GX470 Unsprung weight grenading rear diff

[jewishoverlander]

Hey guys.
Ive got my GX470 and was dead set on Kenda Klever RTs in 33x10.5 because the entire internet mostly claims they are 52lbs-ish. Now I find out they are truly 61.5lbs.

How much should I be concerned with the extra weight when it compares to the Wildpeak AT3Ws which are 52.5lbs at 255/80. I already didnt LOVE the look of 10.5 but figured its liveable. 10" really seems skinny and takes away a lot of the aggressive look. Looks isnt my #1 priority but Im trying to find a nice balance.
That extra 9lbs from the Kendas, should I be significantly more concerned of
1) Grenading the 8" rear diff.
2) Unsprung weight for MPG/Acceleration

I plan to do a lot of hwy miles so MPG and noise are important to me but I do intend to lots of medium rated Jeep trails. Am I hitting the Rubicon anytime soon, no but I will be putting the car to the test for sure.
Future plans are a 8.2" and locker but thats likely not that soon.

 

[Montanatun05]

How do you plan on using the GX? If you’re going to be doing some hardcore crawling (if you’re going to a 33” then I doubt that’s the case) then I would maybe be slightly concerned but otherwise you shouldn’t have any issues. It’s all on how you drive and what you do. Pop over to mud and the 120 section and do some searching around, you will see plenty of guys running that size or larger with no issue

 

[jewishoverlander]

Its hard to do what would be objective "hardcore crawling" (all rigs considered) in a GX without serious modification. But I do intend to push the car to its limits (within its current state of course) so I do expect to be doing trails where I might get stuck and need a yank or get high centered etc due to not enough clearance/articulation. Am I hitting the Rubicon tomorrow, no Im not but I do plan to do trails that are real "jeep trails". Are they the hardest Jeep trails out there? No of course not a 33" GX will never make it. But I to plan to do trails where my JLU buddy leading me will occasionally have to yank me if I cant make it up without assistance.
@Montanatun05

 

[Montanatun05]

That seems reasonable. I still don’t think you’ll have any issues unless you find your self doing a bunch of bouncing which results in situations of little traction that quickly turn to situations of lots of traction. This can kill a diff but that seems pretty obvious that you would want to avoid that regardless. I say, armor up and go have some fun

 

[phsycle]

This may be sacrilege here, but I’ve never liked skinny tires. I never got better performance out of them. Lateral traction suffer, and mpg is exactly the same.

You’ll need to decide if 33’s are worth the mpg hit. If you stick with 33, I like the 285/70/17 size. KO2’s come in LR C, which are 51lbs.

I think 32’s would give you good enough performance offroad and get you decent MPG.

I’d not worry about grenadine the diff. Just don’t go send it every obstacle.

 

[NatersXJ6]

You should be asking about your change in tire diameter and gear ratio more than the change in weight. You will probably see a significant performance decrease, meaning you won’t be spinning any tires, so there is a good chance of not blowing up a differential or breaking an axle.

What size tires do you currently have?

 

[smokeysevin]

The first time I blew the diff in my tundra (8.4 not 8.2), I took 4 teeth off the ring gear and 2 off the pinion gear. I had been drag racing (probably 50-60 passes at the local nhra track) and as any inexperienced teen is known to do, was doing "sick" burnouts on my 285/75/16 bfg ats. I didn't actually blow the diff at the track, it happened a few weeks later while driving like a normal human.

My suspicion is that the wheels going from no traction to full traction when exiting the burnout box put a hell of a shock load on the gears and it damaged them. The open diff probably didn't help that situation. The other times it was either due to the ring gear bolts backing out, the gears not being setup properly, a stuck master cylinder burning up the gears, etc. Never did I damage the casing, the carrier, or the axles.

All of that is to say that in a gx offroad you are really unlikely to come anywhere close to that kind of loading unless you are running rally raid / baja / rock bouncing. The front diff or cv's are way more likely to end up kia than the rear is.

Sean

 

[tacollie]

With open diffs you would have to work for it imo. The 8" will be plenty adequate for what you want to do. If you are traveling with someone don't be afraid to hook up a strap. Buy the tires you want.

 

[Smileyshaun]

That’s weird I have the kendas in a 35x10.50 and they weigh 63 lbs .

 

[Smileyshaun]

people run 37s on beadlocks on Toyota 8” diffs and beat the holy snot out of them and never really have issues , I would be more worried about overloading the rig with gear way over the gvwr leading to diff damage .

 

[phsycle]

Atrac works pretty well, though. And the 4.7, albeit a bit underpowered for a V8, is a nice engine and plenty of power. Use that steady throttle and it’ll get you up the trail.

 

[jewishoverlander]

That’s weird I have the kendas in a 35x10.50 and they weigh 63 lbs .

You weigh'd them? The 35s are supposed to be around 68lbs I would guess its the scale issue for an item in that shape or something.

 

[jewishoverlander]

With open diffs you would have to work for it imo. The 8" will be plenty adequate for what you want to do. If you are traveling with someone don't be afraid to hook up a strap. Buy the tires you want.

Do you mean open diffs as in no lockers? Cause the GX does have a center diff lock. IDK if you participate on GXOR at all (or have a GX470) but lots of people are grenading their 8" - is it every week? No. But the more established members seem to indicate that its more of a when not if type thing. But maybe they just have a confirmation bias. I asked here because the advice seems less subjective and more objective on here

 

[jewishoverlander]

You should be asking about your change in tire diameter and gear ratio more than the change in weight. You will probably see a significant performance decrease, meaning you won’t be spinning any tires, so there is a good chance of not blowing up a differential or breaking an axle.

What size tires do you currently have?

Honestly this was a consideration I had but nobody seems to care so I thought I was being dumb. I felt that the extra unsprung weight literally makes Atrac less useful. If the Atrac system cannot manipulate the wheels as well then its simply not as effective. Im currently onstock tires and the Atrac was insane in what Ive done so far. I did feel that potentially going heavy would actually give worse performance than going heavy. But its not something I ever hear anybody say so.....

 

[Smileyshaun]

You weigh'd them? The 35s are supposed to be around 68lbs I would guess its the scale issue for an item in that shape or something.

I asked Kendra directly and they said 62lbs but at home they weighed at 63.2 lbs . But weight aside I’ve been very happy with the tires with their skinny size only needing an inch of lift clear on my truck with no rubbing, If I would’ve gone the traditional route with more of a 35x12.50 I probably would’ve needed about 5 inches of lift to make it clear