Bicycle Mechanics - downtube shifter on aluminum frame

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rainerbleck
04-05-05, 10:50 PM
I want to install a downtube shifter on my Cannondale aluminum bike. The shifters I see advertised all come with a short tubular piece that is "carved out" to fit on a standard steel frame. Judging from the shape of the fitting on my aluminum frame, I need a part that is not carved out at all. Do such parts exist?


e_guevara
04-06-05, 01:47 AM
I want to install a downtube shifter on my Cannondale aluminum bike. The shifters I see advertised all come with a short tubular piece that is "carved out" to fit on a standard steel frame. Judging from the shape of the fitting on my aluminum frame, I need a part that is not carved out at all. Do such parts exist?

There's a similar thread somewhere here (or in the other forum I think...) What you need is called a "flat adaptor" that goes between the downtube bosses and the shifter. Check this (http://www.loosescrews.com/index.cgi?d=single&c=Shifter&sc=Miscellaneous%20Shimano&tc=Mounts&item_id=SH-6433810-1&id=883150011880).

Or, you could try something like this (http://www.loosescrews.com/index.cgi?d=single&c=Shifter&sc=Road%20Shifters&tc=Index&item_id=ST-DTA6&id=883150011880).

Applehead57
04-06-05, 06:07 AM
I have downtube on my 1977 Peugeot and 9 speed Tiagra shifters on my Gunnar.
And I gotta admit I love shifting on my handlebars. If it made fiscal sense, I'd lose the downtube shifters.

Ok, downtube shifters are nearly indestructable and cheap, but aren't they a pain in usage?


e_guevara
04-06-05, 07:33 AM
Ok, downtube shifters are nearly indestructable and cheap, but aren't they a pain in usage?

Some reasons why I still love downtube shifters:

1. It's a classic frame (Colnago Classic) and I'd like to maintain its vintage...
2. Makes you want to train your legs to spin a harder gear and get faster that way (yes, it's because it's a pain to shift so you'd rather get to an optimum cadence on the current gear :D)
3. Friction mode doesn't care how many sprockets you have. 10s anyone? :p

Anybody else got their reasons?

sydney
04-06-05, 07:46 AM
I want to install a downtube shifter on my Cannondale aluminum bike. The shifters I see advertised all come with a short tubular piece that is "carved out" to fit on a standard steel frame. Judging from the shape of the fitting on my aluminum frame, I need a part that is not carved out at all. Do such parts exist?Yeah they exist.How do you think they used downtube shifters on frames like that? Try www.loosescrews.com

FarHorizon
04-06-05, 09:01 AM
I want to install a downtube shifter on my Cannondale aluminum bike..Do such parts exist?

Cannondale themselves made an adapter that allowed any standard shifter to work with the C-dale "square pad on overside tubing" mounts. I have a pair that I no longer use in my spare parts box. If you want them, e-mail me via private on this board and I'll mail you the pair gratis.

Good luck!

petermi
04-06-05, 09:24 AM
I had the same problem with my dale. I ended up grinding down the curved parts to be flat. If you do this make sure you leave the square indentaion in the part. I know it's a hokey fix, but it did work fine and cost nothing.

scrantr
04-06-05, 02:54 PM
The Dura Ace downtube shifter set I installed recently ($52 from Nashbar) came with flat boss plates.

John E
04-06-05, 08:39 PM
I Ok, downtube shifters are nearly indestructable and cheap, but aren't they a pain in usage? The only reasonable alternative to downtube shifters for my 1959 Capo would be Campag. friction barcons. I do have SunTour ratchet barcons on one Peugeot workhorse and a set ready to install on the other. The only time I see any disadvantage to downtube shifters is on fast descents, but that's why one is supposed to shift early. :)

operator
04-06-05, 08:58 PM
I have downtube on my 1977 Peugeot and 9 speed Tiagra shifters on my Gunnar.
And I gotta admit I love shifting on my handlebars. If it made fiscal sense, I'd lose the downtube shifters.

Ok, downtube shifters are nearly indestructable and cheap, but aren't they a pain in usage?

No, STI has made people lazy.

meb
04-08-05, 01:13 AM
Some reasons why I still love downtube shifters:

1. It's a classic frame (Colnago Classic) and I'd like to maintain its vintage...
2. Makes you want to train your legs to spin a harder gear and get faster that way (yes, it's because it's a pain to shift so you'd rather get to an optimum cadence on the current gear :D)
3. Friction mode doesn't care how many sprockets you have. 10s anyone? :p

Anybody else got their reasons?

2 Is counterintuitive-If it's a pain to shift it is harder to select the ratio that gives you the proper cadence so it would result in broader cadence selection.

meb
04-08-05, 01:24 AM
No, STI has made people lazy.

My sole downtube equipped bike is selectable between STI indexed or friction mode with the rotation of a knob.

I hate downtube shifters because the shift reach is so far from the handlebars and requires leaning down to reach the shifters. I don't find the further leaning down to be comfortable nor deem it as safe as keeping hands near the optimal handlebar positions.

My first road bike (a 68 Schwinn) had the then new innovation of stem mounted shifters, which permitted shifting with less of a movement from the handlebars. That system, though I like it much better than downtube shifters, still falls short of the modern technology or even the older trigger shifters for reason of removing the handlebars a milder distance from the handlebars to shift.