Front derailleur stalk for compact chainrings

[mattwall]

I have a Silvio 1.5 with a 50/34 compact chainring . The front derailleur stalk positions the front derailleur over 10mm from the big chainring , when the gap between the derailleur and the big chainring should be 1.5 mm.
Reading other peoples posts leads me to believe that the front derailleur stalk is still the wrong size for compact chainrings.
I would like Cruzbike to offer front derailleur stalks for compact chainrings as an alternative to the stock front derailleur stalk.
Is there a demand out there from other people?

 

[1happyreader]

I have a Silvio 1.5 with a 50/34 compact chainring . The front derailleur stalk positions the front derailleur over 10mm from the big chainring , when the gap between the derailleur and the big chainring should be 1.5 mm.
Reading other peoples posts leads me to believe that the front derailleur stalk is still the wrong size for compact chainrings.
I would like Cruzbike to offer front derailleur stalks for compact chainrings as an alternative to the stock front derailleur stalk.
Is there a demand out there from other people?

You mean like when some of the guys got Di2 systems and modified their stalks ?????

 

[nobrakes]

I have the same problem. If there's an easy mod I'm very interested. I tried the rotor shim kit but it didn't really help. What you really need is something that bolts onto the stalk that adds a new mounting hole at least a cm closer in.

 

[dtseng]

I designed the chain stay for my own use. It is 430 mm in length and will be ready in about a month. The length can be adjusted as required. The design is to address two problems: 1. clamping of the chain stay on the bearings, not on the BB shell; 2. the stalk is too long for compact chain rings.

 

[dtseng]

I have the same problem. If there's an easy mod I'm very interested. I tried the rotor shim kit but it didn't really help. What you really need is something that bolts onto the stalk that adds a new mounting hole at least a cm closer in.

Use a hacksaw to remove the hanger from the stalk and re-weld it 12 mm lower.

 

[ratz]

There's another fix that @scabinetguy came up with for Di2. That I can post photos of.

I'm at a lost here though guys. Can you post some detailed photos. I've done seven, v20/s30 builds plus the RAAM 8 bikes. These had assortment of rings from Traditional, to Compact, to Eliptical. Never once have I had a problem getting the front derailluer to work correctly on the small rings. @leetaylor55 even has a 40-sometime on his V20 Randeneour setup. Something seems to be missing here. I'd postulate that even here with the hardcore forum members most of use are on compacts. Larry and couple others being the exception riding big rings.

For the record I have also had a 65T on the V20 but that indeed required an adapter.

 

[dtseng]

I suspect this might be a factory QC problem. I would suggest measuring the distance from the lowest point of the hanger to the center of BB.

Most FDs specify that the outer cage is 1 to 2 mm to the large chain ring teeth. All my steel framed road bikes with brazed on hangers can be adjusted to that specification. I think if the distance is 10mm, so be it, it probably would shift just fine.

 

[nobrakes]

I posted a photo on my build thread. It does shift OK if you rotate the FD round a bit, but with the Sram yaw FD because of the way it is angled it is designed to be much closer to push the chain up to the big ring using the correct area of the derailleur cage. So far I've had it throw the chain too far quite a few times, but you can't reduce the limit as then it doesn't push it far enough. I think a non-yaw FD would probably work much better, either that or I'm just not clued up enough. If I can't get it working good I'll probably take it to the local bike guru to see how he does with it. Failing that I will buy an older Force FD which has the other bonus of having two mounting holes rather than one, so it will get closer as well.

 

[ratz]

I posted a photo on my build thread. It does shift OK if you rotate the FD round a bit, but with the Sram yaw FD because of the way it is angled it is designed to be much closer to push the chain up to the big ring using the correct area of the derailleur cage. So far I've had it throw the chain too far quite a few times, but you can't reduce the limit as then it doesn't push it far enough. I think a non-yaw FD would probably work much better, either that or I'm just not clued up enough. If I can't get it working good I'll probably take it to the local bike guru to see how he does with it. Failing that I will buy an older Force FD which has the other bonus of having two mounting holes rather than one, so it will get closer as well.

Hmmmm all of our ours have been YAW.

