Top mounted down tube shifters?

[oliver1850]

Are there any models that were indexed? 2nd choice would be SunTour Power Ratchet type but I don't believe I've ever seen them for top mount. Did anyone make a base that had standard DT bosses?

[rccardr]

Not aware of any that were indexed, but if you're willing to do some modifications like retapping and grinding, the Shimano top mount can be made to work with any Shimano indexed DT shifter.

[fiamme red]

I have top-mount Suntour downtube shifters on two bikes. These were produced from about 1982 to 1985, I believe. Suntour Power Shift (with the ratchet mechanism) was introduced in 1986, and Accushift (index shifting) in 1987.

[mhespenheide]

I'm sorry; I'm not clear on what you're asking.

Are you trying to mount down-tube levers on the top tube? Or on the top of the handlebars?

If on top of the handlebars, is there a reason you're trying to use down tube levers instead of the Paul shifter mounts that use bar-end shift levers?

[dddd]

I recall seeing Shimano top-mount indexed DT shift levers during the 6-speed era.

And I've seen top-mounts that had standard Campy mount studs, which would work with any indexed levers, though these might have been brazed-on only.

Suntour offered a cable housing stop that bolted onto a top-mount stud, and although these are hard to find I believe that someone has done a knock-off of these.
C&V at bikeforums would be the place to post an inquiry, or to simply do a search on the subject.

[m_sasso]

Depending on what your top mount looks like, the part you want is a Shimano SL-7401-7FCBI, this will allow you to mount indexed top mount downtube shifters.



http://www.ventoux.com/7401a.gif

As seen here, sorry no decent close ups,

[weisan]

https://cdn.shopify.com/s/files/1/1403/7343/products/sh15-2_1600x.jpg?v=1471032670

https://cdn.shopify.com/s/files/1/1403/7343/products/sh15-4_1600x.jpg?v=1471032672

[fiamme red]

I'm sorry; I'm not clear on what you're asking.

Are you trying to mount down-tube levers on the top tube? Or on the top of the handlebars?

If on top of the handlebars, is there a reason you're trying to use down tube levers instead of the Paul shifter mounts that use bar-end shift levers?I believe the OP means shifters that mount in one piece to a braze-on on the top of the downtube.

[oliver1850]

I believe the OP means shifters that mount in one piece to a braze-on on the top of the downtube.

Yes, that's what I'm after.

The Shimano part that Marc posted is exactly what I was hoping that might exist. Guessing it may be hard to find though.

Thanks for the replies.

[rccardr]

Pics of an older 4.5mm Shimano top mount that was modified to fit DA down tube shifters to a top mount braze on. Had to grind away some of the internal casting to fit over the braze-on and re-tap the bolt holes from 4.5 to 5mm, but otherwise was no big deal. Hardest part was finding the Shimano top mount. Have another one if you're interested.