Rear Gear,s????

pete walton · Post by **pete walton** » Sat Nov 24, 12 9:42 am

Spoke to Jimbo the other day about the formula for working out how tall your rear gear,s should be,,,,,,were is it Jim????,,,,,i can,t find it???

GTXJim · Post by **GTXJim** » Sat Nov 24, 12 10:10 am

Ive emailed you mate..

pete walton · Post by **pete walton** » Sat Nov 24, 12 3:01 pm

Nice one Jim,,, if my moter is making 700ish hp ,crossing the line at 6750rpm with a 32 inch rear tyre ,,,i should be running 9.11 at 145mph

....surprising thing is my rear gears need to be 4. 41 ish ,,,at the moment they are 4.88....that explains why i am nosing over about 300 ft out.......In a perfect world hey

Mick · Post by **Mick** » Sat Nov 24, 12 6:20 pm

If it's any help Pete, i turn 6700 through the line with a 31" tyre and 4.56 gears. So i would say that's what you need.
Mick

Pete · Post by **Pete** » Sun Nov 25, 12 8:41 pm

What does the car weigh?
If it is nice and light you may be able to get away with taller gears to either keep the rpm down or maybe attain higher mph!!!

Dave-R · Post by **Dave-R** » Mon Nov 26, 12 11:18 am

Mick wrote:If it's any help Pete, i turn 6700 through the line with a 31" tyre and 4.56 gears. So i would say that's what you need.
Mick

Agree.

AllKiller · Post by **AllKiller** » Wed Dec 05, 12 2:27 pm

Got some 5.13s Pete cheap £50 taller tyre and away you go...certainly get you off the line

Six-pack Speedshop · Post by **Six-pack Speedshop** » Wed Dec 05, 12 2:34 pm

Use the biggest tire you can fit and gear it accordingly I would say.

Les Szabo · Post by **Les Szabo** » Wed Dec 05, 12 3:11 pm

700hp at 3000lb all in? with a 4.56 gear
60 Foot E.T. : 1.32
1/8 Mile E.T. : 5.97
1/8 Mile Trap Speed : 113.86
1/4 Mile E.T. : 9.46
1/4 Mile Trap Speed : 142
1/4 Mile Trap RPM : 6,786+ a bit of slip?

with 4.88
60 Foot E.T. : 1.32
1/8 Mile E.T. : 5.97
1/8 Mile Trap Speed : 113.86
1/4 Mile E.T. : 9.46
1/4 Mile Trap Speed : 142
1/4 Mile Trap RPM : 7,262+ slip

why are you nosing over?...Indy Heads etc?.....that should pull well into the 7000rpms with a good cam/carb jetting sorted Pete...
________

this is an example of what Mick runs at 600hp
60 Foot E.T. : 1.41
1/8 Mile E.T. : 6.39
1/8 Mile Trap Speed : 106.41
1/4 Mile E.T. : 10.12
1/4 Mile Trap Speed : 132
1/4 Mile Trap RPM : 6,547+slip
more or less spot on with this calc cept for his mph is a bit down

Les

Pete.S · Post by **Pete.S** » Thu Dec 06, 12 11:54 am

I'd go 4.56