Two or Three gears per sweep on Dura Ace 7900 levers

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mrhelvik
Posts: 4
Joined: Sat Sep 28, 2019 11:11 pm

Two or Three gears per sweep on Dura Ace 7900 levers

Post by mrhelvik »

Hi

I have a question that’s been killing me..

I have an old bike with Dura Ace 7900 groupset. I’ve been quite annoyed that the 7900 right lever (for the rear derailleur) only can downshift two gears per sweep instead of three like I was used to on my MB and other bikes. However, a few days back I borrowed another bike with Dura Ace 7900 groupset and - on that one - I could downshift three gears in one sweep.

To me, these two levers look pretty darn similar. The only difference I can see in the front plate, it’s slightly larger on my two-gear-sweep version. But I figured the plate is not the cause (i.e., removing the plate the lever still stops at the same place, so it’s not the plate that causes the lever to “stop early”)


Any insights?
Do anyone know if my friend’s 7900 is a special (or later) version or something?

My end goals is of course to be able to do three gears per sweep.. so I’m hoping there’s a neat trick or replacement part I can buy to do so..(?) :)
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The two-gear sweep to the right
The two-gear sweep to the right

JerryLook
Posts: 297
Joined: Thu Dec 07, 2017 2:18 am

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by JerryLook »

Do you mean by shifting 3 gears that it will move up two gears each time? For instance, my DA7900 bike can shift through the 10 spd cassette in 4 shifts. 1-3, 4-6, 7,9, and then 10.
I believe the other Shimano 10 spd I have had was the same.
2010 Orbea Opal 54cm
5.97kg

mrhelvik
Posts: 4
Joined: Sat Sep 28, 2019 11:11 pm

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by mrhelvik »

No, not quite.. by "three gears per sweep" I mean it will move up three gears each time.
So my buddy's bike only needs three sweeps for a full shift through: 1->4, 4->7, 7->10
(which is the same as my even older DA7800)

While my DA7900 (and yours I assume) would actually need five sweeps:
1->3, 3->5, 5->7, 7->9, 9->10

JerryLook
Posts: 297
Joined: Thu Dec 07, 2017 2:18 am

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by JerryLook »

If I start out in the first cog that doesn’t count as a sweep. If I sweep it 4 times I’m in the 10th cog. That’s how mine works at least. But I think I get what you’re saying.

I think you’re right about it just being a mod for how far the lever throws. With mine it’s close to clicking one more time, and I’m sure it wouldn’t take much to get it to shift one more gear each time.
2010 Orbea Opal 54cm
5.97kg

Karvalo
Posts: 842
Joined: Fri Aug 10, 2018 6:40 pm

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by Karvalo »

JerryLook wrote:
Mon Sep 30, 2019 1:19 pm
Do you mean by shifting 3 gears that it will move up two gears each time? For instance, my DA7900 bike can shift through the 10 spd cassette in 4 shifts. 1-3, 4-6, 7,9, and then 10.
I think you're either confused or have some kind of setup error in your groupset. 1-3 is 2 clicks. 3-6 is 3 clicks, as is 6-9.

kevinw
Posts: 133
Joined: Fri Jan 25, 2019 3:49 pm

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by kevinw »

I'd be surprised if you cant do 3 clicks in one sweep of the 7900 shifter - you can on the ultegra 6800.

After a little googling I found this in an old 7900 review...

"In a distinct step backwards, you can now only downshift two gears at a time, not three as with 7800."

JerryLook
Posts: 297
Joined: Thu Dec 07, 2017 2:18 am

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by JerryLook »

Mrhelvik was absolutely right with his post of 1-3, 3-5, 5-7, 7-9, and 10. My bad. So 5 total pulls of the lever to get through the cassette. I did my math before I drank my coffee for the day. And I just got back from a bike ride and verified :thumbup:

I never shift like this because I live in coastal FL and hardly ever shift gears. Usually the only time I test this feature is before I put the shifter on the bike :D
2010 Orbea Opal 54cm
5.97kg

joejack951
Posts: 746
Joined: Fri Feb 18, 2005 6:50 pm
Location: Wilmington, DE

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by joejack951 »

I was trying to find documentation on Shimano's site about multiple gear shift capabilities but it seems to be hiding from me (https://si.shimano.com/#/). The User Manuals for all recent shifters only show 2-gear shifts which I know isn't correct (my 5800 bike definitely does 3 at a time). Going back to the 7800/6600/5600 series of shifters, the documentation accurately shows 3-gear shifts.
JerryLook wrote:
Mon Sep 30, 2019 5:05 pm
I never shift like this because I live in coastal FL and hardly ever shift gears. Usually the only time I test this feature is before I put the shifter on the bike :D
Not even when slowing to a stop? If I'm riding along at 30+ kph the last thing I want to do is to try and get moving from 0 in that same gear. Depending on my speed, one or two full sweeps of the lever gets me to an easy starting gear (23-25T cog, assuming I'm in the big ring). Or perhaps you drop to your little chainring up front rather than shift the rear?

Am I odd for shifting this way?

JerryLook
Posts: 297
Joined: Thu Dec 07, 2017 2:18 am

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by JerryLook »

No, what you do is normal for most people I think. I usually ride in the 16t rear cog and a 54t chainring. If I stop I’ll stay in that gear when I take off again.
I don’t know why I even have a small chainring because I never use it. They usually look brand new. Lol.
I would go 1x but I ride in upstate NY in the spring and actually use more than one gear there.

I don’t like the big cadence change when shifting more than one gear at once. If I was changing from flat ground to going up a big hill I would shift gears as my speed slowed.
2010 Orbea Opal 54cm
5.97kg

mrhelvik
Posts: 4
Joined: Sat Sep 28, 2019 11:11 pm

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by mrhelvik »

Thanks for replies guys..

Before posting I did the same googling for specs, forum and old articles etc - and didn't find anything but ppl saying two clicks per sweep on DA7900

Yet, here it is.. DA7900 with three clicks*
Maybe Shimano improved it in the end of the life span..?


*: Took a video for "proof" since I had both bikes: https://www.jottacloud.com/share/2arffbh8e0hg

JerryLook
Posts: 297
Joined: Thu Dec 07, 2017 2:18 am

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by JerryLook »

It’s weird they had 3 clicks for DA7800 and then went back to 2 for DA7900. Then I assume on DA9000 they went back to 3 clicks?

Maybe when they went with the hidden shifter cables for DA7900 they couldn’t have that and 3 clicks. Or something like that. Then they were testing it out towards the end of the DA7900 before the DA9000
2010 Orbea Opal 54cm
5.97kg

mrhelvik
Posts: 4
Joined: Sat Sep 28, 2019 11:11 pm

Re: Two or Three gears per sweep on Dura Ace 7900 levers

Post by mrhelvik »

That is indeed a plausibel theory.
Unfortunately, it doesn't seem (or look like) there's any mods I can do to turn my two-gears-sweep version to turn it into a three-gears-sweep version.

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