Question:
Hey Doc,
My name is Edzry and I live in Malaysia. Can you give me some tuning tips for racing my HPI Baja 5B on grass and hard-packed dirt. I would like a basic setting that will work on both so I don’t have to make many changes.
Thanks
Edzry
Answer:
Hi Edzry,
The HPI Baja 5B is one of my favorite vehicles to race. While these two surfaces (grass and dirt) are quite different, the biggest common denominator with the two is bumps. I would start with something like HPI 40wt fork oil in the front shocks (with a 3-hole piston) and something like HPI 10wt fork oil in the rear (with a 16-hole piston). This should work well in most cases. You can go up or down with the oil depending on track conditions. I typically run the stock black front springs and black rear, dual-rate springs. For a little softer ride, try a yellow upper rear spring.
Anti-roll bars front and rear will help with the responsiveness of the 5B, but could affect handling if the track is too bumpy. If the track is really bumpy, remove the bars and the buggy should be alot easier to drive.
Tire choice is also key, and one of the biggest tuning aids on the 5B. For grass I would try something like the Hot Bodies Proto tire. This tire has nice, large knobbies to dig deep into thick grass or loamy dirt. For smoother track (or hard, compressed grass), try the Hot Bodies Khaos tire. For the fronts, the Hot Bodies Double Blades tire seems to be the hot ticket at most tracks. If you have to much steering, try throwing on the stock HPI 5B tire. I’ve found that doing this really settles the car down if the front is too aggressive.
Another key thing that works great but people don’t try is the clutch spring. All of HPI’s big scalers now come with the red, heavy-duty clutch spring. This spring creates alot of ‘snap’ on the bottom end of the Bajas, but can sometimes be too much, causing the rear tires to break loose and pitch the rear end around. On all of my Baja’s I’ve started running the older, softer clutch spring. The bottom end is MUCH smoother and easier to drive.
The HPI Baja 5’s don’t have alot of tuning other than that; you can play with front caster but that’s about it. I hope this helps! Good luck!
The Doc
