Diff Weights for MT10

[ahr43]

Hey guys, need help. Standard diff weights for the MT10 are 60K - 100K - 3K (Fr - Ctr - Rr).

Did a speed run session on grass yesterday and the chassis is really uncontrollable. Had to limit passes to 90% throttle and then it was a struggle to keep the truck from oscillating right-left-right at speed. 36kph (~22mph) was the best pass.

Will thicker Rr diff oil help straight line performance? 20K-40K? Not a diff guy, so need help on this one. Thanks. 'AC'

 

[Greywolf74]

Hey guys, need help. Standard diff weights for the MT10 are 60K - 100K - 3K (Fr - Ctr - Rr).

Did a speed run session on grass yesterday and the chassis is really uncontrollable. Had to limit passes to 90% throttle and then it was a struggle to keep the truck from oscillating right-left-right at speed. 36kph (~22mph) was the best pass.

Will thicker Rr diff oil help straight line performance? 20K-40K? Not a diff guy, so need help on this one. Thanks. 'AC'

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Id probably try and bumping up the 3k rear to maybe 15 or 20k and see if that makes a difference. If it helps but doesn't solve the issue entirely then Id try to go to 30 or 40k and see what happens. If that doesn't help at all then you may need to adjust your suspension

 

[ahr43]

Thanks, Greywolf. That gives me a start point. I'll bump up the diff weight in the Rr. AE offers 20K and 30K. Got some AE10K but think that's too light to notice any difference.

Present suspension settings are <-1deg camber Fr and Rr (but not zero). 1/8in toe in. Shock oil may be a bit heavy at 50wt AE all the way around. Thinking drop it down to 40wt AE for grass runs. Want to stay with the P-L Trencher tires if possible. They are belted so won't balloon and upset chassis settings.

The YT vids I've watched regarding diff fluids all focus on cornering. They talk to acceleration a bit. And that is coming off a corner usually. That may be diff talk for straight line running? Regards. 'AC'

 

[Greywolf74]

Thanks, Greywolf. That gives me a start point. I'll bump up the diff weight in the Rr. AE offers 20K and 30K. Got some AE10K but think that's too light to notice any difference.

Present suspension settings are <-1deg camber Fr and Rr (but not zero). 1/8in toe in. Shock oil may be a bit heavy at 50wt AE all the way around. Thinking drop it down to 40wt AE for grass runs. Want to stay with the P-L Trencher tires if possible. They are belted so won't balloon and upset chassis settings.

The YT vids I've watched regarding diff fluids all focus on cornering. They talk to acceleration a bit. And that is coming off a corner usually. That may be diff talk for straight line running? Regards. 'AC'

The main thing diff fluid does is allows one wheel to spin at one rate and the other to spin at a different rate. So the only two places (that I'm aware of) this becomes an issue is on cornering because thats when your wheels will need to turn at different rates and straight line running like drag racing where youd want to run super heavy diff fluid to create a limited slip differential (Posi-trac) in order to keep both wheels spinning the same amount the whole time and hopefully keep you running straight down the track. In corners heavier diff fluid can cause understeer because the inside wheel will still be trying to turn at the same rate the outside wheel is turning. The opposite is true also. To thin on the diff fluid can cause oversteer and issues leaving the corner. I'm not a racer so I'm no expert on diff and suspension tuning but this is my understanding of it. Probably wouldnt hurt to go lighter on the shock oil a bit also, especially if you're not jumping it, or at least not doing full sends. Hope this helps.

 

[WickedFog]

Just looked at the truck, and it may be that those squared off looking tires might be grabbing on the corners during bumps and such. Do you have another set of tires you can try on it just as an experiment?

 

[ahr43]

Just looked at the truck, and it may be that those squared off looking tires might be grabbing on the corners during bumps and such. Do you have another set of tires you can try on it just as an experiment?

