is there a way to determine what a driver downsize would equate to in gear change?

[batman]

Strange question, but is there a way to figure that out?

for example, i went from a 9T x 2.52 to a 7T x 3.

the 7t is a slightly smaller radius/diameter than the 9t....what would that equate to in a gearing change?

it went into an 03 summit 151- left clutch and gears stock.

 

[OnTheEdge]

i went from a 9 tooth 2.52 to a 8 tooth 2.52 and with my caculations i will losse about 12% of my speed. you will be loosing around 20mph im guessing

 

[meathooker]

Strange question, but is there a way to figure that out?

Yes there is...it's called MATH!

 

[SnowSnob]

Here ya go, this makes it easy.
http://www.mxzx-revzone.com/article/top-speed-calculation-133.asp

 

[Speednutt]

Here is a online MPH calculator that i built. http://www.racenssr.com/calc.htm Enter in all your info and then just change your driver size to see the difference in speeds.

Nate

 

[batman]

Yes there is...it's called MATH!

thanks pal. yer awesome.

 

[batman]

any idea what to use for a 7T 3" pitch in terms of a constant?


could be safe to say a 7t x 3 is "47-48" ? constant?

Here ya go, this makes it easy.
http://www.mxzx-revzone.com/article/top-speed-calculation-133.asp

 

[batman]

i went from a 9 tooth 2.52 to a 8 tooth 2.52 and with my caculations i will losse about 12% of my speed. you will be loosing around 20mph im guessing

that's about what i thought too. 15-20mph. but, gain some low end.

 

[batman]

nate- couldn't get into your site? says needs a password?

thanks for all the help guys.

 

[batman]

another question, will the change in driver affect the rpm's w/ no clutching or gearing changes?

i would think it could go up due to the gearing down effect the driver created?

it's got the clicker primary, i could just back that down a tick.

i've had the last few posts on this thread....my turn to shut the pie hole.

 

[Butta]

My calculations show that to be a 7.4% drop in track rotation per driveshaft revolution....hence, a 7.4% drop in speed (theoretically).

I went from a 7T 3.0 to a 7T 2.86 and it worked out to about the same as dropping one tooth on the small sprocket.

 

[SnowSnob]

Running the same gearing with your 7th drivers you'll be geared lower which you will lose RPM's since your clutches will shift out faster.
With those small drivers you need to gear up quite a bit, like 21/43.
Try some searching on Dootalk.

 

[batman]

cool, thanks.

so r's will drop? that kind of confuses me. if it shifts out faster, wouldn't it rev high, but just not go as fast? b/c of less load on the motor?

not sure what stock gearing is on a 03 summit 800 151...thought it was 21/43 out of the box?

 

[batman]

nope-i'm drunk. it's a 19/43 out of the box.

ok, so if i had to gear up, could i go w/ a 20 or 21 on the top do you think?

 

[Speednutt]

Not sure why it asked for a password, as i dont have one on there. Must have been a server error. I just tried it and it works just fine. Hope it helps.

Nate

 

[SnowSnob]

Using Speednuts link looks like 21/43 is about right, you could probably go even higher.
Are you using the CNC'd Avid drivers?? cause they're .25" smaller so they'll be like 6.4" Dia.

 

[Butta]

Running the same gearing with your 7th drivers you'll be geared lower which you will lose RPM's since your clutches will shift out faster.
With those small drivers you need to gear up quite a bit, like 21/43.
Try some searching on Dootalk.

By no means am I claiming to know everything about how the clutches work, but if the primary controls RPMs (mostly), and the secondary controls track speed from the primary's RPMs....how does gearing down effect RPMs?? It seems the speed of the secondary shaft is the "feedback" source, and since that speed isn't being changed, only the load on that shaft is being changed (decreased), so the clutching shouldn't be effected??

Plus, my logic tells me that when you gear down you decrease the load on the motor to spin the track, therefore increasing the ability to transfer torque and therefore actually making the RPM's more easily attained.....

Thoughts?

 

[RockyMtn.Kris]

By no means am I claiming to know everything about how the clutches work, but if the primary controls RPMs (mostly), and the secondary controls track speed from the primary's RPMs....how does gearing down effect RPMs?? It seems the speed of the secondary shaft is the "feedback" source, and since that speed isn't being changed, only the load on that shaft is being changed (decreased), so the clutching shouldn't be effected??

Plus, my logic tells me that when you gear down you decrease the load on the motor to spin the track, therefore increasing the ability to transfer torque and therefore actually making the RPM's more easily attained.....

Thoughts?

Often you will lose rpm when gearing down. The secondary is able to shift further with the same load, loading down the motor. This is often disputed, but usually the case. Obviously there are too many variables to account for
to say this across the board for every scenario.

Not more easily attained but rather easily sustained. (Once correctly calibrated)

 

[RockyMtn.Kris]

On the effective gear change with driver size you can figure it out using porportions. Lets say your existing gear ratio is 2.25 with 9t/2.52pitch drivers. You switch to 7t/3.0.

7t Diameter/2.25 = 9t diameter/x

21/2.25 = 22.68/x

Invert and multiply

21x = 51.03

x = 2.43

So, going to 7t 3.0 pitch would be the same as re gearing to 2.43