Cogs?

[PutAwayWet]

I just ordered a couple of new cogs for my new SS wheel. I got the dimension cogs (http://www.ride-this.com/Dimension-SS-or-BMX-Cog-20070020.html). What I'm wondering is this - why are they only $2.99 each compared to the Surly or WTB cogs at $20-$40? Is there that much difference? Even if they last 1/4 as long, I can buy 10 for the price of 1 WTB cog. So what's the deal here?

[DirtRagArt]

Well, those are not wide-based cogs. If your nice new wheel has an aluminum freehub body, the thin steel cog will tear into the splines in relatively short order. Wide-based cogs (see attached) cost more to produce, but won't eat up your freehub.

And the more expensive cogs (http://www.ride-this.com/Surly-Single-Speed-Cog-20070019.html) are made in smaller batches and see more in the way of quality control than the inexpensive ones (http://www.ride-this.com/Dimension-SS-or-BMX-Cog-20070020.html).

[Spatafore]

Just as a guess, the thinner cogs are probably stamped out of steel plate. Then, there might be very minimal machine work to taper the edge and to thread. A press could punch out several of these in a fraction of a second. The thick cogs are most likely machined out of tubing or bar stock. This would require more material and alot more labor. This could also be a one at a time deal with the use of a lathe.

[Goride]

I would hope that more expensive cogs are built to tighter tolerances all around. Potentially rounder and better fitting, especially with boutique hubs. And they might be lighter, some of them considerably so.

The stamped steel one however, may last longer. But we're talking years of life either way - I ride a lot of miles, nearly all singlespeed/fixed. Since the advent of high-end freewheels (White) and cogs (King, Endless, Surly, Misfit etc) I have yet to replace one for wear.

[myron]

The Cod Cogs are very light,nearly negative grams,er such.

[rockyrider]

I've tried the Endless KickAss cogs and the Misfit Cod Cogs, and they both fit very snuggly onto standard geared freehub. Those two cogs have slightly different tooth profiles but I can't say that I've ever lost a chain off either, even on the Kona A FS frame. The KickAss cogs are silver and the Misfit cogs are black.

I had a Gusset conversion kit with the steel cog and it was busy trying to cut a notch through an aluminium freehub splines after a year of use.

[Spatafore]

The Misfit cog Jeff posted is made out of 7000 series aluminum which has zinc to produce a high strength alloy. (6000 series that is in alot of bike frames has magnesium and silicon to produce a moderate strength alloy.) 7000 series is the strongest.

That "T-6" designation means that the material is heat treated in a solution and then it is artificially aged for added strength.

[nogearshere]

The Misfit cog Jeff posted is made out of 7000 series aluminum which has zinc to produce a high strength alloy. (6000 series that is in alot of bike frames has magnesium and silicon to produce a moderate strength alloy.) 7000 series is the strongest.

That "T-6" designation means that the material is heat treated in a solution and then it is artificially aged for added strength.
ya.
what he said!

PAW it comes down to the hub you are going to run it on and just how ready you are to commit.

A steel freehub body is not going to suffer the same damage from a punched steel cog (if any) as say an aluminum or Ti freehub (body).
I also suggest that people experiment with ratios (on steel cogs) before buying the wide base...afterall not everyone can afford 3 @ 30$/ea...meself included.

...and finally remember to consider the total cost of the cog...2.99$ is a 27$ savings...but if it renders a 200$ hub useless...

[2dumb4gears]

I've run (and am currently running) both the Endless and King cogs. There does not seem to be any quality or performance difference; the king is just a little more machined out and consequently lighter. Both work great, and you really don't wear things out very quickly (if ever) with a singlespeed drivetrain. All the wear and tear comes from shifting up and down over the cogs.

Don't run anything without a wide base. Skinny guys dig into your freehub body in a major hurry, and it's not worth killing a hub over.

[DirtRagArt]

7000 series aluminum is more difficult to heat-treat, as well, whereas 6000 series can sometimes be heat-treated in something as simple as a pizza oven. But I think that really pertains more to welding than cold working...

I had a thin based steel cog cut all the way through an aluminum freehub body to where it almost spun freely. Thankfully, it was a full size 9-speed hub, and I was able to adjust my chainline so that the new wide-based cog didn't rest on the damaged portion of the splines.

[sscooley]

Umm... wouldn't it make more sense to save your expensive freehub wheels for your geared bikes and get a single speed specific rear wheel? Shimano freewheels are so cheap as to be nearly free, upgrades are also relatively cheap, until you get to White....

[2dumb4gears]

I've run a freewheel setup for a long time, and I'm glad to be back on a cassette hub. I have a White Industries freewheel, and it runs perfectly. But try changing one out for your nightlaps at a 24 hour race when you want an extra tooth. Or try adjusting your chainline if you run a funky crankset or your wheel is less than perfectly dished or your frame is out of true, etc.

[rockyrider]

...or converting to a dingle speed for one particular ride. That kind of flexibility is nice with a freehub. I have a SS rear wheel with a Misfit hub and it has a short splined freehub that could accommodate two wide based cogs in a dingle format.

[rattlecan]

7000 series aluminum is more difficult to heat-treat, as well, whereas 6000 series can sometimes be heat-treated in something as simple as a pizza oven. But I think that really pertains more to welding than cold working...

