JK sport Body roll, tyres and suspension

[Digger]

Hi All,
Had my JK now for about 6 months, its a 2012 model. It came with 285/70/17 BF Goodrich tyres (about 31" in old scale). No other work was done, so it is a floaty wobbly ride! Also, the tyre sensors don't work anymore and the speedo gives incorrect speed (about 5kms out at 100kms p/hr). Also, I don't want any more ground clearance, just a better ride. I mostly do beach and highway runs.
So my first question is, should I ditch the tyres and go back to a standard size or spend the money on a CRD Stu setup like I had with my old KK Cherokee? The second question is can you get tyre sensors put back on?
Thanks all

[relwell]

If you replace the tires a tire shop will pop on new sensors. You can likely get stock JK rims on gumtree that have all the right parts - selling your current wheels may pay for them as well. That should fix the speedo difference. You don't sound super keen on modding the Jeep so may as well do the cheapest and easiest way to get what you want!

A quick Google says the 2012 Sport came with 255/75R17 - which is about 32" and Google also says those tires it came with on yours measure just shy of 33". An inch seems like a lot for 5km/hr difference - anyone else have thoughts on this?

As for the floaty ride, it shouldn't be that bad I wouldn't think. Is your disco setup working correctly?

[Blugeepunlimited]

Options to correct the speedo difference are to return to stock size tyres or purchase a Procal module to reset the speedo to match larger tyre size. That would also improve gear shift points if your JK happens to be an auto. Quite a few other things can be set/changed with a Procal (Google Procal JK should bring up details).
Lots of possibilities for the floating suspension feeling - leaking/soft shock absorbers, incorrect wheel alignment, worn suspension components etc.

[Thol]

2012 came with 245/75r17
255 was only on some early JKs in Oz

I now run 265/70r17 for same diameter. 245 isn't as common.

[Banshee]

If it reels floaty & wobbly, check the pressures. I ran 285/70 on stock 17 rims & they were no worse than OEM.

Sensors can be fitted or you can get OEM rims with them from someone.

+1 on a Procal or similar to recalibrate the speedo. (I fixed mine with my Aeroforce gauges.)

[st_za]

My advice is to spend the $ getting a tool to adjust the speedometer and stick with the larger tyres, which will give you better handling and comfort than the stock 245/75/r17.

The JK-series never had great handling, especially the 2 door, and you can't really do much about it unless you are willing to go down the suspension modification rabbit hole. A suspension package like those from Murchisons will give you great handling for a JK but it cannot fix the problems inherent to the JK, like body roll from a low roll centre and lots of weight above it and relatively floaty handling from a 5-link solid axle suspension.

Have you had the suspension checked by Jeep experts? Assuming that there aren't problems like worn ball joints causing the floaty handling, I suggest getting a good suspension package and adjusting your expectations a little.

[Digger]

Thanks everyone for your comments. I appreciate your advice and I think I will source the Procal and also get the suspension sorted. The tyres are virtually new so there is plenty of life left in them.
I've contacted Murchisons and will likely go down that route since they did a good job on the KK Cherokee.
The JK has very light power steering so that doesn't help feeling connected to the wheels either - as someone suggested I'll adjust my expectations
Does any one know BTW if later transmissions (6 and 8 speeds) for the 3.6 Pentastar fit the earlier 5 speed models?