Want to swap freewheel, any issues?

[bolyai]

My wife has a Trek Pure Lowstep. It is a 7 speed. She is sometimes outspinning the 14t-34t freewheel that came with it. I am considering swapping the freewheel out for an 11t-32t. If understand correctly, I will have to adjust the rear derailleur and possibly swap out or shorten the chain. Are there any other issues I might run into?

Also, in my naive understanding, this would allow for about 25% increase in top speed at a fixed rpm. Is this correct?

[trevgbb]

Your ex fw is almost certainly a screw on one, I don't think you will find an 11t screw on, which means switching to a cassette rear wheel, ie, a new wheel.
BUT, it is now difficult to find 7 a speed cassette, which means going to 8 speed, which means new shifters, chain, rear changer!!!
Search the shimano site for more info;
http://cycle.shimano-eu.com/
Youn could look at swapping the front chain wheel, but then you have to look at front changer, chain line, etc.

[Painkiller]

It is a fairly easy swap and you may not need to even shorten the chain
are you triple or single chainring on the front?
If you are single on the front maybe go to a bigger ring there also
a 50t - 53t on front matched to an 11t - 30t or 32t would make it more roady
with a combo like this you would need a chain replacement

[bolyai]

I have found an 11t-32t freewheel online, but I can't find much info about the brand (Epoch). The other option is to change the front chain ring, but then the granny gear takes a bigger hit, and the chain guard would probably then be the wrong size. She wasn't even using the high gear when she got the bike last year, so I will probably have to follow your advice and swap out the front chain ring by this time next year.

I was mainly worried there might be something I was missing about the process because I called the LBS and the guy indicated that he didn't know of anything that would really be worth the effort/cost for getting a little more speed out of the bike. To be fair, I doubt they have the 11t freewheels as I had a tough time finding one.

[Painkiller]

if shimano cassette fits walmart online has a 11t - 28t for around $16 us dollars and site to store
free shipping

[nfmisso]

(04-16-2011, 04:51 PM)trevgbb Wrote:  <snip> ...
BUT, it is now difficult to find 7 a speed cassette, ... <snip>

This is not true. Amazon, and many other sources stock 7 speed cassettes from SRAM, Shimano and others.

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(04-16-2011, 04:19 PM)bolyai Wrote:  My wife has a Trek Pure Lowstep. It is a 7 speed. She is sometimes outspinning the 14t-34t freewheel that came with it. I am considering swapping the freewheel out for an 11t-32t. If understand correctly, I will have to adjust the rear derailleur and possibly swap out or shorten the chain. Are there any other issues I might run into?
......

14 - 34 T is almost certainly a freewheel. Freewheels and cassettes are not the same thing.

The best you can do with a freewheel is 13 - 28T like these:
http://www.amazon.com/Shimano-510-0080-13-28-freewheel/dp/B001IORDH0/ref=sr_1_6?s=cycling&ie=UTF8&qid=1303015652&sr=1-6
http://www.amazon.com/SunRace-7spd-13-28-Freewheel/dp/B002FB2Y88/ref=sr_1_20?s=cycling&ie=UTF8&qid=1303015652&sr=1-20

My Raliegh Venture came with a 44T front chain ring, and 14-34T Shimano freewheel. It now has a 13-28T Sunrace freewheel, and a 48-38-28 triple crank set like this one:
http://www.amazon.com/Shimano-FC-M131-Tourney-Crankset-48-38-28/dp/B003ZMDJW6/ref=sr_1_2?s=cycling&ie=UTF8&qid=1303015807&sr=1-2
because it was a lot cheaper than a 48T (or more) single crank set.

I also spent another $15- adding a front derailer, shifter, cable stops and cable from discount sources - works great.

A 52 -39 might have been a better choice, like this one:
http://www.amazon.com/Shimano-Crankset-FC-A050-170-Chainguard/dp/B002K2GR76/ref=sr_1_3?s=cycling&ie=UTF8&qid=1303015981&sr=1-3

You also need a new chain.