Blue dream

[G-Matt]

That is actually quite deceiving. I had the hardest time convincing a shop owner to order bmx bikes with the compact gearing, he said the ring was so small the kids wouldnt be able to get anywhere and wasnt what the local kids wanted. While the front ring is smaller, so is the rear. Old BMX gearing used to be 44/16 or so, decent all around set up. Then street and park riders went down to about 36t up front and 12-14 out back for more ground clearance when riding aggressively and doing things that would damage the lager rings easier. Bikes got up to 35lbs or more! Then there was a movement to make the bmx bikes lighter, hard to do tricks and pedal around on a tank! One thing they did was eliminate the freewheel from the hub and started using small 9t drivers in combination with 25t chainrings up front, smaller ring is lighter, hub is lighter, and even the chain is as well due to not being nearly as long. The reason for going with that gearing was it is very similar in gear-inches to the older 36/14 and 44/16 setups, feels the same and you reach the same speeds when spinning out the cranks.

I am wondering how that gearing feels on the 26" wheel though. I have not run a single speed 26" with 25/9 yet.



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Thanks for the detailed explanation. I wouldn't have to agree with all you've said. Basically changing the fort & rear ratio evenly balances out , but it sure dose look small . Like your cadence would be 100 rpm . Enjoy the bike ride it hard looks great .


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[OddJob]

Hey Jarod, will she be ready to roll on the club ride this Sunday? Like to take a peek at it in person...

Looks good. Like your combination of new and old on this build.

 

[Jarod24]

Hey Jarod, will she be ready to roll on the club ride this Sunday? Like to take a peek at it in person...

Looks good. Like your combination of new and old on this build.

I'm hoping so, need to get some sort of brake set up before then or I'll be riding brakeless haha

 

[RustyGold]

A 44/16 geared bmx bike with 20"x1.95" tire would be 54.7 gear-inches.
A 25/9 geared cruiser with 26"x2.35" tire would be 74.3 gear inches.
To get a the cruiser with Fat Franks to have the same gear as the 20" bmx, you would have to run about a 25/12 combo.

Jason

http://www.bikecalc.com/gear_inches

 

[squirreldh]

Thanks for the link to the gear calculator!

I ran the #s through so i could verify my statement, and the results were what i had expected. If you calculaute for a 20x2.25, with both the 44/16 and the 25/9 you get very similar gear-inches.

20x2.25 tire:
44/16= 56.3 gear inches
25/9= 57 gear inches

A difference barely noticeable while pedalling. But, when going up to the 26" wheel things change, and as Rusty Gold said you would need a larger/lower rear cog to get similar results. I imagine with the taller gearing acceleration will be slower but top speed will be greater. I hope you dont have too many hills to climb!

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