35" tires. Need some help for jk'rs who have done this.

G

glen5264

New member
2013 jku with teraflex 2.5 lift
I have the bug and need to go with 35" bf good ko2.

I am currently running 33's. (Actually 32 is the true size)

So my question

When you go with 35's did you have to go a gear swap as well? I know about the flashing the pcm as I do have a flashcal.

If the gears have to be changed what ratio did you go with or is there a handy chart to look up?


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glen5264 said:
2013 jku with teraflex 2.5 lift
I have the bug and need to go with 35" bf good ko2.

I am currently running 33's. (Actually 32 is the true size)

So my question

When you go with 35's did you have to go a gear swap as well? I know about the flashing the pcm as I do have a flashcal.

If the gears have to be changed what ratio did you go with or is there a handy chart to look up?


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Click to expand...

You don't need to regear, but you should. Going to 35's on stock 3.21 or 3.73 you will notice the power loss specially if you are in a hilly area. I you haven't gusseted your C's I would also recommend doing that...
 
jorgelrod said:
You don't need to regear, but you should. Going to 35's on stock 3.21 or 3.73 you will notice the power loss specially if you are in a hilly area. I you haven't gusseted your C's I would also recommend doing that...
Click to expand...

This^^ you don't have to regear right away and many don't do it at all. Also as mentioned put some C gussets on as well
 
Add to what everybody else has said, you won't have to re gear immediately. But eventually you might want to. Something to think about is if you will stay with 35s or go bigger cause 37s would be happier with something like a 4.88 or 5.13 but 35s and those gears would have your engine screaming more. But if you go to 4.10s and 35s and eventually go to 37s, you will be wanting to re gear again. So I would run the 35s and whatever gears you got for a while and see how the jeep does. I have a rubi with 35s and the factory 4.10s and really for the most part it does well with everything I do. I will prob run 37s (whenever that day comes) on the 4.10s until I can regear and probably swap in a pr44 at the same time.


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I ran 35s and 3.21 for about a year. It wasn't to bad. Although I already had a plan to regear in the future. But when I started using my jeep as a daily driver about 2 weeks in I made the decision to regar. Down shifting going uphill everyday was to much for me so I regeard to 4.88 knowing I'll be going to 37s. 4.88 are on the higher side of rpms for 35s. At 70 I'm pushing about 3k. But again I regeard for 37s. All this being said. You don't have to regear at all. I'd say drive it around on 35s and stock gears for a while and let that be the decision maker. You may not mind the way it drives. As far as flashing it. Flash it to what the tire measures from floor to about bottom of the tread. Don't flash it to what is on the side wall. Good luck.

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Thanks guys.

Now c gussets? I've googled this a little. The gussets that are welded on the front axle where the upper and lower ball joints are??

So the added weight of the tire pits that much more strain on these?

Oh god I have not welded in over 9 years! Any bolt on c gusset supports?




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glen5264 said:
Thanks guys.

Now c gussets? I've googled this a little. The gussets that are welded on the front axle where the upper and lower ball joints are??

So the added weight of the tire pits that much more strain on these?

Oh god I have not welded in over 9 years! Any bolt on c gusset supports?




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No bolt-on gussets. Yeah, the Cs are a weak link on the D30 and D44... Gussets are recommended even for 35s.

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glen5264 said:
Thanks guys.

Now c gussets? I've googled this a little. The gussets that are welded on the front axle where the upper and lower ball joints are??

So the added weight of the tire pits that much more strain on these?

Oh god I have not welded in over 9 years! Any bolt on c gusset supports?




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Ive been reading up a lot on the c's it seems the its the tube that bends before the C's .... correct me if I am wrong but when you read how welding changes the molecular elements of the C's it will in fact weaken them according to some of The engineers?


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I have been on 35's in Winnipeg since mid April and have not regeared (3.73) I don't find much difference here in the flat lands. In May I spent a week in Kelowna and on some of the longer highway hills did notice some downshifting.


