Guess this spring rate?

[Thatspec]

I have an all black secondary spring in my Team clutch, I can't find any info on it and would like to replace. (stripe worn off?)

66-42-.46er (or 44 but set on 42), black spring, clutch has a shim and at least one delrin I can see, 4-6000K, 163/2.5, Carls 910/8300 rpm, black/green primary, tip ground 10-66 weights. I like the way it's clutched for general boondocking but on long climbs in very deep snow yesterday it was loosing rpms (sometimes). This does not happen in 2' of snow or firmer on the same hill. Could have been snow stuck under the throttle flipper as it was not consistent but previous owner mentioned similar issue.

Any ideas what to replace this black secondary spring with?

Thanks!

 

[F-Bomb]

prob a 155-222 bone stock team

now they use a black with red mark as that replacement

black purple is 160-240
gold is 170-240

Those are the other combo's that are common...

I"m guessing:
I think you are experiencing heat fade from the additional load in deeper snow along with the fact that your setup can't consistently hold the balance in those loaded conditions..it's a combo of your ideal power curve and heat. Can you get some EPI 66 gram weights with the blk red to try? Your setup should become much more consistent in all types of snow loads and your power bands high end will be in use all of the time instead of only when it can handle a load at the top of the curve.

The profile of those weights will load your setup initially but they actually act like a lighter 10-60 series on a long loaded top R pull. So the net result is you usually get a better upshift and pulling power PLUS it can handle the top end without thinking it needs to shift down.

 

[Thatspec]

Hey Thanks F-Bomb,
I'm reluctant to change too much and non-adjustable weights are a size-able commitment (could I achieve a similar result with the MTX weights?). If that is the stock secondary spring then it's five seasons old, any chance a fresh one or a stiffer higher end sec spring would solve some of the issue? We don't get those conditions very often anyway.

When you say heat fade I'm assuming you're talking engine, not clutches. Clutches stay relatively cool, still getting away with an 080 belt and no problems.

 

[F-Bomb]

if you can touch your clutches and the belt temp is moderate than it's simply loading your clutches to the point where your system thinks it needs to backshift in it's balancing act..IE your auto transmission is doing it's job as it's designed but that may not give you particularly good performance in those conditions. IE you can't make enough power in your system to pull the load in those particular conditions.

Heat fade is simply high R"s and then slippage which creates so much heat in the sheaves and transferred to your belt that it glazes and will not hold and transfer the power to your track.

With your deal adding some spring tension will increase the top end R's but I doubt that is the solution since you aren't getting heat. That is the advantage of the EPI weights for this deal and why they will shine a bit over the 10-60 profile. You get better initial and mid pull but the finish weight is more equal to about 1 gram less in 10-60. That will give you a better holding finish R without excessive heat in loaded conditions. This is also building on a known correct setup rather than reinventing the entire wheel. Especially if you are having wild fluctuations of rpm in different loads. Guys are getting similar results from the variable weights but it's a mad science and knowing the exact combos can take years and tons of misc spring combos to nail. I'm not necessarily coaching you to try for MORE R"s as much as more consistent overall clutching. That way you get the same sled in a bunch of environments. The net is also you don't wear out belts that cost a lot of money.

in conclusion it sounds to me like your setup is pretty close but the weights are just slightly too much at the top end....that is why I suggest the belly buster style and then simply staying with the exact spring combo that is clearly working...I think you will find those weights to be pretty close to magic for this application as you describe. $85 is all and the spring of course....One notable mechanic and good tuner told me he never feels like you'll need to change a secondary spring from sack. I guess the only way to verify that would be tension testing springs and for me $18 is just easier. I've seen variations of results from all three of the springs that I already discussed with TINY differences in lb of tension so it leads me to state it is critical to be right on.

 

[Thatspec]

Certainly appreciate all the info Fbomb. I've been trying to trade a set of 10-66's in the b/s section and just noticed that they are custom ground to be like Bellybuster's. I'm definitely going to give those a shot next time out. Can't tell exactly what they weigh at this point, they are probably too light but worth a try (previous owner was at 7K+). I thought they were just ground at the tip but (see pic). I can at least tell they are all the same weight on a small balance scale I have here.