cptmohog

Sorry but after searching the forum for an hour, I can't find a specific answer to my question.

I am currently running a trussed hp d30 with chromo's, 4:56 gears ox locked on 33's... Had planned to go to 35's and 4:88's this year but have been offered a "too good to pass up" deal on a set of 36" swampers.

I have several buddies running 35's on stock hp 30's with no problems. We all have a similar "light on the skinny pedal" style.

My question is would 36's really be too much for this axle? And what gear ratio would you recommend for 36's? 4:88?

Btw, running 8.8 ox locked, chromo's ( c clip eliminators) trussed in the rear....
And I know swampers don't last long, but this is not a daily driver and only sees 1000 miles or so a year on average..
TIA

tlkallday

4.88's would be extremely ideal for 36 inch tires, possibly even a auxiliary trans cooler would do some good there as well. As for the hp d30 holding up with that size tire, as long as you're not skipping over huge boulders at high rates of speed you should be golden.

denverd1

sounds well built and geared just under ideal for 36's. I'd roll em.

Fred/N0AZZ

If you do go with the 36's a 4.88 would be fine but your pushing the envelope as far as strength goes. A lot will depend on what type of wheeling you do as far as how long it lasts.

Atmos

ALWAYS

big time. 4.88 will absolutely hate a bigger tire than 35". I've seen (in person, not on the internet) 3 broken pinions. the "I found a killer deal on 36 swampers and decided to run them anyway" story is one I've heard before. they all sold their fully built but still broken D30's for a huge loss and went to a bigger front axle

get rid of the tires

Rockhead

Everything that I have read about Dana 30s and what size tire it can handle points to 35s being the limit. That being said, your Dana 30 seems to be properly built up to handle 35 inch tires, what's an extra inch! Just joking there, but aren't swampers extremely heavy too? Somewhere around 80 pounds a tire I think.

Rock Toy

With Chrome-Molly shafts, and your D/30 TRUSSED, you should be OK if you stay with the 4.56 gears. The 4.56 gears have better ring and pinion engagement, and the truss will help with gear deflection.
If you need a lower crawl ratio go with a 4 to 1 kit in your transfer case or better yet a doubler.