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NoCoGreg
drwelby wrote:

In the event you need to mess around with front derailleur range, there is this tricky item:
https://www.sjscycles.co.uk/gear-spares/thorn-eccentric-front-mech-shim-286-to-349-black-plastic-hand-finished-split/?geoc=US

Droitaubut, thanks for sharing the above link!  That's exactly what I've wanted for a number of my Frankenbike projects as the road FD's don't have the range to work with a MTB triple crankset.  Instead of this I've fashioned my own shims using a few layers of old inner tubes which are glued together.  

Without knowing what bike model I feel like I'm just taking SWAG's...

The Shimano GRX crankset appears to only be available with traditional road BB's so that would indicate a FD shim shouldn't be needed.

By not going to 12 speed, parts are MUCH less expensive and because 10 speed chains and cranksets are compatible it's keep the cost down and makes it a lot easier to find parts if something breaks while traveling.  

As for interchanging SRAM and Shimano cassettes - as long as you're not using the Shimano 11-34 road cassette, then there is no difference in cassette width.  With 10 speed, the SRAM and Shimano cassette bodies differed by 1.0 mm.  All the Shimano 11 speed road and mountain cassettes have the same width EXCEPT for the 11-34 which was designed to fit onto a 10 speed freehub body.  This is awesome for those of us with 10 speed wheels which we'd like to use for gravel and want that lower gear.  

So many "standards", so little room left in my brain...
Greg
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droitaubut
NoCoGreg wrote:

Droitaubut, thanks for sharing the above link!  That's exactly what I've wanted for a number of my Frankenbike projects as the road FD's don't have the range to work with a MTB triple crankset.  Instead of this I've fashioned my own shims using a few layers of old inner tubes which are glued together.  

Without knowing what bike model I feel like I'm just taking SWAG's...

The Shimano GRX crankset appears to only be available with traditional road BB's so that would indicate a FD shim shouldn't be needed.

By not going to 12 speed, parts are MUCH less expensive and because 10 speed chains and cranksets are compatible it's keep the cost down and makes it a lot easier to find parts if something breaks while traveling.  

As for interchanging SRAM and Shimano cassettes - as long as you're not using the Shimano 11-34 road cassette, then there is no difference in cassette width.  With 10 speed, the SRAM and Shimano cassette bodies differed by 1.0 mm.  All the Shimano 11 speed road and mountain cassettes have the same width EXCEPT for the 11-34 which was designed to fit onto a 10 speed freehub body.  This is awesome for those of us with 10 speed wheels which we'd like to use for gravel and want that lower gear.  

So many "standards", so little room left in my brain...
Greg


I wasn't the one who provided the link, so credits to drwelby for that. GRX is with traditional road BB's, but q-factor of crankset is 5mm more, and as such FD is adjusted to chainline of +2.5mm as well.

So how to use the Shimano 11-34 11-speed cassette on a wheel, need a spacer?
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NoCoGreg
droitaubut wrote:

So how to use the Shimano 11-34 11-speed cassette on a wheel, need a spacer?

You'll need a 1.85mm spacer to put the Shimano 11-34 cassette on a road 11 speed freehub body.  Here's a link with a detailed drawing...

https://bikerumor.com/2012/05/01/11-speed-road-bike-hubs-versus-10-speed-tech-breakdown/

BTW the Shimano 11 speed MTB continues with the same width freehub body as the 10 speed road.  So that means any of the 11 speed MTB cassettes will fit an 11 speed road freehub (add 1.8mm spacer), or use it a 10 speed road hub without the spacer.

Oh and thanks for giving Dwerby credit. :-) 

Cheers,
Greg

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drwelby
Also in front derailleur hacking, if you ever need to convert a road derailleur to top-pull:

http://www.speen.de/SportsEquipmentEngineering/speen__store.html

Scroll down to the "umlenkers"
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OffB10Path
Cool!  The "umlenker" looks like a slick alternative to a cross pulley.  I like that eccentric FD clamp adapter Droitaubut posted, too. 
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Cmtgravel
A little off-topic, i know, but with all this talk of FD's...Anyone know if its possible to convert 9spd Deore mtb shifter/FD to work with 2x rather than triple. Have an old Giant hardtail, circa '03-'04, i wanna get up and running with a lighter, simpler 2x crankset at minimal cost. Possible?
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bnystrom
You shouldn't need to "convert" anything. A triple front derailleur has excess capacity, but the limit screws will take care of that. Instead of having two clicks that shift between three chainrings, you'll only use one click to shift between two chainrings.
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Cmtgravel
But is the spacing between rings on a double the same as a triple, or doesn't it matter? Also, can the limit screws be dialed in enough to prevent shifting the chain off the rings in the case of a mis-shift?
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bnystrom
Yes, the spacing between the chainrings is the same; it has to be since they use the same width chain.

You should be able to limit the throw outward sufficiently with the stop screw, as the outer ring on a 2x sits farther outboard that the middle ring on a triple. The inner ring on a 2x sits farther outboard than the inner ring on a triple and you should be able to adjust the inner stop screw appropriately.
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NoCoGreg
Cmtgravel wrote:
A little off-topic, i know, but with all this talk of FD's...Anyone know if its possible to convert 9spd Deore mtb shifter/FD to work with 2x rather than triple.

Adding to bnystrom's info...
The key spec for index shifting is the cable pull.  If you're going to only change the cranks but keep the shifters and FD then you're fine and it's just a matter of adjusting the limit screws and cable tension.

One word of caution in going to a double crankset is to check clearance between the rings and the rear tire and chainstays.  You should be able to get a good idea of clearance by measuring the current setup.  If there is a clearance issue, one workaround is to use a triple crankset but only mount rings in the two outer positions. (ie. just remove the inner chainring).

Hope this helps,
Greg
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owly
drwelby wrote:
Also in front derailleur hacking, if you ever need to convert a road derailleur to top-pull:

http://www.speen.de/SportsEquipmentEngineering/speen__store.html

Scroll down to the "umlenkers"
 

The Carbon-Ti X-Pull is a more simple and efficient option. The Red (Sram) option -which I have- is pretty much sold out everywhere you look though.
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