**NOTE: Before reading further please understand this thread is in no way to imply anything negative about the quality of Taigen 4:1 gearbox. In fact it is a well built item doing what it was designed to do. This thread is about my impression of the performance I have and what I had hoped for.
Been running my Heng Long M26 now for a few months after it was rescued and rebuilt from a garage sale. A little catching up on this M26 if you have not read my prior thread on its rebuild. It started life with me as a used, poorly painted (desert camo) stock HL M26. It was stripped down and rebuilt with a number of improvements to include metal road wheels, metal shocks, "used bin" HL steel gear 3:1 gearbox with stock motors until the Taigen 4:1 with 390 motors arrived. To proved better initial handling performance/control additional weight was added to the tank (~13-16oz) and the track had silicon pads added. Battery used during this time was both 7.2 and 8.4 volts with the 8.4 being used the majority of the run time.
Fast forward to the arrival of the Taigen 4:1 gearbox with 390 motors. Why 390s because I wanted the ability to achieve scale top speeds (~30 mph) as well as ease of low speed handling. The 380 motors I felt might not achieve both. Once installed it was off to my test course. My initial impression was the tank is far to slow with the 7.2 and 8.4 volt batteries. Even with the 8.4 volt (and added weight removed) the M26 could not match the stock speed of the tank with the HL plastic gears and 7.2 volt battery combination. I tried then to run the M26 with a 9.6v battery and this could just match the stock plastic gearbox/7.2volt speed. To say the least this is a disappointment as I had hoped for just a little faster sprint speed from the 4:1 + 390 + 9.6 volt combination. Oh well it is an old tank design and does not look overly slow when running a fully charged 9.6 wide open.
Slow speed handling/crawling is slightly better than the HL 3:1 (steel) gearbox and stock motor (with all plastic track) but it lacks the ability to "bump" the throttle and this leads to reduced ability to climb "step type" obstacles with all three battery voltages tested 7.2, 8.4and 9.6. With the hybrid track (plastic with silicon pads) the 4:1, 390 motors and 9.6 volt battery the crawling ability is equal to that of the HL 3:1(steel) gearbox, stock motors, running 7.2volts, hybrid track and added weight. It is really only in the low speed turning and creeping that the 4:1 outshines the 3:1 and it is this area that make for a slightly more fun drive in tight terrain.
Noise between the two gearboxes is sadly a huge thing. The Taigen 4:1 gearbox with their 390 motors are SUPER noisy at all "power revs" compared to the HL steel 3:1 gearboxes and Taigen 3:1 gearboxes (all with 390 motors) I have in other tanks. This noisiness makes for a rather annoying mix between the gearbox and speaker output. Too bad because I really like the particular engine sound option this M26 has.
Overall I am a bit disappointed in the performance. I knew going in it would be slower than my current modern tanks. I was expecting more from the 390 motors matched to a 9.6 volt battery. A smidgen faster than basic stock or maybe scale top end speeds. I have neither and the crawl performance I do have can be reasonably matched for far less of an investment. I will keep the Taigen 4:1 in the tank for a little while longer and see if it grows on me a bit, but I don't have high hopes.
My advice to anyone is if you absolutely DO NOT want scale speeds close 25 mph then the 4:1 gearbox is for you.
Here are a few photos from testing the Taigen 4:1 gearbox in my Heng Long M26. Yes the track is "backwards", I discovered it has noticeably better traction on "rock and step" obstacles running it this way. As always your constructive input is welcome.
