i checked the faq & searched for this info, yet it eludes me..

i read somewhere on here that if you get a different size tire & rim combo, (drag slicks in this case) you can "change" your rear gearing without going into the pumpkin.

what i want to do is try to get a 3.73 gearing just for the drag strip thru changing rims/tires.


is this true? if so would someone post the info so it can be included in the faq?

thanks,
brooks

 

clonetek
What you have to do is get some tire/wheels that have a OD oberall diamiter that is smaller than the stock tires. In other words you wanr shorter tires than what you have now.

I am not sure what overall diamiter you want I belive the stock tires have a OD of 28.3 inches so to get it to a 3.73 ratio you would have to go to a OD of about 26 inches.

Maybee a set of P295/50R15 with a OD of 26.5 and a width of 12.4 inches might work. Don't hold me to the gear ratio that would give you it is just a guess.

------------------
1999 F150 4x4 4.6V8 regcab/shortbed
Oxford White with Wedgewood Blue two tone, with Blue Captains chairs
Bullet Cat Back, Superchip, K&N FIPK Intake.
Centerline Saber rims 17x8" with Firestone GTA 275/60hr-17 tires.
Alpine CDA-7845, ADS P640 Amp, Focal Poly Kevlar seperates.
SILVER 2001 LIGHTNING on order
http://members.tripod.com/donf150/Welcome/id7.html


[This message has been edited by Don C (edited 01-13-2001).]

 

i don't think the 15" rims will fit on the lightning.. it has to be a 16" or bigger.

thank you for your input Don C!! that helps me out.

 

A tire with a diameter of approx.26.5 in will make the 3.55's act like 3.73's IMO not enough difference to warrant the trouble of a ring and pinion change. I changed the gears in my wifes' Stang when we first got it from 2.73 to 3.08 just 'cause I had the 3.08's laying around and at the time had nothing better to do. That was worth about .05 in et.

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2000 Silver L #4906
Best 1/8th mi stock:9.13
Best with R9 and 5,000 mi: 8.67
1995 Stang : (wifes'car) 12.30 1/4 mi
1972 Skylark: 7.16 1/8, 6.70 on the bottle

 

The approximate rule is for every inch in diameter change, the rear end ratio changes about 0.10. For the example given a tire two inches smaller in diameter will change the 3.55 to approximately 3.75.

 

To figure what size tires you need for a specific final ratio, divide your actual ratio by the desired ratio...

3.55/3.73=.952

and then multiply times the current tire size...

28.21*.952=26.85...

I doubt that you can find drag radials/slicks at this exact size...

26" is commmon, and is readily available for 16" rims...

To find the ACTUAL ratio with 26" tires, divide the current tire size by 26...

28.21/26.0=1.085...

and then multiply by the ACTUAL gear ratio...

3.55*1.085=3.85 FINAL ratio...

Hope this helps!!!

 

thanks for the help everyone!
it's all clear now...

all i need to do is get some 24" tall drag slicks to get that elusive 4.17 gearing! LOL

[This message has been edited by clonetek (edited 01-14-2001).]

 

I was just looking at the Summit cataloge and I came across some options

BF Goodrich makes two dot drag radials
255/60-16 OD 26.1
275/40-17 OD 25.7

Mickey Thompson
26x10.5-16 OD 25.9
26x11.5-16 OD 26.2