Just for conversation lets say hypotheticly that first the weight/roller combo has to overcome the primary spring. And after contacting the belt the weight/rollers have to overcome the secondary spring and helix combo. That hopefully is set to generate just the right side pressure to the belt. Just enough as to not slip and not to much that would cause excessive friction and heat. That being said let say one guy set his primary up with a lighter roller and spring combo and was able to hit his target upshift rpm of 8000. And another guy had a slighty heavier roller and spring combo but was still able to hit the same target upshift rpm of 8000. With both guys using the same secondary which one would have the better back shift?
TRA Talk............
- Thread starter TVC 15
- Start date
For some reason the TRA likes the heavy weight/heavy spring as far as backshift and belt grab are concerned.
I guess it would depend on your definition of "better backshift". The lighter setup will backshift quicker, but will also fluctuate RPM more than the heavier setup. I agree most TRA setups like more pin weight and primary spring....within reason. 
The TRA likes lots of setups depending on the terrain and conditions your riding....Deep snow ountain riding the TRA likes weight and heavy springs in both the primary and secondary.
Different strokes 4 different folks.
OT
Different strokes 4 different folks.
OT
What is considered a heavier setup??
Too many variables to really answer the scenario (track length, gearing, snow load, etc).....but, assuming one sled has light weights/light spring and the other sled has heavier weights/stiffer spring and both sleds have an identical primary ramps and secondary you will get quicker backshift with the light setup but you will have NO low end grunt and will probably not shift out far enough (sled will sound really revy where ever you go and it won't rip your arms out or get up to planing speed fast enough).
I agree that the TRA VII likes heavy weights/stiff spring but backshift IS important to keep it from bogging and losing rpms.......the answer would be to run heavy weights/stiff spring combined with a shallow/steep progressive helix and a stiff secondary spring. This gives you good upshift, good belt pressure, and quick backshift. The only other thing to add is a more aggressive ramp........that way your are really shifting out quick (which the 800R can handle) and it runs great!
Rt
I agree that the TRA VII likes heavy weights/stiff spring but backshift IS important to keep it from bogging and losing rpms.......the answer would be to run heavy weights/stiff spring combined with a shallow/steep progressive helix and a stiff secondary spring. This gives you good upshift, good belt pressure, and quick backshift. The only other thing to add is a more aggressive ramp........that way your are really shifting out quick (which the 800R can handle) and it runs great!
Rt
Lets say the lighter setup is 2 to 3 grams lighter than the heavier one. And the two sleds have drag raced against one another and there basicly a dead heat. Which should have the better/faster backshift?
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I clutch on the theory of using the least weight possible to still make the primary shift, anything extra just makes the sled rev slow and feel lazy. I like it to "rip" Very hard to get to that point, to where the primary shifts hard with light weight and just don't rev, but it's very possible. Less weight is also going to make it less altitude and snow condition senstative.....imo
I'll try to keep this short - I just had my sled in for it's 10hr check up and came back from the dealer with added pin weight, went to double the stock length or weight, how it is measured exactly I don't quite understand. So, from stock of 12mm to now twice that. Didn't change anything else, set to clicker 3. I headed up the groomed trail and after warm up and at the first long straight stretch I cracked it, 7500 rpm, next straight I held it to the bar, 7700 rpm. I knew right then it wasn't going to work, as I think you should be able to over rev on the trail with a good mountain set up. First hill confirmed it, heavily traveled and really compacted hill climb, sled came over the top at about 7400 rpm. Clicked it up to 5 and did some lake drags, flat to the bar on the compacted lake 7900-8000 rpm. Played on one big hill with fairly set up powder snow, about 15-20cm's trench depth when climbing.....couldn't get over 7800-7900rpm. Here's the thing - saw 77km/h track speed for the first time ever on a hill climb. With stock set up in deep/dry snow on clicker 5 I had seen 75km/h.
So I was happy to see this track speed, and I also really liked the way the sled upshifted, pulled hard, put me back in my seat and got the skis off the ground like it never could before when stock. Also, at an idle through the trees or maneuvering through compact trails around creeks and stuff, slow speed riding, I dropped a lot of rpm, would guess at 6-800. Didn't work the sled really hard as it wasn't a deep day, but all in all I would guess the clutch was cooler.
