Do you guys feel drag when pedaling with the engine off?

Discussion in 'Push Trailers' started by Rgvkid, May 18, 2009.

  1. Rgvkid

    Rgvkid Member

    I noticed that Graucho had a freewheel sprocket on a jackshaft from one of his builds on a mini moto. Im curious if it would help with any drag when peddling with the engine of? It may not be neccesary, i won't know until i get mine going. Im running going to be running a jackshaft with a #40 chain so im not sure i would even be able to find a freewheel sprocket or hub to work with the setup. Or if the freewheel sprocket would be strong enough for a 2.5HP or even a 6.5HP.

  2. Gen3Benz

    Gen3Benz Member

    Whats that?
  3. Rgvkid

    Rgvkid Member

    Well just in case something breaks down. Sooner or later we might even have to burn some calories on our bikes. Znsane said he had to peddle his bike 10miles back home one day due to some kind of failure. You never know.
  4. Gen3Benz

    Gen3Benz Member

    I had to pedal home after I lost my chain on a test run.
    Not bad at all, just the weight of the trailer.
    The centrif clutch spins freely when you dont have engine power driving it.
    Last edited: May 19, 2009
  5. loquin

    loquin Active Member

    A freewheel does have less drag. A regular freewheel will work at the drive end of the chain. Staton sells various shaft size freewheel adapters. Then, you just thread on a freewheel sprocket adapter. The better freewheels should hold up OK. White industries is the gold standard as far as BMX style freewheels go, ACS is OK too. About the smallest 'standard' freewheel sprocket (1-3/8 inch, 24 TPI) you can get is 16 tooth, though. The ones for the smaller metric threads are available down to 14 teeth, I believe. Pablo is selling a custom one, made by white, with a 5 hole flange instead of a sprocket; you can then buy the sprocket separately. (For the record, I believe you can buy just the replacement sprockets for White industries freewheels, too.)

    Even though the chain is moving from the rear sprocket up to the freewheel, it only costs about 2-3% of the power to spin, so it's really not noticeable.
  6. loquin

    loquin Active Member

    BTW. One thing that'll help with freewheel life is to not open the throttle wide open as fast as you can - increase the RPMs smoothly until the freewheel pawls engage. THEN, you can open it on up.

    Otherwise, you'll have a lot of moving mass that the freewheel pawls have to catch.
  7. s_beaudry

    s_beaudry Member

    Drag while pedaling???

    Holy cow, both of my pushers weighed in well over 60 pounds, maybe on flat flat flat roads I could pedal it, but ANY kind of incline and I would bog right down.

    I guess the important thing to remember with a pusher is the downfall of it "having" to push you and you not having to pull it.

    I remember last summer when a few miles from home, The pillow block bearing loosened up a little and the chain pupped off and bent a little... could not put it back on safely.... so I had to pedal and walk her home in the midst of summer here in South Carolina!

    Nearly had a heat stroke!!!
  8. Rgvkid

    Rgvkid Member

    Thats the only downfall with a push trailer, you can't just hop on the next bus that comes by. With my Poulan chainsaw MB i was able to put it on the bus bike rack if i had any problems.

    I understand the pulling the weight of the trailer alone, I was more concerned if there was drag from the sprockets and clutch. I don't think it would be that much if any, I was just curious if it would be beneficial to install a frewheel sprocket. Graucho gave me some good insight on his Bikes using the freewheel sprocket and some tips using Metal tape for sprockets that arent the exact size. I think its on the 79cc thread. His built some badass Bikes.

    Loquin, thanks for your insight also.

    We'll see what Znsane says. I know he's been a busy guy going back and forth from this forum and the forum. He has alot of first hand knowledge and is starting to become a guru not only here but over there also. You guys should check it out also if you are building a pushtrailer. There is alot more first hand experience on the DIY Kart forum using these big motors.
    Last edited: May 20, 2009
  9. ZnsaneRyder

    ZnsaneRyder Member

    A freewheel may help, but IMO it's another part to worry about breaking.

