3rd or 4th gear?

Hobby87

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?
 
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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