Now the question - where do I go from here? Would love to keep the low end grunt and would also like to keep the belt shifting as high in the clutch as it was (1/2" or so more than when stock)....should I gear it down and click down to 3, knowing that on a deep day I could click up to 5 or 6 and for long trail rides I could click down to 1?
Is this too much pin weight to start finalizing my set up? Should some come out (15 -16 ish) before playing with it further?
nate
So I was happy to see this track speed, and I also really liked the way the sled upshifted, pulled hard, put me back in my seat and got the skis off the ground like it never could before when stock. Also, at an idle through the trees or maneuvering through compact trails around creeks and stuff, slow speed riding, I dropped a lot of rpm, would guess at 6-800. Didn't work the sled really hard as it wasn't a deep day, but all in all I would guess the clutch was cooler.
Now the question - where do I go from here? Would love to keep the low end grunt and would also like to keep the belt shifting as high in the clutch as it was (1/2" or so more than when stock)....should I gear it down and click down to 3, knowing that on a deep day I could click up to 5 or 6 and for long trail rides I could click down to 1?
Is this too much pin weight to start finalizing my set up? Should some come out (15 -16 ish) before playing with it further?
nate
Nate, your sled is now clutched perfectly for a more powerful motor that could handle this weight, spring and helix. I have the same weight in mine and the ramps are same for the first 2/3 so my acceleration and arm stretch is the same. Where our sleds differ are at higher rpms. You have a reverse angle helix and your 441's are not as steep at the top as my 414's. These differences will load the motor up too much for the power. You have some choices. Change ramps to steeper at top. e.g. 414, change helix to straight and not reverse angle. e.g. 42, add head, Y-pipe and pipe for more power. Or drop some pin weight and loose some acceleration and track speed.
I think the ramps would help alot. I propose we swap ramps and go for a ride to see?
This is why I am wondering if gearing it down to a 19 would help me out....let the clutch work the way it is right now but let the engine run in it's power band at the same time. Does that make sense? I'm no mechanic.
nate
Gearing it down you will lose even more RPM.
Lose rpm? Really? I was prepared to believe that I would not see any gain at all in track speed, but rather just have a clutch working as it is now but with an engine operating at a higher (better) rpm, this would allow my engine to hold rpm's when under load........no?
nate
With the secondary being load sensing.....with lower gearing it will see less load from the track. With less load it will allow the clutches to upshift faster and farther, loading the engine harder (less RPM) if all else remains the same.
The trick is finding the sweet spot with a combination of gearing and clutching to match a particular sled and track length for the type of riding.
Gearing too low makes for sensitive clutching that is always fluctuating RPM....too tall of gearing and things get too hot and inefficient.
The trick is finding the sweet spot with a combination of gearing and clutching to match a particular sled and track length for the type of riding.
Gearing too low makes for sensitive clutching that is always fluctuating RPM....too tall of gearing and things get too hot and inefficient.
Nate, you could also try some 413 ramps just to prove to yourself that the steeper finish will get you where you want. The 413's will not stretch your arms as much on acceleration though. I am getting 85-88 km/hr on the long climbs with packed snow. The reason I am suggesting the 413's is that they may be easy to get your hands on for test purposes.
On the set ups the sled with the heavy weights will brobally back shift faster and up shift faster due to the fact back shift is in the secondary angle of the helix and the spring, the more weight in the primary the better the belt grabbs and less it slips, I've tried both and the heavier set up is faster for me on my sled, and less heat on clutches, lots of people think that the light primary is the way to go but if your pulling the same stiff secondary spring the heavier set up will probally pull it better do to more weight and less belt slip, so I would have to say the heavier one should win going from rolling 30 on up, just my .02
My experience is more weight , the faster upshift and slower backshift as this heavier weight has inertia and resists the backshift from the secondary.
yep x2
Depend on the primary spring also, alot of people overlook this when doing set-ups.
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