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joe
Dodge Dakota
12/12/2001
17:11:39
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 Subject: recalibrating speedo
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Message:
i am in the thinking stages of lifting and putting taller tires on my dak, does dodge offer recalibation for the speedo?
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Joe E.
Dodge Dakota
12/13/2001
23:44:12
|  RE: recalibrating speedo
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Message:
Hey joe,
I am Joe E. I first saw this post and thought, man I dont remember doing that one!
Anyways, I have a 90' Dak with 31's and wonder the same thing. I have asked my dodge dealer and they said no. But I did not persue it too much. But I would love to actually be able to believe my speedo and odo. Have you thought about Superlifts "TruSpeed"? It costs a little but if it worked on Daks, it could be useful. Check it out, tell us what you find! Thanx
Joe E.
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Dan Gruber
GenIII
12/14/2001
04:37:29
|  RE: recalibrating speedo
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A friend with a 99 Durango went from 235's to 31 inch tires and the dealer did a reprogramming in about 20 minutes. The dealer told him that they can reprogram for factory offered tire sizes only. So for newer Daks it is possible as long as you don't go larger than anything offered by the factory. Not sure about older ones.
Dan
2000 CC SLT 4.7 4X4 Auto 3.55 LSD
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joe L
Dodge Dakota
12/14/2001
11:03:11
| RE: recalibrating speedo
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Message:
cool, ill check it out,, i know you can do it with the old 727's so maybe you can with ours too,
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Zeke
Dodge Dakota
12/14/2001
14:01:55
| RE: recalibrating speedo
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Message:
I haven't had my Dakota very long, so have not had a real chance to get under the hood or the rig itself to check things out to see how it is put together.
But, I know on Jeeps that it is a simple speedo gear change to re-calibrate to larger tires/deeper gears...takes about ten minutes, and you are back to normal speedometer readings.
-Zeke
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2THEXTRM
GenIII
12/16/2001
22:06:03
| RE: recalibrating speedo
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I am ordering the Superlift speed recalibrator this week, hope to have it in before x-mas. Don't like my speedo being so far off and the shift points incorrect with the 33's I am running. For $187.00 it is worth it to me if it saves on transmission/drivetrain wear from misshifting and speeding tickets when my wife drives my truck(she never remembers speedo reads about 5-7 miles slower that actual mph). I have not seen or heard of anyone else on this board using the Tru Speed, so I will let everyone know how it works once I get it installed.
Flowmaster stainless cat back, Air Raid CAD and homemade TB connect, Splitfire Plugs, 33x11.50-16's
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Dan Gruber
GenIII
12/18/2001
17:14:15
| RE: recalibrating speedo
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2THEXTRM,
What do you mean when you say the shift points are incorrect? I'm asking because I've talked myself into a lift, 32 or 33 inch tires, and 3.90 gears, and I'm concerned about exactly that...incorrect shift points.
Dan
2000 CC SLT 4.7 4X4 Auto 3.55 LSD
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Joe E.
Dodge Dakota
12/18/2001
21:09:22
| RE: recalibrating speedo
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Message:
Dan, the shift points, from what I understand, are the speeds at which the trans. decides to shift gears. With running bigger tires, your engine must run harder to obtain the same speed as OEM at equal speeds. So you trans is fooled into thinking that the motor is running faster than you really are.
With my 90' Dak, I can be crusin down the highway doing 70 mph. Out of nowhere, my trans will shift down, run RPS way up, and shift back into high gear. All with no speed change.
With TruSpeed, these shifts are suppost to be fixed because the engine and trans computers now realize that you are running larger tires, so they dont see the need to go crazy on you.
Again, this is from what I have heard and understand from alot of hearsay. Talk to someone from a shop or something that has facts. I just thought maybe you could get an idea of the situation.
Joe E.
