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Will these downtube shifters work on this...downtube??

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Will these downtube shifters work on this...downtube??

Old 04-18-20, 05:28 PM
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Will these downtube shifters work on this...downtube??

Here's what I'm looking at:
https://www.ebay.com/itm/SunRace-SLR...20be%7Ciid%3A1

or

https://www.ebay.com/itm/Sunrace-Drop-Tube-Stem-Friction-Shifter-Set-SLR80-3x8-Speed/372964066846?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D225074%26meid%3D18049d95eb624 aa380d2b288f5963688%26pid%3D100678%26rk%3D2%26rkt%3D3%26mehot%3Dnone%26sd%3D264032382810%26itm%3D372 964066846%26pmt%3D0%26noa%3D1%26pg%3D2380057&_trksid=p2380057.c100678.m3607&_trkparms=pageci%3Abdb4c a9e-81bf-11ea-b028-74dbd1803b65%7Cparentrq%3A8f4cdafc1710abc1c9751cb9ffdf20be%7Ciid%3A1

or


https://www.jensonusa.com/Shimano-SL...ntube-Shifters

Here's the mount on the downtube:


I'm only looking to use the right side, 8-speed indexed shifter, but it's currently occupied by the cable guide, so I took a pic of the left side (it's a 1x so it usually just has a Problem Solvers cap over it).

I can't seem to find just a 8 speed bar end shifter by itself, so I'm trying to find as cheaper a set as I can and these might be the ticket?
Thanks for any insight.
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Old 04-18-20, 08:54 PM
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Not as is. The fitting that goes between the shift lever and the frame needs to be flat on the underside, not curved like those shown.

I'm not sure how the Sunrace shift levers fit to that part. For Shimano shift levers that part is called a "lever boss cover".


In this diagram it is item #6 .
643 3810-1 fits a conventional round-tube frame
643 4300 fits a frame with flat-back bosses like your Cannondale.

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Old 04-19-20, 02:50 AM
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It looks like your left side already has the plastic boss cover from a previous shifter. That can be easily pried off and moved to the right side if needed. But with the new set of the Sunrace SLR81's you get the boss covers that you need. I just put a 7 speed version of the Sunrace shifters on an older steel frame with the same type mounts. It works beautifully with a Shimano cassette and an inexpensive Microshift RD. I suspect that the SLR80 with a clamp uses the same levers and may work if you already have the boss covers, But the center screws may not be long enough to reach through the curved cover. And the clamp mount is ugly so the first one is the best bet. Also, Problem Solvers makes a nice cover to clean up the unused left side boss,
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Old 04-19-20, 06:22 AM
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Originally Posted by tommymc View Post
It looks like your left side already has the plastic boss cover from a previous shifter.
Not correct. Pictured is the Cannondale equivalent of a bare downtube braze-on. The boss (with a flat bottom) goes over it.
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Old 04-19-20, 08:56 AM
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Oops, I have an old Cannondale with 7-speed Shimano DT shifters and should have recognized the picture. But It's been at 20 years since I set it up. I believe the Shimano's DT shifters from back then came with the extra flat covers needed for a Cannondale. But it doesn't look like the current SL-R400 comes with anything but the concave mount for round steel tubes. Finding a used set with the flat covers might be a slim chance but used 8-speed bar ends should be easier to find as they were common on touring bikes before 9 speed was trusted travel down the long roads.
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Old 04-19-20, 09:08 AM
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Originally Posted by Jeff Wills View Post
Not as is. The fitting that goes between the shift lever and the frame needs to be flat on the underside, not curved like those shown.

I'm not sure how the Sunrace shift levers fit to that part. For Shimano shift levers that part is called a "lever boss cover".


In this diagram it is item #6 .
643 3810-1 fits a conventional round-tube frame
643 4300 fits a frame with flat-back bosses like your Cannondale.
I think you are incorrect. The “lever boss cover” (part 6 in the picture) comes with the new shifters. The shifter should just bolt onto it. The boss cover may even still be on the cable guide side as the guide needs to sit flat on the frame as well.
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Old 04-19-20, 09:56 AM
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I'm so confused LOL
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Old 04-19-20, 11:41 AM
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OK, here’s the easy answer: yes, that right side lever will fit your downtube mount. In addition to the lever you will need a flat sided lever boss. Search eBay for ‘Shimano lever boss flat’; I just did and got about 20 listings, some of which sell them individually.

One lever,one boss, bingo.
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Old 04-19-20, 12:23 PM
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Yes, your solution is to flip the setup around. Here is what a Cannondale setup looks like, Mine are all black and your are black boss with chrome.




Cannondale downtube boss assemblies are gold.

You will need a flat shifter boss cover not a curved one to make it work.

FWIW, I can't imagine index shifters that could be worse than those Sunrace shifters. I put a set on my wife's bike years ago... for one ride. Total garbage.

