Shimano Flat Bar Shifters and Front Mech's - Compatibility?

[CREPELLO]

Shimano R440 shifters are supposed to only be compatible with the R443 front mech (+other variants). Yet I've read conflicting advice, some suggesting that regular Shimano road mech's will work with these shifters.

Can anyone provide a conclusive answer on this?

[rjb]

Ive been asking this question in the Does anyone know forum - viewtopic.php?f=1&t=54152
Ive had similar conflicting advice but i will be using this mech with road drop bar Tiagra sti levers. When i do the mods i will let you know how i get on.

[CREPELLO]

Yes, it was reading your thread that prompted me to ask this, although I've been thinking about it for some time.

[niggle]

From CJs page on front shifting http://www.ctc.org.uk/DesktopDefault.aspx?TabID=%204068

"If you want to combine big road-bike chainwheels with flat handlebars: no problem. Shimano and now also Campagnolo, cater specifically for the “Fitness Bike” with a line of flat handlebar controls purpose made to pull the smaller amount of cable required by road-bike brakes and front mechs (the rear mechs work the same remember)."

[CREPELLO]

Well this is rather awkward (appearing to question CJ's knowledge ). But there is so much out there on the web that suggests that the R443 mech will work from MTB shifters. Bikeforums discussion and mtbr forum discussion are just two threads which allude to this.

I'd quite like to know because I may use one in the future with a Shimergo setup. Campag triple mech's will become increasingly difficult to find, plus the R443 is still available in a 28.6 clamp size and is cheaper than Campag (currently £23.50 at Parker Int). Shimano road mech's are an unhappy combination with ergo's IMO.

[CJ]

From CJs page on front shifting http://www.ctc.org.uk/DesktopDefault.aspx?TabID=%204068

"If you want to combine big road-bike chainwheels with flat handlebars: no problem. Shimano and now also Campagnolo, cater specifically for the “Fitness Bike” with a line of flat handlebar controls purpose made to pull the smaller amount of cable required by road-bike brakes and front mechs (the rear mechs work the same remember)."

Whoops, I really need to change that. Seems that the shifters are actually mountain/trekking bike shifters in sheep's clothing and what they've actually done with the front indexing is to make some special front mechs that marry a big-ring-roadie cage to a mountain/trekking parallelogram.

So a mountain mech should work just fine with those shifters - provided you also have a compatible chainset on that bike.

But if you try to shift one of those special mechs with drop-bar STIs it simply won't shift far enough.

[gramski]

My experience with R440 shifters is on one of my bikes that has a 105 front mech and Tiagra chainset. I set this up about a year ago and have not had any problems with it.

[niggle]

From CJs page on front shifting http://www.ctc.org.uk/DesktopDefault.aspx?TabID=%204068

"If you want to combine big road-bike chainwheels with flat handlebars: no problem. Shimano and now also Campagnolo, cater specifically for the “Fitness Bike” with a line of flat handlebar controls purpose made to pull the smaller amount of cable required by road-bike brakes and front mechs (the rear mechs work the same remember)."

Whoops, I really need to change that. Seems that the shifters are actually mountain/trekking bike shifters in sheep's clothing and what they've actually done with the front indexing is to make some special front mechs that marry a big-ring-roadie cage to a mountain/trekking parallelogram.

So a mountain mech should work just fine with those shifters - provided you also have a compatible chainset on that bike.

But if you try to shift one of those special mechs with drop-bar STIs it simply won't shift far enough.

So why have the 'Flat Handlebar' designation shifters at all, if they pull the same cable as mtb shifters?? Just to make the groupset look complete I suppose?? This means there are several threads on here that may be misleading....

I thought you were right originally because I have an FD-R440A-F front shifter on my (flat bar) folder, chosen because it is rated to work with the really large 56T chainring and inner 42T ring. When I tried an Alivio shifter pod with it I seemed to get too much throw, though I could well be wrong and being a double this is not a real problem as you can just set the limit screws to suit. In the end I found an old friction thumbie to do the job better, but am currently considering drops for it so need to know which STIs or Ergos I can use. If what you say is true then a Shimano STI for double chainsets may not have enough cable pull??

