3rd or 4th gear?

Hobby87

New member
I am running my 250 on mainly 1/8-1/10th dirt ovals and with the 520 chain set up I have gearing that will allow me to run in either 3rd or 4th gear and keep the final ratio, is there any pro's/con's to each? The ratio's are as follow:

3rd: 1.21 (13/26 = 7.26)
4th: 1.00 (14/28 = 7.26)

trying to stay under 12,500rpm

Thanks, Matt
 
I am running my 250 on mainly 1/8-1/10th dirt ovals and with the 520 chain set up I have gearing that will allow me to run in either 3rd or 4th gear and keep the final ratio, is there any pro's/con's to each? The ratio's are as follow:

3rd: 1.21 (13/26 = 7.26)
4th: 1.00 (14/28 = 7.26)

trying to stay under 12,500rpm

Thanks, Matt
I’m wondering where you come with those numbers?
I have a spreadsheet for transmission gears and matching the ratio from the crank to the axle and it comes up with some way different numbers from what you got, by a bunch, and I’m wondering if my software is that far off.
The Honda 250 final ratio is 1.0 and with a 14/28 that gives a final ratio of 2.0
With a 1.21 13/26 the final ratio is 2.42
The final ratio being from the crank to the axle. Is the spreadsheet off?
 

Hobby87

New member
You had me 2nd guessing myself Al, and you're RIGHT! I did not type that up correctly, while Brian is correct, I left out the primary gearing, I accidently stated that the 14/28 set up in 4th is the same ratio as the 13/26 in 3rd, that is not the case, they are the same 2.0 ratio throughout, so in this case, would both provide a 7.26 final drive in 3rd gear, or 6.00 in 4th, my main concern is which gear provides the better "power band" so that I would not have to shift gears while racing and if either bogs down more than the other if I had to get out of the gas.

Al, the math is (rear gear) / (front gear) X (tranny gear ratio) X (primary) 26/13X1.21X3.0 = 7.26, hopefully your calculator is correct, I always look forward to reading your input regarding gearing, it always gets me thinking!

-Matt
 
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