    About the trailer drag...

    A single wheel, chain drive trailer has very little drag. A 6.5 is a bit heavy, but ok to pull. A 2.5 is lighter and easier to get going. You do feel the rotational inertia of the chain spinning the clutch, but it's not bad enough to need a freewheel IMO. It's mainly heavy to get rolling, but easy to keep speed when pedaling. If you have your chain a bit too tight, it has a lot of drag. Just have a good tire, properly tensioned chain, and it's easy to pedal.

    Two wheels with a posi axle is the hardest. The two wheels fight each other some, and add lots of friction. If You have belt drive, it's even worse. However, two wheels has better balance.

    It's a trailer, and IMO a trailer should be able to be towed. If you have everything right, you should have no problem. Have you considered hauling stuff with your trailer? I love the fact a trailer allows you to carry stuff you normally can't haul with a bicycle.

    Regardless, pedaling your trailer is quite a workout. Pedaling a regular bike after pedaling with a trailer, makes the pedal bike feel really light! LOL
    Last edited: May 20, 2009
  10. s_beaudry

    s_beaudry Member

    To answer the drag question on a two wheel pusher....

    Having built two now, I will tell you that there is an increased amount of drag on it which is very noticeable.

    On a hill that a bike alone would easily roll down, with the two wheel pusher attached it will not roll at all.

    My first thought about adding a freewheel sprocket would be a very noticeable increase in MPG with allowing it to idle down and still roll easily.

    But, same as ZN said, adding more parts complicates things even moreso...
  11. Rgvkid

    Rgvkid Member

    Yes it would complicate things by adding more parts because of the concern of breakage. I think with the 6.5 breakage would always be on the back of your mind with to many parts being used. With the 2.5 i don't think as much as long as you roll on the throttle rather then gun it. Graucho seems to have succes using the Freewheel on his bikes, plus you could always carry a spare $8 sprocket just in case. The link that Graucho gave sells the freewheels for $30. That wouldn't be a bad investment if you were planning on building something for long distance runs, as long as it is durable enough. Plus, I would think it would be less stress on the clutch bushing itself. My trailer is going to ba about 3-4ft long because i want to utilize a cargo area. Im thinking Mini Fishing Pole, sleeping bag, tent and spare parts as cargo. I weigh 150lb. so Im hoping the 2.5 will have enough power to keep me going with cargo.
  12. ZnsaneRyder

    ZnsaneRyder Member

    One trial and error lesson.

    With your push trailer, to reduce the drag, lubricate the chain and sprocket on the clutch. Do it everyday. This reduces the drag a whole lot, and also reduces the wear on the sprocket teeth.

    I found this out, that my clutch-sprocket teeth are wearing, and I sprayed with White Lithium grease, and it reduced my drag, and isn't wearing so much.
  13. tiberius_k

    tiberius_k New Member

    The chain's the thing

    Apologies for bumping this thread with only my second post ever, but...

    For anyone else reading this: If the concern is to avoid extra effort on a 10-mile ride home, a simpler and more reliable solution might be to remove the chain in the event of a breakdown. Whether the chain has a master link or requires a chain breaker, carrying the needed tools will add less weight than a freewheel. You'll also keep the mechanical complexity down. Of course, there are other reasons to have a freewheel; however, I think that for breakdown preparedness, removing the chain is the more elegant route. It could potentially be more effective too, depending on where the failure is.
  14. Virginian

    Virginian Member

    I have the GEBE system and they clain there is minimal drag with the motor off. That is not quite true.

    I trying to locate a rubbing sound so I was riding with the motor off. I rode to the end of the street where I live, which is a very gentle uphill and a distance of just over 0.1 mi. With the belt on and hard pedaling I reached 12 mph at the end of the street. With the belt off, I reached 16 mph. That's quite a difference if you need to pedal any distance.

    For comparison, with the motor on, full throttle, and pedaling hard to help it get rolling well, I reach 29 mph by the end of the street.