Which right angle gearbox for a 80-100?

[DeathBlade]

Well I'm getting rid of my MPIII and going to RC drive the plan it is to use two 80-100's I'm going to press out the origninal drive shaft and put both motors on one chromoly shaft. I will run that into a right angle gearbox (here is were I need some help) on the output of the gearbox I'm going to put a freewheell adapter and put on a white 16T freewheel that will turn either a 32T-48T- 48T or 52T cyclone freewheel crank going to my my stock gears have a 9 speed cassette(11t-34t) in the back. Powering this will be my 12s4p lipo pack of turnigys at 20ah controller is also need to be spec'ed.

I live in a very hilly area of pittsburgh, and I'm overweight (230lbs) and have a XTS downhill frame that weighs a ton(45-60lbs)
Speed isn't a very high concern more for hill climbing capability. ie geared for 15-20mph middle of the cassette

Now for the gearboxes I have my eye on

bayside RS60 gearbox its a 5:1 gear box

second is a GAM Gear DS-TB-055-005G 5:1 ratio

Last is a Alpha SK-100 at 3:1 (this might be to low of a gearing)

So which gearbox do you guys think is the best bet for two 80-100's?

Some of my goofy math.

48v * 130kv = 6240rpm

6240 / 5 = 1248rpm

(6240 / 3 = 2080rpm)

48t / 16t = 3
(52t / 16t = 3.25)

1248 / 3 = 416

 

[comradegerry]

Check out Apex Dynamics offerings.

They have a right angle compact model with a pulley which is neat.

I wanted to buy one, but they did not want to sell to me because I was unsure of the input shaft size.


www.apexdynamicsusa.com

 

[Ratking]

I would not use a angled gearbox since they get very heavy when they have to handle a lot of torque.
I actually bought two gearboxes, but decided to use a belt instead.

A loaded 80-100 130kv motor have approximately 4900rpm at 50-48v loaded, that is what my setup produces.
If you have some serious batteries the sag will be lower and the rpm higher, but the max rpm of the motor will decline with the battery voltage declining.

if you got a lot of money, you could try your idea out, but the gearbox combined with two motors is bulky, where do you plan on having the batteries?
Anything less than 750-1000whr is too little for twin turnigy setup imo. If you plan to use less than that, be prepared to use turnigy A-spec or nanotechs, they are not cheap.

 

[DeathBlade]

I have 960whr of lipo I plan on doubling that soon, as for battery mounting I have a pelican case mounted on the font shock tubes. As for motor mounting I'm putting it underneath the bottom tube inline with the frame. I tried a mount previously that used a belt was to wide kept on snagging my leg on it.
4900rpm load RPM thanks

 

[DeathBlade]

Well looks like I'm going with a bayside RA90 with a 10:1 ratio

ftp://www.compumotor.com/bbs/FAQ/PG_RA.pdf