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Single-pivot BR-6207 with STIs, RD-6208 throw

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Single-pivot BR-6207 with STIs, RD-6208 throw

Old 06-18-19, 04:29 AM
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mboro1876
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Single-pivot BR-6207 with STIs, RD-6208 throw

I'm in the process of upgrading my 1987 Raleigh Road Ace to 8 or 9 speeds from 6. Happy to use e.g. Dura-Ace downtube 9-speed shifters. But the excellent 'retro roadies' thread has got me thinking. The downtube position is relatively onerous for me on this bike due to the geometry, and if there's any of my bikes that would suit that nice STI levers, retro-modern feel, it is this one.

But I don't want to incur a bunch of unanticipated further upgrades. So, any experiences on the following:
-- STI brake levers with the BR-6207/6208 single pivot calipers that I have? The current levers are non-aero, etc.... cable pull differences could cause an issue?
-- does any user of the RD-6208 derailler know if it is has the throw for 9 speed? I think 8 speed should be fine but am not sure.


Cheers!
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Old 06-18-19, 06:25 AM
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Yes to both questions. All will work fine. Dual pivot brakes would be better IMO, but if you're happy with them now, you'll be happy with them after.
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Old 06-19-19, 01:54 PM
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RD-6208 will index an 8 or 9-speed cassette, but there will be gross indexing error on the largest cog, where the chain won't be pushed in quite far enough relative to the cogs.

I've run into this enough times to know that 6-speed SIS road derailers cannot maintain the required linear motion across cassettes wider than 7s.
It will work, but then you will be forever wondering why you can't get it adjusted quite right in terms of running noise or hesitancy to shift.
It's not a matter of the derailer reaching either of it's travel limits, but rather that the actuation ratio trails off as the derailer is shifted to the largest cog.

I think that you'll be fine with the brakes, as long as the cables and pads are fresh enough.

Last edited by dddd; 06-19-19 at 01:58 PM.
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Old 06-19-19, 02:42 PM
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Originally Posted by dddd View Post
RD-6208 will index an 8 or 9-speed cassette, but there will be gross indexing error on the largest cog, where the chain won't be pushed in quite far enough relative to the cogs.

I've run into this enough times to know that 6-speed SIS road derailers cannot maintain the required linear motion across cassettes wider than 7s.
It will work, but then you will be forever wondering why you can't get it adjusted quite right in terms of running noise or hesitancy to shift.
It's not a matter of the derailer reaching either of it's travel limits, but rather that the actuation ratio trails off as the derailer is shifted to the largest cog.

I think that you'll be fine with the brakes, as long as the cables and pads are fresh enough.
Thanks. Great info. The 105 rd-5701 is on very cheap here in the UK so might be a good idea. still very tempted by 9-speed indexed downtube shifters actually 🥰 but we’ll see !
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Old 06-19-19, 07:57 PM
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Originally Posted by dddd View Post
RD-6208 will index an 8 or 9-speed cassette, but there will be gross indexing error on the largest cog, where the chain won't be pushed in quite far enough relative to the cogs.

I've run into this enough times to know that 6-speed SIS road derailers cannot maintain the required linear motion across cassettes wider than 7s.
It will work, but then you will be forever wondering why you can't get it adjusted quite right in terms of running noise or hesitancy to shift.
It's not a matter of the derailer reaching either of it's travel limits, but rather that the actuation ratio trails off as the derailer is shifted to the largest cog.
Mmmmmm.
We may have to agree to disagree.
I've run 6208 RD's on multiple 10 speed setups without issue of any kind. Granted, they were down tube shifters, but still.
Cable pull is cable pull.
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Old 06-20-19, 12:55 AM
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Originally Posted by rccardr View Post
Mmmmmm.
We may have to agree to disagree.
I've run 6208 RD's on multiple 10 speed setups without issue of any kind. Granted, they were down tube shifters, but still.
Cable pull is cable pull.
It will of course depend on your standards for consistent shifting behavior, quietness, etc.

I wanted to believe what you believe, I've tried it with both 600 and 105.
And I've worked on a few other bikes where this was tried. They came to me because of the problems I described, after the bike's owners read on the internet that these various years of derailers had no differences in their actuation ratio.

When Shimano 8s arrived, their road derailers using 8 speeds suddenly had "Integrated 8 SIS" stamped into the rear derailer. I found that this had significance in terms of compatibility, that some subtle dimensional changes had been made to the parallelogram, and/or to the positioning of the parallelogram.

I agree about it not making any difference, indexing-wise, as to whether the shifter is downtube, STI or bar-end.
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Old 06-20-19, 05:20 AM
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Without real-world experience, I can see both sides/possibilities here. Yes cable pull is cable pull but derailleurs need to be very cleverly designed to move the exact same distance for each amount of cable pull. I can well imagine that if the design goal is to achieve this within the 6-speed operating range, when trying to use the derailleur at the very extremes of its range, the linear relationship could break down.

Equally, as I said, I do not yet have real-world experience of this. So thanks both for your inputs and I will find out!
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