Axial Yeti - Formula Offroad Upgrades Build

[SilicaStorm]

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As I live in the desert and lots of sand dunes to climb and jump i come to ask some questions.

Can you experienced FOFF gurus throw some suggestions of mods or upgrades to the Axial Yeti that should be considered to get more enjoyment from Formula Offroading?



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[DRV KRAWLER]

Paddles, gearing and MORE POWER !!!!!! The first time I saw the Yeti all I could think of was FOFF !

[SilicaStorm]

Now we are talking'

Ok Paddles for sure,,,, on order below

Rear: Pro Line Sling Shot 2.2
Front: Pro Line Sand Paw 2.2

So for gearing on the Yeti,,, what ratio gets NASA launch capabilities with some 3S packs ?

Then the juicy part,,, yum yum,,,, more power,,, motor and anything else to go with a new motor,,,, recommendations to a good fit for the Yeti ?


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[Zarizi Tech]

Originally Posted by SilicaStorm

Now we are talking'

Ok Paddles for sure,,,, on order below

Rear: Pro Line Sling Shot 2.2
Front: Pro Line Sand Paw 2.2

So for gearing on the Yeti,,, what ratio gets NASA launch capabilities with some 3S packs ?

Then the juicy part,,, yum yum,,,, more power,,, motor and anything else to go with a new motor,,,, recommendations to a good fit for the Yeti ?


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I would definately go with Proline 2,8" Sand Paws for Yeti, cause that thing is HUUUUGE. And Castle power you can trust!

[SilicaStorm]

Some Castle Power eh ?

.... How about a Castle Mamba Max Pro - ESC ???

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.... and what kV motor would be perfect for FOFF, compatible with the Yeti and can take the hot climate and sand environment here in the United Arab Emirates desert.... ?


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I want this Yeti to fly off the tops of dune crests !

[Zarizi Tech]

Originally Posted by SilicaStorm

Some Castle Power eh ?

.... How about a Castle Mamba Max Pro - ESC ???

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.... and what kV motor would be perfect for FOFF, compatible with the Yeti and can take the hot climate and sand environment here in the United Arab Emirates desert.... ?


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I want this Yeti to fly off the tops of dune crests !

I've been in Dubai couple of times and I noticed that it might just be too hot to run anything long sessions. But I would say 5700kv motor with 3S and it'll fly.

[SilicaStorm]

Thanks Zarizi,,

Yes definitely when the outside ambient temps are +35,,, its too damn hot for me to be out there too,,,,

But I would hope early mornings when temps Sept - April are around 28 - 33 degrees celcius should be the same as the guys running in southern USA.

will do some research on the 5700kV Castle and Mamba Max Pro,,,

thanks again,,,,


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[SilicaStorm]

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Anyone building a Yeti for FOFF ?


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[alexchen86]

If I were to build an FOFF and still have a fun rig to bash around with a simple tire switch of course run sensored brushless.

MMP + Tekin Pro4 HD 3500kv + probably a quick Savox servo coupled with a CC BEC. 32p gearing of course. Sensored brushless on 3s is ballistic. Just with the MMP was a tad smaller but the fan does a great job keeping the ESC cool.

[SilicaStorm]

Originally Posted by alexchen86

If I were to build an FOFF and still have a fun rig to bash around with a simple tire switch of course run sensored brushless.

MMP + Tekin Pro4 HD 3500kv + probably a quick Savox servo coupled with a CC BEC. 32p gearing of course. Sensored brushless on 3s is ballistic. Just with the MMP was a tad smaller but the fan does a great job keeping the ESC cool.

Thanks Alex,

I am as you can see a noob to RCC and still trying to get my head around gearing. You mentioned 32p gearing.

Originally Posted by Harley

I'll attempt to aggregate all the info from the build threads, manual and personal experience here for easy reference for anyone buying/building their Yeti's.

