Frostbite
TY 4 Stroke God
Until today I had casually watched as the latest craze of increasing the size of the rear idler wheels on the track continued. I figured it would pass like they all do.
I was at a snowmobile show today and one of the few gentlemen I know to be reputable said that going to larger 8-9" rear idlers actually increases horse power to the track by 3-5 measurable h.p. with a RX-1 Mountain on a dyno. I guess it does makes sense that the track going around a larger circle would take less H.P. to turn. Just like going from 8 to 10 tooth drivers perhaps?
Now, if this is true and it helps a mountain sled I would think it should also help (maybe to a lesser degree) a short track.
Ok, who's the expert? I must confess I'm ready to sign up if you don't grab the reins soon.
I was at a snowmobile show today and one of the few gentlemen I know to be reputable said that going to larger 8-9" rear idlers actually increases horse power to the track by 3-5 measurable h.p. with a RX-1 Mountain on a dyno. I guess it does makes sense that the track going around a larger circle would take less H.P. to turn. Just like going from 8 to 10 tooth drivers perhaps?
Now, if this is true and it helps a mountain sled I would think it should also help (maybe to a lesser degree) a short track.
Ok, who's the expert? I must confess I'm ready to sign up if you don't grab the reins soon.
BlueBlood
Pro
C'mon Frostbite, don't you know size matters? 
Frostbite
TY 4 Stroke God
Dah! 
Of course it does in things like nuclear arsenals and beer mug sizes but putting bigger wheels on truck made it seem guttless (until I fixed that). 
All kidding aside, I can't see why a mountain sled would benefit much more from larger wheels than a short track. Although, I can notice a exponential increase in the angle the track has to travel back to the drivers as the track length gets longer.
Maybe I should have asked this on the Mountain side?
Of course it does in things like nuclear arsenals and beer mug sizes but putting bigger wheels on truck made it seem guttless (until I fixed that). All kidding aside, I can't see why a mountain sled would benefit much more from larger wheels than a short track. Although, I can notice a exponential increase in the angle the track has to travel back to the drivers as the track length gets longer.
Maybe I should have asked this on the Mountain side?
Buckeye
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Why do you think all the drag sleds are going to the larger rear wheels? It takes less force to rotate the track. It is more efficient.
Frostbite
TY 4 Stroke God
Yup. That's what I thought. They make sense to me.
I was a little worried that it was just a passing craze like UFOs, the stuff you rubbed on the bottom of your sled so the snow wouldn't stick or the spark enhancers called "Swazers".
I was a little worried that it was just a passing craze like UFOs, the stuff you rubbed on the bottom of your sled so the snow wouldn't stick or the spark enhancers called "Swazers".
KbxSrx
TY 4 Stroke Guru
bigger is better
yamadoo
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Guys, better Yes, significant, I wonder. A drag racer who wins by a tenth of a second "wins". So I concur better. But I, like frostbite, am skeptical. So I think I will save the money for gas. I think the difference may be measurable but ? if noticable.
My 2 cents.
Boy I need a cold snap and then SNOW.
yamadoo
My 2 cents.
Boy I need a cold snap and then SNOW.
yamadoo
You'll notice it on top end - good for a couple MPH by my experience.
Frostbite
TY 4 Stroke God
Top end? What top end? I have a 151" x 2 1/4" finger track with 8 tooth Wahl Brothers extrovert drivers. I see 102 to 106mph on the dream meter on the flats which is what 85 mph? Maybe adding these wheels would give me 86mph on a good day?
Yes, I fully understand most modifications only increase performance incrementally. Then of course there's are turbos and nitrous which blow that theory all to heII.
I guess it's a matter of deciding on which modifications warrant the spending of your hard earned money?
The gentleman I refered to in the original post has 8 and 9" wheels. I'm told the 8" wheels fit without any modification but the 9" may require a rail modification to accomodate the larger wheels.
Yes, I fully understand most modifications only increase performance incrementally. Then of course there's are turbos and nitrous which blow that theory all to heII.
I guess it's a matter of deciding on which modifications warrant the spending of your hard earned money?
The gentleman I refered to in the original post has 8 and 9" wheels. I'm told the 8" wheels fit without any modification but the 9" may require a rail modification to accomodate the larger wheels.
RX-1 Moose
Expert
Aren't the stock rear Idler wheels 7 1/2 inches? If so how much would an 8 inch wheel help? 9 inch I could see a little difference but 8 I bet you could not tell. Makes me wonder if its worth the extra money.
Interested in the oversized wheels but need more knowledge.
Interested in the oversized wheels but need more knowledge.
black john
TY 4 Stroke Guru
over size idlers
the stock idlers are 7 in the older yamaha,s were 7 1/2 and they fit right on with little problem. as for makeing a differnce i cant tell. i just needed new rear wheels as my bearings were shot and the bearings in the two out side wheels. and the bearings are molded right in to the stk wheels and i had lots of these on hand so thats what went on. these 7 1/2,s were used on vmx 540,s srx 340/440, enticer, etc etc
the stock idlers are 7 in the older yamaha,s were 7 1/2 and they fit right on with little problem. as for makeing a differnce i cant tell. i just needed new rear wheels as my bearings were shot and the bearings in the two out side wheels. and the bearings are molded right in to the stk wheels and i had lots of these on hand so thats what went on. these 7 1/2,s were used on vmx 540,s srx 340/440, enticer, etc etc
RX1Jim
TY 4 Stroke Junkie
Last January, a bunch of RX-1 owners met at a lake in MA to do some comparisons of stock and modified sleds. Freddie was there as were a few members of this site. The was one guy there who had the large plastic rear wheels he got from Mountain Performance. That sled ran 2 mph faster than the other sleds there with comparable modifications. I bought a set of aluminum 8" dia. rear wheels for mine, mostly for the looks but if it reduces rolling friction, I'll take it.
Jim
Jim
Focker
Pro
I was talking to Bruce at Tracks USA the other day, asking the question "whether or not it was worth my money to order the 8" kit and wheels with my extension purchase?" He shot me straight and said that the bigger wheels really only benefit the mountain sleds. I definately appreciated his honesty and not trying to just sell me more stuff that won't really make a difference besides appearance!
Frostbite
TY 4 Stroke God
If the addition of larger wheels are giving short tracks a couple more mph. on the top end maybe there's enough reason for you guys (short track guys) to give the idea a fresh look?
I wish Yamaha would offer them as an accessory item. I'd like to match the pattern of my other wheels with a larger plastic version. If the 9" are too big to use without rail modification then give me an 8 1/2" (the biggest that will work without modification) and I'd be happy.
I wish Yamaha would offer them as an accessory item. I'd like to match the pattern of my other wheels with a larger plastic version. If the 9" are too big to use without rail modification then give me an 8 1/2" (the biggest that will work without modification) and I'd be happy.
