What is the official design speed for a TJ?
- Thread starter adventureboss
- Start date
My '00 maxes out at 82 MPH with 33" tires and factory 3.73 gears. I'm sure once I swap in the 4.88's it will be much less.
No. The available top speed with increase because the engine will have the leverage to push those tires.
Good to know. I never got it to those speeds when it just had the factory size tire. The engine may sound like it is going to rocket out of the frame with 4.88's.
Hardly. The rpms will still be less than what Jeep rolled off the assembly line with the 32rh transmission.
It’ll be around 3000 with 4.88/33s. Still, nowhere close to rocketing out of the frame. I actually find 3000 to be extremely tolerable as a cruise rpm.
A stock 3.73 automatic with roughly 28” tires would do about 3300 at 70.
Got to say mine doesn't feel scary at all at 75 with 30" tires on stock wheels. The fact that you really know you're doing 75 or 80 in a TJ might be to your advantage in keeping you 100% concentrated vs a vehicle where you can hardly tell you're going that fast making people get lax in their concentration. If anything does happen we may not have side curtain and knee air bags but we got roll cages, that's got to count for something! Still, no reason to get crazy at those speeds, just make sure you have good tires and pay attention 100% of the time.
Driving diesels all my life it's a bit new to me seeing RPMs higher than I'm used to though, but apparently nothing to worry about (except where the next gas station is)
Driving diesels all my life it's a bit new to me seeing RPMs higher than I'm used to though, but apparently nothing to worry about (except where the next gas station is)
No. You will be running the 3k rpm at 75mph with 5 speed. Been there done that for many years.
They will do that, eventually. Fortunately, I replaced mine before it decided to part ways with the rest of the car.
About 6 years ago I did a deep and meticulous service on her while installing a new clutch (this is when I did the balancer). While pulling parts of to get to the trans axle, I discovered by chance that one of the many small coolant hoses had been rubbing on one of the power steering hydraulic lines (likely since it was built) and was close to rupturing. Not sure if you had to mess with yours but it's a bit of a rats nest...and these are only the lines for the hvac and oil cooler...
View attachment 563551
After I found that, I went over pretty much everything and replaced anything even slightly questionable as well as parts that were difficult to access once everything was assembled. She's still solid mechanically, save for the rear brake lines (which I need to fabricate), but she's starting to look a little rough. I've always taken good care of the car, but when I moved to MD 12 years ago (it looked almost showroom new at the time), it got vandalized within the first 6 months and she's been exposed to the elements 24-7-365 until recently when I started renting a place with a garage. Unfortunately the damage is done, the clearcoat is failing from the years of sun exposure as well as copius and constant quantites of bird shit being deposited.
Sorry for the thread diversion.
Shockingly, I never had to deal with the HVAC lines. Thank god. I would've just about lost it. I will say the TJ is far far easier to work on than the Mini, but it's also a very basic vehicle so it's understandable. The reason I got rid of mine was because the 3rd cylinder just lost all compression for whatever reason at 155k miles. No clue why. Never let it run low on oil, never overheated, but yeah I was quoted at 8k or something for a rebuild.
I tested the top speed on my first TJ, lifted on 35s with stock 3.73 gears. Maxed out at 97 mph. Never felt the need to test that or to check my MPGs ever again.
TJRick
TJ Enthusiast
My experience too. I really don't understand why some seem to freak out about normal interstate speeds? Obviously these vehicles aren't built for speed but I still feel like you can drive them like a normal car.
But yes also I agree about the short wheel base. I always keep it in the back of my mind and am even more attentive in my TJ because I know if the backend steps out at those speeds with the wheel base there is no saving it.
I think you just described perfectly why some people (like me) do not think it is a good idea to go above 75MPH in a Jeep TJ.
I would say that goes for a CJ and YJ as well.
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Yep, mine is on 35's with the 32rh and 3.07's. Have taken the speedo to 90 mph (never reprogrammed speedo so actually going much faster) and really has no issues getting there rather quickly. Was still only at like 3700 Rpm's lol! Mine was still riding very well but have no desire to try it again knowing if any fast manuever was to be made things wouldn't end so well!
AdelaideTJ
TJ Enthusiast
Very slight exception, but my non-Rubi export TJ (Aus) is a Dana 44 with 3.07 gears from factory.
Interesting.you guys got trim packages not available here as well right?
Can you post a picture of the rear diff tag?
My 97 Dana 44 was also 3.07:1 stock. My tag went years ago, but my build sheet has DMMP 3.07 Axle Ratio, DRKS Dana 44/226MM Rear Axle, DSAP Anti-Spin Differential Rear Axle
We used to have a car price book available monthly in the UK that would have indiations of price ranges used cars should fetch. It also listed quoted MPG, top speeds and 0-60 times.
The quoted top speed of TJs was 108mph, 0-60mph was 8.8 seconds IIRC.
We used to have a car price book available monthly in the UK that would have indiations of price ranges used cars should fetch. It also listed quoted MPG, top speeds and 0-60 times.
The quoted top speed of TJs was 108mph, 0-60mph was 8.8 seconds IIRC.
I discovered this after simultaneously regearing and swapping in a NP241.
Jeep would not go over 93 mph on the speedo (actual speed 60-70ish due to regearing).
Unplugging the speed sensor at the tcase deactivated the governor until the Speedohealer arrived.
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