Think "stock 800R"] & [In your own particular region]
What is the highest track speed you have seen while climbing?
What is the highest track speed you have heard of your friend or whoever, has seen while climbing?
What is the highest track speed you see on the trail or road to get up to the location you drive in?
Can I ask you to put your answer in a format:
Region -
Month -
Snow type -
Snow depth -
Track speed -
Highest road speed -
Comments:
Example:
Cooke city
Jan/Feb
Fresh heavy powder
3.5 ~ 4.6 feet
29~33 mph
Highest road speed is 70mph
Snowed for a whole day and left 4 feet of fresh powder, hard to maintain rpms, difficult to get on top of snow....tons of fun
.
My observations after winter with xp –
Feedback gathered from xp owners whether stock or clutched - speeds being used most of the time under heavy loaded conditions are from 27mph~37mph. Less load conditions from 38mph 48mph It seemed angles that offered good track speeds [heavy loaded conditions] riders said were good in their own region were anywhere between 43 to 39 degrees. Using a median of 19:45 (2.36) 76mph@1:1 & 92mph @ full o.d. you can lay out a helix with its angles and calculate what angle is being used at any track speed.
With the 43/47 in heavy load the angle 43 will be used approximately from 0~19mph
44 @ 19~35mph
45 @ 36~53mph
46 @ 54~72mph
47 @ 73~92mph
Lets look at a helix many used...44/40
44 @ 0~19mph
43 @ 19~35mph
42 @ 36~53mph
41 @ 54~72mph
40 @ 73~92mph
I made helix's for guys who wanted to test with start angles 42, 41, 40, 39...it was observed that the farther you went away from 42 [lower] the easier the sled would trench when trying to get unstuck. Some guys will remember the QR14[40 start] and QR18[39 start] - You get stuck then try to get out even with guys pulling on the ski's, apply a bit of throttle and and *spinnnnn* the back of the sled goes to china = more digging n lifting.
I have had some experiences with reverse helix's. They work excellent in drag racing. You use a start angle that allows the engine to build rpms quickly and leave the start line with maximum hp as close to the start line as possible, and as the shift increase the angle gets larger making the sled accelerate hard. Downside is if the sled sees a load change - sled drifting into another lane and you have to cycle the throttle, the rpms come down you throttle up and see the rpms hang up the engine will not accelerate again. Seen this in hillclimbs with reverse angle - the sled goes like a rocket but have to go over a hump or dip either you stay on the throttle or cycle it, the rpms will drift low only to recover if you slow the track speed down enough that the engine can overcome the load change, then rpms back up and accelerate again. What will happen with a summit in deep snow when the load changes as the speed increases? - we'll see on the forums come December.