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2THEXTRM
GenIII
12/18/2001
21:41:05
|  RE: recalibrating speedo
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I posted earlier, but I see that it did not go through, dam computer locked up. Looking at from a logical standpoint, your computer is set from the factory or updated at your dealer with the correct size tires you were running when truck was new. Although our computers are considered "learning computers", they cannot learn your new tire size and chose to work with what they know. Since your tire size is changed whether up or down, the shiftpoint will remain calibrated for the stock tire, shifting either too soon if you increased tire size or too late if you decreased. This "misshifting" would seem to not be very efficient and should decrease tranny life. Without being a tranny guru or mechanic, the way I look at it is if you are driving a manual transmission truck and are constantly shifting early, you may not have a big problem under normal acceleration, but add a load in the back or a tow behind with excessive gas pedal and you could smoke the tranny from slipping the clutch. As I said I am no mechanic and this is just my observation. Either way, I would like my speedo to read correctly, I am always checking mileage, etc. and prefer some accuracy. The Truspeed should give me just that.
Flowmaster stainless cat back, Air Raid CAD and homemade TB connect, Splitfire Plugs, 33x11.50-16's
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Joe E.
Dodge Dakota
12/19/2001
16:45:29
| RE: recalibrating speedo
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Message:
Hey 2THEXTRM,
I am glad you are trying the TruSpeed device. I have been wanting to get ahold of one but am not sure if it works with older daks. Do you know? Thanks I would be very happy to know that it would work on my truck.
Joe E.
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2THEXTRM
GenIII
12/19/2001
18:49:13
| RE: recalibrating speedo
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Message:
When I spoke with Superlift Technician, they show Part# 33002 for years 1992-2001 so I if your Dak is within those years your set. Mine should be here by the end of the week or after x-mas depending on the shipping delay due to x-mas and I'll probably put in in the same day I get it.
Flowmaster stainless cat back, Air Raid CAD and homemade TB connect, Splitfire Plugs, 33x11.50-16's
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Joe E.
Dodge Dakota
12/20/2001
00:52:30
| RE: recalibrating speedo
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Message:
Hey that sucks. My Dak is a 1990! I will contact Super Lift about the TruSpeed for my year truck.
Does anyone know: Do Gen I Daks have an electronic speedometer or a cable and gear driven one? I thought we had ele. ones but if TruSpeed says it will work on any ele. speedo, and my truck is not listed on it applications, then I must have a gear/cable speedo. Then that means I can find a new gear to correctly recalibrate my speedo, right?
Thanks for the help, 2THEXTRM, I hope your installiation goes well! Have a nice X-Mas!
Joe E.
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nick
Dodge Dakota
JOIN HERE
1/10/2002
21:56:29
| RE: recalibrating speedo
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91 and older still uses the good old fashioned gear drive, easy to change to correct speedo readings. 92 and newer(first year for the magnums) use electric and gear combo. The gear can be changed to correct speedo but then triggers a code and overdrive dosen't work due to speed readings not matching. Computers do not control the shift points in Chrysler rear drive products until '99 or 2000 but only in the dak and some Jeeps 4.7L only new motor new twist to old design on trans.
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Joe E.
Dodge Dakota
JOIN HERE
1/11/2002
15:26:38
| RE: recalibrating speedo
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Message:
So how do you replace the gear in the speedo? I would love to get my dash staright again. Thanks.
also, where do you get these larger gears and how do you figure out which new gear size to go to?
I know this is alot of questions but Thanks for the help.
Joe E.
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Don Curley
Dodge Dakota
JOIN HERE
1/12/2002
14:56:05
| RE: recalibrating speedo
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Message:
Hey Bob (2THEXTRM),
With regard to your prior post on Superlift's TruSpeed Speed Sensor Calibrator ... just
curious, have you installed that unit yet? If so, do you have any early reactions or comments on the unit, its installation, or performance aspects?
I ask, as I recently put on a set of new 32 x 11.50 BFG All-Terrain KO's on my 1999 Dak Sport Club Cab 4x4 (it came stock with 31 x 10.50 Goodyear Wrangler RT/S tires mounted on 15"x8" rims ... the latter of which I used to mount the new BFG's). As best as I can tell, I am running about 4 to 5 MPH "slower" on my speedo with this new set-up and
I was trying to figure out how best to tackle the speedo recal and tranny shift-point issues ... and it looks like Superlift's TruSpeed Speed Sensor Calibrator might just be the ticket (if it lives up to the limited info available on it).
