I want to build my own front sprocket! but how?

FoSi said:

Hi all..
recently i converted my bike to SS fixed gear! using 17rear sprocket
33front sprocket! i have horizontal "drop-out" so i made a 10mm rear
Cr.Mo bolt axle to fit my Deore Hub! then i also did machined two chain
tensioners.. to micro-adjust the tension, and to have the wheel always
in place! untill here everything its fine!

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !
but i dont know were i can find technical info on how the sprocket is
designed! is there a document with the standards for this?
my setup>> http://img127.imageshack.us/my.php?image=fosisprocketbq6.jpg

i have a 4bolt truvativ hussefelt crank, with the standard truvativ 33t
Cr.Mo sprocket.. i need to design a BMX thick 33t sprocket
like these: http://wethepeople.de/V3/bilder/product/war119_004.jpg
(equal to this one, but to fit the 4bolt crank arm)

can someone please helpme to find technical info about the bmx sprocket
design + plus the truvativ 4bolt crank arm radius? this would be really
helpful!!
thank you very much for reading

Use a road chain...3/32 type. It'll work fine with the front ring and
back cog. If the 17t is a 1/8 pitch, get a 3/32 pitch one.

Thanks for answering! but i would want to use a BMX chain.. 🙂

Qui si parla Campagnolo said:

Use a road chain...3/32 type. It'll work fine with the front ring and
back cog. If the 17t is a 1/8 pitch, get a 3/32 pitch one.

FoSi said:

Thanks for answering! but i would want to use a BMX chain.. 🙂

Qui si parla Campagnolo said:

Use a road chain...3/32 type. It'll work fine with the front ring and
back cog. If the 17t is a 1/8 pitch, get a 3/32 pitch one.

Altho not ideal, you can use the 1/8inch chain on the thinner sprocket.

yes... im using it right now! but i notice that there is some "crack"
sounds, not often! but there is no harmony using this chainring with
the bmx chain!
thanks

Qui si parla Campagnolo said:

FoSi said:

Thanks for answering! but i would want to use a BMX chain.. 🙂

Qui si parla Campagnolo said:

Use a road chain...3/32 type. It'll work fine with the front ring and
back cog. If the 17t is a 1/8 pitch, get a 3/32 pitch one.

Altho not ideal, you can use the 1/8inch chain on the thinner sprocket.

FoSi said:

i have a 4bolt truvativ hussefelt crank, with the standard truvativ 33t
Cr.Mo sprocket.. i need to design a BMX thick 33t sprocket
like these: http://wethepeople.de/V3/bilder/product/war119_004.jpg
(equal to this one, but to fit the 4bolt crank arm)

can someone please helpme to find technical info about the bmx sprocket
design + plus the truvativ 4bolt crank arm radius? this would be really
helpful!!
thank you very much for reading

Unless you have access to some flashy CNC machines, this is a job for
somebody who is already in the business.

http://www.highpath.co.uk/cycles/eggs/01.html

They've been in business for donkeys' years.

If you must do it yourself, the 4 arm design is easy to measure and
the engineering department at your library will help you to design the
tooth shape, which isn't rocket science; much simpler than spur gear
wheel design, for example.

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

FoSi said:

Hi all..

Quoted message said:

can someone please helpme to find technical info about the bmx sprocket
design

Your tensioners are very pretty, but I venture to say that the chainwheel
sprocket you describe is a whole other deal, if it's something you want
to fabricate, as opposed to buy. (There are 1/8 inch fixed/single
cranksets you can buy - I have a 38-tooth one (branded "Cyclone"😉 that I
bought on eBay, and it works great for me with a BMX-style 1/8 inch chain.)

Take a look at the Wikipedia entry for CNC, which is probably what you'd
need if you wanted to fabricate something like a chainwheel from a blank
piece of metal.

Ron Abramson

FoSi said:

Hi all..

Quoted message said:

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !

Even Jim Merz, famous maker of aftermarket chainrings, starts with
pre-toothed blanks (teeth already cut, all you need to do is to cut
out the spider inside of the ring.)

I'd recommend that you find a suitable 33t sprocket - either in your
pattern of chainring, or in any similar spider with a SIGNIFICANTLY
smaller BCD. For example, Specialties TA probably has a high-quality
7075 smaller BCD sprocket - in 4-arm or 5-arm. All you need to do is
mark/cut out the arms, and re-drill / re-countersink the chainring for
your larger-bcd crankarms.

Less pain but equivalent gain ...

- Don Gillies
San Diego, CA

FoSi said:

recently i converted my bike to SS fixed gear! using 17rear sprocket
33front sprocket!

-snip-

Quoted message said:

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !
but i dont know were i can find technical info on how the sprocket is
designed! is there a document with the standards for this?
my setup>> http://img127.imageshack.us/my.php?image=fosisprocketbq6.jpg
i have a 4bolt truvativ hussefelt crank, with the standard truvativ 33t
Cr.Mo sprocket.. i need to design a BMX thick 33t sprocket
like these: http://wethepeople.de/V3/bilder/product/war119_004.jpg
(equal to this one, but to fit the 4bolt crank arm)
can someone please helpme to find technical info about the bmx sprocket
design + plus the truvativ 4bolt crank arm radius? this would be really
helpful!!

