G-18 Gear 10312: Match the Assembly First
A small yellow gear is easy to order by color and still get wrong. Tamiya item 10312 is a ten-piece pack of G-18 gears, described as spares for specific chassis and for items 15434 and 15456. It is a replacement part, not an entire gear train or an automatic ratio change. Identify the installed gear, its companion components and the kit's drivetrain drawing before opening a new packet.
Read the compatibility statement exactly
Tamiya names Super X, Super XX, Super TZ, Super TZ-X, AR and Super-II chassis, plus items 15434 and 15456. That list is more useful than saying the gear fits ‘Mini 4WD’ generally. The official ratio matching table can help locate the full gear pairing, but it does not make every yellow gear interchangeable. If the car was modified, inspect what is actually inside it rather than assuming the original ratio remains.
Diagnose before replacing
Switch the car off, remove batteries and open the gearbox according to the kit instructions. Check the G-18 gear for missing teeth, cracks or a rounded engagement surface. Also inspect the mating gear, shafts and cover for rubbing or debris. A new spare can fail quickly if a distorted shaft or mis-seated cover caused the original damage. Keep old and new parts side by side until you verify their shape.
Reassemble a known pair
Use the kit drawing to preserve gear order and orientation. Turn both axles by hand before powering the car, then run briefly and listen for a new scrape. Label the remaining G-18 spares by item number. Do not advertise a faster lap from a same-part replacement; track performance needs a measured, controlled comparison.
Check current availability and the exact variant on the product listing before ordering.
Related reading
Frequently asked questions
How many G-18 gears are in 10312?
Tamiya labels the item as a ten-piece pack.
Is 10312 a complete 5:1 gear set?
No. It is a G-18 spare; confirm the full pairing in the kit instructions and official matching list.
Sources checked 26 September 2026: https://www.tamiya.com/english/products/10312/index.html, https://www.tamiya.com/cms/english/mini4wd/pdf/gr_table.pdf. Recheck product availability before ordering.