By the way, I noticed that Superlift has a technical bulletin out on this unit on their website (i.e., "Bulletin #T111 - Superlift's TruSpeed Speed Sensor Calibrator"), however, for some reason I cannot access the page. I don't know if this is some potential bad news or "pre-recall"
info on the unit since I can't call it up. In any case, do you know what the bulletin goes into?
Any info or comments on this unit would be much appreciated.
TIA,
Don Curley
La Sal, Utah
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nick
Dodge Dakota
JOIN HERE
1/12/2002
18:02:27
| RE: recalibrating speedo
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Message:
Follow the drive cable down to the transfer case. There should be one bolt holding the piece into the case remove it and remove the drive housing. The gear just slides out. It only takes a few minutes. As for the gear your mopar dealer should be able t help you out. GOOD LUCK any more ? just ask.
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Joe E.
Dodge Dakota
JOIN HERE
1/12/2002
18:22:18
| RE: recalibrating speedo
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Message:
Thanks man,
I will lok into the whole thing next week.
Thanks
Joe E.
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2THEXTRM
GenIII
1/13/2002
12:34:39
| RE: recalibrating speedo
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Message:
Don,
I haven't had the time to install the Truspeed between school, work and keepin my wife's S10 Blazer winter rat running. It's been sitting on my backseat for over 2 weeks:( I am hoping to have it in by this weekend, I need to borrow my friends GPS so I can set the unit accurately and more easily. I will post install and performance results of the unit once I got it in and set. Also, I have not heard of the Bulletin but will be looking into it before I install to make sure I do not have to return it or anything that would require uninstalling from my truck.
Flowmaster stainless cat back, Air Raid CAD and homemade TB connect, Splitfire Plugs, 33x11.50-16's
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Greg
Dodge Dakota
JOIN HERE
5/30/2002
18:27:10
| RE: recalibrating speedo
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Message:
Have you installed the Truspeed yet? I have a '94 Suburban with 37" Hummer tires, and the speedo is way off, and the trans shift points seem strange also.
(My wife forgets that indicated 70 is 82 MPH too!)
Greg
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2THEXTRM
GenIII
5/30/2002
22:08:27
| RE: recalibrating speedo
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Message:
Yep, it's in and works great. Speedo is dead-on, used a GPS to calibrate it, I recommend setting it the same way. With your tire size that is much larger than stock, you should probably notice the better shift points more than I have.
Flowmaster cat back, Air Raid w/homemade TB connect, Poweraid TB Spacer, Splitfire Plugs
3 inch body and 1.5 Block Lift, 305 70-16 X-Terrains on AR Terons
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WhatThe?
Dodge Dakota
JOIN HERE
3/25/2008
14:57:18
| RE: recalibrating speedo
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Message:
So many people think about this and have it backwards. Why do larger tires make your speedo read SLOWER, think about it. Whats actually happening is your axle ratio does not change with any tire change. Larger tires actually have a larger circumference, take the tire, cut it in half and lay it out flat compared to your other tires, that is the distance traveled per revolution. With smaller tires they travel less distance than a large tire. Therefore, since you travel more distance per revolution you actually get a) MORE mileage even though your computer and odometer read it wrong you may have traveled 25 miles instead of the 20 your odometer clocked. b) MORE speed, and this is exponential at 30 you may be doing actually 32 (depending on the tire) but at what you think is 60 you may be doing 75!!! c) way more efficiency. Your tranny DOES NOT work harder to move the tires, for the same distance a larger tire does not rotate the same, going from 30's to 35's for instance you would have a full revolution on the axle to travel 94 inches, where your 35 will only turn 85% of a revolution for the same distance being that one full rev on a 35 is equal to 110 inches. your axle rotation is tied to the rotation of your transmission which in turn means to go 35mph you are actually at a LOWER RPM. your speed and your RPM being thrown off make the vehicle think it needs to shift because now you are trying to cruise at the shift point but your engine actually works less and your vehicle becomes faster. Unless you have the shifting problem and are really worried about your speedometer, DONT do it. no matter what you do, your engine will be at a lower RPM with bigger tires. and the opposite for those running 14" wheels with 1" of rubber on them... their tires must spin just over 2 times to travel the same distance as a 30" tire. This means that they'll be peggin 6kprm while you're at 3000 on the same vehicle to keep up.
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