Srikumar Posted September 1, 2019 Report Share Posted September 1, 2019 Yes, bigger tyres can create issues. But from what I have read it would only for tyre size above 35 inch. Regarding the gear ratio, just check if it's better to go higher up as you would have less wheel spin. In the case of rock crawling higher gear ratio is better as to get the max torque at low speed. But when driving on sand, you ideally need your wheel to spin to get you out of the situation. 1 1 1 Link to comment Share on other sites More sharing options...
Javier M Posted September 1, 2019 Author Report Share Posted September 1, 2019 The guys at the shop recommended 4.10 like the Rubicon or 4.56 I opted for 4.56. Since the stock is 3.21 I felt it wasn't enough torque specially climbing high dunes at lower speed. Let's try them out I have driven a friend's Rubicon and I honestly did not feel any difference. 2 Link to comment Share on other sites More sharing options...
Rahimdad Posted September 1, 2019 Report Share Posted September 1, 2019 This is excellent information. This discussion is worth having it's own thread. 1 Link to comment Share on other sites More sharing options...
Srikumar Posted September 1, 2019 Report Share Posted September 1, 2019 I had researched a lot on this higher differential ratio. The build quality is generally better for the higher ratios, but this fact of wheel spin needs to be checked. When I read about it, didn't seem to make sense to go up the ratio. Correct me if I am wrong, but if the ratio says 4.56, that means for every 4.56 rotation of the engine the wheel would spin 1 time. This is good in Rocky terrain and you have the max torque band in the region of 3000-4000 rpm where you need to rotate the tires just a little over the rocks to cross the obstacle. But in sand it's the opposite. When you need to do the high hill climb, I believe a lower ratio is better as you will have more wheel spin at the same torque band. 2 1 Link to comment Share on other sites More sharing options...
Srikumar Posted September 1, 2019 Report Share Posted September 1, 2019 One more question, if you are changing the rear differential ratio, do you need to change the front as well? 1 1 Link to comment Share on other sites More sharing options...
Javier M Posted September 1, 2019 Author Report Share Posted September 1, 2019 Yes you need to also do the front too. You can't do only one side. The gear ratio determines how many times your driveshaft will have to rotate to spin the wheels once. So the theory is that when larger tires are installed, you have several things working against you: the diameter of the tire, rotational mass, rolling resistance, and the added weight of the tires. By regearing you will increase the amount of force that is being sent to the axle, this allows the Jeep to move the tires with less of a strain on the engine. 1 1 Link to comment Share on other sites More sharing options...
Barry Posted September 1, 2019 Report Share Posted September 1, 2019 A differential isn’t something you can just swap parts on. It needs to be properly set up, pinion height, backlash, bearing preload. I would be tempted to drop the oil out, put some engineers blue on the gears and rotate it a few times to see what’s really going on inside. 2 1 2 Link to comment Share on other sites More sharing options...
Javier M Posted September 1, 2019 Author Report Share Posted September 1, 2019 So I asked on a WhatsApp group for Jeep owners and yeah they will break at one point this is very common. Next time I'll buy an FJ instead of a Jeep 😂. 1 1 1 Link to comment Share on other sites More sharing options...
Gaurav Posted September 1, 2019 Report Share Posted September 1, 2019 37 minutes ago, Javier M said: So I asked on a WhatsApp group for Jeep owners and yeah they will break at one point this is very common. Next time I'll buy an FJ instead of a Jeep 😂. Any solid reasoning for breaking rear differential....? Or just a regular offroad use is enough to break? 1 Let's root for each other & watch each other grow. Link to comment Share on other sites More sharing options...
Javier M Posted September 2, 2019 Author Report Share Posted September 2, 2019 (edited) Basically they all said it's normal wear and tear and after certain time off-road the spider gears will break. They also mentioned that it's because of the bigger tires - usually 33" and above, I am driving 33s. Edited September 2, 2019 by Javier M 1 Link to comment Share on other sites More sharing options...
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