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-   -   Vintage Shimano Compatibility Check (https://www.bikeforums.net/showthread.php?t=1242180)

calamarichris 11-13-21 09:22 AM

Vintage Shimano Compatibility Check
 
Hello fine fellows.

Wondering if this XT GS 7-speed cassette will be compatible with my Shimano Ultegra 6400 7-speed derailleur. And is 28 teeth too much for that road derailleur?

Running non-vintage Velo-Orange hubs, hence the need for Hyperglide. Need easier gearing for my beloved Masi.

https://www.calamarichris.com/wp-con...120-masi13.jpg
.

-Calamarichris in Carlsbad, CA
Thanks in advance for any guidance. Stay well and ride safe

davidad 11-13-21 09:28 AM

No. I used the same gear on my 7sp. Giant.

Viich 11-13-21 09:29 AM

By rule of thumb, should be fine - anything (except front derailleurs) Shimano MTB 9 speed and below will work with anything road 10speed and below, except the current 10sp stuff that uses the same cable pull as 11sp - Tiagra 4700 & GRX400.

Shimano never messed with cassette spacing between MTB & road that I know of.

rccardr 11-13-21 09:56 AM

You should be fine. Might have to mess some with the B screw on the RD to be happy with the 28 tooth rear cog, but indexing should be fine.
All Shimano cog spacing for 7 speed is the same.

calamarichris 11-13-21 02:14 PM

Thank you kindly gents!

Kimmo 11-13-21 08:38 PM

I'm confused - your beloved Masi is rocking ST-6400s, which are 8s.

calamarichris 11-14-21 11:00 AM

Dammit. :(

Ah well. Let's see if the Ebay seller has already shipped it. (Hate it when I do dumb stuff.)
I got it confused with my other bike, a Team Stuttgart Merckx that has those same brifters but on Sante (7-speed) hubs. I guess the guy I bought it from must have manipulated the limit screws to get the 8 speed brifters to work with the 7 speed freewheel.

https://www.calamarichris.com/wp-con...103-merckx.jpg

You have a keen eye. Thank you.

ThermionicScott 11-14-21 11:55 PM

$159, wow.

veganbikes 11-15-21 11:01 AM


Originally Posted by Viich (Post 22305883)
By rule of thumb, should be fine - anything (except front derailleurs) Shimano MTB 9 speed and below will work with anything road 10speed and below, except the current 10sp stuff that uses the same cable pull as 11sp - Tiagra 4700 & GRX400.

Shimano never messed with cassette spacing between MTB & road that I know of.

Also it should be noted 7400 has some eccentricities not that it effects the OP but useful to note.

Viich 11-15-21 11:57 AM


Originally Posted by calamarichris (Post 22306954)
Dammit. :(

Ah well. Let's see if the Ebay seller has already shipped it. (Hate it when I do dumb stuff.)
I got it confused with my other bike, a Team Stuttgart Merckx that has those same brifters but on Sante (7-speed) hubs. I guess the guy I bought it from must have manipulated the limit screws to get the 8 speed brifters to work with the 7 speed freewheel.

You have a keen eye. Thank you.

8sp shifters will work fine with 7sp - or 5 or 6, for that matter - spacing was all the same.

Jeff Neese 11-15-21 12:14 PM

According to Velobase, the RD-6400 has a maximum cog size of 28 and max chainwrap of 26. That of course is independent of whether your shifters are compatible.

https://velobase.com/ViewComponent.a...2-d3236e2fd096

ThermionicScott 11-15-21 12:17 PM


Originally Posted by Viich (Post 22308191)
8sp shifters will work fine with 7sp - or 5 or 6, for that matter - spacing was all the same.

What?? That is completely wrong.

rccardr 11-15-21 01:06 PM


Originally Posted by ThermionicScott (Post 22308237)
What?? That is completely wrong.

Shimano:

5 speed and 6 speed = 5.5mm center to center cog spacing
7 speed = 5.0mm
8 speed = 4.8mm.

So…with regard to 8 speed shifters idexing a 7 speed cassette, they are close, but not the same. If you set 8 speed indexing to be perfectly centered in the middle of a 7 speed cassette, it would be off by .6mm at either end.
Which means it might work, but not that well.

ThermionicScott 11-15-21 01:29 PM


Originally Posted by rccardr (Post 22308316)
Shimano:

5 speed and 6 speed = 5.5mm center to center cog spacing
7 speed = 5.0mm
8 speed = 4.8mm.

So…with regard to 8 speed shifters idexing a 7 speed cassette, they are close, but not the same. If you set 8 speed indexing to be perfectly centered in the middle of a 7 speed cassette, it would be off by .6mm at either end.
Which means it might work, but not that well.

Yeah, I thought of suggesting that the 6400s might shift the 7-speed cassette okay, but didn't want to promise anything since I've never actually tried it.

Viich 11-15-21 02:14 PM


Originally Posted by ThermionicScott (Post 22308237)
What?? That is completely wrong.

You're right, I made a mistake there. Though it's not completely wrong that you can make this stuff work together, I exaggerated compatibility quite a bit.

You can use 8sp with 7sp, and 7sp with 5 or 6.

Spacing per gear:
5 & 6 sp - 5.5mm
7sp - 5mm
8sp - 4.8mm
You can use 7sp shifters with the alternate cable routing described by Sheldon Brown here to pull more cable. (Shimano also publicized this at the time)
You can use the same trick to use 8sp with 7sp - though they're close enough you might be better off with standard routing, depending.

ThermionicScott 11-15-21 02:18 PM


Originally Posted by Viich (Post 22308419)
You're right, I made a mistake there. Though it's not completely wrong that you can make this stuff work together, I exaggerated compatibility quite a bit.

You can use 8sp with 7sp, and 7sp with 5 or 6.

Spacing per gear:
5 & 6 sp - 5.5mm
7sp - 5mm
8sp - 4.8mm
You can use 7sp shifters with the alternate cable routing described by Sheldon Brown here to pull more cable. (Shimano also publicized this at the time)
You can use the same trick to use 8sp with 7sp - though they're close enough you might be better off with standard routing, depending.

Using alternate routing to make 7-speed gear index 5/6-speed is a new one on me. Maybe it can work, but that's still not the same as saying "they're all the same." ;)

Viich 11-15-21 02:20 PM


Originally Posted by ThermionicScott (Post 22308426)
Using alternate routing to make 7-speed gear index 5/6-speed is a new one on me. Maybe it can work, but that's still not the same as saying "they're all the same." ;)

I've done 7 on 5 & 8 on 7. It's been a while, so I forgot about the cable routing trick.

wrk101 11-16-21 03:38 PM


Originally Posted by rccardr (Post 22308316)
Shimano:

5 speed and 6 speed = 5.5mm center to center cog spacing
7 speed = 5.0mm
8 speed = 4.8mm.

So…with regard to 8 speed shifters idexing a 7 speed cassette, they are close, but not the same. If you set 8 speed indexing to be perfectly centered in the middle of a 7 speed cassette, it would be off by .6mm at either end.
Which means it might work, but not that well.

I've done 7 with 8 speed 6400 STI several times. Not perfect, but works. I would think the 5 and 6 speed spacing is asking a lot. 7 versus 8 is about 4% off. 6 versus 8 is more like 15% off.


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