Much like exclamation points!
1/8" chainrings are not essential!
When using a 1/8" chain!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

Quoted message said:

FoSi said:

Hi all..
recently i converted my bike to SS fixed gear! using 17rear sprocket
33front sprocket!

-snip-

Quoted message said:

Quoted message said:

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !
but i dont know were i can find technical info on how the sprocket is
designed! is there a document with the standards for this?
my setup>> http://img127.imageshack.us/my.php?image=fosisprocketbq6.jpg

-snip-

Quoted message said:

Quoted message said:

can someone please helpme to find technical info about the bmx sprocket
design + plus the truvativ 4bolt crank arm radius? this would be really
helpful!!
thank you very much for reading

[email hidden]

Quoted message said:

Quoted message said:

Quoted message said:

Use a road chain...3/32 type. It'll work fine with the front ring and

back cog. If the 17t is a 1/8 pitch, get a 3/32 pitch one.

Why?
He already has a 1/8" cog and chain (which will wear longer than 3/32"😉.

He should not have any issues with 1/8" chain on his 3/32" chainring.
Sure. all one size is nice but no big deal. Like my own Record 3/32
ring with 1/8" Kool Chain. Smooth & quiet.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

FoSi said:

yes... im using it right now! but i notice that there is some "crack"
sounds, not often! but there is no harmony using this chainring with
the bmx chain!

Your chain is too tight - a common and amazingly destructive error.
Leave 12~15mm movement at the tightest spot:
http://www.yellowjersey.org/chainchk.html

Overtightening makes noise and wears bearings, teeth, chain quickly.
Just replaced a cracked freewheel on Christmas day for rider who set his
bike up a week earlier.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

On 29 Dec 2006 14:11:32 -0800, "FoSi" <[email hidden]> may have

Quoted message said:

Hi all..
recently i converted my bike to SS fixed gear! using 17rear sprocket
33front sprocket! i have horizontal "drop-out" so i made a 10mm rear
Cr.Mo bolt axle to fit my Deore Hub! then i also did machined two chain
tensioners.. to micro-adjust the tension, and to have the wheel always
in place! untill here everything its fine!

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !
but i dont know were i can find technical info on how the sprocket is
designed! is there a document with the standards for this?

First observation: The overuse of exclamation points may limit the
enthusiasm of potential respondents.

Second observation: The thin sprocket will work just fine with the
wide chain.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

a have a 20mm movement at tightes spot! ( middle bottom of chain )

A Muzi said:

FoSi said:

yes... im using it right now! but i notice that there is some "crack"
sounds, not often! but there is no harmony using this chainring with
the bmx chain!

Your chain is too tight - a common and amazingly destructive error.
Leave 12~15mm movement at the tightest spot:
http://www.yellowjersey.org/chainchk.html

Overtightening makes noise and wears bearings, teeth, chain quickly.
Just replaced a cracked freewheel on Christmas day for rider who set his
bike up a week earlier.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

yes... i have 3axle 4axle + 5axle cnc access! and i work with Alias
studiotools! im not engineer.. but im a product designer.

Kinky Cowboy said:

FoSi said:

i have a 4bolt truvativ hussefelt crank, with the standard truvativ 33t
Cr.Mo sprocket.. i need to design a BMX thick 33t sprocket
like these: http://wethepeople.de/V3/bilder/product/war119_004.jpg
(equal to this one, but to fit the 4bolt crank arm)

can someone please helpme to find technical info about the bmx sprocket
design + plus the truvativ 4bolt crank arm radius? this would be really
helpful!!
thank you very much for reading

Unless you have access to some flashy CNC machines, this is a job for
somebody who is already in the business.

http://www.highpath.co.uk/cycles/eggs/01.html

They've been in business for donkeys' years.

If you must do it yourself, the 4 arm design is easy to measure and
the engineering department at your library will help you to design the
tooth shape, which isn't rocket science; much simpler than spur gear
wheel design, for example.

Kinky Cowboy*

*Batteries not included
May contain traces of nuts
Your milage may vary

the chaintensioners were designed in rhino + machined in a 3axle cnc!

http://img167.imageshack.us/my.php?image=fosichaindn6.jpg
http://img155.imageshack.us/my.php?image=fosichain1xi9.jpg

ron said:

FoSi said:

Hi all..

Quoted message said:

can someone please helpme to find technical info about the bmx sprocket
design

Your tensioners are very pretty, but I venture to say that the chainwheel
sprocket you describe is a whole other deal, if it's something you want
to fabricate, as opposed to buy. (There are 1/8 inch fixed/single
cranksets you can buy - I have a 38-tooth one (branded "Cyclone"😉 that I
bought on eBay, and it works great for me with a BMX-style 1/8 inch chain.)

