Modding a Flux Centre GearBox.

[FR Rayward]

Now what I'd really like to do is modify my Savage Flux centre gearbox to make it lower, lighter, and simplify it. I am working on using just 3 gears (a pinion, a spur and an idler gear) from the drivetrain to the motor. Is this possible?

Here I have my current gear setup:

Differential Ratio: 3.2222222222222223
Transmission Ratio: 2.215277777777778
Spur Tooth Count: 44
Pinion Tooth Count: 24
Total Voltage: 22.20
Motor KV: 2200
Spur/Pinion Ratio: 1.83 : 1
Total Ratio: 13.08655 : 1
Rollout: 1.40:1
Total Motor Speed: 48840 RPM
Vehicle Speed: 64.84 mph (104.16 km/h)

Ok, so if I keep the lowest gear in the CGB, a 29t idler gear, and pair it with a 20t spur and a 10t pinion, I get these figures:

Differential Ratio: 3.2222222222222223
Transmission Ratio: 2.1
Spur Tooth Count: 20
Pinion Tooth Count: 10
Total Voltage: 22.20
Motor KV: 2200
Spur/Pinion Ratio: 2 : 1
Total Ratio: 13.53333 : 1
Rollout: 1.36:1
Total Motor Speed: 48840 RPM
Vehicle Speed: 62.7 mph (100.72 km/h)

Am I correct in tapping in a 2.1 trans ratio, with the idler and the spur at 29t and 20t, or should it be 1.9?

So it would look like this, looking horizontally along the chassis.

Will these 3 gears be ok to power a 6S flux?

Am I going to get the motor lower or the same height it is stock, or not?

Another one I just thought of, do I need to add a slipper clutch into this design? At the moment, I have cranked down my spur slipper nut (3 of them, all locktite'd) as hard as I possibly could, and haven't had any CGB fails yet.


All these questions even before I start working on the gear mounts and the motor sliding mounts haha..

So, opinions, comments, tips, please roll them in!

 

[FR Rayward]

Sorry, I messed up the spur/trans gear ratio calculations.

Uh say we use the stock spur to the 29t idler:

Differential Ratio: 3.2222222222222223
Transmission Ratio: 1.52
Spur Tooth Count: 44
Pinion Tooth Count: 16
Total Voltage: 22.20
Motor KV: 2200
Spur/Pinion Ratio: 2.75 : 1
Total Ratio: 13.46889 : 1
Rollout: 1.36:1
Total Motor Speed: 48840 RPM
Vehicle Speed: 63 mph (101.2 km/h)


Have I made it better or worse??

 

[FR Rayward]

Did it.. No help from you guys though cornfused

 

[Shaun]

maybe no one has done it so didnt want to comment lol thats why no replies but who knows? great job on figuring it all out on your own and posting it for others!!!!

 

[Cwheeling]

First I have seen this! Let us know how it holds up!

 

[FR Rayward]

maybe no one has done it so didnt want to comment lol thats why no replies but who knows? great job on figuring it all out on your own and posting it for others!!!!

Thanks Shaun. I took it for a pretty hard bash yesterday, it took it no worries. Time will tell I guess. I saved about 200g of top heavy weight with this mod.

 

[Ascender]

Looks like you really need to spend a little cash on some TVPs.

TCS makes an really nice set that is super-strong: http://www.tcscrawlers.com/TCS-5mm-Chassis-for-HPI-Savage-Flux-Black-p-17756.html

If you look around the site, they also make several different colors, and XL-length TVPs, as well.

 

[grumpygramps]

Looks like you really need to spend a little cash on some TVPs.

TCS makes an really nice set that is super-strong: http://www.tcscrawlers.com/TCS-5mm-Chassis-for-HPI-Savage-Flux-Black-p-17756.html

If you look around the site, they also make several different colors, and XL-length TVPs, as well.

????

I think TVP's are about the last thing on this guys mind, for a good reason!

@ FR Rayward- Would be great to see some better pics of the mods, if that's possible? From the pics it looks like the tranny is basically open now, is that not causing any issues with debris getting in? Good on you for trying something new BTW buddy!

 

[frddyj]

maybe no one has done it so didnt want to comment lol thats why no replies but who knows? great job on figuring it all out on your own and posting it for others!!!!

i agree shaun. id like to see some better pics of the work, i find it interesting.

ive not come across anyone interested in attempting a mod like this to make a savage lower and lighter until FR Rayward came up with the idea which is prob why no one commented on it.

i also see the idea of a center diff on a savage come up in conversation from time to time; usually doesnt get a lot of replies either as it presents other problems (like having to rework an idea for front brakes) and usually ends up being more trouble than its worth on a savage.

????

I think TVP's are about the last thing on this guys mind, for a good reason!

i think ascender was just trying to ponit out the next and most-common failure point on a savage and its the stock tvps. ive seen them bend VERY easily on nitro savages never mind adding the speed and stress of 6s.

based on the ease of failure of stock tvps, I'm not seeing your point on "a good reason" not to upgrade them? :dunno: