Do shimano sti shift levers work with DX cranksets?

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Tizme
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Re: Do shimano sti shift levers work with DX cranksets?

Postby Tizme » 17 Jan 2017, 3:25pm

Thanks to all for the replies. Apologies also, conveying what I can physically see, to what you can "see" from my post is often vastly different, especially when I fail to describe in any detail :( . The inner chainring (30T) scraped the paint off the chainstay. At that point I was so glad my grandchildren were in the kitchen and not watching me in the garage!

I would hardly call myself a newbie, I started cycling daily to commute to work in 1980 when I married, as I could not afford to run a car and pay a mortgage whilst my wife used her car to get to work (she drove an 8 mile round trip, I cycled 7 miles each way :) ). My current commute is a 29 mile round trip, which until my hip replacement last year I did daily on a fixed gear. Despite being ordered not to get on my bike by my physio for 3 months after the op, I still managed to ride over 2k miles in 2016. I am more careful with the weather now, especially as it would seem the other hip will need replacing soon. I also work shifts which means I am on the road at 5am for some of my shifts and again at 1830 for others, on both busy A roads and unlit country lanes. I also took part in Ironman Triathlons and would frequently ride in excess of 5k miles a year in training and competitions.

The Vagabond project was a retirement present to myself, I finish work in June after 40 years in the uniform of HM Armed Forces and I intend to cycle from my home in Somerset to Lands End, up to John O'Groats and then back home, carrying all my kit and camping. None of the 4 bikes I currently own would be up to the task in my opinion, which is why I went for a build. The Vagabond frame was my third choice frame (and almost half the price of my first choice), perhaps I should have waited, but I was keen to get started and commute for a month or so to get the feel of the bike. The build kit was a direct match for what someone had put on their own tourer (on my first choice bike), my mistake was assuming that the Vagabond would take the same. I don't like bar end shifters, just a personal thing, but I do like STI levers. Had I known the Vagabond would not take the 10spd Tiagras I would have lowered the spec (which I would still have been happy with - I don't need 30 gears!! (Ignoring overlap). I like the clean lines of the new Tiagras, with the cables hidden under the bar tape, I thought it would also allow easier fitting of a bar bag.

Genesis have finally got back to me with my first query, they recommend a chainline of 43.5mm and as I said before, a trekking triple of 48/36/26.

I asked the question to get advice, which I have listened to and am grateful for. As reohn2 asked, will a 48t big ring be big enough? I think the answer is yes, I don't see a problem there, but as I have never toured fully loaded I don't know if a 26 will be sufficient/too small, or overkill at the other end of the scale.
To answer a previous question, I don't know if the Deore kit will fit, I do not want to spend any more money (much to my wifes' relief - if she only knew how much I have spent already :( ) until I have an idea of what will fit, it may be I have to buy some kit to "try it and see" but obviously I don't want to waste money.
Again, thanks for all your replies and help.
Last edited by Tizme on 17 Jan 2017, 7:24pm, edited 2 times in total.

reohn2
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Re: Do shimano sti shift levers work with DX cranksets?

Postby reohn2 » 17 Jan 2017, 3:54pm

Tizme wrote:....... As reohn2 asked, will a 48t big ring be big enough? I think the answer is yes, I don't see a problem there, but as I have never toured fully loaded I don't know if a 26 will be sufficient/too small, or overkill at the other end of the scale.

Don't underestimate how low you may need to go with the gearing,it's aways betterr to have two gears in hand than find yourself struggling and nothing left on the low end.
A 24 inner ring with a 32 or 34 biggest cog on the cassette is pretty low,but you never know when you might need it,piddling down rain,feeling a bit offside and a bit of hunger knock on a hard day is the difference between riding and walking up a 20% climb pushing a heavily laden bike,which isn't fune either way but I know which is easier.

To answer a previous question, I don't know if the Deore kit will fit, I do not want to spend any more money (much to my wifes' relief - if she only knew how much I have spent already :( ) until I have an idea of what will fit, it may be I have to buy some kit to "try it and see" but obviously I don't want to waste money.
Again, thanks for all your replies and help.

10speed Deore MTB mechs aren't compatable with road STI's,you'll need 10speed road mechs.If you have Tiagra STI's,Tiagra Mechs are more than good enough for the job,but you'll need the long cage 4700 series mech to handle a 34t cog.

EDIT:- just reading up on the 4700 rear mech,it's only compatible with 4700 STI's
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Tizme
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Re: Do shimano sti shift levers work with DX cranksets?

