Middleburn 50mm chainline for touring

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Rabbit
Posts: 287
Joined: 19 Aug 2012, 10:43pm
Location: The New Forest

Middleburn 50mm chainline for touring

Post by Rabbit »

I'm building up a bike for a longish tour and I fancy a Middleburn triple chainset - but they come with a 50mm chainline. I'm planning to use it with an Ultegra front and rear mech. I'm wondering if the fact that it has a 50mm chainline will be ok or will it cause me problems with shifting? The other issue is that apparently there needs to be at least a 48 tooth big ring on the chainset for the Ultegra front mech to work properly, so I was going to have 48 - 36 - 24 or 22. Does that sound ok? Many thanks -
Valbrona
Posts: 2694
Joined: 7 Feb 2011, 4:49pm

Re: Middleburn 50mm chainline for touring

Post by Valbrona »

Rabbit wrote:I'm building up a bike for a longish tour and I fancy a Middleburn triple chainset - but they come with a 50mm chainline. -


How do you know the chainline is 50mm? I have never noticed that the Middleburn people are enlightened enough to give such vital information on their website.
I should coco.
Rabbit
Posts: 287
Joined: 19 Aug 2012, 10:43pm
Location: The New Forest

Re: Middleburn 50mm chainline for touring

Post by Rabbit »

It's what Middleburn say on their website - all chainsets have a 50mm chainline!
Brucey
Posts: 44517
Joined: 4 Jan 2012, 6:25pm

Re: Middleburn 50mm chainline for touring

Post by Brucey »

i think their MTB cranks run H-II type BB systems, and can be shimmed each side to adjust chainline (if not Q) and that their touring cranksets can run different chainlines depending on the BB axle length you choose; they run a ST system.

They are not far away from you, why not pop in or give them a ring(*)?

(*) pun unintended, but funny anyway, huh? :roll:

cheers
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~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~
Rhodrich
Posts: 180
Joined: 10 Jul 2012, 11:17am
Location: Thames Ditton, Surrey

Re: Middleburn 50mm chainline for touring

Post by Rhodrich »

Until yesterday evening, I was running a Middleburn RS7 chainset on my Dawes Galaxy.

I had it set up with the recommended 113mm bottom bracket, and the chain line was indeed about 50mm, which meant that my Shimano 105 triple front mech fouled the chain when I was in the big ring, as it couldn't go out far enough. However, there was oodles of clearance on the inner side, so I could have easily run the chainset with a 107mm bottom bracket to bring the chain line back to 45mm, which would have solved the problem.

I decided not to go down that route, as it's got 175mm cranks, and I prefer 170mm ones. I've therefore moved over to a SPA TD-2 chainset, and have the RS7 crankset up for sale, if you're interested. It's got a 110/74 spider. The only problem is that the left hand crank is not a Middleburn, but a Bontrager (but you can always buy a single crank directly from Middleburn, should you so wish). Pics and details here: http://www.lfgss.com/conversations/256523
Last edited by Rhodrich on 28 Nov 2014, 2:46pm, edited 1 time in total.
trieste
Posts: 37
Joined: 10 Jan 2011, 9:47am

Re: Middleburn 50mm chainline for touring

Post by trieste »

"All middleburn chainsets are designed to achieve a chain line of 48mm for cross country and 50mm for downhill"

http://www.middleburn.co.uk/images/pdf/chainset_assembly.pdf

Yes, this does conflict with the FAQ.
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CJ
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Re: Middleburn 50mm chainline for touring

Post by CJ »

Avoid the Ultegra front mech. It wants a 13T outer-middle difference, which puts the middle ring that much further below the outer cage that it's working very much 'at arms length' when it comes to shifting from middle to inner. It does not so much 'slice' the chain off the ring as vaguely bend it, in the hope that the teeth might then let go. Often they do let go, if it's an authentic Shimano Ultegra middle ring (with pre-worn stumps for teeth that the chain already wants to fall off!) it probably will shift, most times, provided the chain isn't worn much, but anything else (with longer-lasting teeth) and you'll need to slacken off the pedalling - a lot. And it isn't easy to slacken of the pedalling when you find yourself still in middle on a steepening hill!

The middle to inner shift is so vital and so hard when touring, that I would forget about what size you'd like the jump from middle to outer to be, and make this difference as small as you can live with and the mech will tolerate, so as to keep the middle ring reasonably close to the outer cage. So pick the 105 mech instead, that's designed for an 11T difference and will work with 10T if both rings are small enough. I find 46,36,24 works well, with the deep inner cage of this mech clearing the teeth of the middle by a hair's breadth.

Apart from the cage shape, the only differences between 105 and an Ultegra front mechs are colour and price. Or now that Tiagra is also 10-speed, that's an even more rational choice.

And why would you ever want a 'road' rear mech for touring?
Image20120829017 by Chris Juden, on Flickr
Chris Juden
One lady owner, never raced or jumped.
Valbrona
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Joined: 7 Feb 2011, 4:49pm

Re: Middleburn 50mm chainline for touring

Post by Valbrona »

If the OP was happy with a 38 middle then there are loads of 130/74 BCD road-chainline triples on the market, including integrated axle/outboard bearing types. And if OP wants smaller than a 38 middle there are a few 110/74 BCD road-chainline triples available.

