Front and rear derailleurs for my retirement present (to myself)

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geomannie
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Front and rear derailleurs for my retirement present (to myself)

Postby geomannie » 15 Feb 2018, 7:53pm

Hi All

I'd be grateful for some thoughts from the hive mind that is this forum. As a retirement present I am treating myself to a new bike based upon a bespoke frame from Mr Dave Yates, essentially one of his Super Randonneur frames http://www.daveyatescycles.co.uk/Frames/.
Image

As I am a "relaxed" rider not much engaged in sportives and their ilk, I am fitting it with a 28/38/48 triple (Spa Cycles XD-2 already purchased) which I plan to run as a nine speed. At the moment I am minded to go for bar-end shifters (maybe these http://www.wiggle.co.uk/shimano-dura-ac ... lever-set/). The main aspects of the build that I am unsure about is which derailleurs to use front and rear.

The frame will have a braze-on for a clamp-on front derailleur, but as front derailleurs seem to go on for ever, despite my years of cycling I have never needed to buy one. Can anyone here suggest a possible model good for using with a bar-end shifter used in friction mode? The braze-on will be set so that the middle of the adjustment gives the right clearance for a 48tooth ring. Cable-pull will be from below.

Also, any thoughts on a suitable rear mech or are they they "you pays your money and you take your choice".

Thanks all for your thoughts.
geomannie

Brucey
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby Brucey » 15 Feb 2018, 8:24pm

provided you have a barrel adjuster in the cable run somewhere, (eg on the ergo bosses) I would recommend RD-M772 XT rear mech. It is 9s compatible so you can run it in index mode from 9s shifters if you so desire; it will accept a 36T bottom sprocket, and will work very well provided the biggest sprocket doesn't go very much smaller than ~30T.
Image

For a FD I think there is more than one comparable (matching) XT mech that will suit, with conventional (bottom) swing and bottom cable pull. IIRC these mechs were made in various clamp diameters including 28.6mm.

Image

the above is a FD-M751 version and I think should work well, provided the middle to big ring interval matches your chainset. IME this type of MTB FD is more likely than many others to handle a chainline that is closer to a 'road' chainline if needs be. [FWIW top swing MTB front mechs are nothing like so hard-wearing IME, and don't handle road chainlines]

BTW when you say you will have a braze-on for a front mech, do you mean like a road bike often has? If so this will limit the choice of suitable FDs somewhat. I would suggest that you stick with a band-on front mech.

cheers
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cycleruk
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby cycleruk » 15 Feb 2018, 8:56pm

You say "The frame will have a braze-on for a clamp-on front dérailleur"

Being a bit pedantic but "braze-on" will need a braze-on dérailleur. Personally I would not have a braze-on but go for clamp-on. Then there are no problems adjusting the height if, in future, you want to alter the height. On my most recent frame I have a braze-on FD but use a converter clamp to fit it. :roll:
https://www.ribblecycles.co.uk/shimano- ... #pid=20522
(or similar)
Look forward to seeing your build.
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geomannie
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby geomannie » 15 Feb 2018, 9:15pm

Hi Brucey

Thanks a bunch. The rear mech sounds pretty good but can I check on cable pull? My knowledge is a bit sketchy but for a while, following recommendations, I used a 9 speed XT M771 SGS with 10 speed Ultegra STI shifters as I was told that the Ultegra 10 speed pull matched the 9 speed XT derailleur. It worked fine and I actually still have the derailller (not much used). I imagine that it is similar to the RD-M772 XT you suggest but maybe not? So, can I match a 9 speed bar-end road shifters with the MTB XT or is the pull wrong?

For the front derailleur, the mech you suggest seems to be no longer available, at least as a new item. Might there be other options? I am determined that the largest from ring will be no bigger than 48 tooth, but as the whole world wants me to be 10-11 speed, should I just stop being so retro and go with it for shifters/rear mech?

Yes, I have ordered a front mech braze-on for the frame but part of my reason for being here is to check that I am doing the right thing. I can still cancel that and use a band-on mech.

If you have any more thoughts, that would be great.

Cheers
geomannie

Brucey
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby Brucey » 15 Feb 2018, 9:31pm

RD-M771 will be fine. Same cable pull in all shimano 9s rear mechs! The difference between 771 and 772 is the 771 is a twin-pivot design and the 772 is a single-pivot design. IIRC the 772 has a slightly larger capacity.

