Gear Ratio question

[BradC]

If I get a taller tire than OEM will it increase or decrease the overall gear ration? In other words, will I have a stiffer or softer gear?

[AlienInv8r]

I think I remember someone saying somewhere that if you have a taller tire, it will equate to your final ratio being numerically lower since they will slow down your acceleration. But I'm not positive.

[bobrules]

Decrease...

[Justin Kirkham]

softer. If you had wheels that were super-swampers off of a truck you would have a gear ratio of about .5 instead of 3.42, regardless of weight.

-Justin

[AlienInv8r]

so numerically higher = stiffer
and lower = softer??
I never knew that and was wondering if that's how that worked when he said that.

[BradC]

Then why do you see tractors with huge rear tires designed for pulling(torque)?

[Loochy88]

<blockquote>quote:</font><hr>Originally posted by BradC:
Then why do you see tractors with huge rear tires designed for pulling(torque)?<hr></blockquote>

think about it... if those things had really small tires they couldnt pull anything. look at it this way... put a trailer hitch on your camaro, hook it up to something heavy, and put two donuts on the rear wheels. what ar eyou goign to do? youll sit there and spin your wheels. Now put some big *** slicks on the back, and youll be doing some pulling.

[ December 08, 2003: Message edited by: Loochy88 ]</p>

[javifp]

your stock rims (16-inch) and stock tires 235-55-16, then you put some low profile tires 245-45-16 then it will be like going from let's say 3.23 to 3.42 or if you do the opposite and put tall tires such as 265-50-16 then it will be like going from 3.23 to 3.08. see it basically boils down to tire size and revolutions per distance.

[V6Bob]

"your stock rims (16-inch) and stock tires 235-55-16, then you put some low profile tires 245-45-16 then it will be like going from let's say 3.23 to 3.42 or if you do the opposite and put tall tires such as 265-50-16 then it will be like going from 3.23 to 3.08. see it basically boils down to tire size and revolutions per distance."

In the first case, it would be more like going to 3.73s (3.81). In the second case it would be virtually no change (3.18).

Take the profile (45,50,55) and multiply it by the width (235,245,265). Take the ratio of the two numbers that result. That's your difference.

[ December 08, 2003: Message edited by: V6Bob ]</p>

[Bliggida]

... a smaller tire is going to numerically raise your gear ratio.

Numerically higher gear ratios are considered "Lower gears"
Vice versa.

Tall gears are numerically lower (high gears)
Short gears are numerically higher (low gears)

[javifp]

listen V6Bob why are having a cow? you cant argue the fact that some tires are 26 inches tall and some are 29 inches tall. it is obvious that the revolutions per distance will vary as in gear diference with the same tire. So please dont be bashing me and as for your point of view should be in trying to help the board member who asked the question and not trying to look as the all mighty by making me look uneducated.

[V6Bob]

I'm sorry if I offended you.

I was just trying to give the original guy some information about exactly how the effective gear ratio changes, not put you down. I didn't think I was using offensive or emotional language (having a cow?), just straight factual stuff.

But, in any event, I apologize.

[ December 09, 2003: Message edited by: V6Bob ]</p>

[javifp]

thanks for the apology V6Bob and I didn't mean to sound like a cry baby so I am sorry too. Happy holidays.