I just got a 4.11 gear in my car and I have 255 / 45 / 17 tires that are about 26" tall, what tire size do I need to make it right. Do I need to run 15" wheels instead? I want to get some sliks for my car but I don't know what size.
i don't know exactly what you mean by making it right. but i would go to the mickey thompson websight and see what sizes they have. i know the et street drag radials come in a lot of sizes. best thing would be to get a summit or a jegs catalog and you can see at a glance what sizes they have. they are free at their sights.
well I have heard a lot that if you run a different gear ratio you need to have the correct set up so you can get all the power out of it. (for example) If I use a really small wheel and tire it will not ride like using a taller wheel and tire. I'm guessing it has to do with the RPMs if I use a smaller tire my RPMs will be higher and if I use a biger tire my RPMs will be lower. so what I'm trying to find out is what will be the best tire and wheel set up for a 4.11 gear ratio. Or am I just crazy? Does it matters what size tire I need to use? I was told that I needed something tall? but I don't know how tall.....
the biggest i can fit under mine is a 275/50/15. that's about 26" tall. i think others have gotten a 28" tall tire under theirs. i run a 4:33 rear gear in mine and i go through the traps at about 6200 rpm. my other motor goes through at 7200rpm.
I think....(and this is a VERY dangerous occurrence, me thinking) But on the street, the tire height will affect your speedometer, your acceleration(to a certain extent), top-speed (not that anyone on the street knows their top-speed) shift points (when the tranny shifts automatically) and the stance of your car.....there may be some other factors that I'm missing, but that's all I can come up with right now....I'll let the racers tell you about the racetrack.....which may be all you are needing to know.... On a side note, as soon as my wallet allows it, I'll be installing 4.11's in my car. I run a 275/60R15 rear tire on mine......Good luck!
My car will be street and strip I don't really drive it that much at the highway but like 4 times a month. that's why I ended up with the 4.11 and I'm happy with the gear but I just wanted to know if by using a different tire and wheel set up makes any difference?
Don't mess with your tires. They look GREAT as they are. If you put smaller tires on, it will take off faster, but have a slower top speed and drive at higher rpms at cruising speed. On the other hand, taller tires will be slower taking off, but bring rpms down when cruising. For example, when I swapped from my stock "bicycle" tires and 2.79 gears to 3.80 and 245/60r15 (around 26" tall). I took it to the track and didn't notice any difference (well, a little, but not as much as I expected). The bigger tires pretty much canceled out my gear change. Another example...my truck has 33" tall tires but takes off pretty slowly because it only has a 3.83 gear. If I put little 26" tires on it, it would SCREAM off the line (really quick 60' times and quick acceleration), but would look pretty stupid and I would probably be cruising the highway at 4000 rpm at 65mph rather than the 2000rpm it does now. Your speedometer will not be correct. Ever. The "largest" speedo gear Ford makes won't correct it with the 4.11 gears (unless someone knows something I don't). You can buy an autometer electric speedo that will work. At least with the largest tires you can fit under there...it cannot be corrected.
Ford makes several of the little plastic gears that go on the end of the speedo cable that inserts into the back of the tranny. You can add or subtract teeth to get your speedo correct if you don't change everything too much (ie. tire size). But when you start swapping rear gears, then you run in to where Ford has not made gears with the correct number of teeth. They are only a couple bucks, do a search on the internet or go to the Ford dealer.
I am running 4.11 with a 28" tire. Freeway is 3100 rpm at about 60mph. Through the traps at about Dons rpm, 6400
I'm doing about 3200 RPM's @ 60 mph, 3700 RPM @ 65 mph and 4200 RPM @ 70 mph with my 26" tires. I still need to buy a new set of wheels and tires so I can run the car at the strip because I have spacers and I don't think they allow to race with spacers. Am I right, if not I'm going to save some money $$$$.
Depends on the track. Some may let you run, some wont. Depends on how powerful THEY think your car is. If they think it is powerful enough to snap those lugs, they will tell you to go home. Where you going, Baytown or Beltway 8? We might come to watch...
