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Using a double crankset with Dahon-style braze-on frames?

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Using a double crankset with Dahon-style braze-on frames?

Old 02-21-21, 08:19 PM
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Using a double crankset with Dahon-style braze-on frames?

Has anyone managed to get decent results using a front derailleur on a Dahon/Fnhon/Crius that has a built-in front-derailleur hanger? I tried a Shimano 105 FD but the braze-on won't allow it to work, at least not with a 53/39 chainring crank that has an integrated spindle. It doesn't seem like even a clamp-on FD adapter would work with this, because the brazed-on hanger would be in the way of the FD.
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Old 02-22-21, 01:52 AM
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Originally Posted by Nyah View Post
It doesn't seem like even a clamp-on FD adapter would work with this, because the brazed-on hanger would be in the way of the FD.
Do you have pictures?
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Old 02-22-21, 04:18 AM
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That's bizarre because the vitesse is like a speed with braze on FD fitted from factory. Have you got pictures and measurements?

On my 105 FD, there are 2 threaded holes to allow some height/offset adjustment.
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Old 02-22-21, 11:28 PM
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Hopefully these depict the scenario.

Side view.




Derailleur cage is almost centered exactly over the large chanring,

even though the FD is in its resting position.




Viewed from the back.




Distance from above the chainring teeth:

about 12mm, instead of the recommended 1mm-3mm.




Only one mounting hole on the FD-5700.

More than one wouldn't make much difference though,

unless it could also move the FD to the left.
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Old 02-23-21, 12:00 AM
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Have you tried limit screws? Have you tried to find out what chainring size is anticipated with that mount? There are adapters around that allow you to move attachment position for the derailleur, such as Wickwerks Fit-Link. There is also Sugino adapter and maybe one or two more adapters. I am pondering though whether you are not taking on more than you can chew.
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Old 02-23-21, 01:26 AM
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Hmm.... that looks like a braze on mount designed for much larger front sprockets.

One possibility is the same type of FD but in the clamp-on version, there looks like there may be enough room, but of course that does not resolve the question of why it is lying above the big chain ring.
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Old 02-23-21, 07:05 AM
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You might need an adaptor like the rotor one. like these:
https://www.tritoncycles.co.uk/frame...iABEgKExvD_BwE
https://www.google.com/search?q=braz...N-CK31D8MbndeM
https://www.deporvillage.net/sram-re...SABEgJ7L_D_BwE


Have you looked for a FD with 2 threaded hole? What ring are you trying to use? 39/53T? or much smaller?
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Old 02-25-21, 11:58 PM
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After adjusting the low limit screw all the way
to its extreme, the shift from 53t to 39t is
still not going to happen. The FD needs to be closer
to the seat-tube. Like right up next to it.

As for the vertical placement, I really can't see
anything working, other than permanently altering the braze-on.
In order to be within the range recommended by Shimano,
the mounting bolt of the FD would have to pass right through
the bottom edge of the braze-on.

Just to sate my curiosity, I tried a Mi.xim clamp-on
FD adapter
. Even if the braze-on wouldn't be in the way of the FD,
the Mi.xim adapter still doesn't allow the FD to be closer to the seat-tube.

Last edited by Nyah; 02-26-21 at 12:06 AM.
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Old 02-26-21, 01:58 AM
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Can you use a spacer to move the chainrings outboard until they line up with the FD? It would rob the left crank of a few mm of attachment I guess but should work unless you are a very heavy or powerful rider.
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Old 02-26-21, 02:59 AM
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Originally Posted by Falconista View Post
Can you use a spacer to move the chainrings outboard until they line up with the FD? It would rob the left crank of a few mm of attachment I guess but should work unless you are a very heavy or powerful rider.
yes, it needs to be offset towards the outside? what crank do you have? it seem the small ring should be were the big one is.
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Old 02-26-21, 03:24 AM
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This spacer may work.
https://www.amazon.co.uk/Wheels-Manu...00DHN8FUY?th=1
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Old 02-26-21, 03:27 PM
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As a reference, using the B clamp and this front derailleur, both from Litepro, the fork rests (ie. meant to hover above the smallest chainring) at about 35mm from the inside of the clamp:


Using the NC-100 clamp, it's at about 28mm:
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Old 02-26-21, 04:19 PM
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I have had the same problem with several Dahon frames. Like yours, the braze-on hanger put the FD cage WAY above the stock chainring and it was considerably too far from the seat tube as you have experienced. I have solved this problem in a number of ways. Initially, I changed the FD to a SRAM Force 10 speed which has 2 mounting holes. This allowed me to lower the derailleur to be within 1-3mm of the large chainring. Later, I tried a Wickwerks adapter as someone mentioned previously.