Take a look at the Wikipedia entry for CNC, which is probably what you'd
need if you wanted to fabricate something like a chainwheel from a blank
piece of metal.

Ron Abramson

🙂 sorry for my english.. and for the exclamation points! my bad...

Werehatrack said:

On 29 Dec 2006 14:11:32 -0800, "FoSi" <[email hidden]> may have

Quoted message said:

Hi all..
recently i converted my bike to SS fixed gear! using 17rear sprocket
33front sprocket! i have horizontal "drop-out" so i made a 10mm rear
Cr.Mo bolt axle to fit my Deore Hub! then i also did machined two chain
tensioners.. to micro-adjust the tension, and to have the wheel always
in place! untill here everything its fine!

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !
but i dont know were i can find technical info on how the sprocket is
designed! is there a document with the standards for this?

First observation: The overuse of exclamation points may limit the
enthusiasm of potential respondents.

Second observation: The thin sprocket will work just fine with the
wide chain.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

A Muzi said:

Quoted message said:

FoSi said:

Hi all..
recently i converted my bike to SS fixed gear! using 17rear sprocket
33front sprocket!

-snip-

Quoted message said:

Quoted message said:

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !
but i dont know were i can find technical info on how the sprocket is
designed! is there a document with the standards for this?
my setup>> http://img127.imageshack.us/my.php?image=fosisprocketbq6.jpg

-snip-

Quoted message said:

Quoted message said:

can someone please helpme to find technical info about the bmx sprocket
design + plus the truvativ 4bolt crank arm radius? this would be really
helpful!!
thank you very much for reading

[email hidden]

Quoted message said:

Quoted message said:

> Use a road chain...3/32 type. It'll work fine with the front ring and

back cog. If the 17t is a 1/8 pitch, get a 3/32 pitch one.

Why?
He already has a 1/8" cog and chain (which will wear longer than 3/32"😉.

Cheaper and easier than hand making a 1/8inch custom 4 bolt chainring.
Not sure he has a 1/8 inch cog, he didn't mention that.

Quoted message said:

He should not have any issues with 1/8" chain on his 3/32" chainring.
Sure. all one size is nice but no big deal. Like my own Record 3/32
ring with 1/8" Kool Chain. Smooth & quiet.

I use a track chain on my fixie as well. Record carbon crank, 42t ring,
1/8inch track cog..fine and dandy.

Quoted message said:

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

FoSi said:

🙂 sorry for my english.. and for the exclamation points! my bad...

DON'T apologize. I willing to bet your english is way better than our
grasp of your language..good job!

Qui si parla Campagnolo said:

FoSi said:

🙂 sorry for my english.. and for the exclamation points! my bad...

DON'T apologize. I willing to bet your english is way better than our
grasp of your language..good job!

hehe... I Portuguese, and live in Oporto 🙂 so i speak portuguese as my
main language...

"FoSi" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Hi all..
recently i converted my bike to SS fixed gear! using 17rear sprocket
33front sprocket! i have horizontal "drop-out" so i made a 10mm rear
Cr.Mo bolt axle to fit my Deore Hub! then i also did machined two chain
tensioners.. to micro-adjust the tension, and to have the wheel always
in place! untill here everything its fine!

so.. i purchased a BMX 1/2x1/8" chain, puted it in place.. and noticed
that the i need a thicker 33t sprocket at front!! like those BMX
sprockets to fit the 1/8 chain... so im thinking in designing and
building my own 33t front sprocket in 8mm 7075 aluminium !
but i dont know were i can find technical info on how the sprocket is
designed! is there a document with the standards for this?
my setup>> http://img127.imageshack.us/my.php?image=fosisprocketbq6.jpg

i have a 4bolt truvativ hussefelt crank, with the standard truvativ 33t
Cr.Mo sprocket.. i need to design a BMX thick 33t sprocket
like these: http://wethepeople.de/V3/bilder/product/war119_004.jpg
(equal to this one, but to fit the 4bolt crank arm)

can someone please helpme to find technical info about the bmx sprocket
design + plus the truvativ 4bolt crank arm radius? this would be really
helpful!!
thank you very much for reading

Well, you could make your own. But you need a new chainring to use as a
pattern, so you can get the teeth done OK without using a worn chainring
with worn down teeth.
Then you use a rotary table mounted on a milling machine. Drill the center
hole in a plate of aluminum or steel your choice of suitable thickness.
Then carefully mill out the circular shape in the plate of metal.
Then carefully mill out all the teeth. Then after you have your internal
pattern shape doen, mill out the internal web design.
Finally angle the rotary table and carefully mill out the angles as best you
can on all the teeth. You could even use a hand file or two to do this part
too.

Now you could use a CNC machine, but the devil is in the details, as you
have to program in your chainring design. For some people this can be a
major project in itself. But once you have the CNC program done and working
well, you can save it and reproduce your chainring anytime you want to.