[CREPELLO]

Thanks for clarifying the issue CJ. The Shimano exploded views clearly show the difference in length of the actuation arm between the different mech's, which helps to define how much cable pull is required to operate . Both R443 and Deore have similar looking proportions, whereas the 105 has a much shorter arm, needing less cable pull to operate it. (refer to the diagram of the triple mech's for the clearest comparison between all three mech's)

I would speculate that those who have run road series front mech's such as Tiagra or 105 have been able to do so because the left hand R440 shifter has a trim function. Is this like a micro ratchet, like that of the Campag ergo type (which allows easier compatibility of non standard front mech's)? If so, it's easy to see how it would work, although the trimming function would be reduced I would guess.

[niggle]

Thanks for clarifying the issue CJ. The Shimano exploded views clearly show the difference in length of the actuation arm between the different mech's, which helps to define how much cable pull is required to operate . Both R443 and Deore have similar looking proportions, whereas the 105 has a much shorter arm, needing less cable pull to operate it. (refer to the diagram of the triple mech's for the clearest comparison between all three mech's)

I would speculate that those who have run road series front mech's such as Tiagra or 105 have been able to do so because the left hand R440 shifter has a trim function. Is this like a micro ratchet, like that of the Campag ergo type (which allows easier compatibility of non standard front mech's)? If so, it's easy to see how it would work, although the trimming function would be reduced I would guess.

Corrected the 105 link To my untutored eye it looks almost like the R443 mech has an arm with a length that is part way between the other two, is it possible that the flat bar road series stuff has a third intermediate cable pull?

Also with the R440 left shifter operating a road mech I imagine that you only need to get the middle ring indexed right, the outer and inner will be controlled by the limit screws. The other way round, road shifter operating an R443 mech, would have more potential for problems due to the cable pull possibly being insufficient to shift to the outer or inner rings?

[rjb]

I collected a giant rapid 3 with flat bar shifters to convert to drops with sti's. Front mech is FDR-443 8 speed mech and the Left hand flat bar triple shifter STR-225-L pulls 13.5mm for 3 chainrings. This implies that both the front mech and the gear shifters are made to the current road sti standard and should be directly compatible with drop bar sti levers.
This makes life a whole lot easier.

[CREPELLO]

rjb, I'm glad that the components you have are compatible, but it's still not clear to me what is going on. Look at your R443 mech - the actuation arm that pulls the mech; it looks more or less the same length as a MTB mech. But your measurement for cable pull is 13.5mm (road standard, as oppossed to 19mm MTB). The length of the actuation arm is the primary way of specifying the amount of cable pull required.

The other thing is why would Shimano label and market a flat bar specific front mech, but not do the same with a rear mech, unless the front mech was unique in some way? They must make the front mech for some reason, rather than just trying to squeeze more money from us. Aftre all, they could have marketed a whole flat bar specific groupset.

Does anyone one else find this cable pull thing completely confusing? Can anyone try and explain what's going on? I'd love to know!

[rjb]

I have just finished converting the giant flat bar road bike and can report that the front mech is perfectly compatible with the triple road tiagra sti shifters. I think that the flat bar levers are called road levers because they are compatible with dual pivot calipers and not V brakes. The front mech actuation arm does look odd partly due to the operating angle i agree but as it is a combination of the leverage exerted by the arm from the pivot to the cable attachment and the leverage of the linkage to the cage it is not allways obvious what is going on. What is clear is that it works perfectly. The cable pull i measured was from the flat bar road shifters. The front mech is designed for large chainrings ie 52 teeth, way more than any MTB mech. I suppose you could have used any triple compatible road mech designed for large chainrings hence i see you point about why have such a mech. Anyway i am well pleased it is all working ok

[rjb]

Ive just had a closer look at the flat bar levers, the brake cable pivot retainer is located in a slot locked by a plastic spacer. Removing the spacer allows one to relocate the cable pivot to an extended position marked V - which i assume means that you can make these levers compatible with V brakes.

[UpWrong]

I have an RD-443 triple. I've just tried to get this to work with a Deore SL-M590 trigger shifter, and the shifter pulls way too much cable. I have an SRAM Attack shifter lying around and wonder if that might be better, or will it have the same cable pull as the Deore?