rant- proglems getting my cogs working
 

My road bikes had been working well for a number of years so I had forgotten all the intricacies of freewheel cog wear vs. chain wear.

Since I totaled my road bike I'm riding my "garage sale" Trek hybrid. It came with this monster 13-34 freewheel. I had a couple of 13-21 freewheels from my road bikes so I put one of them on, the 16 and 18 cogs were welcome additions. It worked reasonably well but I apparently used the 16 the most and got chain skipping on it. Tried the other 13-21 with the same result. I measured the chain and it was +1/16" or maybe a bit more so I put on a new Hyperglide chain. Now it skips on most of the cogs. I didn't realize that my chains and freewheels had worn together so much on my road bikes. I put the original pizza freewheel back on for my ride today. I have 2 or 3 old freewheels that I haven't tried yet, including a 13-19 straight block. I'm going to try that one next, it would be pretty interesting to have a straight block on something that looks like a mountain bike.

http://i15.photobucket.com/albums/a3.../photo514b.jpg

The only thought I have is why? Why change out the Megadrive gears if their not worn? Sure you probably don't need the granny gear, so then don't use the granny gear. It's not like you're going be racing the Trek Hybrid are you? If the old gears work just slap it back on and be done with it. Just a silly thought.

I can understand dumping the megadrive and going with a narrower cassette especially if the OP is using the bike on the road. If the local terrain doesn't call for very wide gearing, then the closer spacing of mid range gears which actually get used is a major improvement.

I try to set up my bikes so I do most of my riding in the sweet spot of the cassette where the percentage stems are smallest. That gives me them best selection of similar gears to adjust for slight grades, wind, or just an off day within the gear range that I use 80% of the time. Of course if the terrain called for it, I'd want a nice low low gear, but if not, it's just dead weight at the expense of usable gears.

Matching up a used freewheel and new chain will nearly always be problematic. You may have to find the freewheel that works "best" (but not perfectly) and then put up with chain jumps while the new chain wears to match the cogs.

IMO, a Maillard freewheel is inferior to a Shimano. The tooth profiles are almost made to keep the chain from dropping onto the cogs properly.

+1 The older Mailards seemed to have very different feel they seem to be made to hold a gear rather than shift like most modern stuff. They ride great ounce in a good gear but just seem to want to stay there and dislike shifting to another gear.

A new freewheel costs 20 bucks or less. Unless you are on a very tight budget, this might be the easiest way to go. Then the new chain and freewheel can wear together and your problem is solved. I understand wanting to reuse anything you can to save some bucks, but if you're not happy with the performance and are spending a lot of time swapping cassettes without significant improvement, it can be false economy. If your garage sale hybrid is a temporary solution that will soon become your crappy weather, Plan B bike, I'd just put the original freewheel back on and live with it saving the money to go toward the new Plan A.

The gaps from 13 to 15, 15 to 17 and even 17 to 19 are bigger than what I like. On my road bike I mostly used 42x16 for normal cruising. On the heavier hybrid with bigger tires and more upright riding position I find that its 38 would still work well with a 16, but I didn't have one. My area is mostly flat and I used to ride all the time with a straight block 13-19. With the hybrid and my legs that haven't ridden in 2 years I still get by with the center chainring and nothing bigger on the freewheel than a 19. I thought my 13-21 freewheels would be ideal since they added a 14, 16 and 18. Riding with them was much better than with the megadrive even though I got skipping on the 16 if I tried pushing hard. I put on the new chain trying to improve this but made it worse. I put the megadrive back on yesterday for my 40 mile training ride and it went OK although I missed the 14 and 16. I could probably get in the habit of using the 48 chainring but I don't like the chain angle I get with that.

This afternoon I'm going to rummage through my old parts box and find out what other old freewheels I have. I'm certain I have the 13-19 still but I'm not sure what others. I remember a 13-23 that I used to have and maybe a 13-24, but I only have one freewheel remover left and some of those old ones might use a different remover which would eliminate them from candidates for a quick experiment.

And BTW the 13-21 freewheels didn't shift quite as well as the megadrive but they shifted well enough.

Today I put on my old Shimano 13-19 straight block, and it skipped under load. This is the end of my search, I put the original megadrive freewheel back on for the HHH in 3 days.

I don't recall problems with any of these freewheels when used on my road bike, with new or old chains. I don't know what's different about the Trek but I don't have time to fool with it any further, just ride it.