Brilliant or retarded?
 

I'm builidng my old Bottechia road bike as a winter beater/buddy bike(you know, when your buddy wants to try fixed out for size) and I had an inarresting thought. The bike has a cottered crank with a 52 and 43 ring on it. I don't want to buy a new crank set for a beater. It also has an SS wheel on it. I'm going to pull the freewheel and build it as a suicide hub. My options are to run 52X18, a gear ratio that I love, but one that a newb ain't gonna like at all. I can run it 43X16, spinny for the newb, but my Paddy wagon is geared around there, so I'd like the taller 52X18. Long story short, I want to do both; 52x18 and 43X16 on the same bike on a "suicide" hub. I'm running brakes and not skidding with bike, so I'm not much worried about the cog(s) rotafixing off. I'm going to try and use a lock ring if there is enough threading left over after two cogs and some spacers. My reasoning is that if I can get a decent chainline on either chainring with the freewheel, I should have enough room for two cogs. I'm going to run one chain with two master links to switch gear ratios.

Any thoughts? I'll be posting photos when(if) I manage to build this monstrosity. This bike was beat to death before I got it, but I like it.

Do it.

compromise and run a 17?

I don't wanna compromise. The whole point of this excercise in stupidity is to not pull the cottered crank and remove the 43. I think that both gears would have an ok chainline, and I don't recall seeing a dual ration fixed gear suicide hub bike yet. I want a ******** bike. When you see this pile of crap, I think you'll understand.

Check out the Surly Dingle cog: http://surlybikes.com/parts.html

http://surlybikes.com/new/images/FW0604.jpg

17 cog, instead of an 18 and a 16. you wouldn't have to pull any chainrings, just install one less cog. the chainline won't be great but this is a ******** bike so who cares?

That dingle cog is killer. I don't think it will work for me, though. The chain rings have a ten tooth spread and I don't have a track hub. I gotta take the bike to the shop on tuseday morning and see what they say. Alls I need is some spacers and the 18t.

You have a point. I kinda wanted to justify leaving the 43 on there by having a use for it. Oh well, maybe this is what I will do, after all.

In my experience most converted/suicide wheels only have room for 1 cog and a lockring 50% of the time. I know you mentioned a single-speed hub, so I guess that could be different, but with a normal wheel there's no way you'd have enough threading.

You have a point. I kinda wanted to justify leaving the 43 on there by having a use for it. Oh well, maybe this is what I will do, after all.

So I guees the answer to my question in the thread title would be ********. Oh well, thanks everyone. I guess I'll just get a 17t cog.

You could put two cogs on if you thread one on partway, thread in an adjustable BB cup, and thread the second cog onto that. It's sometimes done with freewheels for retrodirects, but i don't know how it would hold up fixed.

I may be missing the point but, at te point of having 2 cogs on the same side, why not go with a multiple geared bike with a RD and a single chain ring?

Yes, you completely missed the point. he doesn't want to replace the crank. He wants both chainrings for different ratios, he likes a very tall gear, his friend wants to try fixed but won't be able to push that, so he wants the smaller chainring for him, but with the same sized cog, his friend will be spinning like mad, so he's thinking about running 2 cogs. I would just run the 17t

I would just stick with the 43 ring. Either get rid of the 52 ring or grind off its teeth if unable to remove for some reason. Keep it simple.