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bike newby: switching from an 7 speed to an 8 speed on a vintage

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bike newby: switching from an 7 speed to an 8 speed on a vintage

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Old 10-16-12, 11:19 AM
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gramley
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bike newby: switching from an 7 speed to an 8 speed on a vintage

hey guys,

I am a newby, I am looking to my upgrade my 7 speed cassette to an 8 speed cassette on my sr 400. Does anybody know if there is enough room between the back fork to add that extra gear. When I purchased the bike off CL, I had to replace the shifters up with 8 speed dura ace and would like to find a matching set gearwise. And just an FYI, the deraileur is a shimano 600. everybody points to ebay, but honestly I don't know the exact casette and I want to make sure I find the right one. Thanks in advance for any advice you might be able to give.

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Old 10-16-12, 12:01 PM
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You'll need more than just a new cassette. You will also need to change the freehub at the minimum, and probably a longer axle, or a whole new hub/wheel. Are the new shifters downtube shift levers?
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Old 10-16-12, 02:06 PM
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wow this is sounding like a lot more than the $50 I was hoping to spend. the newshifters are sti.
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Old 10-16-12, 02:21 PM
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My own '87 SR400 has a SIX-speed freewheel, so at least you're one better, even if you stay with what you've got.

I looked into doing the same, but quickly decided to stay put and just ride it. Didn't want to change the rear hub to go cassette. Didn't want to bend that beautiful frame to accommodate a new, wider wheel, either.

I also have Shimano 600, but I thought it wound not go 8-speed... Maybe yours is newer. Mine is 600 SIS.
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Old 10-16-12, 02:27 PM
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I don't think it is worth the hassle to go from 7 to 8 speed.
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Old 10-16-12, 02:31 PM
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Eight of nine on seven?

Maybe not. You'd need 9 speed shifters and chain.

Last edited by Grand Bois; 10-16-12 at 02:35 PM.
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Old 10-16-12, 05:23 PM
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I'm sure you could trade the DA STI's for some sort of 7-speed shifters.
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Old 10-16-12, 05:59 PM
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If the rear spacing is 130 you could put a new freehub body on the old wheel. More than likely though the spacing is 126. Can still put on a new freehub, but the wheel probably will need be to be re-dished as well. With this you would just need an 8 speed cassette and chain. Could also buy a new wheelset.
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Old 10-16-12, 06:52 PM
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I personally think it's worth the upgrade, having done it and liked it.

The rear wheel upgrade is swapping out the 7-sp freehub for an 8-sp freehub, a Shimano UG. That requires a longer rear axle, the freehub swap, and a simple re-dish of the wheel about 4mm.

The rear of the frame will take the expansion, just be careful mounting the wheel in there.

Someone else can chime in if the DA 7400 RD is required or not. I'm simply not sure.
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Old 10-16-12, 06:56 PM
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Tell me again why anyone needs more than five gears?

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Old 10-16-12, 07:54 PM
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Old 10-16-12, 08:24 PM
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Watch your local Craigslist, you MIGHT find a new rear wheel/cassette that will work for you. WE updated my son's 86 Fugi to a 9 speed cassette, just changed the wheel and chain. The Suntour FRICTION shifter and Sprint RD handles it fine. Had to flex the frame just a little to "Slip" it is.
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Old 10-16-12, 08:56 PM
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Originally Posted by RobbieTunes View Post
I personally think it's worth the upgrade, having done it and liked it.

The rear wheel upgrade is swapping out the 7-sp freehub for an 8-sp freehub, a Shimano UG. That requires a longer rear axle, the freehub swap, and a simple re-dish of the wheel about 4mm.

The rear of the frame will take the expansion, just be careful mounting the wheel in there.

Someone else can chime in if the DA 7400 RD is required or not. I'm simply not sure.
I don't think a longer axle is required. Pretty sure I read an article by Sheldon Brown stating this. I could be mistaken however.
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Old 10-16-12, 08:58 PM
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Originally Posted by AZORCH View Post
Tell me again why anyone needs more than five gears?

It's an available option. Ride what you prefer.
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Old 10-16-12, 09:37 PM
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I'm a 7-speed guy, and at this point in time, the selection of cassettes is way better than than of 8-speed. If you're going to stretch the rear spacing and upgrade, you might as well go 9-speed.
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Old 10-16-12, 09:50 PM
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Originally Posted by RobbieTunes View Post
Someone else can chime in if the DA 7400 RD is required or not. I'm simply not sure.
Its one of my favorite groups, a 7400 series RD or alternative cable routing is required.
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Old 10-17-12, 05:38 AM
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Originally Posted by wrk101 View Post
Its one of my favorite groups, a 7400 series RD or alternative cable routing is required.
So to keep the shifters, you'd need a new rear derailleur, and a new freehub and cassette at a minimum.
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