81t spur vs. 87t spur gear

[chokoboy]

Had my b-max for some weeks but not started building it before now since my champions pack arrived today!
Im going to run a Tekin 7.5 sensored brushless motor and my question is should i use the stock 87 spur or the champions pack 81t spur gear?
Looking for some positive replys!

[traffman]

Its up to you , i fitted the champ pack 81 spur , but you cant go any lower than a 21 tooth , a 20 tooth may just catch it but i had enough trouble meshing a 21 tooth properly.
I tried the 87 spur and fitted a 17 tooth . I then returned to the 81 tooth spur and thats what im going to continue to use.

[sosidge]

Originally Posted by chokoboy

Had my b-max for some weeks but not started building it before now since my champions pack arrived today!
Im going to run a Tekin 7.5 sensored brushless motor and my question is should i use the stock 87 spur or the champions pack 81t spur gear?
Looking for some positive replys!

Unless you are on a really big track or use a mild motor you are going to struggle to get a good ratio with the 81 spur.

I would probably build with the 87, if you just can't get enough top end, try the 81. Danger of building with the 81 is that you will cook the electrics before you have had a chance to get the right ratio.

I'll just post the ratios you can get...

87/17 = 12.02
87/18 = 11.35
87/19 = 10.76
87/20 = 10.22

81/21 = 9.06
81/22 = 8.65
81/23 = 8.27
81/24 = 7.93
81/25 = 7.61

There is also an 84T spur listed (don't know if it is out yet) which would fill that big gap in the ratios nicely.

[chokoboy]

Thanks Sosidge...ill go for the stock 87t first

[Pedros20]

I ran mine wednesday for the 1st time, with the 87t spur & 18t pinion.
It was a quite open indoor track, i found it to rapid out of the corners, & more than fast enough down the straight & the electrics came off cool.
Its a superb car! You'll love it!