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Drag Racing Discussions => Front Engine Dragsters => Topic started by: wideopen231 on June 20, 2020, 08:47:30 AM

Title: tire speed vs low gear ratio
Post by: wideopen231 on June 20, 2020, 08:47:30 AM
Maybe my thinking is off base.After 7 months of job I am doing its highly possible.

 Wouldn't a higher(lower number) ratio give you more wheel speed at the hit?Provided you have enough power to get it rolling. Part of another thread and did not want to derail it. I had advice from a old guy in Kansas not to go 1.80 low but rather the 1.69 low because of shake. Hard to argue with those guys. LOL  So far only shake I have had was from stupid tune.which goes back to under powered thing.Always a probleM. NEED MORE POWER!!!!!!!
Title: Re: tire speed vs low gear ratio
Post by: buickfed on June 20, 2020, 10:50:46 AM
good question. bought an altered and we will run al least one v6 in it. the tires are 36x17-16. a lot of diameter for the v6. BUT, my tranny guy likes R&D and has built a t350 modified with a 700r4 first gear, but no changes for 2-3.  that first is 3.08. add a 4.56 and you get a wild granny gear. now the decision is what rear gear to use.
normal stuff is so boring......  ;D
Title: Re: tire speed vs low gear ratio
Post by: THE FRENCHTOWN FLYER on June 20, 2020, 12:17:10 PM
Let me respectfully suggest your tire us WAAAaaay too big for a V6. I switched from a 15 x 12 x 31.5 to a 15 x 10.5 x 28S last Sunday and ran my best 60' - 1.18 in years, down .13 sec from the previous 12 x 31.5s.

This is with a 305 ci inline six bracket engine (around 550 HP).
Title: Re: tire speed vs low gear ratio
Post by: buickfed on June 20, 2020, 02:08:33 PM
it had a bbc in it. that's the tire/rim combo that came with the car. if i went smaller it wouldn't look right. ;D
Title: Re: tire speed vs low gear ratio
Post by: THE FRENCHTOWN FLYER on June 20, 2020, 04:53:13 PM
My big tires looked baddass.
The littles looked goofy.
But it ran like JackTheBear with them on.
Now I realize how beautiful they look.
Title: Re: tire speed vs low gear ratio
Post by: wideopen231 on June 20, 2020, 06:16:31 PM
Best looking thing for race car is ET slip with small numbers and big mph numbers. IMO
Title: Re: tire speed vs low gear ratio
Post by: JrFuel Hayden on June 20, 2020, 10:47:43 PM
WideOpen; the reason I suggested a 1.80 gear was he had trouble with tire shake so I thought the 1.80 gear would help getting the tire up to speed at the hit. More gear is a torque multiplier , so it multipies the HP, again more power helps with tire shake. Another option is to go with a lower [ bigger number] rear gear.
when I 1'st started JF racing I too met that "old guy from Kansas, he turned me onto a 1.68 1'st gear to slow up the tire speed some , now most of the jF guys are running 1.68 or 1.69 gear with one team running a 1.54.
Jon
Title: Re: tire speed vs low gear ratio
Post by: wideopen231 on June 21, 2020, 04:28:56 AM
Oh . I understand your reasoning and was not replying to your suggestion,  Heck I agree that if not enough power or too much tire(same effect) you may have to hit it harder to break it loose. Main reason that I stated earlier that if I run into shake that I can not tune out other wise I will drop about 25 to 30% load in tank and see if that will get tire some more speed at hit, Hey even at 27 bucks a gallon its a cheap attempt to see if more power would help. Poor boy can't carry 3 or 4 sets of tires to swap arond.LOL