You should be able to track down a NOS 9s XT front mech if you keep looking, and want one to match perfectly. But in truth there are lots of FDs that would work OK.

I recommend that you don't have a braze-on mount for a FD fitted because

a) it will limit your choice of FDs (where by contrast if you did want to use a braze on mech on a band-on frame, you can always use an adaptor as cycleruk has) and

b) the braze-on constrains your choice of big ring; usually they work OK between 48 and 53T big rings but outside of that you may be out of luck because there is limited adjustment for height.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

Valbrona
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby Valbrona » 15 Feb 2018, 10:21pm

You could use Shimano 105 10 speed Triple STI ... if you tweeked your chainring combination, to say 24/36/48 (this is what I use). This is because the 105 triple FD needs more of a jump than 10 teeth from middle to outer.

I use my 105 FD with Ulfegra GS RD and Ulfegra Triple STI. The Ulfegra Triple FD is different shaped cage and needs an even bigger jump between middle/outer chainrings.

Good stuff - Ulfegra!
I should coco.

BigG
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby BigG » 15 Feb 2018, 10:44pm

You may find the Shimano RD761 SGS better than the 771 as it has the cable adjuster built in. It is usually available on ebay. In all other respects, the two types perform equally well.

freeflow
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby freeflow » 16 Feb 2018, 12:45am

I'm sorry to hear you've already acquired your chainset. I would have recommended going smaller

E.g. 44/32/22.

A standard ultegra front mech (6703) does the job very well on my steed.

Albeit, the setup is somewhat outside of Mr Shimano's recommendations.

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The utility cyclist
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby The utility cyclist » 16 Feb 2018, 1:50am

Valbrona wrote:You could use Shimano 105 10 speed Triple STI ... if you tweeked your chainring combination, to say 24/36/48 (this is what I use). This is because the 105 triple FD needs more of a jump than 10 teeth from middle to outer.

I use my 105 FD with Ulfegra GS RD and Ulfegra Triple STI. The Ulfegra Triple FD is different shaped cage and needs an even bigger jump between middle/outer chainrings.

Good stuff - Ulfegra!

I used a ('93/'94) Shimano 400LX with 10 speed 105STIs (the earlier non hidden cable variant) with a 48/36/26 (maybe 24 I forget now) and it worked absolutely beautifully.
Currently using an FD-6703 on a 50/39/24 (with 6700 STIs) and that works bob on too, it'd be fine if I went to a 48 as well I reckon.

Brucey
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby Brucey » 16 Feb 2018, 5:00am

I think a (complete?) list of 9s XT rear mechs (in order of introduction) runs thusly;

RD-M750 (H,T)
RD-M760 (L, T)
RD-M751 (H,T)
RD-M761 (H,T)
RD-M770 (L, T, nb)
RD-M771 (H,T, nb)
RD-M772 (H,S, nb, 36T)

where
H = high normal
L = low normal
T = two sprung pivots
S = single sprung pivot ('shadow' type)
nb = no barrel adjuster on mech
36T = 36T max sprocket size (the others are nominally 34T max)

RD-M773 onwards are 10s mechs which have a different pull ratio.
RD-M751 (which shimano 'launched' in a hurry once they realised that the world wasn't wildly enthusiastic about low normal mechs like the RD-M760) is almost identical to RD-M750 but it lacks some of the rubber boots on RD-M750, and uses cage plates that are 'styled' (yuk) like the RD-M760 ones. It also has an optional rubber buffer on the lower knuckle that means that it doesn't clonk annoyingly when fitted on some full suspension designs (eg Giant NRS, ask me how I know.... :roll: )

All models are available in several different cage lengths (SGS is the longest one) and weigh about the same in any given variant. I have replaced the (steel) inner cage plate with an aluminium one in some cases which makes a significant weight saving (down to ~225g IIRC). The replacement inner plate can be shaped so that it won't so easily snag in the spokes too.... :roll: All models work reasonably well but the styling on some is a bit, er, 'more challenging' than on others. In theory RD-M772 ought to last longer because there is only one sprung pivot that is meant to move when the mech is in service, but the jury is out on that one. They are all good mechs but I personally can't abide the low normal approach on RD-M760 and RD-M770.