Measurements

Front Links (eye to eye)
Steering Links: 77mm
Caster Links: 77mm

Rear Links (eye to eye)
Trailing arms: 140mm
Front to first shock position: 78.5mm
Front to second shock position: 102.5mm
Upper links: 145mm


Front Shocks:
Extended: 92mm
Compressed: 70mm
Shock travel = 22mm
Front springs = 54mm @ 4.33lbs/in (Yellow)
Preloaded spring length = 45mm
Preloaded spring compressions = 9mm = .37"
Preloaded spring force = 1.60 lbs
Compressed spring length = 23mm
Total Spring Compression = 31mm = 1.22"
Compressed spring force = 5.28 lbs

Rear Shocks:
Extended: 128mm
Compressed: 85mm

Wheelbase: 14.25"
Front Track width: 12.75"
Front Track width with Vanquish SLW 225 Hubs: 12.25"

Battery Compartment size:
49.3mm Wide x 150mm Long x 23.2-35.2mm Tall (adjustable)

Parts Compatibility

Exo Compatible Parts
Front Bulkhead – AX80091
Diff Case – AX80002
Diff Gear Set – AX30390
Input Shaft (Diff Pinion) – AX30408
Differential Gear (Ring and Pinion Gear) – AX30392
Steering Knuckle Kingpins – AX30382
Exo Heavy Duty Differential Input Shaft (dog bone cup on the T-case) – AX30383
Exo Heavy Duty Differential Output Shaft (dog bone cup for front axle) – AX30381
Exo Dogbone 7x96 (front axle shafts) – AX30418
Front Suspension Arms – AX80111
Front Steering Knuckle Carriers – AX80106
EXO RTR Links – AX80119

EXO Compatible Option Parts
Universal Front Axles - AX30415

Wraith Compatible Parts
AR60 OCP Axle Housing – AX80069
AR60 OCP Differential Cover (also includes link mounts and bearing caps) – AX80070
AR60 OCP 4-link Mount – AX80072
AR60 OCP Straight Axle Adapter – AX80071
AR60 Rear Axle Shafts – AX30776
Input Shaft (Diff Pinion shaft) – AX30408
Differential Gear (Ring and Pinion Gear) – AX30392
Diff Case – AX80002
Heavy Duty Locker – AX30500

Y-380 Cage/Body Parts
Cage Top, Rear and Tire Carrier – AX31117
Cage Front and inserts – AX31116
Cage Sides – AX3115
Clear Body – AX31140
Clear Interior – AX31141
Driver Heads – AX31049
Exo Rear Light Bezel and Radiator set – AX80103
Required Hardware to complete body
AXA0437 x 2 = 20 screws (12 needed)
AXA436 x 1 = 10 screws (6 needed)
AXA0422 x 2 = 20 screws (16 needed)
AXA435 x 1 = 10 screws (2 needed)
AXA117 x 1 = 10 screws (3 needed)
Total Weight - ~12 ounces


Transmission Parts List
Spur Gear Cover - AX31107
Motor Mount - AX31106
Case - AX31108
Top Shaft - AX31127
Bottom Shaft - AX31129
Internal Gear set - AX31130
Transfer Case Gear set - AX31131
Transfer Case Output Shaft - AX31134
Spur Gear - AX31065
Slipper Pad - AX31068
Slipper Spring - AX30413
Slipper Plate (front) - AX31059
Slipper Plate (rear) - Ax31067
5x11x4 Bearings (x10)
4mm E-clips (x2) - AXA1391
2x10mm Gear Pin (x2) - AX30163
2x11mm Gear Pin (x1) - AX31028
M3x18mm Countersunk Screw (x4) - AXA148
M3x25mm Countersunk Screw (x2) - AXA150
M3x12mm Countersunk Screw (x1) - AXA146
M4x12mm Caphead Screw (x2) - AX31121
M4 Washer (x2) - AXA1071
M4 Locknut (x1) - AXA1045



Gear Ratios
Stock Pinion and Spur: 16/64 = 4:1
"Inside" Transmission: 26/28 = 1.08:1
Transfer Case" 15/15/27 = 1.8:1

Overall Gear Ratio with different pinion and spur ratios
Attachment 290181

Transmission Gearing Comparison of Yeti to Wraith

Yeti Transmission w/o pinion and spur: 1.94:1
Wraith Transmission w/o pinion and spur: 2.6:1
Yeti Transmission with 16/64 gearing: 7.75:1
Wraith Transmission with 20/80 gearing: 10.4:1
Yeti Transmission with 12/64 gearing: 10.3:1


Rear Sway Bar
Arm Length: 2.5"
Overall Width: 4.75"
Width between mounts: 3.5625"
Sway Bar Links: 2.25"


Fuel Cell
A larger version of this image can be found on Page 3 of this thread
Attachment 290234

Harley Sticky above has detail but looking at it I can not determine which ratio is applicable for FOFf and high speed dune bashing ?