Another good point, Kevin. Have a set of P-L 2.8in Demolisher MT's that might work better. The outer edge is rounded a bit more than the Trencher. Either that or sand a radius onto the outer edge of the Trencher. Used to do that with RC drag racing foams to prevent the tire edge from grabbing and snap rolling the car. Good thought. Thanks. 'AC'

 

[WickedFog]

It's was just a thought, but I would be curious to know your results. The Granite has Badlands on it and fairly soft suspension, and it rips through the grass at full speed.

Softening up the shocks a bit might help too. I always like my basher shocks to have thick enough oil to just keep the truck from slapping the chassis on the ground after a jump. If you're only hitting small jumps, I'd drop that oil down to 30 or 40. For springs, I set the pre-load just before it starts to droop, or maybe even just a tad bit of droop. If you can back off the pre-load first before swapping oil, see what that does. Doing both pre-load and oil adjustments at the same time might yeild undesirable results, so test one change at a time.

 

[ahr43]

Ordered a bottle of AE 30K for the Rr diff. That's 10x the weight in there now. Should make for a noticeable difference-good or bad. And its half the weight of what's in the Fr diff. Unsure if a balance between Fr and Rr diff weight is of consequence in speed running. See how it shakes out.

Reset the camber to -2deg all around. That lifts the outside edge of the tire clear of the running surface. See if that helps in the edge grab you talk to Kevin. I could go -3deg if there is an improvement at -2 without sacrificing too much footprint. The Trencher is a wide flat tread.

Appreciate the help and comments, guys. Cheers. 'AC'

 

[WickedFog]

That's a good idea. That might help.

Can you get a video of what it is doing? That would clear things up a bit.

 

[cbaker65]

Hey guys, need help. Standard diff weights for the MT10 are 60K - 100K - 3K (Fr - Ctr - Rr).

Did a speed run session on grass yesterday and the chassis is really uncontrollable. Had to limit passes to 90% throttle and then it was a struggle to keep the truck from oscillating right-left-right at speed. 36kph (~22mph) was the best pass.

Will thicker Rr diff oil help straight line performance? 20K-40K? Not a diff guy, so need help on this one. Thanks. 'AC'

View attachment 154822

Does the truck have sway bars ,MT trucks has what you call the wiggle wobble!..
But yea ,that can be tamed with different fluids ,nice truck!..

 

[ahr43]

ROFLOL. Yeah, Bake, she's got the MT wiggle-wobble! Indeed, the MT10 does have sway bars-Fr and Rr. A redeeming design factor for the platform.

Regarding vids, Kevin. A bridge too far right now as I run alone. Baker, what cam are you using for your vids? Looking at the GNSS pattern of the MT's runs online, I can see how erratic she is. But it's not something I've been able to capture as a doc I could post up.

Summing up, for now it looks like a change of Rr diff fluid and shock oil weights. Those are the big two for the next session of runs. Cheers. 'AC'

 

[WickedFog]

For a vid, you could just use your phone, since all you need to show is a straight line run. Then upload to YT and paste us a link

 

[cbaker65]

ROFLOL. Yeah, Bake, she's got the MT wiggle-wobble! Indeed, the MT10 does have sway bars-Fr and Rr. A redeeming design factor for the platform.

Regarding vids, Kevin. A bridge too far right now as I run alone. Baker, what cam are you using for your vids? Looking at the GNSS pattern of the MT's runs online, I can see how erratic she is. But it's not something I've been able to capture as a doc I could post up.

Summing up, for now it looks like a change of Rr diff fluid and shock oil weights. Those are the big two for the next session of runs. Cheers. 'AC'

Lol..yea yea I know ,I am fixing to get a new one here soon with external mic!..

For a vid, you could just use your phone, since all you need to show is a straight line run. Then upload to YT and paste us a link

I dont have or use a cell phone!..

 

[WickedFog]

I dont have or use a cell phone!..

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I am surprized you even use the internet. But I guess the world has to have a few cool old hipsters out there