New Shimano 105 front derailleur

Sprool

I rode a hire bike recently with the newer Shimano 105 front derailleur on it, with longer pivot arm - shifting was way smoother and easier than my current 3-yr old 105 (but with new cables & recently serviced..). Is there an upgrade you can buy, just the longer arm part or does the whole shifter, derailleur, brakes need to be replaced ?

arlowood

Sprool wrote:

I rode a hire bike recently with the newer Shimano 105 front derailleur on it, with longer pivot arm - shifting was way smoother and easier than my current 3-yr old 105 (but with new cables & recently serviced..). Is there an upgrade you can buy, just the longer arm part or does the whole shifter, derailleur, brakes need to be replaced ?

The 5800 did initially come with the long pivot arm as you've indicated. However before the launch of the latest 105 R7000 groupset, they did introduce a modified FD5801

https://www.merlincycles.com/shimano-10 ... 12752.html

This design mirrored the advances seen in the Ultegra R8000 groupset where the front derailleur has had a major reconfiguration to include a cable tensioning device (much like the built in barrel adjusters seen on rear derailleurs. I think this was prompted by the advance of internal cable frame designs where they had to include an in-line barrel adjuster for the front deraillleur. The new 8000. 7000 and 5801 all have the inbuilt barrel adjuster.

With the advent of the R7000 grouset you may be able to pick up a 5801 derailleur relatively cheaply. IMHO I would hold off buying one of the older long arm front mechs

Sprool

Thanks for the advice, will look into this. I have a 10-speed cassette - this specifies 11-speed, any issues?

svetty

If your existing bike is 10spd 105 this implies 5700 or 5600 series. The cable pull is different to the 5800 (long arm) front mech so the shifter isn't compatible. You'd need an upgrade to an 11 speed shifter and mech - or a whole new shiny groupset

timothyw

It might be OK just replacing the derailleur, but the likelihood is that you will also need to replace the left shifter.

If you are stuck with 10 speed for some reason (old wheels perhaps), you could move to the 4700 tiagra group, which despite nominally being a lesser group than 105 is in my experience a better group than the 10 speed 5700 105 because it uses the new pull ratios you've experienced on the 105 hire bike.

svetty

TimothyW wrote:

It might be OK just replacing the derailleur, but the likelihood is that you will also need to replace the left shifter.

If you are stuck with 10 speed for some reason (old wheels perhaps), you could move to the 4700 tiagra group, which despite nominally being a lesser group than 105 is in my experience a better group than the 10 speed 5700 105 because it uses the new pull ratios you've experienced on the 105 hire bike.

The new Ultegra HG 800 11-34 11 spd cassette is compatible with 10 speed wheels - I believe the same applies to the latest 105 R7000 equivalent - so you could upgrade to 11speed utilising your existing 10 speed wheels if you wished.

Sprool

TBH i have no interest in upgrading to 11 speed as you're then talking loads more cash for new brake shifters, rear mech, cassette, FD, maybe new wheels. I just want a more efficient FD at around £35 or less.

timothyw

You have little to lose by trying it. Planet X have the long arm tiagra derailleurs for £13 at the moment.

arlowood

Svetty wrote:

If your existing bike is 10spd 105 this implies 5700 or 5600 series. The cable pull is different to the 5800 (long arm) front mech so the shifter isn't compatible. You'd need an upgrade to an 11 speed shifter and mech - or a whole new shiny groupset

Not entirely sure that this is the case as evidenced by the fact that Shimano introduced the FD 5801 with the onboard cable tension adjuster just before the release of the new R7000 groupset. This new FD reverted to the short activation arm without any change in the shifters so that suggests that the cable pull is not a critical parameter when switching from a long arm to short arm design.

If the OP is running 5600 or 5700 (both of which used a short arm derailleur design) then he could well be fine switching to a 5801

However if he would prefer to stick with the long arm design then he should equally be fine. Essentially the long arm will require a shorter pull than the equivalent short arm derailleur. Since his front 5600/5700 shifter will be capable of pulling more cable to activate the 5600/5700 derailleur then he should be fine fitting a long arm FD.

He can pick up a FD5800 for abt £18 so not much of a downside if he hits problems

https://www.merlincycles.com/shimano-10 ... 72393.html

svetty

arlowood wrote:

Svetty wrote:

If your existing bike is 10spd 105 this implies 5700 or 5600 series. The cable pull is different to the 5800 (long arm) front mech so the shifter isn't compatible. You'd need an upgrade to an 11 speed shifter and mech - or a whole new shiny groupset

Not entirely sure that this is the case as evidenced by the fact that Shimano introduced the FD 5801 with the onboard cable tension adjuster just before the release of the new R7000 groupset. This new FD reverted to the short activation arm without any change in the shifters so that suggests that the cable pull is not a critical parameter when switching from a long arm to short arm design.

If the OP is running 5600 or 5700 (both of which used a short arm derailleur design) then he could well be fine switching to a 5801

However if he would prefer to stick with the long arm design then he should equally be fine. Essentially the long arm will require a shorter pull than the equivalent short arm derailleur. Since his front 5600/5700 shifter will be capable of pulling more cable to activate the 5600/5700 derailleur then he should be fine fitting a long arm FD.

He can pick up a FD5800 for abt £18 so not much of a downside if he hits problems

https://www.merlincycles.com/shimano-10 ... 72393.html

The cable pull for the 'long arm' front mechs is the same as the latest R9100/R8000/R7000 series - and the FD5801. This is different to the older 10sp shifters the OP has. It may work OK with his old shifter but won't be optimal.

migrantwing

Svetty wrote:

If your existing bike is 10spd 105 this implies 5700 or 5600 series. The cable pull is different to the 5800 (long arm) front mech so the shifter isn't compatible. You'd need an upgrade to an 11 speed shifter and mech - or a whole new shiny groupset

What you say is theoretically true. However, I have full 5700 on my bike and bought a new 5800 FD a year or so ago and the shifting is better than the original 5700 FD by a country mile. No left shifter change needed. The 5800 FD comes with the routing tool for the pin on the FD arm which changes the amount of pull required. I believe the 5700 and 5800 front chainring spacing is the same. I'm running a compact 50/34 BTW.

LiamW

Just to say i've fitted a 5800 FM and used it with a SRAM left hand lever. Works far better than the original Rival front mech that was originally on the bike.

migrantwing wrote:

Svetty wrote:

If your existing bike is 10spd 105 this implies 5700 or 5600 series. The cable pull is different to the 5800 (long arm) front mech so the shifter isn't compatible. You'd need an upgrade to an 11 speed shifter and mech - or a whole new shiny groupset

What you say is theoretically true. However, I have full 5700 on my bike and bought a new 5800 FD a year or so ago and the shifting is better than the original 5700 FD by a country mile. No left shifter change needed. The 5800 FD comes with the routing tool for the pin on the FD arm which changes the amount of pull required. I believe the 5700 and 5800 front chainring spacing is the same. I'm running a compact 50/34 BTW.