35s, 4.10s and a 6-speed...bad idea?

PackersJeep

PackersJeep

New member
Did a search and it didn't talk much about auto vs manual as far as tire size, gear ratios and how bad it will be.

Basically I'm looking to upgrade to 35s probably this summer (or maybe fall) and would like to not have to re-gear for now. I've got the 4:1 so on the trails I'm not worried. Where I am concerned is on-road. I know I'll lose some power, but will it be down right annoying running 35s on 4.10s with the 6-speed? I do some very hilly driving on my way to several close by trails, will I be shifting nearly constantly?
 
PackersJeep

PackersJeep

New member
Awesome - thank you! Do you think that 6th gear will still be an option on the highway or not so much until I re-gear?
 
Philip *AZ*

Philip *AZ*

Banned
Yeah, I definitely lost some power, but nothing drastic. It doesnt like hills (Auto), but around town and regular day to day driving I think it does pretty good. Im going to start with a Procal and then Im going to run 4:88's. After a couple months of saving I will be hopping up to 37's and throwin a truss on my D30 with chromoly axle shafts n lockers. Im not a hardcore wheeler, but I would prefer to have the additional strength for the warm n fuzzy.


Paratroopers stay up longer!
 
jasont0311

jasont0311

Caught the Bug
I run 35's with an auto and it isn't bad at all. I think with a 6 speed you'll be fine. If you're really concerned with performance try and find a light tire like the duratracs.
 
PackersJeep

PackersJeep

New member
I'm leaning towards either the MTR kevlars or the KM2s. MTRs are probably on the super heavy side but do cost less and my uncle seems to really like them on his TJ Rubi.
 
Philip *AZ*

Philip *AZ*

Banned
I run 35" Treadwright Guard Dogs. To me they feel a bit heavier than your typical 35, but like I said before, I get around just fine. I think you will be pleasantly surprised with how well it does. Though Moby is highly modified, he's on 40's with a standard 3.8l, and that Jeep has made lots of trips. Havent heard Eddie complain about his 3.8, if anything he talks it up.


Paratroopers stay up longer!
 
dis_dis

dis_dis

Banned
PackersJeep said:
Awesome - thank you! Do you think that 6th gear will still be an option on the highway or not so much until I re-gear?
Click to expand...

I am running 35s on a 08 manual Rubi and hit 90 mph in 6th gear the other day on the highway, so ....
Normally I am in 5th or 6th gear on the highway going 60-75 mph in the 2K rpm range
It is a bit harder to climb hills though, but meh
 
PackersJeep

PackersJeep

New member
Good to know! I know with the old '98 XJ with the HO 4.0 when I went to 33's it was tough to just get her rolling on an up-hill stop. Granted that was with 3.07 gears, but I was still nervous. I figured 4.10s would be ok and could likely get me by for a while before I have to bite the bullet, sounds like I can manage for a lot longer than I thought :rock:

@ dis_dis - what is your mileage like?

@ Philip *AZ* - what is your mileage like?
 
Rivertoys

Rivertoys

New member
I have 3:73 / 6-manual, and recently went to from stock BFG 32"s to 315/70's (@~34.6"). Before making the switch, was planning I would regear to 4:56. Just today I was pondering if 4:11 would be enough.... I think if I go to the trouble of a regear, I will go 4:56 but if I was already at 4:10, I probably wouldn't bother. Just a guess though.

I have had one full tank through since the tires, and it was 14.6mpg. I was getting right about 17 before. 16.5-17.2 usually. My driving pretty well mixed frwy and street, but more street with stop and go frwy mixed in, and some full speed frwy daily.

I used to get about 240 miles per tank, and the first tank after tires was 211.
 
R

RubiconNate

New member
I am running 35s Toyo Open Country in my 08 Rubi with 4:10. It does alright on the highway in 6th. Even poking around town at 50 I can use 6th. But when you push on the skinny pedal it does nothing. Mountain roads aren't to bad. I pull them in 4-5 just a lot slower. I'm looking at getting a superchips or Diablo tuner. Maybe that will wake up the motor a little. And cost less than gears.
 
rinkishjk

rinkishjk

New member
I have been running my 35's and 4.10's for over two years, and the only real time I notice is on an incline on the highway.. I'll just have to put it in 5th gear and it's good.
I would bet with 4.88, or 5.13 it would be alot better, but I haven't felt a need yet, nor had the cash to regear. When I get 37's I will regear to 4.88.
A tuner helped me alot. I run 87 tune and 87 fuel.
 
PackersJeep

PackersJeep

New member
Sounds like the MPG wont change very much, that's a relief! I go to Ouray or somewhere else about 5 hours away with my family and their Rubicons each year so I'm glad that just the gas to get there and back wont kill me. Maybe down the road 4.88s will make their way into the Jeep...but I'd prefer to explore the hemi route instead (but who wouldn't :brows: )
 
StrizzyChris

StrizzyChris

New member
I didn't read all the responses...but a manual will do much better with oversized tires than an auto. There will be power loss compared to stock, but you'll get to choose your shift points, unlike the auto
 
BlackKnight

BlackKnight

Member
StrizzyChris said:
I didn't read all the responses...but a manual will do much better with oversized tires than an auto. There will be power loss compared to stock, but you'll get to choose your shift points, unlike the auto
Click to expand...

Actually nowadays with the slapshifting Automatics you can control your shift points alot better, they are basically an Auto clutching manual, but as you said they are less efficient due to all the clutches, lots of slip...
 
StrizzyChris

StrizzyChris

New member
BlackKnight said:
Actually nowadays with the slapshifting Automatics you can control your shift points alot better, they are basically an Auto clutching manual, but as you said they are less efficient due to all the clutches, lots of slip...
Click to expand...

Yeah, I have a 2013 auto...it doesnt always like to listen to me when a hill comes or I push to hard on the gas lol

Big tires and not re-gearing is always better in a manual especially in a 3.8 like the OP has
 
Rivertoys

Rivertoys

New member
BlackKnight said:
Actually nowadays with the slapshifting Automatics you can control your shift points alot better, they are basically an Auto clutching manual, but as you said they are less efficient due to all the clutches, lots of slip...
Click to expand...

Do they have a torque converter or a clutch?
 
GetOut

GetOut

New member
I ran mine for about 3 years on 35s with 4.10s and the 6spd and can't really complain. You will never win any speed titles but there is more than enough power to get out of your own way, the superchips tuner on the 93 octane tune will make a world of difference though. In that configuration I towed a 6x12 box trailer loaded with all of my tools/guns/household goods (probably close to 3000lbs) from Arizona to Michigan and had no problems on the highway/grades or passing semis.
 
PackersJeep

PackersJeep

New member
Sounds like the consensus is to get some sort of tune done to help, new question is - which one? I don't really like the idea of having to go above 87 octane when I'm only getting a bit over 17 mpg as it is. What tuners would be good to use for that octane?
 
BlackKnight

BlackKnight

Member
Rivertoys said:
Do they have a torque converter or a clutch?
Click to expand...

Torque Converter for the engine to Trans, which because of the fluid dynamics is not an efficient conduit for power, and also inside the transmission there are clutches and friction disks between the gears, which also plays into the loss of efficiency..
 
You must log in or register to reply here.
Top Bottom