My FLM Savage Build

[lincpimp]

Originally Posted by tonkabilly

The packs are 160mm x 51mm x 46mm. They just fit in without touching the spur. Have maybe 1/2" to spare. The biggest problem is the width. I am now seeing what you said about them being too close to the motor. Once I get the Medusa in that will be the determining factor as to what needs to be done.

Well, you can put them in on their side, so they will be 46mm wide. The medusa is 36mm wide. If you can put the pack in and measure the distance between the center of the spur gear, and the edge of the pack where the motor would touch it. I should be able to calculate what distance you have left, and we will see what gearing you could run.

Also, can you list your motor and tire height again, and if you plan to run the 2 speed and mech brakes, or lock it in either gear? That will help with figuring the correct gear ratios...

I had to do this with my flm chassis and ended up with the 52t spur to get adequate clearance for the lipos.

[tonkabilly]

Will try that when I get home from work tonight and see what we get. As for the spur, I was already planning on using the 52 just for that reason. Have plenty of 47, 49 and 52T spurs with a 14, 15, 16, 17 and 18 pinion already so I do have some options on this.
Thanks

[lincpimp]

Originally Posted by tonkabilly

Will try that when I get home from work tonight and see what we get. As for the spur, I was already planning on using the 52 just for that reason. Have plenty of 47, 49 and 52T spurs with a 14, 15, 16, 17 and 18 pinion already so I do have some options on this.
Thanks

Just let me know, Thanks!

[tonkabilly]

Well I think all the best laid plans just went to hell. I put the motor in and it touches the battery using 52/17 gears. I think I am going to have to start over. I think 4s will be the way to go. Now just have to figure out if I keep the Medusa (1600kv) and the ESC. From what I read the motor might be a little lacking? Should I go up to a 2000 or 2200KV motor?

[lincpimp]

Originally Posted by tonkabilly

Well I think all the best laid plans just went to hell. I put the motor in and it touches the battery using 52/17 gears. I think I am going to have to start over. I think 4s will be the way to go. Now just have to figure out if I keep the Medusa (1600kv) and the ESC. From what I read the motor might be a little lacking? Should I go up to a 2000 or 2200KV motor?

For a heavy truck 6s is better... Did you try the battery both ways, as it is narrower on its side? Also you can put spacers under the motor mount, which raises it up so that the motor shaft is closer to the center line of the spur, where the spur is widest. I have seen people do this to gain clearance between the motor and batteries.

If you go with the flux center shaft for the tranny it effectively locks it in 1st, which will require a larger pinion to get the correct top speed...

I will plug some numbers in to the calc.

you have 6s lipo, a 1600kv motor and something like 6" tall tires, correct?

[tonkabilly]

Yup. Set-up is Medusa 1600, 6s Lipo, and I have Proline Holeshot MTR tires. I would like to stay with 6s but there is just no space for the two. Obviosly I have some tinkering to do but just can't see this working without reducing the Lipo size to at least a 5s?? Yes I did flip the batteries.

[lincpimp]

Ok, if you run the flux center shaft/gear in the x tranny, pn hpi100905, it is just like locking the X tranny in 1st gear.

With that tranny ratio and your 6s/1600kv combo you could run a 52/25 spur/pinion combo. That would get the motor well away from the tranny. If the motor mount does not have enough adjustment, you could go with a 47/23 spur/pinion setup and that would yeild the same ratio (about) I figured that you are using 40 series bowties (by the pics) which are around 5.75" tall.

Set the motor and mount up with out a pinion, and place the battery in the chassis, adjust the motor as close to the battery as you feel comfortable (leave 1-2mm between) and measure from the center of the spur gear to the center of the motor shaft.

The 52/25 combo would place the center of the motor shaft about 40mm from the center of the spur, the 47/23 would give around 37mm. Your 52/17 combo is about 36mm, so the 52/25 would most likely get the job done.

Plus you only need to buy the flux center shaft/gear and the 25t pinion from mike, (25-30 bucks for the 2) which is much cheaper than another lipo or motor...

Calc info for the 52/25 gearing with flux tranny ratio:

Differential Ratio: 3.3076923076923075
Transmission Ratio: 2.215277777777778
Other Ratio: 1
Spur Tooth Count: 52
Pinion Tooth Count: 25
Total Voltage: 22.2
Motor KV: 1600
Tire Diameter (inches): 5.75
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0
Spur/Pinion Ratio: 2.08 : 1
Total Ratio: 15.24111 : 1
Tire Circumference (inches): 18.06 inches (458.83 mm)
Total Motor Speed: 35520 RPM
Vehicle Speed: 39.87 mph (64.04 km/h)
Effective KV Value: 1600

If you have room you can run the smaller 49-47t spurs to up the speed a bit...

I went thru all of this with my flm chassis savage... Hope the info helps! And keep in mind with the flux internals on the tranny you can use motor brakes and motor reverse, instead of mech brakes.

[tonkabilly]

linc, you rule
I will give this a try and order some extra parts and see what I come up with. Thanks for the help. Didn't think about the extra size on the pinions
Just mean another 2 weeks before this thing is running.