To solve the problem of the FD being too far out from the seat tube, I used a series of spacers on the crank spindle to move the chainrings further out. I have done this with several cranks including the stock Prowheel crank, a Shimano Ultegra 6600 crank and a 105 5700 crank.

Later, I switched the large chainring to a 58T and this larger ring made it possible to use any front derailleur without any kind of adapter.
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Old 03-19-21, 10:56 PM
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Friction shifter

Originally Posted by Nyah View Post
Has anyone managed to get decent results using a front derailleur on a Dahon/Fnhon/Crius that has a built-in front-derailleur hanger? I tried a Shimano 105 FD but the braze-on won't allow it to work, at least not with a 53/39 chainring crank that has an integrated spindle. It doesn't seem like even a clamp-on FD adapter would work with this, because the brazed-on hanger would be in the way of the FD.


I have the same bike with the same problem which is too much space between the front derailleur(ultegra) and the crankset(52/34). The chain will always fall off when shifted. I've tried many things to stop this but nothing has worked. Finally, I think I've solved the problem. To stop the chain from falling off I've installed a friction shifter. If done carefully the chain will not fall off.
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Old 03-20-21, 04:37 AM
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So the issue is the shifter pushing the chain too far outward?
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Old 03-20-21, 05:56 AM
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Originally Posted by Winfried View Post
So the issue is the shifter pushing the chain too far outward?

No. The limit screw will stop that. It's because the distance between the derailleur and the crankset is more than 3mm. If it was 1-3mm this would not be a problem.
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Old 03-20-21, 08:56 AM
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Tricky thing to check before buying a deraillleur online.

Incidently, I also use a friction shifter on my Brompton, so didn't experience that issue with the Tiagra derailleur I'm using, but could have with an indexed shifter.

Last edited by Winfried; 03-20-21 at 09:07 AM.
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Old 04-11-21, 03:46 PM
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Originally Posted by Hinge View Post
I have had the same problem with several Dahon frames. Like yours, the braze-on hanger put the FD cage WAY above the stock chainring and it was considerably too far from the seat tube as you have experienced. I have solved this problem in a number of ways. Initially, I changed the FD to a SRAM Force 10 speed which has 2 mounting holes. This allowed me to lower the derailleur to be within 1-3mm of the large chainring. Later, I tried a Wickwerks adapter as someone mentioned previously.


To solve the problem of the FD being too far out from the seat tube, I used a series of spacers on the crank spindle to move the chainrings further out. I have done this with several cranks including the stock Prowheel crank, a Shimano Ultegra 6600 crank and a 105 5700 crank.


Later, I switched the large chainring to a 58T and this larger ring made it possible to use any front derailleur without any kind of adapter.
Thank you very much for sharing this info. I've followed what you did and obtained the same Sram FD. Also, I have some spindle shims that I think will work. I'm curious, though, what smaller chainring you successfully paired with the 58t one. I don't think I've found any Shimano pairings with anything bigger than 56t. I might be able to put together a 58/44 from Litepro or other company's offerings, which would be pretty nice if it works right.
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Old 04-12-21, 05:29 PM
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I 3d printed my own braze on to screw into the older litepro clamp, but the newer nc or whatever rebrand is cheaper at $10 and I only want the clamp to mount the 3d printed part. My frame did not come with a braze on do I was free to adjust my height. If you want to use a braze on adapter clamp without first cutting off your existing braze on, you could also use smaller chainrings to get more clearance. Every 2t drop will lower your fd by 4mm. I use 44/24t double. That would drop you from 53t by around 18mm.

