Add gears to Trek Pure Lowstep

[Kerry1976]

I have a Trek Pure Lowstep that I love, except for the gearing. It is a 7 speed and I am not happy with the first and second gears. So, I want more gears. I asked my LBS and he said it couldn't be done and suggested instead that i should try the Trek Shift 1. Uh....no - my Pure is a crank forward bike and that is just what I want.

but not being able to add any gears? Is that really the case? Trek used to sell a sport version of my bike - same body eith 21 speeds. It doesn't make sense to me that the bike is not upgradeable. Some ideas that I have been given on the Bentrider Forum was to try putting a 9 tooth back dérailleur to get a couple of more gears, or to try putting on a Patterson Metropolis drive. Would love any of your thoughts on this. Also plan to call some area LBS and see what they say too.

I also looked into the Electra Townie 21d and of course the RANS. However, there are no dealers of either within 3 hours and I really would be interested in modifying my current bike to make it work if possible. Sucks that my LBS won't help. The nearest bike shop is a good hour away.

[Kerry1976]

The Felt looks good, but it doesn't really look crank forward?

[OakLeaf]

A 9-speed freehub is wider than a 7-speed. You can spread the dropouts on a steel frame, but I've never heard of anyone doing that to aluminum - I would think it would be too brittle. Unlikely.

Swapping out the crank and adding a front derailleur and shifter *might* or might not be possible (I'm pretty vague on the intricacies of bottom brackets and chainlines), but it would cost you more than a whole new bike. If you *really* want to explore that, what I'd do is go to your local bike co-op and talk to the most experienced mechanic they have about both the technicalities of doing it, and the availability of used parts, with the understanding that you will have to learn to do the work yourself under the co-op mechanic's supervision.

A LBS mechanic isn't going to be too excited about teaching you how to jerry-rig stuff. It would be very major work. Think of swapping your car's engine out with an engine designed for a different vehicle. Neither cheap nor simple, right? Same exact thing here.

What don't you like about the current gearing? If your low gear is too low and too big a jump, it looks like there's a cassette available with a 28T low gear in place of the 34 you have.

[Becky]

On a "crank-forward" frame, I'd be surprised if there's a way to mount a front derailleur.

[OakLeaf]

She's right though, they used to sell a 21-speed. Unfortunately the photo doesn't show how the FD was mounted. But that would be an additional complication/expense ... either find the correct bracket from a junk frame, or have a machinist fabricate one. WAY more trouble and cost than that bike is worth.



ETA ... since there was a '12 model of the 21-speed, it's entirely possible some LBS somewhere has one lying around in your size. I don't know what Trek's dealer network is like in terms of being able to search for stuff like that, but if that's the bike you really want, it's probably well worth some digging. And failing that, eBay or Craigslist for a used one.

[Becky]

She's right though, they used to sell a 21-speed. Unfortunately the photo doesn't show how the FD was mounted. But that would be an additional complication/expense ... either find the correct bracket from a junk frame, or have a machinist fabricate one. WAY more trouble and cost than that bike is worth.

Thanks for the link. After looking at the picture, it jogged my memory. I've built up some bikes like that one, and there was a stub that was used as a place to clamp the front derailleur, almost like a false seat tube. I agree....tons of hassle and cost to retrofit this bike.

FWIW, I was able to dig up a 2 year old Fuji road bike, new in box in a warehouse, just by asking my shop to check Fuji's online inventory. I expect that Trek's system is very similar. Oak is right....try to find the 2012!