34 Tooth Sprocket RPM's?

Discussion in 'Frame Mounted Engines' started by mcassMB6, Jul 20, 2008.

  1. mcassMB6

    mcassMB6 Member

    Hi- I'm running at 44 Tooth sprocket now. I'm soon upgrading to a 34 tooth.

    Can anyone tell me how much of an RPM difference there is once I switch over?

  2. It will be a DOG starting off but will be faster up top. Cruising the RPM difference would be quite a bit although I don't have actual stats. Expect to be peddling up to speed.
  3. HI,

    You will have about a 23% reduction in engine RPMs for any given speed .....FWIW....I currently run a 36T in hilly VA and am going to gear up when I get a chance (smaller rear sprocket)...I run a DAX 70...And can do 34.4 MPH at 6400 RPM with this setup (26" wheel)
    6400 RPM is way too fast for sustained running tho (engine making funny noises....so rather than risking blowing it....I'll either run slower or gear up)....36T is pretty good for cruise BUT 34T or below would be better I think....I will change over when I get my other bike going.
    Hope this helps you.

    PS - I do run a tuned pipe tho....The 36T and smaller can be run without the pipe (I tried the 36T without the tuned pipe....just slower acceleration and harder to pull hills....didn't try a top end run tho since I liked the power sooo much the pipe wen back on ASAP).
  4. relaxxx

    relaxxx Member

    I'm working a new bike and decided to go smaller gear because the motor was literally screaming at 32km/h. I got frustrated trying to find a decent priced 34-36 tooth so I ripped the largest bike gear off my old bike wheel, it's a 28 tooth. hopefully that's not too low a number because I'm probably going to have to cut my chain and never be able to go back to 44.

    I should have it going in a few days. I just put the 28 tooth on the wheel with 12 bolts through a custom made steel and rubber hardware. No too cute but it should work. nearly idling along at 32Km/h should be a **** of a lot better MPG too.

    Sorry, heck of a lot better MPG. LOL
  5. japennell

    japennell Guest

    I switched from a 44t to a 36t and it does provide faster cruising speeds. I have 2 - 3 steep hills on my way to and back from work. My mileage has plummeted from 200+ mpg to 120 mpg or so.

    My theory is I need to go full throttle while peddling up those steep hills. Thus, its killing my mileage compared to what I had before.

    I am considering going back to the 44t sprocket. I need to get a new chain as I didnt save the pieces I cut off when I went down to a 36t.

    The only thing preventing me from going back is I keep wondering even though its costing me more in fuel, perhaps I am getting more life out of my HT because of the lower rpms.
  6. Hmmmmmm.....that is interesting about the MPG's....I can't say I have ever measured it myself (a tank with me lasts seemingly forever!).....

    To put the mileage figures in perspective though, were you riding the 36T a lot faster than you were with the 44T?...If so, I wonder how mileage would compare if operated at the same or similar speeds?...Just curious but maybe aero drag accounts for the large loss?....Interesting none the less....

    Thanks for sharing your findings!

  7. lildeezul

    lildeezul Member

    i am running a 44t, with a 48cc motor, i want to get a 36 tooth, because my rpms are crzy and i top out like a 25mph and it gets there to quick.

    i have alot of flats, and alot of hills, very diverse. with this 44t spocket, i am riding WOT and at Top speed going on long strait aways
  8. iron_monkey

    iron_monkey Guest

    I didnt notice a great/noticeable increase in mileage from 44 to 36. Probably because alot of my riding was start stop in the metro area, or maybe because since I never actually measured the fuel consumption any significant(but not great) mileage gains are unnoticable.

    Im waiting for a 31T sprocket thats taking more than 16 working days (more than 3 weeks) to arrive. :(
    Last edited by a moderator: Jul 21, 2008
  9. mcassMB6

    mcassMB6 Member

    yeah me too...it's been almost a month for me and still no sprocket.
  10. HI Iron Monkey & mcassMB6,

    Are you guys waiting for a sprocket from me?...If so, Please PM me your names and addresses / approximate order dates / and any other info you think may be helpful and I will research it ASAP....I try to get everything out in generally 48 Hours or so.

