Speed in gear


Cyberbeer

15+ Year Member

Joined
Jan 30, 2009
Messages
264
Points
3,101
City
Spotsylvania, VA
Vehicle Year
1987
Transmission
Manual
Can someone give me an idea of maximum speed in each gear for a 87 5 speed? My tach is broken, it stays at 1400 rpm's until I rev past it, then it hit 3 grand and flies to 5.
 
I shift at 1st to 2nd 15mph(2200PRM), 2nd to 3rd 25mph(2400RPM), 3rd to 4th 35mph(2500RPM), 4th to 5th 55mph(2600RPM). This is with 3.73 gearing. If you know how to drive a stick, you should not been dependent on RPM, it is all about the feel of the truck. The truck should tell you when it wants to shift.

What size tires do you have, and what rear end? You can calculate RPM if you know all the gears and tire size.
Nick
 
Last edited:
Have to get back to you on that info, its dark now. Anyway to tell this info by the VIN #? I've only ever driven sticks..just rather be safe and know.
 
No, you will have to look on the door tag for the axle number, and read the tire for the dia.
Nick
 
Sorry, meant if you could tell gears from # not VIN. Tires are 215/75/R15. Axle code on drivers door says F6
 
The rear end is a 7.5" Ford limited slip with 3.73 gears. Your tires are 27.7" in diameter. I am going to say that your transmission is going to be the Mishubishi FM-145, or code D on the door sticker.

The ratios on this transmission are as such: 3.76 / 2.21 / 1.51 / 1.00 / 0.81.

Use the 27.7 x 3.14= 86.978"/Rotation
If you want to shift where I do, 2500RPM's then use all your ratios to get a final drive ratios.
3.73 x 3.74(1st) = 13.9502 Final Drive.
Divide 2500RPM / 13.9502 = 179.2008 RPM of the tire.
86.978 / 12 x 179.2008 = 1298.8772 ft/min
1298.8772 x 60 = 77932.6312 ft/hr
77932.6312 / 5280(1mile) = 14.75 MPH

Just use the same thing to get the different gears speed. This is exactly how fast you will be going.
Nick
 
No problem.
Nick
 
Yea its a code D trans. Fixing the FPR has made everything way easier. I thought I was shifting at to low RPM's and causing the engine to stutter, but it turns out my FPR was shooting fuel thru the entire vacuum system. Nothing like a 2 liter suprise inside your brake booster.
 
One thing to check is the TFI. It is the little box with 4 wires on it coming from the back of the dizzy on the passenger side. I had almost the same problem as you, but me FPR was fine. If it comes loose it can do that.
Nick
 
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