Derailleur with 65 mm chainline

[anotherkiwi]

I have brought this subject up before and the solution to the offset is a problem savers direct high mount adaptor.

All well and good but there isn't to my knowledge a direct mount front derailleur which accepts a 48 tooth (or 50 tooth) chainwheel. It only needs to be capable of a 16 tooth difference on the other hand. Will a 42 tooth max front derailleur accept the extra 6 teeth? On web sites a 2 tooth larger chainwheel isn't a problem.

Experts your recommendations please.

 

[anotherkiwi]

OK your silence speaks a thousand words...

New plan:

Braze on Sora 2x9 speed derailleur, 50-34 or 48-32 capable out of the box.
Braze on adaptor, $8 shipped from Taiwan, Make an extension from CF that fits on to the adaptor and holds the derailleur 2 cm further outboard.

The forces on a derailleur must be minimal, the adaptors are made from aluminum? My extension will probably be stronger than the adaptor itself.

 

[Deleted member 4366]

Some photos might help explain what you're trying to do. What you wrote might as well be in Chinese as far as my comprehension goes.

 

[Gringo]

“I know that you understand what you think You said, but I'm not sure you realize that what I read is not what You meant.

 

[anotherkiwi]

Translation:

Front derailleurs have a maximum chainring size and capacity.

I need a front derailleur that can handle 48 or 50 teeth and 32 or 34 teeth chainwheels (capacity 16).

A BBS0x or a GSM has a chainline of about 65mm or more, a little too wide for a normal derailleur.

Problem solvers make a high direct mount adaptor for fat bikes that hangs the derailleur out far enough.

Some MTB derailleurs (e.g. Shimano XT) are direct mount but they don't accept large 48 or 50 tooth chainwheels and are limited in capacity...

So far so good?

After many hours searching the inter webs I have decided the easiest solution is to use a road front derailleur and make my own extender with carbon fiber for a braise on derailleur adaptor.

Sorry but some times I have to think out loud...

 

[Deleted member 4366]

You can slide the clamp-on ones up and down, so you can fit any size chain-wheels.

 

[anotherkiwi]

It isn't the 4 extra teeth on the large chainwheel that worry me much, rather the 16 tooth difference between the two. I'm worried about the metal bar that closes the derailleur cage on the bottom rubbing the chain - when using small chainring small cog on rear derailleur.

 

[DouglasXK]

I tried the same and ran into the same insurmountable problem that there is no direct fit derailleur that takes anything above a 42t chain ring. It’s just trouble all the way. However, having bought an Origin8 direct mount adaptor (same as your ProblemSolvers?), a normal braze on derailleur can be fitted using a braze on adaptor which is screwed into the Origin8 adaptor.

The braze on adaptors I bought a year ago in another failed attempt to get multiple chain rings on my TSDZ2 setup and I just can not find the invoice and despite searching for it, I still can’t find it on the internet. Its right angled with 2 countersunk 5mm clearance holes which you use to attach to the Origin8 adaptor which must be bought with at least one spacer if not 2 for what you want to do.

The direct mount adaptor is the only way of doing this simply but then you run into the maximum chain ring t rating of direct mount derailleurs. I’m of a mind to take apart a triple 52/53t derailleur and try and fit the cage etc to a direct fit. It’s annoying me.

 

[anotherkiwi]

Something like this?

http://www.moruyabicycles.com.au/contents/en-uk/d87_front-derailleur.html

Glad to know I am not alone!

 

[craiggor]

It isn't the 4 extra teeth on the large chainwheel that worry me much, rather the 16 tooth difference between the two. I'm worried about the metal bar that closes the derailleur cage on the bottom rubbing the chain - when using small chainring small cog on rear derailleur.

Using the small chainring and small cog on the rear is called cross chaining and most people advise against it due to extra chain wear/stress.

Sent from my T1005 using Tapatalk

 

[DouglasXK]

Yes, that’s it, the TCR advanced and Giant now rings a bell

Without the Origin8 spacer, the cage of a 2sp is correct for a 50mm chainline. The spacer is 16.5mm which will therefore give a 65mm chainline.

I don’t need the spacer nor a spare TCR adaptor. Are these of any use?


I found the invoice, Giant UK call it a WG39!

 

[anotherkiwi]

Using the small chainring and small cog on the rear is called cross chaining and most people advise against it due to extra chain wear/stress.

Sent from my T1005 using Tapatalk

I don't think you can cross chain on a trike. There is 61 cm between the idler pulley and the rear mech and that is invariable. Chain length is a problem I haven't sorted but I think I could eventually get that right - I want to get my seat position right and the motor in before correcting that.

 

[craiggor]

You could cut weld two front cages together to make an extended one if you still have trouble with the chain hitting the bar across the front cage.

Sent from my T1005 using Tapatalk

 

[anotherkiwi]

Yes, that’s it, the TCR advanced and Giant now rings a bell

Without the Origin8 spacer, the cage of a 2sp is correct for a 50mm chainline. The spacer is 16.5mm which will therefore give a 65mm chainline.

I don’t need the spacer nor a spare TCR adaptor. Are these of any use?


I found the invoice, Giant UK call it a WG39!

Thanks for the offer I'll keep it in mind. For the moment I am forging ahead on building a CF spacer for the braze on adaptor which is on its way from China (Taiwan) for 7€.

The big surprise so far is the price of a Sora flat bar 2x9 trigger shifter

In my reading earlier there was talk of having to upgrade to a 60 tooth chainwheel when converting a trike to a vélomobile to prevent spinning out... But that is for much later. I may put a 50-34 road compact chainwheel set and a precialps 130 BCD spider on my shopping list though.

 

[Martin56]

How did it work out for you? I am trying to find a front derailleur for a 39/50 chainwheel and a 60mm chainline so your advice would be appreciated, thanks.

 

[anotherkiwi]

How did it work out for you? I am trying to find a front derailleur for a 39/50 chainwheel and a 60mm chainline so your advice would be appreciated, thanks.

We creep closer each day to the motor being put on!

I have moved and the trike hasn't been out since - hills to get out and hills to get back home. I have been comuting and so need my bike every day.

Stay tuned!