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27" Tyre Help or Hinder |
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5787 |
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Posted: Feb/25/2014 at 12:37am |
Have the chance to pick up some 255/60/15 (27") drag radials for a good price, I'm currently running 265/50/14 (24.4") BF Goodrich Radial T/As that are probably 20 years old. 60' times are pretty crap at the moment, around 2.2-2.4 seconds and it spins off the line if you load it up so presumably more traction would help. The only problem is that I currently have 2.87 rear gears so the 27" tyre is going the wrong way in terms of gearing so I don't know if I will go forwards or backwards with these tyres.
Have some 3.5 gears planned for down the track, which would probably help with the larger tires or just forget the tires and change the gears?
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spottydog360
AMC Apprentice Joined: Oct/08/2013 Location: aus Status: Offline Points: 126 |
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20 year old tyres is the answer,we have 18 year old Eager 265 50 14s on the back of Lisas 68,Im ok to drive around on them but don't expect them to stick to anything,they will be as hard as heck.
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spottydog360
AMC Apprentice Joined: Oct/08/2013 Location: aus Status: Offline Points: 126 |
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Sorry answer should be taller tyres acceleration deficiency should be offset by better grip.Unless the new tyres are also 20 years old.
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FuzzFace2
AMC Addicted Joined: Jul/05/2007 Location: Angier, N.C. Status: Offline Points: 10343 |
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With the shorter tire and that they spin off the line helps get the motor up in RPM/power band.
Say you have the same short tire you have now but does not spin off the line again with that gear it will pull the RPM down below the power curve and be a dog.
Now add a taller tire & does not spin it will be even worst.
My 75 Gremlin stock 304/auto w/2.87 gear and street 14" tires I would try and get the tires to spin a little off the line to get the motor up in RPM faster. Thru the lights (1320) I could do it in 2nd gear or 3rd and get the same time as it would go into 3rd almost at the line.
Thats me story and I am sticking to it
Dave ----
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TSM = Technical Service Manual
75 Gremlin X v8 for sale 70 Javelin 360/auto drag car 70 Javelin 360/T5 Street car |
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5787 |
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Yes, I can hold second over the line as well or change up just before with the 2.87 gears.
I'm thinking the 27" tire may be a bit too tall even with the 3.45 gears, most other tyre options would put me around 25.5"-26.0". I need to get away from the 14" wheels because there really isn't much out there in the way of tires for them these days, particularly if you are chasing a bit of traction.
Basically looking to get from a high 13 to a low 13 or maybe even dip into the 12's if I can manage it. I should have enough power to get there, has run just over 102 mph, mainly need to get out of the hole a bit quicker. Edited by WesternRed - Feb/26/2014 at 12:06am |
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spottydog360
AMC Apprentice Joined: Oct/08/2013 Location: aus Status: Offline Points: 126 |
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Yeah I can see that,I have no experience in this.Other than street burnouts
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FuzzFace2
AMC Addicted Joined: Jul/05/2007 Location: Angier, N.C. Status: Offline Points: 10343 |
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In my Drag car (70 Javelin) 4.56 gear and 28" tire is turning a little over 6k at the line and the converter slip is with in spec. 13-13.5 sec little over 100mph IIRC
For my combo a 4.10 gear would be good but 4.56 is all I have for now.
Play with the numbers at the below sites may help
I would say 27" tire with better traction with 3.73 gear might be the ticket.
Dave ----
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TSM = Technical Service Manual
75 Gremlin X v8 for sale 70 Javelin 360/auto drag car 70 Javelin 360/T5 Street car |
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5787 |
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Looks like I will be testing this out, will have to give it at least one run with the 2.87 gears to see what happens. Does anybody want to lay bets on faster or slower?
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WesternRed
AMC Addicted Joined: Aug/03/2010 Location: Australia Status: Offline Points: 5787 |
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390spirit
AMC Addicted Joined: Jun/28/2008 Location: U.S.A. Status: Offline Points: 1849 |
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you won't have any traction problems with the M/T ET Street tires, if you do then its time to look at the rear suspension....springs, shocks and pinion angle to make sure they are good and set right
I had the rear out of my car last year and when I put it back in I tightened the 4 link bars just a little too much and it wouldn't let the suspension work the way its intended to...at the track all it would do is spin all the way threw 2nd gear, 2.0's for 60' times, I came home and loosened all the mounting bolts, let the car set on the ground and then just tighten till the lock nuts touched, next weekend it was putting down 1.52 60foot times just food for thought |
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