Postby Tizme » 17 Jan 2017, 4:36pm

Thanks reohn2. I agree, you can never go too low (at least with my spindly legs :) )

I also sent a query to SJS Cycles and they say the Tiagra 4703 FD will work fine with 26-36-48 chainset and fit it to some of their bikes (one place I forgot to look for ideas for gearing - I checked out Spa to see what they use). So perhaps I can get away with it. Just need the chainset and see what happens.

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531colin
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Re: Do shimano sti shift levers work with DX cranksets?

Postby 531colin » 17 Jan 2017, 4:51pm

43.5" chainline........
even if they mean millimetres, it still doesn't make sense.
MTB/Trekking triples have a 50mm chainline. This means the middle ring is 50mm out from the bike centreline.
Road triples have a 45mm chainline, ie the middle ring is 45mm out from the centre.
(Road doubles have the middle of the gap between the 2 rings 45mm out from the middle, so the inner ring is 42.5mm from the centre)
Does it perhaps mean that the inner ring should be 43.5mm out from centre, therefore the middle ring (chainline) will be 48.5mm, in which case MTB chainline is near enough?
(edit 4703 chainset is 30, 39, 50, so 26/36/48 or 24/34/46 seem appropriate. i would expect to have to use an eccentric shim to get the Tiagra F mech to work on a 50mm chainline)

reohn2
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Re: Do shimano sti shift levers work with DX cranksets?

Postby reohn2 » 17 Jan 2017, 5:20pm

Just been out to the workshop for a proper dose of measuring with a steel rule and some serious eyeballing:-
Spa's own and Stronglight Impact chainsets with 115mm UN54 BB's,chainline is 44m measured centre of frame to centre of middle ring.
a 118mm BB will give another 1.5mm making it 45.5mm
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Tizme
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Re: Do shimano sti shift levers work with DX cranksets?

Postby Tizme » 17 Jan 2017, 7:25pm

Sorry, my mistake and now corrected to mm not inches! However 43.5mm was the reply I was given. I am looking at going down the Spa crankset and BB route. Will let you know :)

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531colin
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Re: Do shimano sti shift levers work with DX cranksets?

Postby 531colin » 17 Jan 2017, 8:07pm

reohn2 wrote:Just been out to the workshop for a proper dose of measuring with a steel rule and some serious eyeballing:-
Spa's own and Stronglight Impact chainsets with 115mm UN54 BB's,chainline is 44m measured centre of frame to centre of middle ring.
a 118mm BB will give another 1.5mm making it 45.5mm


Well, there are 2 Stronglight Impact triple chainsets, one where you can see all 5 chainring bolts,. and one where one bolt is hidden behind the crank....they take different length axles
Spas XD2 and TD2 take different axle lengths..........

reohn2
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Re: Do shimano sti shift levers work with DX cranksets?

Postby reohn2 » 17 Jan 2017, 8:43pm

531colin wrote:
reohn2 wrote:Just been out to the workshop for a proper dose of measuring with a steel rule and some serious eyeballing:-
Spa's own and Stronglight Impact chainsets with 115mm UN54 BB's,chainline is 44m measured centre of frame to centre of middle ring.
a 118mm BB will give another 1.5mm making it 45.5mm


Well, there are 2 Stronglight Impact triple chainsets, one where you can see all 5 chainring bolts,. and one where one bolt is hidden behind the crank....they take different length axles
Spas XD2 and TD2 take different axle lengths..........

Five visible bolts,sorry Colin forgot about the other types :oops:
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recordacefromnew
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Re: Do shimano sti shift levers work with DX cranksets?

Postby recordacefromnew » 17 Jan 2017, 9:47pm

To be safe, it might be best to remove the inner ring of the existing chainset, torque it up, and do some careful measurements to find out what chainline is needed for what inner ring size. Each additional tooth increases the radius by 2mm.

If going for the square taper route to game the chainline (and to test the road fd's limit :shock:), the chainline increments for 115mm/118mm/121mm from 113mm UNxx are 0mm/2mm/5mm respectively. But chainset and spindle manufacturing tolerance meant ymmv slightly.

Not sure if the op can look at some mtb fd's, based on what the cable run is like, but it might also be worthwhile considering modding a mtb fd to match the 4700 fd cable pull (see e.g. http://forums.mtbr.com/shimano/successf ... 33644.html). The merit of the mod is you can then use a mtb chainset with properly low gears with no shift performance compromise due to chainset / fd cage profile mismatch.

Valbrona
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Re: Do shimano sti shift levers work with DX cranksets?

Postby Valbrona » 18 Jan 2017, 2:40am

If someone says 'a 4703 FD will work with a 36/48 triple', they are saying that the inner plate of the cage will not hit the middle chainring when it moves outward. The same also applies to a 5703 triple FD, but FWIW an Ultegra 6703 FD will not work with 36/48 (different cage).

