Overdriving the Front Axle?

[Big Tex]

Originally Posted by 05Fronty4x

Lol, come on guys...underdriving rear/overdriving front, it's the exact same thing: an offset gear ratio between the front and rear axles.

Putting the underdrives in the rear has a greater effect, not because it's the rear, not because it's underdriven instead of overdriven, but simply because the offset in gear ratios is greater than if you were to put the available overdrives the front. Though this difference is so small you wouldn't even notice, so do which ever you want, it's the same for all intensive purposes.

Stock (38/13) = 2.92:1
Over (36/14) = 2.57:1 or a .35 offset
Under (43/13) = 3.31:1 or a .39 offset

Imagine our rigs came with 43/13, and you put 38/13 in the front, that would be considered overdriving the front, right? Yet my rig has those same exact gear ratios front and back, but it's considered to have an underdriven rear because we started with 38/13.

My point is that the words are basically meaningless, it's the numbers and more importantly the difference (offset) between front and rear ratios that count.

while the might be true, ive actually tried both, OD only and UD only, and with the UD only i felt less torque and i kinda wanted to change my gearing, but for the best outcome and performance, IMO either run both or OD only

[Big Tex]

Originally Posted by SCX10Dingo

Nice demonstration!

Since you bring up vehicle weight..... I think my dingo is about 8lbs. I have aluminum wheels (motoworks or something like that), and about 3 1/4 oz in each wheel. Does this sound pretty close, or should I add more weight to the wheels? I wanted to make it a little heavier for better traction, but not so heavy that it would have more heft to pull up steep climbs.

whatever you do dont listen to anyone on wheel weights, yess 2oz-4oz in the fronts with work, some are hardcore and run 4oz in all 4 some run 4oz in the front (just a hypothetical weight example) and some will run none, just try it out.

like i said earlier get out there and try it out! some rigs are rear heavy and need front weights some rigs are front heavy and dont need weights if at all. its all up to you and your rigs behavior.

[craddock35]

Originally Posted by Texas Creeper

you cant tell from the camera angle here but this climb is almost straight up, right there my rig weighed about 9lbs 14oz so almost 10lbs,

the overdrive helps with not rolling onto your back as much by the front pulling your rear end up the hill instead of the rear pushing up.

Lol now I have a short vid of the rig I got form you. This is the only rig I have od and ud gears in and I am going to do it to the rest of them as soon as money allows. My wraith has ud rear and stock ratio in the front in hd gears and I can tell a difference in climbing but not as much as I can in this one. My others just have stock gearing and don't climb as well. The only issue I have had and it might not have been from the different gear ratios but my stock locker broke in my wraith but since I put the vp lockers in I have had 0 issues. I am going to do more lockers and od ud to all of them asap now though.

[Big Tex]

Originally Posted by craddock35

Lol now I have a short vid of the rig I got form you. This is the only rig I have od and ud gears in and I am going to do it to the rest of them as soon as money allows. My wraith has ud rear and stock ratio in the front in hd gears and I can tell a difference in climbing but not as much as I can in this one. My others just have stock gearing and don't climb as well. The only issue I have had and it might not have been from the different gear ratios but my stock locker broke in my wraith but since I put the vp lockers in I have had 0 issues. I am going to do more lockers and od ud to all of them asap now though.

so i take it you dig the setup lol well that was probably the best setup rigs ive owned, the balance was right around 60% front and 40% rear, i tried UD only in that one and hated it, it just felt soggy in the bottom end, OD in the front worked good but BOTH works best, as you can see

[rm25x]

Good info, I think I am going to try the ud/od in my Wraith since I do a lot of hill climbing.

[B94Cast]

This was great information for me - just ordered front and rear od/ud hd gearsets for my JK build!
Thanks!

[B94Cast]

One question now that I am thinking more about it - how does this affect tire life with softer compound tires? Is it a noticeable difference?
Thanks!

[craddock35]

Originally Posted by B94Cast

One question now that I am thinking more about it - how does this affect tire life with softer compound tires? Is it a noticeable difference?
Thanks!