John

Edit added: Microshift makes 8 speed downtube and bar end shifters. I have not used them, but I have heard good things about Microshift shifters. I just checked on eBay.

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Old 04-19-20, 12:24 PM
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Originally Posted by rccardr View Post
OK, here’s the easy answer: yes, that right side lever will fit your downtube mount. In addition to the lever you will need a flat sided lever boss. Search eBay for ‘Shimano lever boss flat’; I just did and got about 20 listings, some of which sell them individually.

One lever,one boss, bingo.
OK so I assume that means you're referring to the Shimano ones from JensonUSA. Will that part also be needed if I got the SunRace ones in the first link?

EDIT: looks like it's a yes based on 70sSanO 's reply as I was typing the above!
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Old 04-19-20, 12:47 PM
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No, they won't work.

I believe the Sunrace stem mount shifters can be used as downtube shifters and the ones I saw online come with a curved shifter boss cover not a flat one. I imagine you can sand the curved edge flat and make it work.

John
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Old 04-19-20, 12:54 PM
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Originally Posted by 70sSanO View Post
No, they won't work.

I believe the Sunrace stem mount shifters can be used as downtube shifters and the ones I saw online come with a curved shifter boss cover not a flat one. I imagine you can sand the curved edge flat and make it work.

John
You don't think they can be paired with the shimano flat bosses? Sorry that was my question from above but I definitely didn't say it in a way that indicated that LOL
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Old 04-19-20, 01:32 PM
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I am so ashamed. For years my wife has been telling me I hold onto junk that I will never use and then I find these. I really need to do some soul searching after today.


Shimano will not work (far right). You'll have to grind/file the Sunrace ones down.

John
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Old 04-19-20, 06:11 PM
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Shimano made two lever bosses, one flat, one curved.
The curved ones will,not work on a Cannondale.
The flat ones work just fine on a Cannondale with any shifter intended to be imstalled on a downtube.
In a pinch, you can file down a curved lever boss for this application.
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Old 04-19-20, 09:36 PM
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Originally Posted by cyccommute View Post
I think you are incorrect. The “lever boss cover” (part 6 in the picture) comes with the new shifters. The shifter should just bolt onto it. The boss cover may even still be on the cable guide side as the guide needs to sit flat on the frame as well.
The "lever boss cover" with the concave bottom (p/n 643 3810-1) comes with Shimano downtube shifters. It fits Campagnolo-style shift lever bosses. The other (p/n 643 4300) has a flat bottom is/was available to fit bikes with a corresponding shift lever boss such as Vitus or Cannondale.

Shimano has kept these parts the same for decades. This PDF for Shimano 600 shifters illustrates the different "lever boss covers" nicely:

https://si.shimano.com/pdfs/ev/EV-SL-6208-0735G.pdf
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Old 04-19-20, 10:15 PM
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I think I finally understand. Thanks for the info everyone! Much appreciated.
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Old 04-20-20, 09:25 AM
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Originally Posted by Jeff Wills View Post
The "lever boss cover" with the concave bottom (p/n 643 3810-1) comes with Shimano downtube shifters. It fits Campagnolo-style shift lever bosses. The other (p/n 643 4300) has a flat bottom is/was available to fit bikes with a corresponding shift lever boss such as Vitus or Cannondale.

Shimano has kept these parts the same for decades. This PDF for Shimano 600 shifters illustrates the different "lever boss covers" nicely:

https://si.shimano.com/pdfs/ev/EV-SL-6208-0735G.pdf
The lever boss cover isn’t an integral part of the frame. It is an add on. The lever boss may be a braze-on or it may be only bolted through but the cover is only applied to the boss. The SunRace levers come with their own boss that can replace the one that is currently installed on the Cannondale. Given that the SunRace levers are probably Shimano knockoffs, it may even just bolt to the existing boss on the frame.
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Old 04-20-20, 09:11 PM
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Originally Posted by cyccommute View Post
The lever boss cover isn’t an integral part of the frame. It is an add on. The lever boss may be a braze-on or it may be only bolted through but the cover is only applied to the boss. The SunRace levers come with their own boss that can replace the one that is currently installed on the Cannondale. Given that the SunRace levers are probably Shimano knockoffs, it may even just bolt to the existing boss on the frame.
Take a look at 70sSanO's post (above). He says the SunRace part won't work without modification.
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Old 04-20-20, 10:24 PM
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The truth is the Shimano boss cover does not work with the Sunrace shift levers. It doesn’t fit.

The issue is the alignment tab on the Sunrace boss cover and corresponding slot on the shifter is narrower than the Shimano tab. There may also be a diameter problem but the real issue is you can’t fit a wider tab into a narrower slot.

You can grind/file the Sunrace boss cover flat, but consider the effort expended if you end up hating these shifters.

John
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