Chainline is another matter ...
I should coco.

gloomyandy
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Re: Do shimano sti shift levers work with DX cranksets?

Postby gloomyandy » 18 Jan 2017, 8:34am

On the chainline and road v MTB issue. An interesting thing I came across when researching my own touring bike build (a Croix de Fer with a MTB double/MTB Cassette and rear mech with road shifters and front mech), is that in the SRAM world they now make road crank sets that are designed to run at a MTB chainline. This is because of the many bikes with short stays and disc brakes (which typically use a MTB style rear spacing). If you look at the SRAM cranks you will see that in some of the range two versions with different length axles are available. I think this also means that with SRAM at least some of the road front mechs are designed to work with both road and MTB chainlines. Certainly I've found that the Force 22 front mech can easily be setup to work with my MTB front chainset.

None of this is of help to the OP, who is using Shimano and wants a triple! But I thought it was interesting that things are changing in this area.

Valbrona
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Re: Do shimano sti shift levers work with DX cranksets?

Postby Valbrona » 18 Jan 2017, 1:22pm

gloomyandy wrote:On the chainline and road v MTB issue. An interesting thing I came across when researching my own touring bike build (a Croix de Fer with a MTB double/MTB Cassette and rear mech with road shifters and front mech), is that in the SRAM world they now make road crank sets that are designed to run at a MTB chainline. This is because of the many bikes with short stays and disc brakes (which typically use a MTB style rear spacing). If you look at the SRAM cranks you will see that in some of the range two versions with different length axles are available. I think this also means that with SRAM at least some of the road front mechs are designed to work with both road and MTB chainlines. Certainly I've found that the Force 22 front mech can easily be setup to work with my MTB front chainset.

None of this is of help to the OP, who is using Shimano and wants a triple! But I thought it was interesting that things are changing in this area.


I use a SRAM Wide Axle crankset with a tripleizer middle ring. Works out at about 45mm chainline. Their Wide Axle cranksets are essentially doubles for disc brake/135mm chainline.

SRAM do not have specific front derailleurs to match their Wide Axle cranksets. They just use an FD clamp that sticks out further. These are also designated 'Wide Axle'.

FSA also do disc brake specific cranksets for 135mm rear spacing. These are denoted 'DB' in their range and are BB386, so fit pretty much anything including BSA 68.
I should coco.

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RickH
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Re: Do shimano sti shift levers work with DX cranksets?

Postby RickH » 27 Jan 2017, 1:11pm

Reading this topic make me wonder that, as this seem to crop up repeatedly, whether there would be a market for someone (such as Problem Solvers) to make a braze on front mech clamp with a bit of extra reach?

Or even an offset widget that would step a standard braze on clamp to MTB chainline (albeit with the clamp mounted higher, or lower, to compensate)?

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531colin
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Re: Do shimano sti shift levers work with DX cranksets?

Postby 531colin » 27 Jan 2017, 3:17pm

St John St do an eccentric shim to space a road F. mech. out a bit......there is a photo of mine on the first page

Tizme
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Re: Do shimano sti shift levers work with DX cranksets?

Postby Tizme » 23 Mar 2018, 1:57pm

So I thought I would give an update on how I finally got on!

Unfortunately I don't seem to be able to post photos, they come up as being too large, but it is on Cyclechat in the photo gallery under "show us your Genesis" and in the "self-builds". White frame with a "One Less Car" logo.

The initial problem arose when I bought a Genesis Vagabond frame rather than the Tour de Fer, incorrectly assuming that the gearing from the Tour would go across to the Vagabond. I then had the problem that the inner chainring on a triple scraped the chainstay. This caused much swearing, followed by multiple purchases to work around the problem, with one member of this community ending up with a good deal on an almost brand new triple chainset (and spare inner ring).

It now sports Tiagra 4703 STI's and Front and Rear Derailleurs with a Deore M615, 40Tx26T chainset (26T replacing the original 28T ) this coupled with an 11-34 cassette gives me 21.5 gear inches at one end and 102 on the other, which hopefully will be enough! Shifting is perfect and so far it is riding beautifully.

Considering this was my first ever self-build I am pleased with the way it has turned out and I must really thank everyone for their suggestions and comments when I first posted my problem. It is slightly frustrating at the moment as I am awaiting my second hip replacement (the right was replaced in 2015) and it is much more painful after I get off the bike than the right ever was, once on the bike I am relatively pain free, I just can't walk after I get off it!

My wife and I walked the Pennine Way to celebrate her 50th and she is adamant we will do it again for her 60th, in 18 months time, hopefully getting fit for that (and the odd ride or two :wink: ) will get me fit enough to tackle LEJOGLE, solo, unsupported before I hit 65!