RoadBikeReview.com's Forum Archives - Fixed Gear


Archive Home >> Fixed Gear


What to look for in rear cogs(9 posts)

What to look for in rear cogswolfereeno
Jan 12, 2004 7:12 PM
I'm going to swap my rear 16 tooth gear with either a 17 or 18. Its currently an 81" gear and I want to go to something 72-76"

I was looking on Excelsports site and they have a couple of different cogs. Some indicate shimano compatibility - don't know if I need that. And another's listed as a BMX cog that can be used for fixed gears. I have no idea what kind of cog I need. The bike's a Bianchi Pista.

I may also buy a 44 front ring for a different combination I want to try. Any suggestions?

Also, I guess I need a bottom bracket wrench to take off the lock ring, correct?

Thanks
-Bill
Quality......... {NM}gspot
Jan 12, 2004 7:36 PM
re: What to look for in rear cogstrout_bum
Jan 12, 2004 7:38 PM
You want to use a track cog on a Pista. I believe the newer ones are 3/32" pitch. Mine is a 2003 and is 3/32. You can use Surly track cogs from excel or go to www.harriscyclery.com - they sell Dura Ace track cogs for $21.95. D/A is what comes stock on the pista, so you know these will fit perfectly.
The pista has a flipflop hub so you can mount a BMX freewheel on the other side of rear wheel - but not recommended to do without a brake(s)
As for the lockring a Park HCW-5 works well.
For the front you want 130T 3/32 rings
Good luck!
re: What to look for in rear cogswolfereeno
Jan 12, 2004 7:57 PM
Ok, so to utilize the flip flop on occasion, I'd need two different types of cogs. One that's BMX thread on. And another for the fixed side that's Shimano compatible? Yes?

What's 130T 3/32 mean for the front? I want a 44 tooth ring with 5 holes.

Pardon my ignorance.

Thanks!
re: What to look for in rear cogsgspot
Jan 12, 2004 8:27 PM
a BMX freewheel as mentioned before is a single speed freewheel. this allows you to coast, like on a geared bike. you can mount this on the other side of the hub, but its not a good idea without front and rear brakes.
you can buy 2 track cogs and put a larger one on one side and a smaller one on the other side, thus giving you 2 gearing combinations.

130 is the BCD of your crank arms. This is the size of the ring. Buy this size to insure it will fit with your current crank arms.
3/32 is the pitch of the chain, as some track chains are 1/8 pitch., but not your pista. (I think)

sorry for my unhelpful post above... :D)
re: What to look for in rear cogswolfereeno
Jan 12, 2004 8:38 PM
Sorry to be so dense

>>you can buy 2 track cogs and put a larger one on one side and a smaller one on the other side<<

So are they two different types of cogs? One for freewheeling one for fixed?

Thanks
-Bill
re: What to look for in rear cogsgspot
Jan 13, 2004 12:03 PM
sort of... there are track cogs, and there are bmx freewheels. bmx freewheels are used on single speed bikes, (not fixed gears) like bmx bikes. hence the name bmx freewheel.
a bmx freewheel allows you to ability to coast, while a track cog will not let you coast. They both will fit on to your hub. Do not use a bmx freewheel without front and rear brakes. It is dangerous.
this is a a track cog looks like.
I got this from :
http://harriscyclery.net/site/page.cfm?PageID=49&SKU=FW6880
this is like the one you need, only in a bigger size.
re: What to look for in rear cogsgspot
Jan 13, 2004 12:07 PM
a bmx freewheel looks like this. there are bearings inside to allow you to coast.
no worries on your knowledge, i'm here to help. ask any more questions you may have.
Ok, I get it!wolfereeno
Jan 13, 2004 2:32 PM
I just assumed that the freewheel cogs relied on the freewheel being in the hub. Didn't realize they have bearings of their own.

Thanks