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Discussion Starter · #1 ·
I have a 1990 Specialized Sirrus with a 7 speed cassette and DT shifters. I pulled a 9 speed wheel off another bike and it fit fine in the drop outs. I then switched the DT shifters to friction and adjusted the limiter on the rear deraileur and was able to shift all the way from top to bottom. The only problem is that the chain is just a little too wide to fit onto the middle gears correctly. Without any precise measuring equipment, I just took a cresent wrench and adjusted it to the chain width on the 7 speed chain and then took the wrench over to the 9 speed chain and see that the 9 speed chain is definitely thinner.

Is the only thing I need to make this conversion is a 9 speed chain??? Could it possibly be that easy? Will the 7 speed cassette still work with a 9 speed chain if I need to switch them back? Can I just buy a 9 speed cassette to replace the 7 speed cassette and have two 9's?

Thanks for any help. I attached a couple pics to show the fit.
 

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NeoRetroGrouch
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handsomerob said:
I have a 1990 Specialized Sirrus with a 7 speed cassette and DT shifters. I pulled a 9 speed wheel off another bike and it fit fine in the drop outs. I then switched the DT shifters to friction and adjusted the limiter on the rear deraileur and was able to shift all the way from top to bottom. The only problem is that the chain is just a little too wide to fit onto the middle gears correctly. Without any precise measuring equipment, I just took a cresent wrench and adjusted it to the chain width on the 7 speed chain and then took the wrench over to the 9 speed chain and see that the 9 speed chain is definitely thinner.

Is the only thing I need to make this conversion is a 9 speed chain??? Could it possibly be that easy? Will the 7 speed cassette still work with a 9 speed chain if I need to switch them back? Can I just buy a 9 speed cassette to replace the 7 speed cassette and have two 9's?

Thanks for any help. I attached a couple pics to show the fit.
As long as you stay with friction shifting, the 9 speed chain is all you need.

I believe the 9-speed chain will be too small on the inside to fit on the 7 speed cogs.

A 9-speed cassette will not fit on the 7-speed freehub. (If you take the 7-speed cassette off and find a spacer behind it, it probably is a 9-speed hub.)

TF
 

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Discussion Starter · #3 ·
TurboTurtle said:
As long as you stay with friction shifting, the 9 speed chain is all you need.

I believe the 9-speed chain will be too small on the inside to fit on the 7 speed cogs.

A 9-speed cassette will not fit on the 7-speed freehub. (If you take the 7-speed cassette off and find a spacer behind it, it probably is a 9-speed hub.)

TF
Can I tell if there is a spacer without removing the cassette?
 

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NeoRetroGrouch
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handsomerob said:
Can I tell if there is a spacer without removing the cassette?
Don't know, I've never done it. - TF
 

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If you are going to wrench your own bike removing a cassette is just about the easiest thing you can do. After you've done it a couple of times it should not take more than 5 minutes to remove and re-install your cassette. You'll need a chain whip and a lockring tool.

Al
 

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Bike Dude
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After you pull the cassette off

If you find there isn't a spacer back there (dosen't look like one in the photo) there's a fairly inexpensive way to convert that old hub into a 8/9 speed.
Pull the axle and bearings off and lay them out after cleaning in the order you pulled them off. Pull the axle off of the non-drive side. What you'll have is the hub with the splined cassette carrier. Look down into the carrier and you'll see a large allen head bolt, this holds the carrier onto the hub. Unscrew the bolt and remove the carrier. Buy a new 8/9 speed cassette carrier, re-grease bearings, install axle and slide on a new 8 or 9 speed casstte. It's very easy to do. Buy yourself a cassette removal tool, chain whip and metric allen wrenches if you don't already own any. Your local bike shop can help you with the right Shimano cassette carrier. I've done this swap many times, very easy and straight forward. Good luck and don't forget the new chain.
 

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change from 7-9

Don't forget that if you go from a 7 speed cassette body to an 8/9/10, you will need to get a longer axle, maybe new skewer, etc. It's can work but easier to just get a new hub.
 

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TurboTurtle said:
As long as you stay with friction shifting, the 9 speed chain is all you need.

I believe the 9-speed chain will be too small on the inside to fit on the 7 speed cogs.

A 9-speed cassette will not fit on the 7-speed freehub. (If you take the 7-speed cassette off and find a spacer behind it, it probably is a 9-speed hub.)

TF
I don't think it is the inside distance that changes. Aren't all chains either 1/8" (track) or 3/32" road? I am currently running a 9-speed deraileur with a 7 speed hub in friction mode- no troubles (on my winter bike).
 
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