Hinge Pins and Reinforced Sheets: Your RC Suspension FAQ
By BEZGAR | Published: 2026-11-02
Category: Product Reviews
Straight answers on lower suspension arms hinge pins, reinforced sheet wear, and when a front and rear hinge pin set is the right fix for HP161-series RC cars.
Quick answer
If your HP161, HP161S, or HP163S has play at the arm mounts or a scored hinge pin, replace the pins and reinforced sheets together with the original M25425+M1640 (M1641+M1642) set. Matching the part number is the safest way to restore a tight front and rear suspension.
Why pins and sheets should be judged as a pair
A hinge pin and its reinforced sheet wear against each other. A new pin dropped into a wallowed sheet still rocks, and a fresh sheet over a grooved pin wears quickly. That is why the original set bundles front and rear hardware rather than selling one corner at a time.
This also explains the honest limitation of the listing: it does not publish pin diameter or sheet thickness. If you are mixing parts from other models, measure your old pieces before ordering rather than assuming they interchange.
When replacement is the wrong first move
If the arm itself is cracked or the mount on the chassis is deformed, new pins and sheets will not fix the play. Inspect the arm and chassis mounting points first. Also skip replacement if the play comes from a loose screw or a missing spacer, because hardware torque is a separate check from pin wear.
Common questions about hinge pins and reinforced sheets
- What are the early hinge pin wear signs?
- Look for visible slop when you wiggle the arm up and down, a dark ring of grit around the pin, or a groove you can feel with a fingernail. A pin that has worn through its finish will keep accelerating wear in the sheet. Check both front and rear arms; wear rarely stays on one corner.
- Do I need the front and rear hinge pin set or just one end?
- If one end shows play, inspect the other before ordering. The original set covers front and rear together, which is practical when both ends have seen the same run time.
- Will this set fit my HP161S or HP163S?
- The catalog lists HP161, HP161S, and HP163S as applicable models. Confirm your model and part number before ordering, because the listing does not publish dimensions for cross-fitting to other chassis.
- What else belongs in a suspension rebuild?
- Clean the mounting holes, check the arms for cracks, and replace any bent screws. Pins and sheets restore the pivot; they do not repair a damaged arm or chassis mount. If the arm or mount is damaged, fix that before judging pin fit.
Product facts
- Lower Suspension Arms Hinge Pins(F&R) and Reinforced Sheet(F&R): Original spare part number M25425+M1640 (M1641+M1642), listed as 100% applicable to HP161, HP161S, and HP163S. Ordering by this number avoids the guesswork of matching hinge pins by eye.
Lower Suspension Arms Hinge Pins(F&R) and Reinforced Sheet(F&R)