I have no intention of rock crawling as there are no rocks in the Arabian desert .

Since I am waiting for my pre-order i would like to have all parts ordered and waiting to install on the Yeti arrival which looks like another month. (but thats not the topic)

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[stelerzman]

It's not that easy to pick gear ratios, especially on a new vehicle. Trial and error will need to be applied. Your idea of perfect will be different then my idea of perfect, on anything.

Heres my 2cents. If your not gunna go slow, there is no need for sensored motors, it will save you a little money that you can put towards a good range of gears. 32p is definitely the way to go. When I when this way I got a 54,56, and 58t spur gear from Robinson Racing. I also got a range of pinions. Look into 12 through 18t , all even tooth count pinions. No need to buy every pinion, just every other. This should give a cool to hot setup

Another piece of info, keep a close eye on temps. If you don't already have an inferred temp gun then get one before you start running. If you get too hot too fast, you can burn up the motor and esc rather quickly. I've been there done that.

Good luck on you build.

[stelerzman]

Oh and if possible, get the 2.8" tires paddle tires. They will took much better then the 2.2".

Look around this section for some pic's and see if you agree.

[SilicaStorm]

Originally Posted by stelerzman

Oh and if possible, get the 2.8" tires paddle tires. They will took much better then the 2.2".

Look around this section for some pic's and see if you agree.

Thanks Stelerzman,

Some good advice there,,, I have purchased online a laser temp gun,,, what temps should i be weary of regarding the motor?

Here in the Arabian desert during certain months can be an issue, but running early mornings can avoid high temps;but actually monitoring the motor temps i will be critical as you have pointed out !

cheers,

[BuhBoombuh]

TTIUWP

[stelerzman]

Originally Posted by SilicaStorm

Thanks Stelerzman,

Some good advice there,,, I have purchased online a laser temp gun,,, what temps should i be weary of regarding the motor?

Here in the Arabian desert during certain months can be an issue, but running early mornings can avoid high temps;but actually monitoring the motor temps i will be critical as you have pointed out !

cheers,

It will depend on the type of motor, but in most cases keeping the motor under 160°. This temp will be concidered HOT. Keeping the motor under 160° and lower will allow you to run the motor a lot longer and not burn it up. A friend of mine ran a 13.5t brushless motor to over 220° and it lasted about 2 more hours.

Good luck.

[evan03]

I found little help from Harleys threads.


5700 kv for a rig slated for a super hot climate.

If mine I'd probly fit a sensor ed 2650 kv motor in it and run a RX8 esc esc along with some 6s 1800-2200 batteries. Youl get about 15 minutes run time and be running efficient and cool probly close to out side air temp.

I would invest in a good temp gun. I'd tune gearing so motor temp is running 10 degree over outside temp

DrI ing style greatly influenced heat generated. What works for Harley is nor going to work for everyone.

I come frome rc helis and planed where the pilot build and tunes each aircraft not to a sticky on website.

Harleys guides are guides they are starting points. You may need to do no tuning from this starting point or you may need to tune from it a lot

[BCK]

From experience I can tell you that if you're gonna run 6S in a hot climate, don't run more than 2000kv with a long 550 sized motor (same as stock motor size).

Due to the IMMENSE start up current required, 5,700kv is for 2S only. Castle and Tekin both advise its a bad idea ,running higher voltage at such high kv as you'll fry your electrics with high load running. The amount of esc's and motors ive killed running 4,000kv+ on 3S is testament to that, and I run everything from beaches, to grass, to gravel.

If you want off-tap power then I suggest a PRO4-HD Tekin thats around 2000kv on 6S, or run a motor around 2600kv on 4S for longer run times.
Tune to make use of the torque.

As for gearing, just buy a bunch of different sized pinions that are larger than stock, and a a Robinson racing Steel spur gear that's a size smaller than stock, as with high power you're gonna need the stronger spur.

Then tune it so motor temps don't exceed 170deg F.

As long as the driveline holds up and has been modified to handle the power, it'll fly with the above setup.