Clamp vs. Band Front Derailleur
 

Are these two types of derailleurs interchangeable, what's the reason for the band? I imagine it's easier to change the size of the derailleur by using a different band, where a clamp is fixed (or smaller only with shim).


https://cimg5.ibsrv.net/gimg/bikefor...a422ab5655.jpg

Band

https://cimg7.ibsrv.net/gimg/bikefor...9c33c92020.jpg

Clamp

My experience is that band tighen more firmly and never move. Until the band snaps. Alwaye use a piece of high quality transparent tape under the band as the adjustment process can make a mess of your paint.

Bands were also useful when you used non standard or modified tubing. I had a late 80's Douglas mtn bike with oversized, ovalized tubes near the BB and that same Deore DX shown in your pics was the only FD I could find to fit, The band shapes itself to the tubing profile.

Easier for the manufacturer to make their FDs work on 28.6, 31.8 or any other diameter tubing, I'm thinking. With the various sizes of steel, OS steel, Aluminum, carbon composite and what have you, it makes sense to make one model of FD and a bunch of different bands to fit it on multiple different seat tubes. I'm guessing Shimano was mostly prompted by the transition from MTBs going from the standard steel tubing sizes the the new, fatter aluminum sizes.

Those are Shims, down Tube thicknesses vary by Tube manufacturers/Brand/Type.

Looks like a 28.6 band and a 31.8 band. Some Shimano and some Suntour.
Some bands will do both sizes. Most won't.
Same system used in downtube shifters.
Campy had the adjustable clamp for a short time.
Suntour had one that bolted into a hole drilled into the seat tube.
These days, shims are often used. Or braze-ons.

The banded Superbe Pro looks pretty nice, sorta like a braze-on FD. It's a tiny little thing and lighter than the campy record 3-hole FD.

This .Especially SunTour, with their propensity of using soft metal fasteners.

Top

Like this? Simplex SJA222

http://www.theworld.com/~muller/pics/SJA222.jpg

On a frame standard diameter ST, the previous owner took off all the original paint and then powder coated it, which resulted in a thicker seat tube. When I got it I built it up with a Huret Jubilee front mech, it was a tight fit, and fatigued and broke in the clamp. Of course this couldn't have happened with a steel clamp. Other front clamp-ons are fine on the same frame, I think I have an IRD compact front derailleur on there now, to go with the Defiant 46/30 chainset. It's on a braze on to .

To be fair, I had a Campy Racing Triple clamp-on break its clamp pivot pin (a roll pin) when some sloppy shifting (mea culpa) got the chain confused as to what ring it was supposed to be on. I was running a Campy Racing T chainset in friction shifting, on that.

I cursed Campy and bought a solid steel clamp pivot pin, but somebody cautioned me, "what if that happens again and the force is taken by the seat tube?" Thanks to Ebay I replaced the mech and went on my way.

Yes, and also Suntour Superbe Pro.

Band style fasteners were originally introduced by Sun Tour circa 1981. Originally they were called "endless clamp" mounting but this was later changed to "endless band". It was offered on both shift levers and front derailleurs. The prime purpose was to apply the clamping force uniformly along the band, reducing the possibility of deforming thin wall tubing, such as Reynolds 753, Columbus KL, Tange Champion Pro and Ishiwata 017. Secondary attributes included a sleeker appearance, less weight and, since this was the birth of the aerodynamic era, less frontal area for reduced aerodynamic drag. As noted, there was special version of some models of front derailleurs which used a brazed-on fitting.

Suntour Supebe Pro FD with Band - 90g
Suntour Mountech with Clamp - 106g

The weight savings between the two mounting styles is best illustrated by the New Cyclone front derailleur, which was produced in both styles. The standard, hinged clamp version (FD-3300) had a claimed weight of 101g, while the endless band version (FD-3700) had a claimed weight of 94 g. Though the actual weight saving was not great, it was a significant 7% reduction in component weight.

Thanks all for providing info. A seeming original equipment band type FD is in use on a recently acquired '88 Cannondale ST700.

I was curious if I needed to use the same type if I ever needed or wanted to replace it, or if a clamp type was also appropriate?

The seat tube is 31.8mm. Were band type FDs more often employed on aluminum bikes? Perhaps aluminum bikes are more likely to have unusual seat tube diameters and or shapes as mentioned.

Unrelated, the ride is definitely more jarring on this bike (despite its steel fork). I'm trying to remedy with fit adjustments, lower tire pressure and potentially wider tires

I ran into my bike mechanic who recommended never removing the band front derailleur saying they're very difficult to get back on, he mentioned something about a spring.

i can only speak to the Suntour band ... it's not that difficult.

To preserve your paint, you may want to file the band of any rough edges or use a piece of tape under the band as clubman mentioned above.

If you like the 28.6 Suntour FD bands, stock up on the Suntour Symmetric band shifters (clones). There's an abundance of these in the market.

Pair the front Mountech with a Cyclone GT, or circa 85/86 XC RD- and you've got gold.

Any of the "tech" stuff was a solution looking for a problem that became a problem in and of itself.