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Swapping cogs made easy

9K views 40 replies 23 participants last post by  Hauffy 
#1 ·
After being introduced to a new cog technology on a previous thread, I decided to give the "quick-cog" by Lunar Bikes a chance.

The design is very solid with high quality manufacturing. I purchased this with 2 optional cogs that attach to the base. Changing them is very easy by simply removing a securing ring. I'm impressed with this product so I figured I would share.

I recently moved to a new area and I'm working on finding the best gear for the various rides. Also, as in most places, the terrain is vastly different from one trail to another so I can gear appropriately prior to heading to a certain location in only a minute.

For the record: I paid, my own hard earned money, for the quick-cog and I have no affiliation with Lunar Bike whatsoever. I'm just excited about this new product and wanted to let y'all know.
 

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#8 ·
Does this require a special tool or something I would ordinarily carry on my rides?
I looked into this a while ago and according to the site the cog can be swapped without special tools. IIRC anything pointy will do, like a knife blade, flat screwdriver or similar.

I'm very tempted to get this Lunar cog. Mostly I just ride 34/20 and don't worry about speed, but I have the feeling I'm missing out on something and can't be arsed to buy a 19t cog and change it. The chainwhip and lockring tool are a turn-off for me, I like to avoid touching them.

The gear clamp looks like a brilliant innovation as well.
 
#16 ·
There aren't any special tools needed and there isn't any play at all between the cog and the base. It's manufactured very tight and solid. I like the feeling of swapping it out without using the other tools and what I feel can turn out to be wear and tear on the freewheel body. The lock ring/spring, or whatever it's called, can be pulled off using a thumbnail.
 
#24 ·
Although the cogs are very easy to change, that was not the primary goal of the design. In fact the 1st prototype was a 3-piece design with the cog in the center and the cassette had to be dissembled to change the cog.

The primary goal was to make a low cost cog out of the highest quality material and manufacturing processes available. By using a two piece design, there is not much wasted material and machine time as you would get trying to machine it from one solid part. We are able to sell what is probably the highest quality cog out there for only $25; it would have cost 4-5 times that if it was machined from single piece. Also the cassette spline of any cog usually has no wear compared to the teeth, so paying for that to be machined every time you buy a new cog is a waste. Our driver can be reused with other cog sizes so there is no waste.

We have tested this design for the past nine months with heavy strong riders and so far not even a hint of any wear on the cog teeth or spline interface. The deep, large diameter spline interface has so much surface area that the load in pounds/sq.in is very low and will not cause any displacement or wear of the material.
 
#25 ·
Although the cogs are very easy to change, that was not the primary goal of the design. In fact the 1st prototype was a 3-piece design with the cog in the center and the cassette had to be dissembled to change the cog.

The primary goal was to make a low cost cog out of the highest quality material and manufacturing processes available. By using a two piece design, there is not much wasted material and machine time as you would get trying to machine it from one solid part. We are able to sell what is probably the highest quality cog out there for only $25; it would have cost 4-5 times that if it was machined from single piece.
Thanks for the background. The additional context really highlights the creativity and innovation that was applied to the product.
 
#27 ·
That's a good idea. I guess the only drawback is all the different spline sizes. Which ones do you think are the most popular?

FYI, we will have a matching SS four bolt 32T chainring coming out soon. Aluminum rings just don't hold up very long to heavy singlespeed use. I have already went through a few without any sign of wear on the cog.
 
#35 ·
The gear clamp does not really make any sense. If you have to take the cassette apart to change cogs, then just use spacers. Worst of all is having a loose cog in between the clamps, the standard spline is so small the last thing you want is a cog moving around on it and there is no way to develope any preload. A cog clamped with spacers and a lockring is going to be way better.

I agree it is a ugly solution to a problem that does not exist, actually it just creates more problems.
 
#39 ·
I've got one of each size Chris King Cog from 15-20 and use them all pretty regularly but when it comes to my local trails I needed a 22 to avoid killing myself. King doesn't make anything bigger then a 20 so I looked to Lunar for a solution with other possible advantages(easy swap cogs). So far I only have the 22 but I'm about to order an 18 & 20 to make swapping cogs during a 10 day bike camping trip easier. As far as durability goes, I've use it on only the steepest trails you can find, you know the ones that have most geared riders walking after a 1/2 mile and it hasn't skipped a beat. So far it's got about 200 miles on it with I luring one extremely steep 8hr endurance race.

As for the question of play between the carrier and cog. Well as a machinist myself there is a bit more then I would have expected but were only talking like a deg or two of play. It feels like a lot when you are over analyzing it but in reality it nothing your going to feel and will most likely to away after a bit of grim finds its way into all the nooks and crannys. Just for the hell of it I just powder coated my 22 orange because you can never be to customized. The extra couple .001 of powder coat has pretty much taken up any of the play that way originally there.

Orange Circle Gear Composite material Aluminium
 
#40 ·
I'm using the quick-cog since few months now and works great, there is a very very little play of the cog between the springs but don't affect the chainline, I think that a small play is good so the cog can follow the chainline better.

Interested to know how long the color last on the cog.

Having colored bases will be great!!
 
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