the capability of braze-on Front derailleur
 

Hello,

Just as the title states its about braze-on FD (front derailleur) so I am very curious as i am doing research to study a bit more about road bike so i can learn any limits on these road bike would have with any type of components especially with FD and RD and the crankset

so i wanted to know is there any braze-on FD that can handle up to 52 teeth (outer chain ring)? or was it 50 the maximum teeth for outer chain ring?

the reason why i created this topic is due to the fact that i am deciding which road bike frame to buy.. there are two type of frames that has used two type of FD: clamp and braze-on.. and i am trying to find out which frame with a type of FD i can buy that would work with 52 teeth chain ring

I would appreciate it that anyone can teach me about the capability of braze-on or any type of FD such as clamp or E-type.. and i already know that e-type is only capable with up to 44 teeth.

The chain ring range a "braze on" front derailleur can accommodate is determined by where the frame manufacturer places the mount on the seat tube. I suspect most frames designed for road use would be able to accommodate a 52T ring, but the only way to be sure it to try it.

Personally, I'm not terribly fond of "braze on" front derailleurs for exactly that reason. The only place they make sense to me is with non-round seat tubes where a clamp can't hold the derailleur.

Yeah. The braze-on mount height and length of screw slot determines the big ring size range. I haven't come across a recent road bike that did span 50 to 53.

Every road bike (which is designed for a FD) on the market today is braze on capable, all you need is an adapter to fit the frame.

Having a braze on FD makes more sense than a band on, as you can swap it between any frame (also less SKU's for the manufacture/shop to carry), where as a band on is limited to round tube frames, with the tube diameter to match the band.

I currently have 2 road bikes with braze on type derailleurs. Both have 52 tooth large chainrings. On both bikes the derailleur is at about the mid point of its vertical adjustment, so I could probably use a large ring anywhere from 48 teeth to 55 teeth in size, maybe even a bit larger, but I don't plan on finding out

I'm sure any road bike frame with a braze-on front derailleur tab will accommodate a 52 or 53T chainring as that is almost the norm for "standard" geared road cranks. That said, if you have the choice buy the frame without the braze-on tab and use a braze-on type front derailleur with a proper diameter adapter clamp. That provides the convenience of a braze-on front derailleur with far more versatility.

As John D Thompson noted, the only reason for a true braze-on front derailleur is on a frame with a non-round seat tube where the adapter can't be used.

By Definition If its brazed on its location is fixed ... But .. the FD can be Rotated a bit in the mount ..

with wedges between the mount and the part of the derailleur that clamps in the mount.

Bring the Tail end of the cage Up or Down..

Braze on mounts have a vertical slot that allows the derailleur to be moved up and down to suit chainring size. There is no need for wedges to move the tail of the derailleur up and down, you loosen the bolt that attaches the derailleur to the mount and slide it up or down to the correct height. The mount has a curved channel that allows the derailleur to be pivoted a few degrees so that the cage can be lined up with the chainring

Are there any that can NOT handle 52, 53 ? I would be surprised.

But if it goes down to reach a 50 t but really does not follow the Arc of the smaller diameter .. That Can Be Tweaked .

Me too

In practice, this is seldom a problem. Some companies make a compact specific front derailleur model

this is a shopping not creative forum I realize..


Of Course this hamster wheel site is all about Guessing, sight unseen ..

Campy offered "compact specific" front derailleurs when compact cranks were first introduced but Shimano never did and said they weren't necessary. Apparently Campy soon agreed since the dedicated fd's were dropped from their line.

Hmm, why be creative in a situation when creativity isn't needed?

I was thinking about Campagnolo, since my bikes are Campy equipped. They did drop their compact specific front derailleurs at the time that they introduced 11 speed. On the other hand, the compact specific derailleurs also worked very well with triples

Campy's "standard" triple (53/42/30) 10-speed front derailleurs also shift just fine with a 50/39/30 triple crank. I have had both crank types on one bike and the same Chorus triple 10-speed fd shifted both crank configurations very well.

I prefer using a braze on derailleur with a clamp-on band.

I could train a chimpanzee to tune a rear derailleur but fronts can be something else. I've found that most of the time, when I've trouble getting a front derailleur tuned, the underlying issue was the position of the derailleur on the seatpost. The height of the derailleur relative to the chainring can be a critical item and it can be hard to fine tune. The braze-on derailleur with clamp-on adapter allows me to adjust the derailleur height without affecting the positioning in any other way.

Another advantage to an adapter, particularly Shimano and Campy models with a fixed non-adjustable derailleur position, is that all of the initial height and rotation adjustment is done using the adapter itself. Once the adapter is tightened in position, the derailleur itself can be removed and replaced with no readjustments. A slotted adapter requires height and rotation adjustment every time the derailleur is removed but it is easier than with a clamp-on.

Some vintage deraillers like the 1981 - 1984 Dura Ace AX and 600 AX ones will not follow the curve of a 52 teeth chainring unless a shim is used at the top of the derailler/brazeon interface to lower the tail of the derailler cage.

http://bikeforums.net/attachment.php...hmentid=500139http://bikeforums.net/attachment.php...hmentid=500140

To correct that it would take either a 1mm shim at the top or a tapering job to remove 1mm from the mount.

Cheers

Campagnolo:
http://i32.photobucket.com/albums/d7...ps027a6d51.jpg

Shimano:
http://i32.photobucket.com/albums/d7...ps86035d9b.jpg

so are you saying that braze-on is much easier to install on road bike than any clamp-on (bandon) FD would be?

in my opinion, a braze-on may be easier but i dont know if it has its own limit.. if it can handle up to 53T depends on the FD we are looking at, or was it the braze-on that the frame of a road bike has.. like Scooper was talking about.. very interesting.. but for a clamp (band-on) is much easier because you would know how to adjust it accord to the size of a chainring... up to 56.. so there is no limit to the clamp-on FD, but we both know that FD have limits for chainring (outer) to Middle or small chainring....

as we know if its triple FD, then we know most FD can handle the capacity of teeth up to 22... (from outer chainring to inner chainring). i am sure you know what i am talking.. so back to clamp-on as long as you know what you are doing on how to adjusting, it may be much useful than braze-on for any size of the outer chainring. and no limit. so whats your thought about what i said about the difference between braze-on and the clamp?

I think, considering your language difficulties, it might be better if you ask something more specific.
For example, you could ask "will THIS front derailleur work with THIS frame and THIS crankset?" Anything beyond that will be lost in translation.

Since the vast majority of road bikes are equipped with large rings of either 50 or 53 teeth, manufacturers install their braze on mounts in a location so that the derailleur will work for chainrings of those sizes. The brand of the derailleur doesn't matter

One more time. An adapter clamp with a braze-on derailleur is the most versatile method unless your frame cannot use an adapter or band-on of any kind. The height and rotation can be set to use any model derailleur and chainring size.