Consequences of replacing 11-34 7-speed cassette with alternate 7-speed cassette
 

So my GF's rear wheel on her 2003 Trek 7200 was stolen the other day. In looking to get a replacement set up, the wheel seems easy enough (700c x 35), but the stock cassette - a HD-50 7-speed 11-34 - is no longer made by Shimano (Sunrace does make one that appears as if it may be compatible). I'm assuming this basically eliminates the chance of finding a used 700c rear wheel with an acceptable cassette already installed, but I wanted to inquire about the "consequences" of replacing the 11-34 with a more commonly found 7-speed cassette (say, a 12-32, 13-34)? She uses the bike mostly for commuting on paved roads with little elevation, so the top and bottom gears would likely not come into play that often, if at all. (the bike also has those grip shifters, which aren't all that "precise" to begin with).

Does anyone know (or can anyone tell) if the sunrace 7-speed cassette (or the Shimano HD-50 7 speed cassette on the lost wheel) is for a freewheel or a freehub? http://www.amazon.com/SunRace-CSM63-.../dp/B002G3BMKQ

I've looked into getting a new wheel and casette, but I'm having trouble finding a wheel with an appropriate freehub for the 7-speed cassette (the Sunrace one mentioned above), either new or used, so perhaps it is a freewheel setup? I've seen many wheels with freehubs for 8 & 9-speeds, but it seems I can only find freewheel setups for 7-speed.

I'm trying to do this on a bit of a budget, so if anyone has any advice or alternatives, I'm all ears and thanks in advance!

I'm assuming that the rear dropouts are 130mm in width since its a road bike.

With that said, you should be able to find tons of 700c wheels with that width rear setup. That is the important part.

If they have a 8-9-10 speed sized hub, it is easy enough to add a spacer to the freehub and use a 7 speed cassette.

If it were me though, what I would do is look for nice used 700c wheel with an 8-9-10 speed freehub, a decent 8 speed cassette, and a nice set of 8 speed shifters and install them in place of the 7 speed stuff.

That way you would get rid of the awful grip shifters and upgrade the wheel at the same time.

You probably won't find any new 700c wheels that have a 7 speed sized freehub which is why lots will use spacers with an 8-9-10 speed freehub if they insist on using a 7 speed cassette.

1. Measure the distance between the rear dropouts in millimeters. If it's 130 mm or 135 mm that's good. That should match your new wheel's OLD (over locknut dimension).

2. Find a 700c rear wheel with the required OLD. Don't worry that it's an 8/9/10 speed freehub body.

3. Find a 7-speed cassette with the cogs you're looking for. If your girl friend doesn't use the easiest hill climbing gear, get one with closer spacing between the gears.

4. You'll also need a 4.5 mm cassette spacer. When your new wheel arrives, put the spacer on first. Now look at your cassette. If it's held together with rivets, file off the little nubs on the big cog side of the cassette before installing it on your new wheel.

5. You'll derailleur may need some fine tuneing but fine tuneing should be all it takes.

Are you sure it was a 7 speed? Trek shows an 8 speed for a 2003 7300. http://www.trekbikes.com/us/en/bikes/2003/archive/7300. I'm going to guess the rear axle is 135mm but I don't know for sure.

Rear axle is almost definitely 135mm OLD... hybrids generally use mountain bike parts.

http://www.bikepedia.com/QuickBike/B...7200&Type=bike

Bikepedia confirms the OPs statement that the 203 7200 came with 7 speed, but does not specify if it is freehub or freewheel . No matter, as whatever wheel is purchased, get a cassette or freewheel to match. I would recommend getting a freehub wheel, which will most likely be a 8/9/10 speed, any 7 speed cassette* installed with an extra spacer to compensate for the wider 8/9/10 speed freehub body, a new tire, tube, and rim-strip. To buy all this new will likely cost between $100 and $150.

*Since you had just about the widest possible range - the smallest cog and almost the largest cog - on the original wheel, you only need to slap whatever new cogs on that you can find, adjust the limit screws ont he derailleur, and adjust the cable tension. No other modifications should be necessary.


A 7-speed freewheel compatible wheel and 7 speed freewheel might be a little bit cheaper than a cassette wheel, and should also work fine. You choices of 7 speed freewheels might be more limited than that of 7 speed cassettes, though.

According to OP, it is a 2003 7200.

Thanks for all the info all - I have an inquiry into Niagara cycle to see if the sunrace 7-sp 11-34 is FW or FH. It seems I have options though - our hope is to find a decent used wheel (hopefully with a tire serviceable tube, rimstrip, and tire) and just have to replace the cassette. However, I read the following on SHeldon Brown's site regarding cassettes with an 11 tooth sprocket:

Shimano uses the trademark "Hyperglide-C" to designate a system with an 11 tooth sprocket. The "C" stands for "compact". These systems are used with smaller-than-usual chainwheel sizes, or on bicycles that have a small drive wheel, or to achieve higher gears.

Due to clearance problems, the cutaway between the splines on 11-tooth sprockets only goes halfway through the sprocket. The matching splines on Hyperglide-C bodies don't go all the way to the outer end of the body.

If you install a cassette with an 11 tooth sprocket on an older, non-compact body, the cassette will not be properly secured, and the sprockets (other than the 11) will be loose and wobbly.

Is this something I need to be concerned with when determining what "type" of FH (is it the FH body Sheldon is referring to?) would be compatible with the 7-speed 11-34 cassette?

Tirees, tubes, rim tape are all wear items... you are much more likely to find a wheel with a cassette or freewheel installed but without a tire and tube. Plus, tires and tubes can be purchased for $10 - $20 new for very basic ones.

It's a hybrid, not a road bike.

The "C" body is only a concern IF you plan on using an 11T small cog.
A larger small cog can be used on a "C" body.

I picked up a rear Hybrid wheel for about $40 on Amazon a couple months back.
Add a 4.5MM spacer to the 8/9 speed hub body and you have a 7 speed hub body.
The LBS will have spacers for a couple$.

Might as well get a cassette that lets her use all the gears.
One of the first things I did on my Hybrid was get rid of the ridiculous 11 & 32T cogs I had.
They were both useless to me.
Something like a 13-26 might be good.
If the bike has 28-38-48T rings, the 26T works good with the middle ring for a start gear and flitting around the neighborhood.
If you get out "cruising", you can switch to the big ring.

The consequences are that you get rid of the useless 11 tooth cog.

Excellent - this (and the info from others) is what I was hoping to hear. I actually have an older Rolf Vector rear wheel that, while not ideal, does seem to fit and may be a serviceable stop gap while we look for a replacement wheel (it currently has an 8-speed cassette on it, so I still need to put a 7-speed cassette on it + spacer). The wheel / tire is slightly narrower than the front (I think 28 or 32mm vs 35mm in the front), so we'll have to test how the bike reacts before any long commute, but there doesn't seem to be any clearance issues...