    Thanks for your patience if it was me and I will definitely research it if it was me and make it right...

  11. iron_monkey

    iron_monkey Guest

    The issue shouldn't be you, its with USPS and local post (I'm from australia). I've already emailed you.

    Although if I dont receive this week I'll PM you for one last verification before an insurance claim is filed.
  12. relaxxx

    relaxxx Member

    I'm very surprised to hear someones MPG actually went down. I hope this is not the case for me. I'm expecting a substantial increase MPG. I've got the 28 tooth on the wheel, I just need to mount the motor, and cut the chain (no going back after that). I might even have it running tomorrow if the wife will leave me alone.
  13. mcassMB6

    mcassMB6 Member

    andy- yes it was me. It arrived finally. You shouldn't advertise 48 hour manufacturing if you cannot deliver that consistently. The sprocket seems sound. Also- if there was a manufacturing delay (servo assembly for your hobbing machine) as you say, it is your responsibility to inform the customer of the delay- I was not happy about the "i don't know for sure" and the "let me look into that" or your operation. If I didn't raise those questions, they certainly weren't going to be considered.
  14. lildeezul

    lildeezul Member

    should my 48cc be able to power a 36 tooth sprocket ??

    o am hitting 25mph right now, should i get 30mph or so with the 36tooth.

    Andy I live in the states, and hopefully my delivery times will be way better than the other guys..

    how much are 36tooth sprockets from you ?
  15. HI lildeezul,

    I am not too familiar with the power output of the 48CC engines so it would be hard for me to say how well it would do pulling a taller (smaller sprocket)....Maybe somebody with a similar sized engine and smaller sprocket can chime in with their findings?

    On a 26 inch wheel, each tooth you lose off the sprocket will gain you approximately 1 MPH additional top end assuming the engine can pull it to the same RPM as before...I have a Dax 70 on a mountain bike running a 36T sprocket and can go to 34.4 MPH at 6400 RPM (I would NOT recommend that high an RPM because the engine starts making funny noises)...30 MPH or below keeps the revs OK in my opinion....I am thinking of putting on a smaller sprocket on my bike when I get a chance...

    36T plain (non-anodized) sprockets delivered in the USA are $50 ($37.50 for the sprocket plus $12.50 Shipping for up to 5 sprockets)...You may be able to save some money if you can use a 34T (our best sellers) because on eBay auctions they typically go for less....

    As far as delivery times, over 99% of our sprockets go out within 48 Hours after payment is received (assuming I have all the needed info and don't have to email or phone for it)....Current average is 41 Hours....BUT things can happen occasionally and we are working on better ways of catching potential problems before they happen and hopefully better follow-ups too.

    Hope this helps you and thanks to all for your past, present and future business...

  16. lildeezul

    lildeezul Member

    oh yeah i seen your ebay auctions.
    it has a very big long description.
    I actually thought about buying from there on ebay, but then i seen u on the forum, and to my suprise you all are the same people.
  17. fatboy67

    fatboy67 Member

    has anyone used a 36T on a 48cc?????????????????????????????????
    I personally think it would be a bit to much for a 48,, but I have never tried it.
  18. lildeezul

    lildeezul Member

    same here.

    has anyone done this.
    i really am debating on buying one, but i want opinions first
  19. Boomer

    Boomer New Member

    You too huh...lol
    Mine was shipped last week Monday UPS, should have been here last week Thurs or Friday at the latest. So this is Monday and still no sprocket.
    It sure doesn't make for positive Ebay Feedback, so far no feedback, still waiting, sure took the paypal money in a hurry...lol
  20. HI Boomer,

    As far as I know all of our current orders have been processed and shipped out....Please email me or PM as much pertinent info as you have and I will research ASAP (name, address, approximate order date, eBay item # if applicable, Pay Pal name etc).


    PS - If it had already been shipped (which it may have per you notes above) I can get you a tracking number if needed....UPS is generally pretty quick...