I haven't seen a tire yet that was true to size. My 33" tires measure 32" on the jeep with 26 psi. Don't know why folks are afraid of 3000 rpm's.
Gear ratios and bad advice
- Thread starter Brantley
- Start date
I haven't seen a tire yet that was true to size. My 33" tires measure 32" on the jeep with 26 psi. Don't know why folks are afraid of 3000 rpm's.
I know one video that you particularly wouldn't like, it's where he adapted some dual piston calipers to his rear Dana 44. Then, his solution to "make it work" was get a combo valve with so much adjustability that he could limit the fluid back down to where they wouldn't lock up.
My question is, why not pay the $150 bucks for some calipers that are actually designed for that axle? He had the dual pistons on hand but that doesn't make it reasonable to go through all the work to adapt them and then limit 90% of their performance with a combo valve. Makes no sense to me. He never posted a follow up of actually using them or the combo valve so I don't know how it ended up turning out.
I have linked his two videos of this process in case you're bored enough to watch them if you haven't come across them already.
Lol whoops I read right over that.
I will say that for a 4.0, with 42rle, I'd recommend 5.13 ratio for 33's instead of the 4.88.
I've seen a few people say that. I have no personal experience but I see more say 4.88 so that's what I went with. I've checked both out on the sites like Grimm Jeeper and based off of those numbers, the performance on the highway would still be very good.
I think the only issue that comes with 5.13 is that when it does decide to downshift on grades, the RPM in 3rd gear will be through the roof with 5.13 and 33's.
I'm sure I'd be happy with either 4.88 or 5.13 if I had to pick.
sgtjdgelinas
TJ Enthusiast
You're not a fan of people who don't completely agree with you huh? If you can private message on here you can ask why I conceded the argument without admitting that you were 100% correct, but I'm not getting into with you about that subject publicly anymore.
Yes, let's keep this thread nice and polite if possible.
This is a good thread, it brings to light what a lot of us already knew, but serves to be a great eye opener for those who simply didn't know any better (which was all of us at some point).
This is a good thread, it brings to light what a lot of us already knew, but serves to be a great eye opener for those who simply didn't know any better (which was all of us at some point).
Blaine brings up an important point, the actual size of the tire, not what is printed on the side. At a minimum, go to the tire manufacturer website and check the listed diameter. Will at least get you closer to the number you are looking for.
X2. They may print 33" on the tire, but that doesn't mean it's exactly 33". And even 1/2" can make a big difference when it's rotating as fast as it is.
My RPM is off by about 200 from what it would be if my tires were actual size.
My 31x10.5R15 measure out somewhere around 29.5" and so my RPM is at 2825 at 75 rather than the 2633 that the chart suggests with my 4.10 gears and AX15. Definitely can't go off of the sidewall number.
My 31x10.5R15 measure out somewhere around 29.5" and so my RPM is at 2825 at 75 rather than the 2633 that the chart suggests with my 4.10 gears and AX15. Definitely can't go off of the sidewall number.
Every inch is roughly 100 rpm given the same ratio. Some tires are ridiculously undersized. I have seen some 33's list a dia of less than 32". Gearing for 33" but ending up with a 31.8" or whatever is quite a bit different.
Exactly. Plus you aren't running them at full psi, more likely 26-28 psi, which will decrease the effective diameter as well.
It isn't an issue of agreeing with me, it is an issue of understanding. It takes a lot of effort to build shit and make demonstrations to show how stuff works instead of how you think it works and to have that summarily dismissed without any logic or examples to the contrary while ignoring pointed queries that show the exact opposite of your position, makes one wonder why to even try?
Your answer? Weld a fucking washer over it. I can get that answer from the dumbasses on 20 different forums all over the internet and the question, why does making the hole back to the same size magically solve the problem if it started out that size, goes unanswered. The answer is simple, hole size doesn't. Something else changed that fixed the problem and making the hole the size it started isn't it.
The actual number you are looking for is RPM or revolutions per mile. Most good tire sites have them. It's just easier to go off the rolling radius.
sgtjdgelinas
TJ Enthusiast
I'm sure the gentleman who started this thread about gear ratios doesn't want to read you cussing at me about a disagreement over the root cause of bolt failure. I joined this forum cause I was impressed with the civility, even during disagreements. You seem to be a respected member of this forum, for the sake of keeping a new member from leaving the forum, please act like it.
sgtjdgelinas
TJ Enthusiast
Like I said, I'd probably replace the bracket, I'm a fan of fixing things right the first time.
Rob80x
TJ Enthusiast
Good thread. I bought my 02 4.0 w/ 32RH and 3.73 gear in October. The previous owner had 35's on it. It wasn't too terrible but I think it's going to be much better with the 32's I am putting on it now.