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Hubs, Gearboxes, Sprockets and Chains Can't find 'em, grind em - hubs and transmissions, problems and modifications to make you run smooth and trouble free

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Old 01-18-2014, 12:57 PM
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mapbike mapbike is offline
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Join Date: Mar 2010
Location: Central Texas
Posts: 5,379
Default Re: Gear ratios and speed help?

Originally Posted by rogergendron1 View Post
yeh my motors dont last long becaus of the consistant high rmp driving all the time and compared to a stock motor my milage is nearly cut in half lol !!!

i recently upped the comp to slightly over 13:1 and now i run 93 oct mixed 30% with xylene or toluene (witch is 117 oct) or mmt concentrate if i can find it get 100.2 octane, then i mix in upper cylinder lube and full synthetic 2 stroke race oil, like amsiol or lucas to get a final mix of 32 to 1, 100 octane !

aaaaah yeh my bike has never ran better or had more power ! i like it a lot and i am willing to pay the 6$ a gallon to make the race fuel and i am willing to cut my engine life in half to gain a ton of power ! after all a new dax 70cc motor is only 120$ and with the mods i have they last at least a year of super hard every day riding so i do get my moneys worth ! for all the power i can suck from thease things now i think 120$ a year and 10 hours of my time is worth it !

i love my torque machine's too man !

Sounds cun to me bro...... torque is king and if I rode everyday I'd probably do mine different, it's just a fun hobby among my other hobbies and living in rural central Texas im about 10 miles from the closest small city and about 7 miles from my local little town population 422 I ride in spring, summer and fall wben weather is good usually in the early morning or late evening for mostly just a relaxing joy ride, I luke to ride the dirt back roads in my area and look around at what the other country folks around me are doing and watch the deer and wild turkey either look at me like what the heck is that or just run like crazy as if their life depended on it, my riding and use of my bikes is way different than y'all city folks, and my bikes take a real beating on these rough very dusty roads around here, since I ride lots of open road and several miles a a time at cruise speeds I enjoy a high gear ratio that will let me cruise at 30+ mph fairly comfortably, when I ride a bike into town that is roughly a 30 mile round tdip everytime so I want my bike to be solid, dependable and have a nice cruise speed so it doesnt take me half a day just to ride to town and back, so all the advice I give people is based on my experience with what I have found to work good for my riding conditions since I built my first bike back in 2009 from a elcheapo rough running red bat ebay engine kit from boygofast, it still runsgreat but is the weakest engine in my herd now and the vibes are horrible above 28mph even with a 32T rear sprocket on a 24" wheel, this engine will be a project in the future for a better trued crank to smooth it up and some port work to get it breathing better....blah blah blah.....!

If you are getting such good power you should consid r at least trying a 36T on the rear, your power will drop a tad on the lower end but, your cruise speed will jump several mph or at least if you keep it at around 40 like I do your rpms will come down and add life to the engine and smooth up the ride a bit, heck even a 40T is a really good overall gear in my opinion not to low and not to high if someone wants a comfy 30 mph cruiser, personally I like to have at least 35mph cruise speed if I can but some people dont feel comfortable over 25-30 mph so a 40T or even 44T works nice for that if there engine doesnt have really severe vibe issues.

Happy safe riding...

I dont always ride WOT, but when I do..I do my best to keep the rubber side down..Ride safely my friends!
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Old 11-22-2016, 06:56 PM
Austritch Austritch is offline
Motorized Bicycle Newbie
Join Date: Apr 2016
Location: NC
Posts: 17
Default Re: Gear ratios and speed help?

Hey guys, I'm building my 150cc fat tire bike. I have used the ratio/speed calculator and got a 8:1 ratio for ~48mph. Is this a realistic speed for my bike with 26" rim?
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