Easing the FD operation

[John Tolhurst]

I found it is in fact possible to reduce the spring strength of the FD. We can do this by altering the angle the cable arrives at the FD. To make the FD work with less effort and be less likely to back off unexpectedly, simply run the cable to the RHS of the roller, around the roller clockwise, then up to the FD. This increases the normal (perpendicular) distance of the cable from the FD pivot, thus increasing the leverage over the spring.

The result is the FD does the upshift with less effort on the twist shift and reduces the tendency to inadvertently downshift when wheeling the bike and the like.

 

[OleBent1]

I think I know the answer to this, but to be clear, clockwise when viewed from which direction?

Any additional FD adjustment required? Having a greater cable to pivot perpendicular distance suggests the FD travel will be less for the same cable travel distance...

 

[Doug Burton]

I've tested this; it works great. See photo.

 

[John Tolhurst]

OleBent1 wrote: Any additional FD adjustment required? Having a greater cable to pivot perpendicular distance suggests the FD travel will be less for the same cable travel distance...

Correct.

 

[oldrotator]

John Tolhurst wrote: I found it is in fact possible to reduce the spring strength of the FD. We can do this by altering the angle the cable arrives at the FD. To make the FD work with less effort and be less likely to back off unexpectedly, simply run the cable to the RHS of the roller, around the roller clockwise, then up to the FD. This increases the normal (perpendicular) distance of the cable from the FD pivot, thus increasing the leverage over the spring.

The result is the FD does the upshift with less effort on the twist shift and reduces the tendency to inadvertently downshift when wheeling the bike and the like.

On my Quest 559 with the "silver" derailer mount this approach will appear to have the wire crossing itself on the way to the derailer. Is that correct? This is different from what is shown in Doug's photo with the black derailer mount.

Len

 

[WhiteSilvio]

Doug Burton wrote: I've tested this; it works great. See photo (above).

Hi Doug,
While I don't have a Quest, I'm just wondering if the "black cap" where the cable exits to go to the derailleur needs to be, or can be, enlarged so that the cable doesn't rub on the cap?

With constant use I'm thinking that the cable will wear prematurely, and fail, almost certainly at some inopportune time (like the furthest point from one's destination; a Murphy thing I'm guessing ).

Regards,
John R

 

[John Tolhurst]

oldrotator wrote:
On my Quest 559 with the "silver" derailer mount this approach will appear to have the wire crossing itself on the way to the derailer. Is that correct? This is different from what is shown in Doug's photo with the black derailer mount.

Len

Yes, that is correct. The cable leading to the FD goes under the other and does not rub. Pretty sure that is true for the silver as well as black FD mount. If the wires touch where they cross, swap one to the other side so they do not.

 

[oldrotator]

....Yes, that is correct. The cable leading to the FD goes under the other and does not rub. Pretty sure that is true for the silver as well as black FD mount. If the wires touch where they cross, swap one to the other side so they do not......

John,
The wires were exactly in the same plane until I realized that I could move the cable housing stop further from the "boom". Then they would cross without interference.

Len

 

[John Tolhurst]

oldrotator wrote: ....Yes, that is correct. The cable leading to the FD goes under the other and does not rub. Pretty sure that is true for the silver as well as black FD mount. If the wires touch where they cross, swap one to the other side so they do not......

John,
The wires were exactly in the same plane until I realized that I could move the cable housing stop further from the "boom". Then they would cross without interference.

Len

I see ... adjusting the cable hanger gets around nicely.

 

[defjack]

Thats what I did. Jack

 

[Trevski]

This works on Sofrider as well

 

[super slim]

It also works on the Silvio.

Is there an even larger grooved pulley that would decrease the front derailleur cable pull load, and what would the cost be?

Super Slim

 

[marshall2389]

is there any fix to prevent the rear (low) derailler from down shifting so easily?

 

[kling]

I had my LBS fit Shimano Deore shifters (Rapidfire Plus), works well with the Microshift derailleurs. Haven't had a problem with inadvertent downshift since.

cheers
Kendrick

 

[defjack]

My cables streched a lot in the first 1000 miles nowat 1500 mi shifting is great. Jack

 

[marshall2389]

i tried the said modification to the top derailleur and it worked out great! Took five minutes and well worth it.

 

[Doug Huffman]

Young's Modulus of steel

I don't know just what alloy are the shifter cables but the general steel Young's Modulus is 200 GPa/30 x 10⁶lbf/in² You ain't stretching shifter cables!

 

[John Tolhurst]

cables - housings

I think what happens is the housing compresses, particularly around the cable end caps which are plastic. I think they slowly deform to a point, and then adjustment to the length of the housing is no longer needed.