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Discussion Starter · #1 ·
Who has experience with going with larger rear idlers/axle relocation in a 137" rMotion?
I'm exploring set ups for drag racing for next winter for my turbo 1200.
My goal is to run this set up full time, not just to race.
What diameter have you run?
Do I need to get into a longer track when running the bigger diameters?
Thanks gents.

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Buddy of mine put the the 9 inch idlers on this year from tricked toys. He has the 4 wheel kit on a 850 Gen4 XRS. Did not change the track. It lowered the rolling resistance a lot. He said he can roll the secondary over with one finger now, He increased his top speed by 10 kilometres on the dream meter and his fuel range has improved. He normally took a litre less than me at a mid day fuel stop. Now he is 3 maybe 4 litres less at mid day. He is truly impressed with the performance difference this change made to his sled. Very high quality pieces from tricked toys.
 

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You can go up to 9 inch without going longer track and using up too much suspension. 10 inch need longer track and use up too much suspension for every day riding.

You use an offset axle going forward and up with 9 or 8.5 inch wheels and keep the same track. The 10 inch kit on a stock skid are essentially like rail extensions (short adapters) and would take you from 137 to 146. 144/146 seems to be the ideal sled drag race set up though. Enough hook and you can keep the front down enough.. and the sled going forward.

Anyway to my way of thinking 9 inch are about the max for normal trail riding and some racing. I have both the 9 inch and the 10 inch set ups. Bigger drivers are a plus too, but limit lug size and stud length unless you have a longer summit case on your 129/137" sled. It is tough to compete with the guys that do this full time on a part time basis. Have to do it for fun.
 

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You can go up to 9 inch without going longer track and using up too much suspension. 10 inch need longer track and use up too much suspension for every day riding.

You use an offset axle going forward and up with 9 or 8.5 inch wheels and keep the same track. The 10 inch kit on a stock skid are essentially like rail extensions (short adapters) and would take you from 137 to 146. 144/146 seems to be the ideal sled drag race set up though. Enough hook and you can keep the front down enough.. and the sled going forward.

Anyway to my way of thinking 9 inch are about the max for normal trail riding and some racing. I have both the 9 inch and the 10 inch set ups. Bigger drivers are a plus too, but limit lug size and stud length unless you have a longer summit case on your 129/137" sled. It is tough to compete with the guys that do this full time on a part time basis. Have to do it for fun.
8.5 won't work on rmotion x with tricked toys axle just went thru them on this. Didn't wanna go all the way to 9 inch so ended up with 8. I shouldn't say won't work, but you may not be able to run transfer blocks on 1 with 8.5 in wheels on rmotion x you can run 9's no problem
 

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Discussion Starter · #10 ·
Thank you all for your input and ideas. Just ordered up a 9" rear idler kit, along with the 6 front idlers from Tricked Toys.

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Keep in mind for your drag racing purposes, you are gonna lose track on the ground at your most important point , the very back. Not a big change, but it's going the wrong way when you already have too little track on the ground for your hp.
 

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Keep in mind for your drag racing purposes, you are gonna lose track on the ground at your most important point , the very back. Not a big change, but it's going the wrong way when you already have too little track on the ground for your hp.
Theoretically you are correct, but in practice, I have found the performance gain from the 9" wheels to offset the small loss in traction and this is in shorter hill drags where the traction effect would be more evident. And if he was really into the drag racing aspect, he would go with bigger front drivers and turn the offset 9 inch axle around and run a 144 optimum with 2.52 pitch drivers or a 146 inch track with 2.86 (less efficient that the 2.52 pitch). Seems like the 144/146 track dominate when drag racing. Better traction and better control of the sled.
 

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Theoretically you are correct, but in practice, I have found the performance gain from the 9" wheels to offset the small loss in traction and this is in shorter hill drags where the traction effect would be more evident. And if he was really into the drag racing aspect, he would go with bigger front drivers and turn the offset 9 inch axle around and run a 144 optimum with 2.52 pitch drivers or a 146 inch track with 2.86 (less efficient that the 2.52 pitch). Seems like the 144/146 track dominate when drag racing. Better traction and better control of the sled.
Actually, 159" is the choice for 250 plus hp nowadays if you want to be out front. OP is way over that number...
 