I havn't been able to tell a difference in wear. I run pitbulls on that truggy and have been running trails and rock with it. I am sure if you run alot of concrete it will make a bit of a difference but mine hasn't even sat on concrete so I couldn't say for sure.

[B94Cast]

Great - thanks again!

[Big Tex]

Originally Posted by craddock35

I havn't been able to tell a difference in wear. I run pitbulls on that truggy and have been running trails and rock with it. I am sure if you run alot of concrete it will make a bit of a difference but mine hasn't even sat on concrete so I couldn't say for sure.

i second that motion, i ran claws, and iroks in the softer x2ss compound from rc4wd on that jeep @ 9lbs 14oz
and i currently run OD and UD in my jk with treps @ 7lbs 4oz and theres no difference in wear,

unless your a brushless guy and have a heavy foot running on bare rocks
then yessir, they do disappear fairly quick regardless of OD or UD

[05Fronty4x]

Originally Posted by Texas Creeper

while the might be true, ive actually tried both, OD only and UD only, and with the UD only i felt less torque and i kinda wanted to change my gearing, but for the best outcome and performance, IMO either run both or OD only

We all have opinions, but in this case we are strictly dealing with numbers which leaves little room for speculation and "feel" so actually it is true.

While having the stock ratio in one axle, the difference between the other 2 (UD/OD) ratios compared to the stock ratio is so small you wouldn't ever know the difference, and if you did notice the difference (as you state you have) you should have actually noticed the opposite effect since 43:13 is a lower ratio. And even more contradicting is that it sounds like you favor a high offset by recommending both, yet you choose to put 36/14 in the front if you were to only do one. This is totally bass ackwards since that offers the least amount of offset possible. Just overdriving the front is closer to stock than just underdriving the rear.

It kind of sounds like you are stuck on the terms and not really breaking through to the concept. What if our rigs came with 43/13...your arguement is that it's better to overdrive the front. Well, that puts you at 38/13 in front, and 43/13 in rear and that is exactly what "underdriving" is for us since they come with 38/13. If the offset from stock wasn't so close to identical between our OD/UD options then there would be more room to favor one or the other.

[05Fronty4x]

Originally Posted by B94Cast

One question now that I am thinking more about it - how does this affect tire life with softer compound tires? Is it a noticeable difference?
Thanks!

Your front tires will wear out faster no matter which option you go with since they will be turning faster than the rear. Assuming equal traction with all 4 tires of course.

[johnnyh66]

Originally Posted by 05Fronty4x

Your front tires will wear out faster no matter which option you go with since they will be turning faster than the rear.

negligible.

[Big Tex]

Originally Posted by 05Fronty4x

We all have opinions, but in this case we are strictly dealing with numbers which leaves little room for speculation and "feel" so actually it is true.

While having the stock ratio in one axle, the difference between the other 2 (UD/OD) ratios compared to the stock ratio is so small you wouldn't ever know the difference, and if you did notice the difference (as you state you have) you should have actually noticed the opposite effect since 43:13 is a lower ratio. And even more contradicting is that it sounds like you favor a high offset by recommending both, yet you choose to put 36/14 in the front if you were to only do one. This is totally bass ackwards since that offers the least amount of offset possible. Just overdriving the front is closer to stock than just underdriving the rear.

It kind of sounds like you are stuck on the terms and not really breaking through to the concept. What if our rigs came with 43/13...your arguement is that it's better to overdrive the front. Well, that puts you at 38/13 in front, and 43/13 in rear and that is exactly what "underdriving" is for us since they come with 38/13. If the offset from stock wasn't so close to identical between our OD/UD options then there would be more room to favor one or the other.

woahhh nelly! lol ok, the phrase "IMO" was mentioned so lets just leave it there, i dont think i need a novel written on my opinion, because thats just what evryone on here has, opinions, its up to him to go test it out and feel for himself the difference, and yea i might be "stuck on the terms" in your opinion, but there we go again, thats YOUR opinion, lol but IMO thats just my take on what i felt with 38T/13T front and rear versus an UD in the rear alone, it literally felt like my lipo had low voltage.