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I ran 3.73 gears on the exact tires you are getting for 3 years with little to no complaint driving around town and even wheeling in the desert. I changed to 4.56 Nitro gears back in April and I prefer the way it drives now, but I never hated the stock 3.73 gears. Biggest difference around town is going up a grade seems easier on the tranny and motor, and off-road in 4 low the Jeep had tons of crawl power. I have a '14 JKU willys, and I much prefer the 4.56 gears.

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You can keep the same gears you have now if you want only street and be happy but !!!!!!........ what are you using your Jeep for ? Do you take it off pavement ? If so those 3:73 gears are not gonna make you happy, If you are half and half go at least 4:88 . I think you need to determine what type of off road you want to be . Personally i went with 4:88 and if i had to do it again 5:13 or 5:38


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mo0s3 said:
Ive been reading up a lot on the c's it seems the its the tube that bends before the C's .... correct me if I am wrong but when you read how welding changes the molecular elements of the C's it will in fact weaken them according to some of The engineers?


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You're probably referring to one guy on wrangler forums who claims a c has never been bent and that a Dana engineer told him welding a gusset makes the c weaker than stock. No proof. Then again I have not seen any proof of a bent c with a straight axle tube. My conclusion? I had the gussets welded in. $50 for brackets $85 for a pro welder.
 
I have 35 Cooper st maxx with 373 gears and manual transmission it's not bad but I plan on 488 when funds permit. If you have a 6 speed manual 6th gear is useless on 35s @ 70 mph I'm at 2000ish rpms I spend a majority or the time in 4th

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35" tires. Need some help for jk'rs who have done this.

zimm said:
You're probably referring to one guy on wrangler forums who claims a c has never been bent and that a Dana engineer told him welding a gusset makes the c weaker than stock. No proof. Then again I have not seen any proof of a bent c with a straight axle tube. My conclusion? I had the gussets welded in. $50 for brackets $85 for a pro welder.
Click to expand...

Exactly, I have been welding for over 25 years and what is said make total sense. I can see it as hey c's bend or hey tubes bend ! But out of all the Jeeps I wheel with haven't had a C bend........ with that said we run hammer trails that make the Rubicon look like John Bull trail. No bent C's
And as far as welding on a cast or forged C it does make sense.

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Last edited:
mo0s3 said:
Ive been reading up a lot on the c's it seems the its the tube that bends before the C's .... correct me if I am wrong but when you read how welding changes the molecular elements of the C's it will in fact weaken them according to some of The engineers?


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Where people get a little confused is when you heat up an entire area 1600-2000 degrees for an extended period and slowly cool down this is what makes metal softer (annealing). For welding applications such as C gussets you wouldn't get that area that hot for an extended period and air cooling would cool it too fast to make the metal anneal.


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JMac79 said:
Where people get a little confused is when you heat up an entire area 1600-2000 degrees for an extended period and slowly cool down this is what makes metal softer (annealing). For welding applications such as C gussets you wouldn't get that area that hot for an extended period and air cooling would cool it too fast to make the metal anneal.


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Makes sense :)


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Yes, you don't gave to regear right away but you should. I had 35's on 3' lift and the stock 4.10 was struggling, especially on uphills. It would never get to 5th gear. I swapped to 5.13 and now finally it drives like a stock, even better. I am enjoying the new gears tremendously. The RPM is a little high but that's not a problem at all. For example with 5.13s I am driving 75mph with 31-3200 RPM a supposed to 2500 with the stock gears. I thought the fuel economy would suffer but that hasn't been the case. It's the same and I'd say even a little improvement. In short, regear and you'll see the difference. It's worth it.


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I just went from 4.10 gear with stock Rubicon tires/wheels to 4.88 gear with 37" Falken tires. On the Rubicon, 4.88 with 37" tires is close to stock performance. In fact the RPM is now a little higher at speed than it was with the stock tires and 4.10 gears. If I had run 5.13s I'd never reach 70 MPH.


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