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Topic: Removal of FD and relying on RD for shifting = chain dropping during rides?

Posted on: 20th Feb 2015 8:05 PM    Quote and Reply

Hi all,
 sorry for a lame question.
Will the removal of my FD and relying on my RD for shifting cause the chain to drop?
The reason being, the frame geomtry on my velo doesnt go well with Shimano groupset as i am not able to go on the smaller 39t chainring. It rubs the moment i shift down.
I am comtemplating removing my FD together with the smaller chainring and just using the RD but wonder if the chain will drop.i am currenting using DA groupset.
thanks all, for any kind advice.
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Posted on: 20th Feb 2015 8:15 PM    Quote and Reply


The rear derailer will tension the chain, it will not fall off. That will still not solve your frame problem. It is just a work around. Maybe you would want to bring your bike to a good mechanic to see how they can solve your frame issue. Else you just need to downgrade your group set.

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Posted on: 20th Feb 2015 8:18 PM    Quote and Reply


deraileur is a deraileur. it's not meant to be a chain guard or chain tensioner. Find a good mechanic to get it fixed. And to answer your question, No, the chain should not drop. 


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Posted on: 20th Feb 2015 8:33 PM    Quote and Reply


thanks bros, velomobile and dextral.
thanks for the advice, might just take it off since its not gonna be useful.

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Posted on: 20th Feb 2015 10:58 PM    Quote and Reply


Having the front derailer there and not shifting it is the same as removing the front derailer and cannot shift it. Best to check with a good mechanic before you do something to your bike. Just my two cents worth. 

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Posted on: 21st Feb 2015 12:42 AM    Quote and Reply


i was thinking that since i cant use it i might as well remove it.
i am using a bull bar with grip shifters so i tot if i remove the left gear and change it to TT brake levers and change the rear shift system (like TT bar end shifters or MTB shifters).
if that can be done. it will shave off a little dead weight and my cock pit will be slightly neater. : )

yes. i have spoken to my LBS and his advice was different from you guys. no disrespect to him, maybe he is trying to play safe but i felt that sometimes things can be done differently to achieve certain results.



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Posted on: 21st Feb 2015 7:40 AM    Quote and Reply


Chainrings on doubles / triples are designed to derail the chain easy and smooth, they are ramped and have very low profile teeth. The FD not only shifts rings but acts as a guide to keep the chain on the ring. Single rings have longer teeth and are unramped to hold the chain in place without an FD. If you remove the FD with a ramped ring it is much more likely that the chain will come off the ring when you hit a bump, or the like.
LBS guy is probably right in this case

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Posted on: 21st Feb 2015 11:09 AM    Quote and Reply


Hi bro Zappa, thanks for the input, never ever tot of the point of "longer tooth" on the chainring could have an effect on derailing the chain. i might have to consider changing my crankset to a fixie type... : I

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Posted on: 21st Feb 2015 11:24 AM    Quote and Reply


Personally I would just take the small ring off andrun with the big ring and the FD. You can adust (or replace with a longer one) the lower limit screw on the FD to stop the it moving to the smaller position, you can ditch the front shifter and cable if you want then. gets expensive if you start replacing cranks and chainrings.

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Posted on: 21st Feb 2015 12:12 PM    Quote and Reply


The rubbing is on the FD, when i shift to the small chainring. i never knew that there are options that you mention. tks!

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Posted on: 21st Feb 2015 6:05 PM    Quote and Reply


The bicycle seat tube geometry is probably beyond the design specs of the FD.  I suspect that's why it's the chain is rubbing against the FD when you shift to the smaller ring.

It's possible to address that problem if you have a braze-on FD.  Sulaiman of the Rebound Centre fashioned an adaptor for someone's mini-velo when that frame wasn't designed for FD usage.  You may want to contact him and ask his advice.

If yours is a clamp-on, then I am not sure what may be done.  Perhaps Sulaiman can advise on that too.

If you prefer to just go with a single ring without removing anything, then Zappadeedoohdah's suggestion works nicely.

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