LRP Spher comp and B4

[chris68nufc]

Just got delivery of LRP Sphere Comp and was wondering if somebody knows the best starting pinion/spur ratio with a sintered 4.5 motor?
I know you have to gear them lower than a brushed motor but a bit of advice would be appreciated. Thanks.

[bigred5765]

4.5 is way to hot for most cars in uk on uk tracks
u would need a 12 -13 tooth pinion

[burgie]

yep, i agree with Carl.

I run an LRP Sphere (original) with a 3 star motor in it (9t equivalent), and that, in fairness is on the verge of too quick for a 2wd. It's certainly too quick for me to be fast with it, if you see what I mean.

[Rob]

No way should you be running a sintered 4.5 in a 2WD. Last year I tried a bonded 5.5 it was just about controllable in the dry but if it was slightly damp the car was undrivable. I've now got a 6.5 in and its a lot better.

[jimmy]

Ignore them Chris! bet it will be a good laugh! haha

[paulc]

Originally Posted by Rob

No way should you be running a sintered 4.5 in a 2WD. Last year I tried a bonded 5.5 it was just about controllable in the dry but if it was slightly damp the car was undrivable. I've now got a 6.5 in and its a lot better.

hi all
rob what pinion do you use for the 6.5 and is that with the standard spur gear 81t ?? i also have a lrp 2 star i think about a 22 to 81 sounds about right ??

cheers paul

[chris68nufc]

Maybe i have made a mistake then. Surely i can tame the 4.5 until i get a different motor? Forgive my ignorance but do i need to use a larger spur than kit 81 to give me the correct ratios for 2wd? Thanks.

[bigred5765]

81 15 would give you a overall ratio of 13.5 so close to what novak say you should be on
i think

to work out your ratio it spur diveded buy pinion times internal ratio (2.5)i believe on the b4

[chris68nufc]

Excellent.Couldnt find internal drive ratio in manual. Tried it out in the street tonight and it is quick. Bought it for my xx4 but it might destroy it after 1 lap with the power.

[LEGEND]

Hello

On my B4 i run a 3* lrp brushless system and i run a 81 tooth spur with an 18 tooth pinion and it is spot on, never failed me yet.

[bigred5765]

Originally Posted by LEGEND

Hello

On my B4 i run a 3* lrp brushless system and i run a 81 tooth spur with an 18 tooth pinion and it is spot on, never failed me yet.

are you talking about the old lrp 3star motors
if u are there different to the new sintered rotor in novaks.and cant be compared at all

[mark christopher]

Originally Posted by chris68nufc

Maybe i have made a mistake then. Surely i can tame the 4.5 until i get a different motor? Forgive my ignorance but do i need to use a larger spur than kit 81 to give me the correct ratios for 2wd? Thanks.

4.5 turn is roughly a 5 turn brushed

[chris68nufc]

Is there a setting on LRP Sphere Comp to turn the power down or do i need to get a different motor?

[Col]

Chris, I don't run brushless yet, so don't take it as gospel: You cannot turn "power" down, just punch (so it will still go Xspeed, just take longer to get there) This is what I did with my Quantum 2 while I was getting used to a new car, speedo and motor combo and t worked for me

[Chris Doughty]

I run an LRP 6.5 bonded motor on 20/84, I think this is a little over geared but it worked well at Tivvy.

a 4.5 Sintered can be geared higher than a bonded rotor brushless motor, it is able to produce more torque.

start out on something like 17 or 18 on the stock 81 spur.

you can turn the punch down a bit, but the motor will still be killer fast, look at the sphere manual and change the 'ADPC' setting to its lowest.

also with a sintered rotor, turn the initial brake and drag brake down a lot.

[chris68nufc]

Can you recommend a starting setup for the LRP with a 4.5 in it or do i run factory settings? I dont get any time to try speedo setups so i dont fancy doing it whilst trying to do well at Regionals etc.Thanks. Chris.

[Chris Doughty]

I have not actually run a 4.5 in 2WD, but I would start with this

2-1-1-0 (asuming you are running nmhi cells)

[chris68nufc]

Thanks Chris.Will give this a whirl at the weekend. On another note. Would the speedo stop working if i had cells that were dead in the car?I was trying in the street last night and it stopped for no reason. I put newly charged cells in and it seemed fine? Thanks for the help.

[Chris Doughty]

yes, that would be the low voltage protection cutting in. set 'option' one to be setting '2' as in '2'-1-1-0 and this will stop this.

make sure you change it back to '1' ('1'-1-1-0) when running LiPo.

hope that makes sense

[AndyM]

what setting do people usually use with a nosram 2007 edition speedo, 6.5 motor outdoors in a b4/x6 etc.

cheers