kinger
VIP Member
Building my apex and currently running 9T extros with 24/38 stock apex gearing.
I am going to be significantly reworking the chassis and possibly removing the front heat exchanger.
I would like people's opinion on what would be the ideal set up for drivers/gearing?
I want to lower my approach angle as much as possible WITHOUT a drop and roll. Goal would be climbing up on the snow like my winder BTX and not losing any top speed.
I have had 10T drivers, Large gears (IIRC it was 22/42??) I noticed only loss of top speed/accel and not any other real gains on a 240hp apex. That said I was 121" going from a 1" track to a 121 1.25" predator back to 9T and stock gearing (where it is today) and it was night and day better. So I am wondering if maybe it was the track and not the drivetrain where I felt the gains.
Without a front cooler, I could go to a 10 or possibly even 11 T 2.52" driver from Avid that will fit my MD HD 1.25" shaft. OD would be around 27.7" on the 11T.
I plan to run a 151x 1.5" lug crossover track. This is a trail sled that will be around 400hp and will see 140+ mph speeds regularly on a lake.
Thoughts? Hoping some of you experts have been down this road and can help guide me. Thanks guys!
I am going to be significantly reworking the chassis and possibly removing the front heat exchanger.
I would like people's opinion on what would be the ideal set up for drivers/gearing?
I want to lower my approach angle as much as possible WITHOUT a drop and roll. Goal would be climbing up on the snow like my winder BTX and not losing any top speed.
I have had 10T drivers, Large gears (IIRC it was 22/42??) I noticed only loss of top speed/accel and not any other real gains on a 240hp apex. That said I was 121" going from a 1" track to a 121 1.25" predator back to 9T and stock gearing (where it is today) and it was night and day better. So I am wondering if maybe it was the track and not the drivetrain where I felt the gains.
Without a front cooler, I could go to a 10 or possibly even 11 T 2.52" driver from Avid that will fit my MD HD 1.25" shaft. OD would be around 27.7" on the 11T.
I plan to run a 151x 1.5" lug crossover track. This is a trail sled that will be around 400hp and will see 140+ mph speeds regularly on a lake.
Thoughts? Hoping some of you experts have been down this road and can help guide me. Thanks guys!
kinger
VIP Member
Some quick math and the 11T driver will stick the track 0.8" into the cooler further then it is today. I will have to go get the chassis out and start seeing if I can even do that and what impact that has on approach angle. Then I need to go to 22/42 gearing to equal the same speed as my current 24/38 9T combo.
Does a bigger driver hurt TQ to snow? Seems like it would be harder to get it spinning then a smaller driver no matter what gearing you put in the case?
Does a bigger driver hurt TQ to snow? Seems like it would be harder to get it spinning then a smaller driver no matter what gearing you put in the case?
- Joined
- Apr 17, 2003
- Messages
- 5,428
- Location
- Menno, SD
- Website
- www.ulmerracing.com
- Country
- USA
- Snowmobile
- 2014 Yamaha SR Viper LTX, 2014 Yamaha SR Viper RTX SE, 2015 Yamaha SR Viper MTX SE 162 (turbo), 2015 Yamaha SR Viper MTX SE 153
- LOCATION
- Menno, SD
- WEBSITE
- www.ulmerracing.com
The less bend radius in the track the more efficient it will be. Also the larger the driver the more contact between the track and driver you have which will help with ratcheting, etc.
- Joined
- Apr 17, 2003
- Messages
- 5,428
- Location
- Menno, SD
- Website
- www.ulmerracing.com
- Country
- USA
- Snowmobile
- 2014 Yamaha SR Viper LTX, 2014 Yamaha SR Viper RTX SE, 2015 Yamaha SR Viper MTX SE 162 (turbo), 2015 Yamaha SR Viper MTX SE 153
- LOCATION
- Menno, SD
- WEBSITE
- www.ulmerracing.com
kinger
VIP Member
No extro's Allen?
- Joined
- Apr 17, 2003
- Messages
- 5,428
- Location
- Menno, SD
- Website
- www.ulmerracing.com
- Country
- USA
- Snowmobile
- 2014 Yamaha SR Viper LTX, 2014 Yamaha SR Viper RTX SE, 2015 Yamaha SR Viper MTX SE 162 (turbo), 2015 Yamaha SR Viper MTX SE 153
- LOCATION
- Menno, SD
- WEBSITE
- www.ulmerracing.com
I would say extros will be a must.
kinger
VIP Member
No one else wants to weigh in? Bigger is better or just keep on keepn' on with what I have?
We run 10T on our big RX turbo. Agree with Allen's comments re: rolling resistance. One thing to consider is if an 11T driver would stick out below the front bulkhead: if you looked under the sled from front towards the track, would an 11T driver be visible? If it is, then the drive axle would receive the impact from any hard knocks on the trail with the potential to bend the shaft itself. I know on a Winder a 10T driver just fits up inside, while an 11T is exposed. No problem if the sled is going to spend its life racing on a track, concerning if it will ever spend time on the trails...
Brotherdan
Expert
- Joined
- Sep 8, 2017
- Messages
- 371
- Age
- 52
- Location
- Belmont,maine
- Country
- USA
- Snowmobile
- 2011 apex xtx blue, starr suspension,gytr front shocks,camso 1.5 track cut down, snowtrackers work in process,2003 rx1er originally 121 converted to 136"monoshock 2 ck136 rear suspension with clicker vector ltx shock,muffin works tunnel extension, seat concepts(wrp) seat,apex hooked handlebars converted to all underhood wiring,8"lake effect billet aluminum riser,gytr frontshocks,yamaheater hand warmer kit,rocks ridelite,rocks power supply, rocks heated bag,, tunnel braces,blue skid plate,garmin gps, aggressive snowtrackers on apex single keel skis,rollerski ski wheel kit,108 warthog studs&blue studboy backers,pioneer wheel lowering kit, dupont slides, 4th wheel kit,yamaha saddle, tank& windshield bags, powermadd led handguards, bar mount mirror kit, apex radiator& electric fan added, apex rear cooler,autometer temp guage, apex new style large diameter drive shaft with extroverts machined for chaincase,thunder products clutching,1987 enticer 340ltr 2100miles,1984 enticer 340,1996 wolverine 350,big wheel kit,winch,racks,k&n,full skidplates
Of course we want bigger as bigger is better (well in this instance anyway )its your sled& therefore you have to wrench on it while we sit back& read about this beast so we want to see at least 400hp lol
kinger
VIP Member
Thanks for the input guys! I think I will stay with 9T for now and see how it acts.
