i know that all buggies have a user manual, ou can see here the reference if not you can use a good
remove the vehicle part, then count the number of
teeth, then compare it with 17 teeth pinion and 5 mm of diameter.
if you cant identify this, it is very capable to use a 14t metal gear.
unless your 1/8 has a 24 p pinion gear ( very un common ) it should fit , measure your motor shaft if it is 5mm it will more than likely be 32p .. its 2 buck s buy it with the rest of your order if it does not fit you lost 2 bucks ... :).
You have three questions in one. 17T => depends on your motor, google for a reference (motor with same Kv) and look for gear specifications. 5mm => depends on your motor, measure the shaft. 32 Pitch. This depends on the Pitch of your spur gear. These sould match. Google for the specs of the Spur gear and find out what the Pitch on this gear is!
these pinions are for 32p/mod.5 and are for hugely powered brushless motors. if you want one like the one you want, you will need to go to your lhs or to ****************. they will have what you are looking for.