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Actually, 159" is the choice for 250 plus hp nowadays if you want to be out front. OP is way over that number...
Ok, I didn't know we were talking Turbo Charged high horsepower sleds; and if that is the case; why is he talking 137 inch skid? I did not read his signature line nor his post well enough; so just assumed he was talking normally aspirated sled since he was talking 137. You guys are out of my league. If he is not going longer. I would go summit chain case drop the drive shaft, run 10, 11 or 12 lug 2.52 and a 144, if he wants to keep it in that package and trail ride. that way he has big wheels on both ends. And I assume if he is going to trail ride he doesn't want to be over a 13/4" or 2 inch track. Or is this going to be a 1" speed track with lots of Triggers and chisels.. . Assume these are snow drags and not ice drags? Then the 1.5" lug two ply cross over track that comes 144, 151 or 159 in 2.52 pitch? You have me curious now. Hard to win with that much horsepower and 137 inch track.
 

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Ok, I didn't know we were talking Turbo Charged high horsepower sleds; and if that is the case; why is he talking 137 inch skid? I did not read his signature line nor his post well enough; so just assumed he was talking normally aspirated sled since he was talking 137. You guys are out of my league. If he is not going longer. I would go summit chain case drop the drive shaft, run 10, 11 or 12 lug 2.52 and a 144, if he wants to keep it in that package and trail ride. that way he has big wheels on both ends. And I assume if he is going to trail ride he doesn't want to be over a 13/4" or 2 inch track. Or is this going to be a 1" speed track with lots of Triggers and chisels.. . Assume these are snow drags and not ice drags? Then the 1.5" lug two ply cross over track that comes 144, 151 or 159 in 2.52 pitch? You have me curious now. Hard to win with that much horsepower and 137 inch track.
Any of these with the biggest chisel your favorite brand makes are winning setups in the northeast on snow.
92278c4699c4f48ffa4b3401f79bf002.jpg
 

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Any of these with the biggest chisel your favorite brand makes are winning setups in the northeast on snow.
92278c4699c4f48ffa4b3401f79bf002.jpg
That I understand, but how is your bud going to be competitive on a 137 with that much horsepower? And trail ride it too?
 

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That I understand, but how is your bud going to be competitive on a 137 with that much horsepower?
Depending on where he goes will determine how competitive, several groups putting on races in the northeast but only 1 really draws the serious racers. Doesn't mean you can't have fun at the others I'm sure. I believe he's just dabbling in the racing thing with a big hp trail sled. I only know the sled from posts on here, but have been doing the race thing myself in the same area for 15 years.
 

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Depending on where he goes will determine how competitive, several groups putting on races in the northeast but only 1 really draws the serious racers. Doesn't mean you can't have fun at the others I'm sure. I believe he's just dabbling in the racing thing with a big hp trail sled. I only know the sled from posts on here, but have been doing the race thing myself in the same area for 15 years.
Same here only typically run stock or trail mod classes here in midwest; more on the hill stuff. The turbo and unlimited stuff has sure become big in the last few years.
 

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Discussion Starter · #19 ·
Theoretically you are correct, but in practice, I have found the performance gain from the 9" wheels to offset the small loss in traction and this is in shorter hill drags where the traction effect would be more evident. And if he was really into the drag racing aspect, he would go with bigger front drivers and turn the offset 9 inch axle around and run a 144 optimum with 2.52 pitch drivers or a 146 inch track with 2.86 (less efficient that the 2.52 pitch). Seems like the 144/146 track dominate when drag racing. Better traction and better control of the sled.
Hey, thanks for all this info. Thanks to 440x as well. I am a trail rider first and foremost. I got into a bit of racing this past winter and had a pretty fair amount of success and a lot of fun. Around here in Western/Central New York, we have a mix of flat drags from 300' to 500', and hill drags around 350'. I wish they were a bit longer distances. The flats typically have hard pack dirt or ice starting lines. This is a real handicap for my sled, as I'm currently running an M-20 Airwave rear skid. It's the smoothest riding suspension out there, but weight transfer is definitely not it's forte.
The hill climbs are typically loose snow starting lines. I have much better success here. I have an 1.5" track which I'm sure helps. So my goal for next winter is to upgrade my traction off the line. I've picked up a 137" rMotion that I'll be installing. I already went with 10 tooth Avid anti ratchet drivers in 2.52" pitch a few years ago when I went with my current bigger turbo set up. Track is 1.5" Intense 2 ply with 216 Triggers. I'm very confident that my starting line performance will greatly improve with just the skid swap.
djm, your comment about reversing the TT offset axle is an intriguing thought. I'm seriously considering doing this and goin to a 144". Have you done this before, and does it actually get you to a 144" track?
Thanks again guys.