Did you follow the YAW install process that start with the derailleur in the big ring position via the lower limit screen? I just posted the video about that in Jesse's thread a couple day ago. I get flaw less results when I do the process correctly. The absolution hardest thing to do on the v20 is get the top view of the derailleur for the Angle to match the chain. The usually results if the FD being rotate with the inside, back, corner being too far inward toward the center line of the bike. When that happens it will fail to upshift.

 

[nobrakes]

I tried to get it into the big ring using the lower limit screw but it wouldn't go that far, because I think the slanted cage was too far away from the chain. I will try again.

Cheers

 

[nobrakes]

Am also thinking that the fact you have installed many of these without issue using a multitude of different hardware suggests user error at my end

 

[ratz]

Am also thinking that the fact you have installed many of these without issue using a multitude of different hardware suggests user error at my end

That or something is up with the new chainstays and best to find out now. @dtseng Silvio 1.5 issue is a whole nother kettle of fish.

I know you can get it too close because on a Qring I often do; if I miss set it to 2 mm clearance on the small diameter of (48T) and then it jams on the tall diameter when I test it. Kiddies learn interesting words when daddy does that.

I will say this it took me forever to learn to do it right; and it takes a lot of tension on the cable and a perfect upper limit screw setting; then it's butter. But for the lower limit I always find that a PITA because of the chain angle; so I always install the $20 SRAM chain spotter. We had them on every RAAM bike. That just completely removes the low-drop-chain problem and lets you focus on the up ring being perfect.

The other nice thing is since you can see your feet; if you over shift its so easy to fix on a CB; back pedal a quarter down shift and start pedaling slowly. I'm always bumping into the nose of my bike on the trainer so that FD is always out of tune; so I get really good at the oops backpedal.

 

[dtseng]

The above video shows amply clear that the outer cage is very close to the large chain ring teeth, while the mounting screw is at the center of the hanger hole. In nobrake's photo, the distance is 10 mm while the mounting screw is at the bottom of the hole. This is definitely not a user error, it is a manufacturing error.

 

[mattwall]

This photo shows that the derailleur is adjusted as close to the chainring as it can go, but the gap is 10mm , not the recommended 1.5 to 2mm

 

[nobrakes]

ratz, the RAAM Bikes had the new chainstay did they not? Did you get the FD within 2 mm on these, or are you 10mm away like myself and matwall above?

 

[ratz]

I've confirmed my theory that this started to be a problem when SRAM dropped the second bolt hole from their design to save weight. The old YAW's have 2 bolt holes; the new ones only have the lower one and the metal piece is smaller.

I've raise the issue for evaluation and for potential future modification.

In the mean time here's the best solution for anyone that wants to get inside the tighter tolerances.

https://wickwerks.com/products/fit-link-adapter/



If you use a Qring 50T or bigger you won't have the problem. That's where I'd put the cash instead of the adapter. but both now provide options.

 

[nobrakes]

Thanks ratz, that looks like exactly the part that I was thinking of in my mind. I'm going to methodically go through the Sram instructions and videos once more to see if I can improve things before I buy anything else.

 

[dtseng]

ratz, I would suggest the following changes: (1) make the hanger twice as long as the current one for wider applications: standard chain rings, compact chain rings, and non-circular chain rings; (2) move the cable stop and pulley to the left side of the stalk.

 

[ratz]

(2) move the cable stop and pulley to the left side of the stalk.

That's already possible now. Changed like 1 or 2 versions back to accommodate different derailleurs. I use mine on the left on our trainer bikes.

 

[LMT]

There's another fix that @scabinetguy came up with for Di2. That I can post photos of.

I'm at a lost here though guys. Can you post some detailed photos. I've done seven, v20/s30 builds plus the RAAM 8 bikes. These had assortment of rings from Traditional, to Compact, to Eliptical. Never once have I had a problem getting the front derailluer to work correctly on the small rings. @leetaylor55 even has a 40-sometime on his V20 Randeneour setup. Something seems to be missing here. I'd postulate that even here with the hardcore forum members most of use are on compacts. Larry and couple others being the exception riding big rings.

For the record I have also had a 65T on the V20 but that indeed required an adapter.

Yes I did fit a 94BCD 40/24 and it did work however:-

Because of the where the stalk was there was about an inch between the cage of the mech and the chainring.

Because of this I had to fit a triple mech and shifter to get the required movement in the mech in order for the chain to move chain rings.

I have still got the chainset and would lkke to fit it to my S40. Anybody know of any shims that work that I can buy online?

TIA