Thanks for the info. I am still deciding between 4.56 and 4.88. I have a MT and am moving up to LT305/70R17/E Nitto Terra Grapplers. I haul a raft trailer (~2,500) lbs nearly every weekend from Apr - Sept. Also, I live in Colorado at high elevation and it feels bogged down as it is towing. Recommendations?
I'm running 285/75/17 Toyo MT tires (71 lbs. each!) on a heavy auto tranny FJC and I'm happy with 4.56 gears, even in the mountains, but if I was towing a trailer in the mountains I would seriously consider the 4.88 gears. Actually, I don't think there would be a question in my mind, I would definitely go with 4.88 but that's just me.
TLCA # 16550
High Desert Cruisers
Last edited by 1911; 03-11-2009 at 07:09 AM.
Reason: fixed typo
1911. How do you think your vehicle would respond with 4.10's instead of the 4.56's? Thanks!
I considered 4.10 (4.11?) gears, but decided against them for two reasons:
1) They're only 10% lower gearing than stock. Using this nifty on-line calculator: 4Lo.com :: Final Gear Ratio, Crawl Ratio, Tire Size Calculators I was able to see exactly what rpm I would be turning for any speed with my size of tires, and I didn't think that 10% lower was enough for 34" tires and the weight of my truck.
2) The only 4.10 gears I could find for the front diff were Toyota, and let me tell you they are proud of them! 1.5-2x the cost of quality aftermarket gears.
Having said that, Jim D here on the forum runs 4.10 gears with 33" tires and likes them I believe. Using the calculator I gave the link to above will let you play with and accurately see the effects of any diff gear, tire size, and transfer case combo.
TLCA # 16550
High Desert Cruisers
regearing is well worth the money.....on 33" tires you can get by with 4.11 to get back to stock ratio or close to it....4.56 to give you a little extra umph off line and offroad.....IMO 4.88 are too much unless 90% offroad vehicle or tires are 37 or larger.
it helps get the rotational mass of tire moving with less effort so can save fuel and keep engine from lugging at lower speeds as was mentioned above...going too much on the gearing though will make rpms too high at highway speeds and also cause excessive use of fuel as mine drops considerably over 2200 RPMs.
I would say 4.56 max for your setup....4.11 if you want to get it close to stock feel. I am staying 33" tires and will be regearing next year unless something breaks before then. JT has the gears that do not require new housing..... or can use to put an ARB up front as well.
I think it is a good choice for anyone with oversized tires...onroad or offroad.
I created a quick chart that compares some gearing/tire options for MT. It is not all inclusive by any means...but rather just some info that I put together in making my decision for gearing/inchworm/tire size. I calculated these numbers...so if you see any errors, just tell me. You are going to have to maximize the images.
With all due respect to your work there, an easy to read chart is available at the same site 1911 and I have been using and referring to. Take a look at this link, it may be easier to read and compare different tire sizes and gear ratios... 4Lo.com :: Gear Ratio & Tire Size Chart
The AutoGuide.com network consists of the largest network of enthusiast-owned enthusiast-operated automotive communities.
AutoGuide.com provides the latest car reviews, auto show coverage, new car prices, and automotive news. The AutoGuide network operates more than 100 automotive forums where our users consult peers for shopping information and advice, and share opinions as a community.