2017 JK Sport On 35" tires - Recommendations

NateG

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Hi everyone. I am a relatively new Jeep owner and first time poster. Also, I figure this conversation has already been had - however I cannot find a thread - so apologies for restarting.
I have a 2017 JK 2Door (Big Bear edition) sitting on the sport base (so assume 3:21 gear ratios). I am running an AEV 2.5" suspension lift with geometry correction brackets. I want to put 35" tires on (17" x 9" wheels) and am prepared to regear. My question is can the regear wait? I want to see what the jeep feels like with 35" tires on before regarding. Is there risk of damage to engine/transmission/other if I wait before regearing? Thoughts?
 
My JKU had 35's with 3.21's and it wasn't a friendly combination but it was driveable. Just don't do any offroading would be my suggestion. Is yours a auto or manual trans, the manual would be better suited for the tires without the gear change I think.

You will need to recalibrate the Speedometer with the taller tires.
 
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Hi everyone. I am a relatively new Jeep owner and first time poster. Also, I figure this conversation has already been had - however I cannot find a thread - so apologies for restarting.
I have a 2017 JK 2Door (Big Bear edition) sitting on the sport base (so assume 3:21 gear ratios). I am running an AEV 2.5" suspension lift with geometry correction brackets. I want to put 35" tires on (17" x 9" wheels) and am prepared to regear. My question is can the regear wait? I want to see what the jeep feels like with 35" tires on before regarding. Is there risk of damage to engine/transmission/other if I wait before regearing? Thoughts?
Since you did not specify manual or auto trans, I'll post both charts so you can see where your JK runs best:

1647278603634.png


As you can see with both charts, your JK will perform at it optimum RPM with either 4.10 or 4.56 gears. I don't need to tell you your Big Bear will feel like a hibernating bear that can't get out of its own way if you're running 3.21 with the 35s; you'll find that out quick enough.
 
Wonderful. Thanks everyone for your quick responses. Btw. It's Auto transmission. Sounds like I should regear almost immediately once the tires are on - so should do together.
 
Wonderful. Thanks everyone for your quick responses. Btw. It's Auto transmission. Sounds like I should regear almost immediately once the tires are on - so should do together.
And, if you don't have JScan or another OBD connected device to reset your speedo, have them do that as well. If you do it yourself, don't just enter the 35" tire height- it won't be accurate. Inflate the tires to the pressure you will normally road drive them and measure height from ground to top of tire for each corner as close to the nearest 1/4" as possible. Then divide that by 4 and use that.
 
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Also, I would double check what your current ratio is. Those special editions change a number of things. Willy's for example comes with limited slip diff in the back.
 
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