Gearing 101

[@alexcowell42]

I could listen to sled tech from a professional all day!

[@FeederCountry]

Great video. Love anytime I can listen to Eric talk. Please keep them coming!

[@allblowdup]

I have done testing on a dyno between chain and belt and the belt is more efficient. Basically a 700 rmk engine mounted in a bulkhead with clutch locked at 1:1 through through the chain case/ belt drive and the dyno mounted to the drive shaft. Belt won hands down at 8000 jackshaft rpm.

[@TheVOHK]

We found the belt drive to offer an advantage at low-speed and during acceleration due to its low inertia and efficiency but at higher speeds we found the exact opposite. We performed both empirical testing as well as logged data analysis and worked with very reputable companies throughout. Not certain why your testing revealed the opposite result, I have no opinion and just report the facts as we observed them. Thanks for the input 👍.

[@lobbyrobby]

Does a chain on a trail sled and belt on a mountain sled make any sense?

[@vincelombardi2669]

Eric, Being that this video is a couple years old now wanting to know what your finding have been now with the Boost and the 9r. I currently have 155 khaos boost 2.75 track QD2 and 146 khaos 9r 2.6 track QD1. I am looking to change both unit to the TKI kit. However I am wanting to change gearing and not just run the standard ratio if I am spending the money to change to the TKI kit. Any thought?

[@nathangrenier]

Very nice information! What is the formula to calculate the final ratio when I already know my belt drive ratio? 2.63 with 8 tooth 3" pitch

[@TheVOHK]

The industry chose to commonize that variable to create a relatable final value that transcends brand and model. Otherwise the relevant consideration wouldn't be final drive it would be gear ratio. Which in most cases is all that really matters. I think it's nonsense also and believe that individual final drive should be considerate of individual driver configurations... don't blame the messenger:-)...

[@JasonMcMurray]

I currently am running the pro gears on my 2020 850 khaos 155 2.6" lug. I ride 90% of the time in tight trees at elevations from 3000-8000'. Tons of slow speed maneuvers and short punchy run ins for jumps. It still doesn't have the low end grunt to get me going that I want. I noticed a good improvement over stock once I go about 3-4 sled lengths it pulls good and continues to pull hard, its just that initial jump out of the hole that's still unimpressive. It is exaggerated even more when the snow becomes heavy and thick. It does have slightly longer belt life but would like even more low end if possible. I am looking at the kurts gear down and the QD2. From what I understand there shouldn't be much difference between the pro gears and the kurts kit. Both have a gear ratio of around 2.09ish so I can't see the kurts gear down giving me what I want. What about putting the QD2 gearing on my machine with my stock 2.86 pitch driver? Any idea what my final drive ratio would be? Would it be too much? I just don't want to make it worse by gearing down too far.

[@TheVOHK]

The Kurt's gear down is slightly higher than the QD2, and by the sounds of your use demand I expect you would be pleased with the result if you were to employ the QD2. Regarding final drive ratios I put up a chart in this video and explained the process of calculating them.. GL. Thanks for the question.

[@C500-s6m]

Thanks for the video! I ride a 21 khous 7-10 lbs of boost with a qd1-163, 2.6 lug will a qd2 or tki kit get this sled to wheelie ! I need this sled to erupt on the bottom end ?

[@TheVOHK]

It is unlikely that a gearing change is going to make a massive difference in the sense that your snowmobile will be completely transformed. Turbos tend not to be as explosive as many would hope. There's not much you can do about that. If you're looking to increase your units tendency to wheelie perhaps looking to suspension setup would make as big a difference is anything. But yes, gearing down will move you in that direction...

[@C500-s6m]

Thank you !!

[@chasebatchelder6467]

Got a 22 matryx slash 146 QD1 with the 2’’ track. Was wanting to go with a 2.5 challenger track for it will be more fitting to my UP riding and for out west. I ride some trails still but ultimately want good low end pull. Just curious if I could keep my QD1 drive or if I should change to the QD2 drive. Thanks! Great video.

[@TheVOHK]

That's a tough call, it's right on the bubble, the correct answer is really going to be determined by your preference, however from the hip and if it were mine, I would switch to QD2 gearing. It may come at the sacrifice of some top speed at lower altitude, but in my opinion it's well worth the gain and response.

[@spakepac88]

Thoughts on putting Pro Rmk gears on an Axys?

[@TheVOHK]

Pro RMK Gears are 21:44 (2.09), QD1 gears are 22:43 (1.95) so applied to Axys will land at 2.37 final drive considering the 7 tooth 2.86 driver on the unit.

[@benseinen9597]

Why would you give a lower theoretical final drive if you haven’t changed the drivers. If you have 22/50 (2.27) QD2 and then run a 29/69 (2.38), clearly the 29/69 is lower as they are both using the same sized drivers. If a skidoo is 21/53, (2.52), with 6 tooth 3.5” pitch drivers, why would you change the final ratio without actually making a driver change. That’s what they come with. I feel like the info provide wasn’t very clear.

[@TheVOHK]

You are absolutely correct, that was something I clarified in comments earlier. That information was essentially Incorrect or at least unclear with respect to the SkiDoo. I apologize for that.

[@benseinen9597]

@@TheVOHK same as the Polaris gear down. There is no need to factor in drivers as your not make an actual driver change. The 22/50 QD2 is a higher gear ratio then the Kurt’s 29/69.

[@TheVOHK]

Maybe it would be easier if you gave me a call so I can explain. It boils down to all manufacturers commonizing the final variable of final drive and that is why you make the driver correction. It is an effort to create data that will transcend models and manufacturers and still offer a relative expression of final drive. Otherwise we would just be talking gear ratio. Happy to chat with you sometime feel free to give me a call at the shop. 970-724-9655

[@TheVOHK]

Where you're going wrong is at the time that we were testing and that I made that video as indicated in the above comment the Kurt's gear down kit was a 32 67 ... that was all they sold and that was all that was available at the time. They have sent altered their gear down kit and it is indeed now a gear down kit but like I said at the time the video was made the Kurt's gear down kit was actually a gear up kit. The facts don't lie.

[@joshnelson1164]

Great video….even tho I’m a Cat guy lol….just fyi the oem gearing on the alpha you had was correct but the alpha uses a 3.5 pitch 7tooth driver not 3.0 unless you’re referring to the twin rail non-alpha which used the 3.0 pitch 7tooth so the final drive ratio on your chart is incorrect for the alpha being that low.

[@bradclarke6016]

hey who's this guy? i agree with him wich is rare on the tubes. I get this into expaining why we are doing something a certain way with a friend and i ony get hf way before they say something aong the lines of "ohh the wifes caling! Think oim going to give up sled'n and get into booz'n ~" lol