Mt Viper Gearing

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snomoguy

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Nov 8, 2005
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Wyoming
Just some food for thought! I am running a 21/42 gearing which equals 2.25 with 8 tooth drivers. I was told it would be better to run 20/40 gearing which is also 2.25 with 8 tooth drivers...........OK....what's the difference?
 
21 x 42 has less tight bend then 20 x 40 on the drive gear but more on the final. Over all not much to worry about. I myself run 21 x 40 with 8 tooth. I think small gear diameters are a mistake. I.E. i would never run a 16 x 50 (not real numbers) to avoid the tight turn on the 16 tooth, too much heat and wear on a tight bend. In a perfect world a 42 x 84 is better than a 21 x 42, less bend, less wear and heat. Just my humble opinion.
 
AK
That was my thought to running the 21/42, being that it was a less'or of a bend on the chain, so I guess that was my wonder as to why he suggested a 20/40, maybe some others will chime in here.
Off subject........how is the avy danger down your way? We had some really wet snow and rain yesterday here in the Hills, but was planning on heading to the Snowies here in a week or so.
 
It is getting better except for the high winds are stacking up some big Cornices (sp?), but since Mark and Brian died Dec 27th a lot of us are having a hard time going back up to ride. No matter what, ride with a beacon (learn how to use it), a probe pole and a shovel. Never more than one sled on a hill at a time and spot for your buddies.
 
snomoguy said:
AK
That was my thought to running the 21/42, being that it was a less'or of a bend on the chain, so I guess that was my wonder as to why he suggested a 20/40, maybe some others will chime in here.
Off subject........how is the avy danger down your way? We had some really wet snow and rain yesterday here in the Hills, but was planning on heading to the Snowies here in a week or so.
Click to expand...

If running 21 x 42 vs 20 x 40 added a link to the chain you would be adding rotating mass. In my opinion a good thing. Slower build up of RPM, but slower decrease of RPM. In a oval track race you want your sled to rev up quickly out of the corner, but on a hill climb you want it to hold its RPM for as long as possible, I.E. more roceptercating weight. Did I say this right?
 
My 2004 modded MNT Viper with 156"x2" track runs 20/42 gearing with 8 tooth extroverts. 8DN 10's 43gr with silver secondary spring and a Shockwave helix. Pulls harder than my AC 800ZRT MC I had.
 
Powder Trax said:
My 2004 modded MNT Viper with 156"x2" track runs 20/42 gearing with 8 tooth extroverts. 8DN 10's 43gr with silver secondary spring and a Shockwave helix. Pulls harder than my AC 800ZRT MC I had.
Click to expand...

2003 Mtn Viper set up.

Here is what I'm running. I ride at 8,500 to 11,000 with this set up and get about 8-9 MPG. I'm a hair lean at 8,500 and a hair rich at 10,500. Carb heaters off.
PTO 145, CENTER 147.5, MAG 147.5, Pilots 45, Needles 2.0, Air screws 1 7/8.
Torsion spring silver, Torsion cam 43 degrees, 90 degree twist on secondary.
13.3 steel outer rivet, 13.3 Alum inner, 8DN 10 weights, Green-White-Green spring
I engage at 4,050 rpm and max out at 9,100 out of the hole and settles to 9,000
21 x 40 gearing. I'm jetted for 20 to 0 degrees air temp. If its colder out I my sled runs a little lean, warmer is richer of course. On deep powder hill climbs I can hold about 45 mph track speed. I know the MPG sounds low, butttt most my riding is off trail in untracked powder.
I love a 1/8 mile drag, unless you are turbo or super charged. Yes I ride with better sleds, but boy did they spend a s*** Load of more $ then me.
 
I have been running a 19/38 with 8 extrovert? drivers
because my gear selection of 19, 21,22 top and 38, 41 bottom
19/38=2.25
21/41=2.14
was told 2.25 was best gearing for piped Vipers
really need a 20 top gear or 42 bottom anybody want to trade?
 
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