strange pinion problem
 

hi everyone. i own a non worlds bj4 and have fitted an LRP Sphere comp 2007 with an x11 6.5t motor. i was told to run a 14t pinion but when meshed correctly the motor is too close to the drive cup which is rubbing against the motor :wtf:. has anyone got any solutions?? or ideas/reasons?

thanks very much

14 is a bit small

i run a 19 pinion with my 4* (bout 5.5 i believe)

see what others say

what size spur are you running ???

i think its a 78 but am not fully sure

well i used to run my 6.5 in my S4 (same drive train as bj4) on a 18/81 so if your running a 78 spur the put it on a 17 or even an 18 ..

78x17 would give you a overall ratio of 10.323
which isnt to fare of for a 5.5 4*

ive got 78x17 as a ratio of 11.47 ??? thats for an S4

Sounds a bit over geared does that carl??
Last year I was told to run 13:00 overall ratio by Jurgen himself with the 3star. thats a 15t pinion on the Worlds car. At the weekend I was running the 5.5 motor in my Tamiya 501X with 12.6 ratio (15/87)

so are you saying i need a 16/17t pinion with my x11 6.5 and 78 spur??

yes matt , thats what i would be looking at running. try 16 1st see how you get on ..

sorry for this but the spur is actually a 72

so im guessing by that the 14t pinion is actually correct then :wtf:. so has anyone got ideas on what i could do to stop it rubbing on the drive cup??

okay, im very confused now lol

i would change the spur to be honest matt ..

same i would put the spur up to something like 78 or even 81. Then i would increase thje pinion size by a few to around 16-17 maybe higher.

this is on my non-worlds car, and am not sure a 78 or 81 will fit as the 72 is almost level with the chassis already

Get a Worlds Edition!

I never ran anything smaller than a 17t on the origonal car but I think that fitted no problem. Based on how I've been gearing my 5.5 recently i the WE you might get away with a 15t, but 14t is what you want to gear it on really.

I think RW make some white machined spur gears that you can get in 73/74 ect that would fit, so long as it doesnt stick out below the chassis you'll be fine.

i would, but they cost more money, of which i dont have :(. with a 14t pinion i get a final drive ratio of around 12.85 which is bang in the middle of what LRP recommend, with a 15t it comes out at 12, will this still be okay?? as LRP suggest 13.5:1 for high traction tracks and 12.5:1 for low traction tracks.

I gear my 5.5 X11 at 12.65 (16/81 in the WE).

12:1 might be a bit on the high side, put the smallest pinion you can fit on and run it for a minute or so, stop and check how hot it is.

do yoo think it will be ok if i fit a fan to the motor?