Gearing Suggestions?

[michaelscycles]

I am going to build my next project bike and I am looking for suggestions on gearing. It looks like I will most likely use a 3-speed hub. It will have a 20x3" tire which stands about 1-1/2" taller then a standard 20". The bike will be mainly ridden on Rails-To-Trails, but there are some hills I need to consider. What size sprockets and crank length should I start with?

I had hoped to try and use a 5-speed, but I don't know if I will be able to make it work with the wider tire. Would it make sense to try and spread the frame, add a spacer on the other side, and dish the wheel over. The way I am thinking, 1/2" spacer and re dished wheel would only give me a 1/4" more clearance. Might be enough. I haven't tried to put anything together to see how it looks yet. With it being Easter, if I step into the shop, I will be headed for divorce court. I am lucky I can still get on here.

Thanks,
Mike

 

[Wildcat]

I experimented with different size sprockets on 3 speeds in the past. I always wound up needing a fourth gear when I was riding. I would keep it with the original gearing, because if you get a better first gear for hill climbing, second gear won't be good for cruising, and third gear will be just out of range. As for crank length, I would use the longest the bike can handle and still get clearance.

 

[michaelscycles]

It is a complete build so I do not have original gearing, the hub is from a 26" bike so even the rear could need adjusted. I just wonder what to start with. I do need some power for hills, not so much top speed. I want to draw attention with the bike, not go flying by everyone. I have a really cool front 44 tooth, just thought It might be too big. I guess if I need to go smaller later, it will be easier to shorten the chain.

 

[karfer67]

you can use a large front you will just need a large rear as well say around a 20 or a 22

 

[michaelscycles]

Great, I have a 22 coming for the rear and a 44 for the front. I'll start with that and see what happens. I have some smaller fronts if I need them, it is just I found a cool skull one that I could only get in 44 or 45.

Thanks!

 

[karfer67]

a smaller front will make it easier to take off but less top end speed