Board index The Tech Shop Mud Racing Tech Gear Ratio???

Gear Ratio???


Post Tue Mar 16, 2010 9:27 pm

Posts: 234
O.k folks, here we go again. This one is for a friend. 40in rear tires, 33in front tire, 6.00 rear gear. What front gear should he run and what percent overdrive would it be. Thanks
    Ryan Dolan
    Rawlings, MD
    (301)876-3145
    MRA# 381

Post Tue Mar 16, 2010 10:31 pm

Posts: 1246
Location: paulding,oh
don't go by what i say ''i hate trying to figure out gear ratio's'' but i want to post what i would put in it to see if everybody else comes up with the same thing. i would put 4.88 in it. come on guys how wrong am i :oops: :oops: eric
Image
Eric Bidlack
MRA 133
NMRO 3035
419-438-3876
fataladdictionmudracing@yahoo.com

Post Tue Mar 16, 2010 10:37 pm

Posts: 218
Location: Plymouth, IN
i dont have my spreadsheet at home but i run 35's and 33's on the front with 488's and 543's and i show that to have .03.04% over spin.

Post Tue Mar 16, 2010 11:34 pm

Posts: 17
HMM there is alot of ways to do this but from what I was taught I came up with 4:95 Ratio Needed, You want to be as close to that number as possible! :D


NEXT ;)

Post Wed Mar 17, 2010 5:26 am

Posts: 169
Location: SAULT STE MARIE ONTARIO CANADA
from what i calculate if im right in mile per hour tire speed with 6.0 and 4.88 and the tires your running there would be 2 miles faster in the front.....http://www.4lo.com/calc/gearratio.htm

Post Wed Mar 17, 2010 5:35 am

Posts: 1170
(Front tire Dia. (roll out) X rear gear ratio) Divided by the rear tire Dia. (roll out) = front gear needed.

33" tire x 6.00 gear = 198

198 divided by 40" tire = 4.95 gear (4.88 gears would give him less then 1% overdrive) most like around 6-10% overdrive (a 4.56 gear would give around 8%)

To be more accurate, it is best to use formula using roll out of the tires on the vehicle rather then just tire diameter.

Post Wed Mar 17, 2010 7:56 am

Posts: 234
Well 4.56 is what I thought to begin with. I guess I'm not as far off as I think I am with this stuff LOL :mrgreen: Thanks again guys.
    Ryan Dolan
    Rawlings, MD
    (301)876-3145
    MRA# 381

Post Wed Mar 17, 2010 8:44 am

Posts: 1246
Location: paulding,oh
traveler wrote:
(Front tire Dia. (roll out) X rear gear ratio) Divided by the rear tire Dia. (roll out) = front gear needed.

33" tire x 6.00 gear = 198

198 divided by 40" tire = 4.95 gear (4.88 gears would give him less then 1% overdrive) most like around 6-10% overdrive (a 4.56 gear would give around 8%)

To be more accurate, it is best to use formula using roll out of the tires on the vehicle rather then just tire diameter.

i always run as close to straight up as possible maybe thats why mine drives like chit :shock: eric
Image
Eric Bidlack
MRA 133
NMRO 3035
419-438-3876
fataladdictionmudracing@yahoo.com

Post Wed Mar 17, 2010 8:50 am

Posts: 1246
Location: paulding,oh
ok terry so 44's rear 5.86 rear gear 34.5x9.50 swampers front what gear do i need for front? i came up with 4.56:oops: :oops: eric
Image
Eric Bidlack
MRA 133
NMRO 3035
419-438-3876
fataladdictionmudracing@yahoo.com

Post Wed Mar 17, 2010 12:27 pm

Posts: 93
Location: Taos, New Mexico

I use the calculator on www.markwilliams.com It usually gets me close enough for the girls I date :D Gives transmission rations too.
Norbert Mondragon
(575) 770-7144
www.batcaveracing.com
NMMRA

Next

Return to Mud Racing Tech