Why a XT 9s rear mech? They are very versatile mechs; they will work OK on all shimano 6s, 7s and 8s index systems (apart from with 6/7/8s dura-ace shifters) will (obviously) work with all road/MTB 9s systems , as well as with all 'road' 10s STIs (apart from ST-4700). They seem to have more durable pivot bushings, and more durable parallelogram bushings than the basic Deore 9s models or earlier 8s mechs. They are (like ultegra mechs) also fitted with much more durable pulleys; the upper pulley is sealed and has ceramic bushings, the lower pulley has a 2RS type cartridge bearing with additional dust shields. If you keep the mech adjusted correctly, and repack both pulley bearings with a decent grease (eg finish line Teflon) at suitable intervals the pulleys will outlast the rest of the mech.

So yeah, if you have RD-M771, use it. The only reason for buying another mech like RD-M772 is that it has a slightly larger capacity, and perhaps if you don't buy one now, you many not be able to in a year or two's time (the oldest was launched nineteen years ago, and the youngest about eight years ago.... :shock: ). I have a small stash of XT 9s rear mechs squirrelled away; having ones available that I can throw onto almost any dedangler-bike I own as needed is a bit of a plus point.

cheers
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pwa
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby pwa » 16 Feb 2018, 8:45am

I'd go for band-on front mech and leave out the braze-on fitting if it isn't too late. Band-on works just as well and allows you to change your mind about ring sizes. When I put a band-on mech on I make sure the frame has a strip of tape around the frame first, and I don't use much torque. They don't need a huge amount of tightening to stay as intended.

My bikes have Dura Ace bar end levers working XT rear mechs on 9 speed and it all works beautifully. Bar end levers effectively lengthen the bottom of the bars, so I cut about 3 or 4cm off each end to avoid the knees nudging the levers. And before putting the bar tape on I fit small foam wedges between the cable and bar, a couple of cm in front of the lever bodies, to get the cable outer to leave the bar zone earlier and avoid getting in the way of my fingers when I'm on the drops.

I like the bike you have planned and I hope it means this next phase in your life will see you upping the miles a bit.

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geomannie
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby geomannie » 16 Feb 2018, 5:25pm

Thanks all for all your input and suggestions. I have now cancelled the braze-on and am hunting a suitable 9 speed botton pull mech. A reputable touring cycle supplier has suggested a 9-speed compatible SHIMANO Sora FD-R3030 Triple Front Mech. Any thoughts?
geomannie

Brucey
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby Brucey » 16 Feb 2018, 7:16pm

FD-R3030

is designed to work with the matching FC-R3030 which has an 11T gap betwixt middle and big rings. It will probably work OK on a 10T gap. It comes with a set of plastic shims to make it fit a variety of seat tube sizes.

Fundamentally there are two readily available sets of FDs that might work for you

1) 'road triple' ones (like the FD-R3030) which have a short cable pull and are primarily intended for a 'road' chainline

2) Some MTB ones (bottom pull, bottom swing) which have long cable pull and are primarily intended for an MTB chainline.

The latter group don't all swing in far enough to allow use at a 'road' chainline, (and conversely the former group won't all work on an MTB chainline) but the longer MTB cable pull makes for easier shifting (about 40% easier). Both types can be controlled using bar-end shifters.

Because older MTB front mechs (even from the 1980s) fit and work OK on touring setups such as the one you are aiming at and NOS ones keep popping up, your chances of sourcing something on e-bay that will work OK are pretty good. There is no need to settle for something that is 'current' even if you want one that is unused.

For example I have an ancient FD-M700 (Deore XT 'deerhead') on one bike running 9s chain and it works fine. I doubt it will ever break or wear out...
Image
The geometry of this FD was also used in a large number of subsequent FDs through the 1990s; it will allow use over a wide range of chainlines, and the workings are largely not taking up space between the rear mudguard and the seat tube. Neither feature has been exactly commonplace since that time.

I suggested the XT ones because they would 'match' an XT rear mech but it is no big deal, most FDs are pretty anonymous looking anyway.

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

rmurphy195
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby rmurphy195 » 16 Feb 2018, 11:54pm

Does your frame builder have any recommendations?
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pwa
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Re: Front and rear derailleurs for my retirement present (to myself)

Postby pwa » 17 Feb 2018, 7:23am

geomannie wrote:Thanks all for all your input and suggestions. I have now cancelled the braze-on and am hunting a suitable 9 speed botton pull mech. A reputable touring cycle supplier has suggested a 9-speed compatible SHIMANO Sora FD-R3030 Triple Front Mech. Any thoughts?


Nothing wrong with any Sora front mechs I've seen.