I have never really liked Middleburn because of their failure to make a 110/74 BCD 'road compact triple'.
I should coco.
Rabbit
Posts: 287
Joined: 19 Aug 2012, 10:43pm
Location: The New Forest

Re: Middleburn 50mm chainline for touring

Post by Rabbit »

Brucey, Chris, Valbrona, Rhodrich and Trieste thanks so much for your thoughtful comments - much appreciated. As for the Ultegra front and rear mech situation - I think I need a rethink! Basically I am having a frame built by a well known builder in Derby but I am providing the components. They're suggesting Ultegra 'because we know it works' and said that means a large ring on front of at least 48, which is bigger than I really want or need. But being a relative newcomer to this kind of thing I'm nervous about handing them a kit of parts which don't then mesh together and work. Basically I want a configuration that will take a fully loaded bike over the Rocky Mountains - so ideally I wanted a 30 or 32 rear cassette, a 22 or 24 granny ring and a rear and front mech that would handle that with 9 or 10 speed bar end shifters.
tim_f
Posts: 251
Joined: 12 Oct 2009, 10:37pm

Re: Middleburn 50mm chainline for touring

Post by tim_f »

If you are going to be using bar end shifters then you have the option of using a mountain bike front mech or a road bike front mech.

I would go for 9 speed as bit more tolerant of being out of adjustment than 10 speed.

you have a few linked decisions to make.

1) do you want traditional square tapper bb and chainset or external bearing type.

2) is low range or high rage important to you.

If you happy with external bearing and low range is important then you could have
11 to 34 cassette 9 speed Deore rear mech http://www.chainreactioncycles.com/shimano-deore-m591-9-speed-rear-mech/rp-prod40543, 9 speed mtb front mech http://www.chainreactioncycles.com/shimano-xt-m771-conventional-9sp-front-mech/rp-prod20685 + XT 9 speed 44 -32 -22 chainset http://www.chainreactioncycles.com/shimano-xt-m770-triple-chainset/rp-prod20679

can also get shimanio mountain bike chainsets in 48,36, 26.

If you want a higher range of gears and /or you want square taper than Spa Cycles is the place to go. If you have square taper you can chose the bb length to give you either mtb or road chainline. They can also supply square tapper chainsets with mountain bike like ratios.

Same 9 speed deore rear mach is probably best choice, If you have road chainline then a Sora front mech is best choice.

If the supplier of your frame has not explained all this to you then maybe they are not a good place to go to for a touring frame. Ultega mechs are not good for a real touring bike.

If the bike is for touring and you have other bikes to ride without luggage then a 44 32 22 chainset is probably the way to go paired with a 11 -32 or 11 -34 9 cassette. This gives a low gear to allow you to spin up long climbs.

Tim
freeflow
Posts: 1636
Joined: 29 Aug 2011, 1:54pm

Re: Middleburn 50mm chainline for touring

Post by freeflow »

I'm currently running a deore XT 44/32/22 chainset with a 6607 Ultegra front mech with XT 9 speed rear mech and 11-36 cassette. The shifters are 6603 STI. It all works fine. The front mech sits higher than recommended by Shimano to ensure that the front mech doesn't hit the chainstay when on the inner ring. Done a number of 200k Audax with no issues including one with 3 AAA points. It definitely helps me get my 100+ kg up the hills :D.
NetworkMan
Posts: 727
Joined: 25 Aug 2014, 11:13am
Location: South Devon

Re: Middleburn 50mm chainline for touring

Post by NetworkMan »

If you are open to suggestions I've recently used a Spa XD2 chainset on my Spa Steel Touring build. It's a bargain at £35 though you'll need to buy crankbolts as well. It comes with 48/38/28 rings but I've changed the inner one from 28T to 24T. It's still a bargain even if you do this. If you are building a 9 speed system you can use a 9 speed Sora front mech. which is what Spa do on their own builds. You can go even lower geared on the inner ring with a 4 arm mountain bike chainset, also available from Spa. This is not my choice because I like the 38T middle and 48T top, YMMV.
freeflow
Posts: 1636
Joined: 29 Aug 2011, 1:54pm

Re: Middleburn 50mm chainline for touring

Post by freeflow »

Some pictures of my XT chainset setup I referenced above.

IMG_20140921_155507729.jpg


IMG_20140921_155553044.jpg
NetworkMan
Posts: 727
Joined: 25 Aug 2014, 11:13am
Location: South Devon

Re: Middleburn 50mm chainline for touring

Post by NetworkMan »

Gosh. With the cage so far above the middle ring I'm suprised, as CJ mentions above, that you don't get trouble with the shift onto the little one! The danger is that the chain can flex without actually dislodging from the middle ring.
I find that with my 8 speed road changer and 48/38/24 I can get the cage as close to the rings as I like.
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