Author Topic: Drivers and sprockets  (Read 5572 times)

Offline 87master

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Drivers and sprockets
« on: August 27, 2009, 07:32:42 PM »
Anything under 44/16 gearing is a mystery to me so can anyone answer a couple of questions for me?

First off, drivers. Are they universal, like freewheels? Been thinking about getting a freecoaster, probably a 9t geisha light but not sure if i can run that small a gearing.

Secondly, when do sprockets get into 'micro gearing' . Micro gearing has different crank fittings right? If i change gearing now any sprocket i get will have to fit a one piece crank.

Third, so i can try and work out what chain clearance i have, can anyone tell me the overall diameter (including teeth) of a 9t and 11t driver, and the overall diameter of a 24, 28 and 30 sprocket.


Thanks.

Offline Jason

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Re: Drivers and sprockets
« Reply #1 on: August 27, 2009, 08:01:11 PM »
I would not recommend a 9t driver.

My personal opinion is poor because I blew up the bearings in my 9t in less than an hour and was stuck riding it all day til I got back home to replace it with the 11t.  The differnce is the bearings, 10 & 11 drivers use slightly larger bearings.

Don't get me wrong here tho…I'm not bagging the quality because some people will tell you otherwise and recommend the 9t. I gave mine to Jesse Puente because he loves it & needed it over the 10t he was running.

If you are worried about chain clearance I would think that running a 24-11 or larger in the front would be perfectly acceptable and not quite micro. I run 18-11 and if my chain has anything more than an 1/8" of play it will slap the frame when I set it down rough. 
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Offline 87master

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Re: Drivers and sprockets
« Reply #2 on: August 27, 2009, 08:08:33 PM »
I dont want to go as low as 18/11!

Im running 40/16 at the moment and i like it. I would go a little lower if need be.

so something like 11/28 would probably suit me good.

I was thinking of ordering the hub from FF but it comes with a 9t driver. Another $50 for an 11t driver.

Still cheaper than anything else i guess though.


Do you know the diameters of 11t and 28t? Dont want to order everything then find out it doesnt clear.

Offline sbroflatland

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Re: Drivers and sprockets
« Reply #3 on: August 27, 2009, 11:27:55 PM »
I Do you know the diameters of 11t and 28t? Dont want to order everything then find out it doesnt clear.

to find diameter you need to use some of your 8th grade geometry. C = pi(3.14) x D

so knowing the distance from each chain link bar is .5 in your circumfrence for the 11t is 5.5 and for the 28t is 14

so then just plug it into the formula as
5.5 = 3.14 x D 5.5/3.14 = 1.75   11t diameter is 1.75
14  = 3.14 x D  14/3.14 = 4.46   28t diameter is 4.46
this diameter is from the middle of the chain posts so it might be bigger by about 1/8" to 1/16" with your chain on

and if used together the ratio for 28/11 is 2.54
compared to your current ratio 40/16 is 2.5
these two set-ups are going to feel the same
« Last Edit: August 27, 2009, 11:33:09 PM by ga_goosh »

Offline chris_bmdx

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Re: Drivers and sprockets
« Reply #4 on: August 27, 2009, 11:32:08 PM »
28/11 was exactly what I was running until yesterday ... now I switched to 23/9 which is about the same ratio. I just measured the diameters of 28T and 11T ...

28T = 105mm (118mm including teeth height)
11T = 37 mm (49mm including teeth height)

hope this helps!

btw, if you run your chain not too loose, 23/9 works still fine for me.

chris

Offline 87master

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Re: Drivers and sprockets
« Reply #5 on: August 27, 2009, 11:36:04 PM »
I Do you know the diameters of 11t and 28t? Dont want to order everything then find out it doesnt clear.

to find diameter you need to use some of your 8th grade geometry. C = pi(3.14) x D

so knowing the distance from each chain link bar is .5 in your circumfrence for the 11t is 5.5 and for the 28t is 14

so then just plug it into the formula as
5.5 = 3.14 x D 5.5/3.14 = 1.75   11t diameter is 1.75
14  = 3.14 x D  14/3.14 = 4.46   28t diameter is 4.46
this diameter is from the middle of the chain posts so it might be bigger by about 1/8" to 1/16" with your chain on

and if used together the ratio for 28/11 is 2.54
compared to your current ratio 40/16 is 2.5
these two set-ups are going to feel the same




Give me a lump of alloy, a piercing saw and a file and ill make the most beutiful custom sprocket you can imagine.

Give me an equasion and im lost LOL

I have been playing with electronics recently but the math theory drove me nuts!!

