Anyone running 5.29s with a 2.7l 5spd?

I’m running a single cab 2.7l, 5 speed, on 285/70/17 mud tires, 529 nitros. I can average 50mph in 4th gear at 2200 rpm no problem, 65mph in 5th gear at 2200-2500 rpm. But I’m running way lighter mud tires than the boggers you have mounted, so you might get a different outcome than me. I mounted my 15x12 on 31 swampers tsl/sx and I’m still turning low rpm numbers for the most part.

 

I actually have cooper ht plus right now. Thant remember the size but they’re a 33

and wow 65 22-2500? That’s not bad at all lol I was expecting to be around 2900-3000 at that speed. Unless ur tires are pretty big

 

Ok we’re gettin weird. Ive got the 5.29s on my floor been lookin at em for a couple months now been hella busy.

i have to say I’ve been back n forth about 5.29s being a bad move since I do so much highway driving. BUT… one thing I realized today, and I guarantee most people aren’t considering this at all.

a 33” tire most the time is not going to measure out to be 33” tall. Don’t believe me go out and measure your tires. Ive never had a tire that measured its advertised height. They are close though somewhat. My boggers (33x10.5) measured to be about 31.5-32” tall. And my coopers 275/60/20 are spec’d out at 32.95” tall, however, in the physical form they’re 31.5 or so.. BUT, from an rpm-to-speed standpoint, on an rpm calculator, my 4.10s at 65mph equal the same rpm I’m doing in the dash when I enter in a 31” tall tire value….

so, for those of you purchasing gears, take that into consideration?

Now, back to my original reasoning for posting. I was back n forth and got kinda stressed out wondering if I chose the right gears or not, my trucks a 5spd 2.7l with 4.10s….

Relate back that my “33s” only measured out to 31.5” tall… and projected rpm values at a given speed similar to that of a 31” tall tire… so 31/32.95 ~ equal to around 93%….

SO, I think it might be safe to say that the stock size being advertised at 30.47”… I could take 93% of that to project and mimic what my truck was doing with my stock tire size in turns of rpms at a given rpm/speed range…

So, having said all that bs… my conclusion is that comparing my truck on stock tires and taking 93% of that (28.47 tire height value) at 70mph gives me 2750 rpm

Whereas with 5.29s installed and running a 33 (31” in the calculator) with rpm values at 70 I’ll be doing 3250 rpm.

now while I’ll admit 3250rpm is quite a bit… it really isn’t all that far off from stock. Now I know all that sounds silly but I used to be an engineering major and did lotsa math. So I reckon if my hypothesis is even somewhat feesible, then honestly? 5.29s would only be putting me 500 rpm over stock at that speed. Or virtually any speed for that matter. And that’s really not that bad in my eyes? I can even drop it down to 65 and be doing 3000 rpms if I wanted to make myself feel better.

So I’m conclusion I don’t think 5.29s would be too aggressive. I think that would be a matter of opinion if anything. 4.88s would only make a 200rpm difference closer to stock rpm ranges, which would be easier on fuel yes. But hey, you be the judge.

 

Can’t you just go drive your truck at 70mph, and note the RPM. Multiple that RPM by 5.29 then divide by 4.10 (your current gear ratio). That will give you the RPM you’ll run at 70mph with 5.29’s.

 

another reason to regear:
I'll buy your 4.10's

 

I didn’t know that was a trick but yea I suppose that would work. I’ll do it tomorrow and see what I find. Even though I’ll be looking at needle rather than a specific value. But ya sounds legit

 

you really want em?

 

Well I just got my gears in. During my second test drive I took the truck up to 60mph. Speedos off by a lot now which is ok idc. With my 33s though I was runnin:

60mph @ 2650 RPM
65mph @ 2900 RPM

Trucks pretty quiet at 2900 r’s too. Glad I went with the 5.29