I'm currently in the process of modifying a 1993 Schwinn Crosscut into a drop bar configuration (actually using a Salsa Woodchipper).

This is the factory spec sheet

Its completely stock and in good shape. I'll be using hood brake levers and bar end shifters. Since you can't find 7 speed bar end shifters easily anymore, I'm getting the 8 speed Ultegra units. I figure, if possible, I'll add an extra cog in the back for a little more range. I've already figured out that the rear derailleur will be compatible with an 8speed setup.

The 7-speed freehub body is too narrow to fit an 8-speed cassette.

I've never been personally satisfied with the results of mixing and matching 7-speed cassettes and 8-speed shifters and vice versa, but some other people report do report satisfactory results.

Another possibility would be to eliminate the largest cog off of an 8-speed cassette. The resulting cassette would fit your 7-speed freehub body and would be spaced to index perfectly with 8-speed shifters.

Yet another option would be to use the 8-speed shifters in friction mode. If it was my bike I'd try to make the shifters index with the 7-speed cassette and, if that didn't work, convert the shifters to friction.

7-speed freehub bodies are shorter than 8/9/10-speed bodies, so no. You can do 8 of 9 on a 7-speed body, but it'll require a 9-speed shifter to index well.

Going to have to do a lot of work, 8 is wider than 7, so wheel is wider ,
and frame rear, wider to fit.

just buy replacements.. with maybe a different set of 7 in mind.

you have a reason to need the 8th sprocket, need a 12 T cog?

I guess I need to measure the rear spacing as I was planning on building up a new set of wheels for the bike in the future anyway. I assumed it was 130mm since its a hybrid and has mostly mountain components but I guess I need to confirm. If this is the case, I'll just go 8 speed when I get new wheels built. If not...I need to rethink how I'm going about this build. Luckily I haven't ordered any parts yet.

And to answer the question, range is always nice but I don't NEED 8 gears in the rear. Unless I stumble upon some 7 speed bar end shifters, I really can only find 8 speed shifters which is what is driving this change in the first place.

As is the bike functions beautifully except for a grabby front brake resulting from an uneven braking surface on the front rim (one of the reasons I'm getting new wheels).

If you do rebuild the rear wheel and buy new shifters it would make more sense to use 9-speed shifters, cassette, and chain. 8-speed components are becoming hard to find.

If it is a shimano freehub you can find an eight speed freehub body to fit it. You may have to change the spacing.

I would imagine since the sweep distance is the same between an 8 and 9 speed cassette, my derailleur should be able to handle a 9 speed configuration? Since I haven't bought the shifters yet, it shouldn't be a problem. I was just trying to avoid redoing the entire drive train.

Your derailleur should handle the 9-speed width, but the shifters and chain need to match the cassette.
Staying with 7-speed is not a bad idea, but you'll need 7-speed shifters. If your hub is a cassette/freehub there is the possibility that the freehub can be replaced with a 9-speed freehub meaning that you would not have to rebuild the wheel. It depends on your particular hub.

This really helped, thanks. When I bought the bike, I intended on getting new wheels for it. I'm about 205lbs and it'll be pulling commuting duties (bags) and functioning as my grocery getter in an urban environment. The wheels on it now are not very stout.

So it looks like a wheel set, a 9spd cassette, and 9 speed shifters are the way to go. Thanks for the help guys.

I recently built an 8 of 9 on 7 setup and it works very well with 9 speed bar end shifters. The advantage to this is that you can use your 7 speed hub. I used an 11-28 9speed cassette, removed the 11 and 12 cogs and replaced them with a 12t lockring and cog. I'm really pleased with this arrangement. I didn't need an 11t cog, 9 speed cassettes and chains are reasonably priced and readily available. I tried to set the indexing with the extra position at the small cog end of the cassette but it didn't work well. I then set it with the extra, unused click at the large cog end and it works great. No idea why it wouldn't be the same either way. Possibly has to do with cable pull not being the same for each position.

I had a 7 speed cassette with 6 speed bar ends, upgraded wheels and now have a 9 speed cassette with the same bar ends (though have a set of 9 speed to upgrade, just need time). I use it in friction, and have no problem at all. The derailleur and shifter handle the 9 speed with no issues. For awhile I also used the 7 speed cassette on the new wheels, just needed a spacer ring. Sheldon Brown has some good info on compatibility questions.

Exactly. First pull is longer, to get the slack out of the system.

Wescoe, Unless the 7S used an 8S freehub and a spacer between the hub and cassette, you're SOL. I suspect that your freehub, as early as it is, isn't wide enough.

Brad

https://share.ovi.com/media/currentre...resident.10061

You may need to spread the frame slightly at the dropouts to fit a 9-speed hub. But with a steel frame this should not be a problem. With 9-speed shifters and cassette you will also need a new 9-speed chain.

Ended up with 2 bikes ($15 beat craigslist find 10 mins from the other bike I bought), one is a flatbar setup with old Shimano Alivio 8 speed shifters from an old MTB. Its using a 7 speed cassette and I just limited the rear derailleur out to the cassette limits like you'd normally do. It indicates gears 2-8 are being used on the shifter pod but I don't care. It works.

For the drop bar setup that I got 10 speed bar end shifters, a 10 speed cassette and a 10 speed chain to be used with Shimano 105 hubs laced to Mavic A719 wheels. I'm waiting for wheels to arrive so I can finish the build.

Even though I ended up spending more than anticipated, I ended up with a beater bike that cleaned up well that cost me $15 and some donations from the spare parts bin that I won't sweat leaving locked up and a nice rando/touring rig that is going to end up being nicer than anticipated. I'm happy.

I find the ratio set of Shimano's K cassette is excellent,
8th is just adding another cog , to little benefit.
work out the ratio math and decide if you need another ratio.