I use sram 11 speed yaw fd which I found have a couple of millimeters extra inward clearance than shimano fd. It also did not require trim.
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Old 04-13-21, 04:11 PM
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Originally Posted by Nyah View Post
I'm curious, though, what smaller chainring you successfully paired with the 58t one. I don't think I've found any Shimano pairings with anything bigger than 56t. I might be able to put together a 58/44 from Litepro or other company's offerings, which would be pretty nice if it works right.
Glad this was helpful. I have tried several combinations but honestly, I can't remember all of them. Currently, I am using 58/48 and it feels pretty good. I think 58/44 or 58/42 would probably be fine also and I probably tried both of those combinations. There was probably some reason other than feel that I settled on 58/48 but I can't remember. On paper, the SRAM Force FD has a capacity of 16 teeth (the difference between the 2 chainrings) but there's a good chance it could handle more if you wanted to.

Keep us posted on your progress.
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Old 04-13-21, 04:20 PM
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Originally Posted by tomtomtom123 View Post
I 3d printed my own braze on to screw into the older litepro clamp, but the newer nc or whatever rebrand is cheaper at $10 and I only want the clamp to mount the 3d printed part. My frame did not come with a braze on do I was free to adjust my height. If you want to use a braze on adapter clamp without first cutting off your existing braze on, you could also use smaller chainrings to get more clearance. Every 2t drop will lower your fd by 4mm. I use 44/24t double. That would drop you from 53t by around 18mm.

I use sram 11 speed yaw fd which I found have a couple of millimeters extra inward clearance than shimano fd. It also did not require trim.
Any chance you could post a pic of your creation? It sounds very cool.

With a 44/24 setup in the front, I'm curious what range your cassette is.

Also, what is the exact SRAM FD you used? Force? Red? Does it have 2 mounting holes or only one?

Thanks
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Old 04-16-21, 04:18 PM
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There were photos in several other miscellaneous threads, but I don't remember them all. Some of the main photos are here:
How to bend a front derailleur to fit folding bike frames with thick seat tubes

As far as I remembered, there are only 3 SRAM YAW FD, and the cheaper 2 are almost identical. I took the cheapest one. I think the main difference was that the more expensive one used lighter weight material. The most expensive one I think had a narrower cage width, which is what I didn't want.

I custom assembled my 10 speed cassette 12-34t to go with the 44/24 double.
I'm usually on 7th or 8th which is 58 or 62 gear inches, on my Big Ben Plus 2.1" tires which I measured at 19.8" effective diameter, which is measured by sitting on the bike and rolling it 3 revolutions, dividing the travel distance by 3, at 2.8 bar.

I'm probably only on 10th for a maximum of 30 seconds to 1 minute per 30 minute ride.


If I were to do it again with a new bike, I may try 11 speed
11-12-13-14-15-16-18-20-23-28-34, or
12-13-14-15-16-18-20-22-25-29-34, or
11-12-13-14-15-16-18-20-22-26-32
For 11 speed custom cogs, only Miche would work, since most other brands put the big cogs riveted to a spider.

Last edited by tomtomtom123; 04-16-21 at 04:30 PM.
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Old 04-17-21, 02:58 AM
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I'll add a related question.

At rest, ie. with the cable released and the fork sitting closest to the seat tube, it looks like the distance can be slightly different between the fork and the derailleur — from the center of the part that connects the fork to the main body.

For instance, I notice there's a few mm difference between a Shimano Tiagra and a Litepro, where the Litepro is sitting further away.

As a result, the derailleur might be too far outboard, messing the chainline.

Do you confirm?

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Old 04-17-21, 07:47 AM
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I think the main issue is that the inner cage plate is too far out, causing chain rub?
The center to center distance of the pivot to the cage width would not relate since every model has different cage width and spring diameter.

Did the OP completely release the low limit screw to the maximum? Does the spring in the parallelogram mechanism go all the way inward until touching the seat post, or is there still a gap to the seatpost?
When I do this until the spring touches the seatpost, the SRAM yaw FD has a couple of millimeters of extra inward clearance than the Shimano 4700.
I back in the low limit screw slightly, so that there is maybe 0.5mm gap to the seatpost and slip in between a metal shim to protect the seatpost from damage when the spring gets released on the downshift.
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