GT4 Versus Q-matic

Discussion in 'Frame Mounted Engines' started by Mike St, May 14, 2011.

  1. Mike St

    Mike St Member

    I'd like to get a clear answer here on how the G4T compares to the Q-matic for low end speed from a standing start. I have the q-matic with a 56T rear sprocket and it definitely lacks power from 0-10mph. I'm told I can improve the low end power by going to a 64T or 72T rear sprocket. I see the G4T
    uses a 50T rear sprocket, and seems to have more low end torque than my set-up. Any comments here from actual users?

  2. The 4G's clutch locks very quickly, so it will have better take-off than a Q-matic. The clutch on the Q-matic doesn't lock until 18-20MPH or so. Then it will all but fly.

    I have 1300 miles on my HS142F and Honda 4G, but I'm also running the SBP shift kit and a Sturmey Archer 3-speed hub. Take-off power in 1st is very good without pedaling. With pedaling (and a little pulling back on handlebars), my bike is capable of pulling a wheelie off the line. It's low-speed cruise is also far better than Q-matic because the clutch doesn't slip. Try cruising around at 10-12MPH on a Q-matic, you'll heat that clutch up quick.

    In the end, you simply have to pedal if you want better acceleration, regardless of gearbox you use. These are motor assisted bicycles - still a bicycle first. If you don't want to pedal at all, perhaps you should get something else.
  3. Mike St

    Mike St Member

    Thanks for the info. I'd like to see a video of a wheelie, what a sales pitch for SBP! I suspected the 4G had better low end power than the q-matic just by looking at the videos. I purchased a 72T sprocket for the q-matic and will report the results. I expect a great improvement from what I have now.
  4. Stoltzee

    Stoltzee Member

    I just test rode my bike with a new Q-matic drive yesterday. Unfortunately I did not listen to my inner self and go with a 62 or 64 tooth sprocket. In a real world scenario the 56 does not apply. The 56 is great for long open roads in the country , and going downhill. 72 tooth sprocket is great for fast stop and go traffic, or pulling a load, and hill climbing, (Real Hills). I read a post by someone stating their top speed with the 72 tooth is 31 mph. The speed with the 56 is above 40 mph with reports of 45 mph and occasional 50 mph. On You Tube I watched a video, The person had a 62 tooth sprocket/HS 142f. He pulled off the line with reasonable speed, and went right up to 41 mph.
    With this information, and splitting the difference between 56 and 72 the difference is 64 teeth. Now were left with personal preference, rider weight, saddlebags, and preferred cruising speed, "AND" Speed Laws for this type of vehicle. Where I live it's 30 mph. I weigh around 185 lbs, and have saddle bags, so a 64 would probably be best, but I still want the bike's taxable horse power in the 25 mph to 30 mph range, so if the 64 tooth's top speed is 41, or more, to me anything below 62 is useless.
    I just realized I could have ran across the busy intersection faster than the 56 tooth got me across. I would have to say I felt like a road hazard to other vehicles. Also it seemed like I spent more time listening to the engine lug than enjoying the ride. The engine actually started knocking after one big hill.

    Keep in mind that a lot of the videos and post are 4 or more years old.
  5. Stoltzee

    Stoltzee Member

    I want to say that I love the Q-matic Silent Drive. Especially the way in slows the bike down when I let off the throttle helping with the braking.
    Also when that thing gets moving it's rolling down the road quite easily. I may have been cruising at 40 mph a few times, which is plenty fast on a Schwinn cruiser on beat up city streets.

    Road rash is a thing of the past.
  6. Racie35

    Racie35 Member

    on grubees website......isnt the tg4 available with different sprockets? then you can always go bigger in the back too?.....lighter springs on the clutch should let it engage earlier too?
  7. Stoltzee

    Stoltzee Member

    The guys at EZM have pretty much designed a fool proof transmission with a Max Torque clutch, which is probably the best thing out there, so I'm not going to fool with something that cost me $279.00.
    I checked the tire pressure which was low because of the drop in temperature around here, and that alleviated a bit of the issue. I'm also thinking that there may be a little belt slip too. I looked at it and didn't feel too much resistance on the tension-er. Sometimes I feel a little slippage also, and notice a slight smell when I'm done riding. I'm gunning it a little more on take offs which helps also to get up to speed. One of my concerns is that sometimes I'm going a little faster than I probably should be, and quite frankly doesn't feel that safe to me on a bicycle.
    The problem could just be me getting use to the difference of the old transmission and sprocket which went right up hills, but topped out at about 24 mph, or less. All in all though I'm still having more fun than before, and I can ride the thing with more confidence in reliability. Maybe a little belt slip on take offs keeps the back wheel together too, since the Q-matic
  8. Racie35

    Racie35 Member

    lotta times.....a little time shaping the clutch shoes for a better fit helps too. you can see where they dont touch and sand some and retry etc till its better.
  9. Stoltzee

    Stoltzee Member

    Thanks Racie, I've read some post were guys have said it starts kicking in better after a few weeks. Sometimes I get impatient, and jump to conclusions.
    (Who Me?) lol
  10. Stoltzee

    Stoltzee Member

    UPDATE! I can't seem to ride my bike enough.

    I put more air in the tires. = Better

    I opened up the stock air breather as much as possible without drilling holes in it. Just used a drill bit and reamed the slot as much as possible.

    The basic Huasheng 142f exhaust. Consist of a long baffle, and a skinny tube.
    I read the post about modes to these, but I doubted them. I could tell the engine ran like a weed eater, so I removed the exhaust cap and looked inside. Not one to leave well enough alone I drilled a couple small holes in the little tube, and removed the first flange exposing about 3 inches of the baffle. After that the engine started to get a better sound, and seemed to have more power from the get go.
    After I installed the Q-Matic I would start to reach traveling speed, and could notice it losing the growl and blend into a lawn mower sound. So I surmised that at this range it's choking up. I read where someone drilled a 3/8 hole in the end cap, so OK. Whats the worst that could happen except have to by a better exhaust. I drilled a hole, and went riding around. When I take off it builds up speed quicker, and when I'm cruising along at 30+ mph it sounds really good and smooth. If I throttle it more the engine growls, and increases the speed. The fact of the matter is I've gotten the engine to breathe and perform the way I expect an engine to work, and it's only a little loud when the engine growls. well people can hear me now.
    I'm am no longer worried about a sprocket change, and if I do change. It will just be something I felt like trying. No matter how fast or slow I'm going the engine likes it. Hooray!

    The Q-matic works wonderfully. I'm not beating people off the line, but I can get where I want to go confidently. Also I'm not really noticing the clutch slipping. I can cruise at fairly low speeds.
    Last edited: Nov 15, 2012