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Hey, thanks for all this info. Thanks to 440x as well. I am a trail rider first and foremost. I got into a bit of racing this past winter and had a pretty fair amount of success and a lot of fun. Around here in Western/Central New York, we have a mix of flat drags from 300' to 500', and hill drags around 350'. I wish they were a bit longer distances. The flats typically have hard pack dirt or ice starting lines. This is a real handicap for my sled, as I'm currently running an M-20 Airwave rear skid. It's the smoothest riding suspension out there, but weight transfer is definitely not it's forte.
The hill climbs are typically loose snow starting lines. I have much better success here. I have an 1.5" track which I'm sure helps. So my goal for next winter is to upgrade my traction off the line. I've picked up a 137" rMotion that I'll be installing. I already went with 10 tooth Avid anti ratchet drivers in 2.52" pitch a few years ago when I went with my current bigger turbo set up. Track is 1.5" Intense 2 ply with 216 Triggers. I'm very confident that my starting line performance will greatly improve with just the skid swap.
djm, your comment about reversing the TT offset axle is an intriguing thought. I'm seriously considering doing this and goin to a 144". Have you done this before, and does it actually get you to a 144" track?
Thanks again guys.

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Thanks for the update. Makes a lot more sense to me now.

Ha ha.. funny you should ask on going 144 and turning the 9 inch wheels around. We did it once a couple of years ago on my buds XP Renegade with a 146" mountain track for a trip to Togwotee/Dubois, Wyoming area. And that was with 8 lug stock 2.86 drivers 7.47" diameter . It just made it, used all of the adjustment in the rails to get the track tight. So with either bigger drivers or a 2 inch shorter 144 inch track it should not be an issue. I have a 129" that I am going to try it with a 137 inch track here in the next few weeks. The change in length is the same. I have 9 lug 2.86" Avid drivers mounted on a spare axle to use. Their diameter is roughly 8.37 inches vs your your 10 lug 8.15" diameter. I would like to go to 11 lug 2.52 involutes drivers at 8.94 inch diameter; but I would be spending money for a track and the drivers. Plus I believe based on input from Wileo who has done this before with the 9 lug 2.86, than he had trouble hitting the tunnel on the outside edges of the track with 1.45 " studs. He said if one studded just the inners that one could go to 1.63" but don't think giving up the outers is an option for traction. So debating putting a Summit Chain case on. Which is essentially a drop and roll over the MXZ chain case which would allow me to use 1.5 lug or even 1.75 lug and taller studs. I do all snow hill drags.

But mine is also my trail sled. I also have a couple of XP's one a 146 summit and the other a 137 renegade that I use. Just recently sold my 154 inch 850 summit as we seem to be doing more trail riding then cross country which we used to do. If 9 inch rolls nice on the one end, 9 inch or nearly 9 inch drivers specially if they were involutes should roll even nicer. But do I want to do the summit chain case? Decisions decisions. I also have a 137 R motion skid and tunnel extension I could use and go 144 also.. . Just have to make up my mind. So I have been staring at a used summit chain case, 11 lug avid or aluminum Wahl brother involute drivers for the last couple of days. Did the chain case swap once before on a Rev, just don't know if I want to cut on my tunnel or not. Doesn't usually help the resell value.

Anyway, will stay in touch and let you know which way I go.
 
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