they might just be "terms" and "concept" to you and here we go again YOUR opinion, but whats sounds good and makes sense on paper doesnt tranfer perfectly over to the trail since we are almost literally on 2 different corners of the country, now IMO yes front OD only or BOTH works best, remember IMO

and geez dont scare the guy, the front DO NOT drastically wear differently, and as before mentioned unless your a throttle guy, you'll be fine as far as wear, and just follow the rule of thumb of tire rotation front to rear and vise versa, i usually rotate mine every other trail ride maybe 2-4 trails and ive never noticed a difference in wear and ive always run OD and UD in my axles.

[05Fronty4x]

Originally Posted by Texas Creeper

yes front OD only or BOTH works best

Again...

Stock (38/13) = 2.92:1
Over (36/14) = 2.57:1 or a .35 offset
Under (43/13) = 3.31:1 or a .39 offset

... or do both for a .74 offset


What you are saying is that an offset somewhere between .35-.74 works best... guess what? .39 (UD rear) falls into that category.

Yes, opinion this, opinion that...I'm leaving my opinion out on the matter by indroducing factual information. Your opinion is based on your "feel" that day, for all that matters it could have been the position of the moon, or what you ate for breakfast.

Suggesting to put 36/14 in the front, or do both, but not just the rear doesn't make a bit of sense since doing just the rear falls right in between the two.

Originally Posted by Texas Creeper

i dont think i need a novel written on my opinion

I'm not doing it for you, or because I think you need it. I'm doing it for those who want a little more substance than what pure opinion offers when they take the time to research.

[Dostradamas]

Thanks for the input all. I am confident I made the right choice now.

[PontiacGT201]

Anyone have a link to the parts need to overdrive the front axle? Thanks

[Dostradamas]

The ax 30395 gear set is the heavy duty stock replacement set, also by the picture in the link its straight cut gear and pinion.
The ax30402 gear set is the heavy duty underdrive gear set, also its bevel cut.
The ax30401 gear set is the heavy duty overdrive gear set and is also bevel cut.

That is a start for axials

I find almost all manuals on google in pdf by searching the model name then manual & pdf.
Most manuals cover upgrade and optional parts (including part #'s)

[Big Tex]

Originally Posted by Dostradamas

Thanks for the input all. I am confident I made the right choice now.

lol i like that

[Big Tex]

Originally Posted by 05Fronty4x

Again...

Stock (38/13) = 2.92:1
Over (36/14) = 2.57:1 or a .35 offset
Under (43/13) = 3.31:1 or a .39 offset

... or do both for a .74 offset

Yes, opinion this, opinion that...I'm leaving my opinion out on the matter by indroducing factual information. Your opinion is based on your "feel" that day, for all that matters it could have been the position of the moon, or what you ate for breakfast.

Suggesting to put 36/14 in the front, or do both, but not just the rear doesn't make a bit of sense since doing just the rear falls right in between the two.

I'm not doing it for you, or because I think you need it. I'm doing it for those who want a little more substance than what pure opinion offers when they take the time to research.

ok, this isnt what i wanted to do at all, NO ONE asked for facts, and if you have em, sweet man thats cool to see em in numbers,

YES they make sense, YES the rear makes more sense FACTUALLY, but here we go again,

IMO i rather have my front end spinning faster and my rear spinning at factory speed, than my rear spinning slower and my front at factory speed,

if you wanna get factual, this ENTIRE argument is over .04 of a ratio, literally the most indestinct difference in wheel speed ever,

all i stated was my opinion because thats all anyone asked for, and thats all that gets posted is opinions, cool, thats all anyone has to offer someone with a simple question,

no one wants to get scientific about this hobby, especially over .04 of a difference in a gear ratio,

now please, i get it that this is your factual opinion, awesome bud, really,

now let my opinion stand for what it is, just my opinion, and btw yes the moon and the stars were in perfect alignment and i had my wheaties