.

actually you have that backwards. 7005 has a post weld heat treat that can just be artificially aged by baking it for about 10 hours, however 7075 is not a weldable alloy but it is heat treated after it is extruded, then is machined. no heat treating is nessescary after machining any aluminum alloy. 7075 is a good chice for this aplication because of the surface hardness is much tougher than that of 6061 or 2024. 2024 is a good alloy for parts like stems and setposts and handlebars where no welding and no surface abrasions are involved. it is very soft, incredibly strong, and produces a beautiful machined finish. 6061 is the generic alloy of aluminum- it is weldable , machinable, and most available and least expensive of the aluminum alloys. its post weld heat treating is very energy consuming however. for example - say a 6061 frame- it gets welded and near the weld zones its temper is affected so you have to bring the entire frame up to almost the melting point then quench(cool) it in water and glycol solution to bring the frame all to the same SOFT(t-0) state... then you slowly add temper to it by an aging process similar to that of 7005. 7005 is the miracle aluminum for welded bike frames but the material is 4X more expensive than 6061, if you can even find it. ive looked into geting some bars spit out from a local extruder then selling them to bike companys- my investor(cha ching$$$$) was not impressed by the numbers. basically there are two sorces for 7005 and one is easton and the other is out of taiwan.(big surprise)

i still question the durabilaty of ANY aluminum cog, to me it just doesent seem like a good idea (way way too soft of a material)but who knows- maybe you will have good luck with the five or so grams you save over a steel cog.
if i was to design a cog id want the hardest steel i could find and make it wide at the base.( i like the surly design) think about that part of your bike for a minute. its dirty, full of very hard and abrasive grit and under massive pressure from hardened steel rollers and chain side plates. i think ti would be a better choice than aluminum but that stuff still likes to gall. i wonder what anodizing misfit is using on their cogs. you can increase the surface hardness dramatically with a good ultra hard ano. (think about those old mavic rims from back in the day) but still, under pressures a coating is still only as good a the material underneath.

anyway---

jeff, what do you have to say about the boone ti cog you have? ive gotten a bunch of emails from kids asking about that cog. she sure is a pretty flower.

i just got a set of dt 240 single speed cassete hubs for my 29er and im kinda looking for a 19 t... i wouldnt mind getting a misfit cog, just to see how long it lasts under a normal season of single speeding. it isnt that expensive and they look cool. i am just super curious about the durability.


here is a joke...

ya know that guy who invented the aluminum extrusion process?

he just took a dump.



eric.

[tryandgetme]

...or converting to a dingle speed for one particular ride. That kind of flexibility is nice with a freehub. I have a SS rear wheel with a Misfit hub and it has a short splined freehub that could accommodate two wide based cogs in a dingle format.

I ride like that 100% of the time. Still need the wrench to change ratios, so I still call it a singlespeed. I put the big cog on the outside to throw the attentive for a loop. It's two regular steel cogs with a spacer though, but I'm pretty sure Peter used a steel freehub body there. I'm a big fan of that hub.

[PutAwayWet]

Umm... wouldn't it make more sense to save your expensive freehub wheels for your geared bikes and get a single speed specific rear wheel? Shimano freewheels are so cheap as to be nearly free, upgrades are also relatively cheap, until you get to White....

I've been running a Surly flip/flop hub with ACS/Shimano freewheels for two years, just upgraded to a Hadley SS hub with a SS cassette body. I've got my ratios down pat, so I'm really not experimenting any more. If I do want to, I've got the Surly still. Really what I was looking for was the more engagement points on the freehub. SSing in rocky/rooty areas requires mucho rachetting (sp?), and lots of people tell me that I'll really appreciate the difference from 24 to 72. I ended up ordering the Surly cog. The Hadley is a Ti freehub body, so I'll keep a close eye on it and if it does start to carve a notch I'll switch over to the Endless cogs, which are even wider. Thanks a ton for all the input!

[DirtRagArt]

I'm a little late, but I just found the hub I mentioned earlier. Here's a photo of what can happen...

[nogearshere]

I'm a little late, but I just found the hub I mentioned earlier. Here's a photo of what can happen...

clearly a surplus of power coming from that engine...if you lowered the ratio herc that wouldn't happen.

[phlatlander]

clearly a surplus of power coming from that engine...if you lowered the ratio herc that wouldn't happen.

I have seen a pic of Jeff's leg sliced wide open. Enlarged to 1600%, I could clearly see the bionics.

ps Jeff, do not show us that pic again.

[DirtRagArt]

I have seen a pic of Jeff's leg sliced wide open. Enlarged to 1600%, I could clearly see the bionics.

ps Jeff, do not show us that pic again.

This one???

[PutAwayWet]

I'm a little late, but I just found the hub I mentioned earlier. Here's a photo of what can happen...

Nice gash. Also, I decided to order some stuff from a random company I found whilst surfing the inter-web - something like Moshpit....or mashed potato...or was it misled? Oh - Misfit! I gotta stop smoking oregano. Gots me a cog and some other misc small parts on order from those fine people. :) I'll be damned if I'm gonna cut through the only piece of Ti I own.

[vladamir]

I've got a Surley cog on the MTB and have been running it for a year with no wear to be found, I have been running an ACS cromo freewheel on my commuter for four years and it shows significant wear.

Four years and two chains is not bad IMO. I hope the Surley holds up as long.

[vladamir]

This one???

Thats gross Jeff! I hate it when you show that pic!:D

[nogearshere]

Also, I decided to order some stuff from a random company I found whilst surfing the inter-web - something like Moshpit....or mashed potato...or was it misled? Oh - Misfit! I gotta stop smoking oregano. Gots me a cog and some other misc small parts on order from those fine people. :) I'll be damned if I'm gonna cut through the only piece of Ti I own.
oh sorry to hear that...got this off the misfartsicles blog.