Thanks for the info though, thats great

Thanks to chris to for saving me even having to convert to metric  :beer:

Offline chris_bmdx

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Re: Drivers and sprockets
« Reply #6 on: August 27, 2009, 11:40:17 PM »
ah, forgot, micro-gearing is everything with sprockets smaller than 23T as far as I know. for 22T and less you need a micro-drive compatible crank or a spline-drive sprocket and a profile-style axle

Offline 87master

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Re: Drivers and sprockets
« Reply #7 on: August 27, 2009, 11:50:43 PM »
Yeah, i make anything i can really. Lack of workspace limits me alot though.


A quick look from the measuremnts given, roughly using a length of brake cable outer to show where the chain would be, i think 28/11 will clear everything.

It should be about 7-8mm above the brake mount center bolt but i could take a mm or 2 off the top of the bolt if needed.

Ive got room to lower the brake mounts but that would mean getting the local road bike builder to sort that out form me. I could MIG weld them, but thats not ideal for cro-mo.

Under the chain stays things are a little wierd. The chain clears but movement is odd.

The chain probably has about 10mm clearance up, but only 2mm ish side to side. I guess chains dont flap too much side to side?
Chainstays are an odd shape on the haro master, but if they werent the shape they are i dont think there would be any chance of it fitting.

Its all tight, but may work just fine.  Ill see if i can borrow this gearing and try it just to make sure.
« Last Edit: August 27, 2009, 11:53:03 PM by 87master »

Offline 87master

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Re: Drivers and sprockets
« Reply #8 on: August 27, 2009, 11:51:28 PM »
ah, forgot, micro-gearing is everything with sprockets smaller than 23T as far as I know. for 22T and less you need a micro-drive compatible crank or a spline-drive sprocket and a profile-style axle

Well i deffo wont be going that small so no problems :)

Offline chris_bmdx

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Re: Drivers and sprockets
« Reply #9 on: August 27, 2009, 11:53:28 PM »
forgot something else lol

if you order from FF, they would probably just change the 9T driver to an 11T for free if you ask

Offline 87master

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Re: Drivers and sprockets
« Reply #10 on: August 27, 2009, 11:54:20 PM »
Ill ask :)

Im going to order a stem and some forks anyway

Offline FReAM

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Re: Drivers and sprockets
« Reply #11 on: August 27, 2009, 11:59:26 PM »
Yeah, like was already covered 44/16 and 28/11 will feel pretty close to the same.  I am about to be running 28/11 myself.

Also, I ordered a Geisha from flatlandfuel recently also.  I had them swap the 9t driver for an 11t.  If you want an 11t driver instead of the 9t you can just request that they send you an 11t instead.  Pat will hook it up, no problem.  That way you won't be paying extra for something you don't need. I hope that helps some.  Yes they can do it.
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Offline brian84corvette

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Re: Drivers and sprockets
« Reply #12 on: August 29, 2009, 05:37:31 AM »
crank arm leingth also plays a roll in this scenereo.

if you run 175mm arms on a standard 44/16 gear ratio
that is "normal bmx feeling"  when pedaling around

but if you switched to 160mm arms using 44/16 its going to feel harder
to pedal now since you have taken away some torque ratio from the crank arm leingth
so maby a 42 tooth sprocket would give the same "normal bmx feeling"  when pedaling around

?
its all personal preferance realley.
ive used crank arms from 145 to 185 and luckly had enough parts avalable to swap around until I found the desired ratios I wanted for myself.

for flatlanding - i enjoy using 160mm arms and 22/9 gear ratio.
and for all around use I still use 160mm arms but go 24/9 for more top speed at the cost of low end take off power.
Old dudes can still rip

Offline JUGGARNAUT

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Re: Drivers and sprockets
« Reply #13 on: August 29, 2009, 06:30:46 AM »
crank arm leingth also plays a roll in this scenereo.

if you run 175mm arms on a standard 44/16 gear ratio
that is "normal bmx feeling"  when pedaling around

but if you switched to 160mm arms using 44/16 its going to feel harder
to pedal now since you have taken away some torque ratio from the crank arm leingth
so maby a 42 tooth sprocket would give the same "normal bmx feeling"  when pedaling around

?
its all personal preferance realley.
ive used crank arms from 145 to 185 and luckly had enough parts avalable to swap around until I found the desired ratios I wanted for myself.

for flatlanding - i enjoy using 160mm arms and 22/9 gear ratio.
and for all around use I still use 160mm arms but go 24/9 for more top speed at the cost of low end take off power.
Spoken like a Pro Builder Bri! ;D :beer: