GRX rear spacing
07-01-21, 07:17 PM
#1
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GRX rear spacing
Didn't know where else to post this. I have a 2001 Novara Randonee that I am redoing for light touring. The GRX 400 stuff I think would be perfect for what I need, except for 2 things.
#1 Hydro brifters My bike is cantilever brake only so to fix that I am going to use Tiagra 4700 shifters. Problem solved.
#2 rear spacing ( I think) The GRX grouppo is built for disc brakes and correct me if I am wrong, the narrowest disc brake spacing is 135mm(?) My bike is 130mm.
Here is my question..........Since the GRX crankset and front derailleur are offset outboard 2.5mm to correct chainline and to support use of bigger tires, will the chainline be all screwed up on my bike? if so, I think the simple fix wound be get a non disc 135mm mountain bike hub, lace it up to 700c rim and cold set my rear spacing to match.
Opinions please.............
#1 Hydro brifters My bike is cantilever brake only so to fix that I am going to use Tiagra 4700 shifters. Problem solved.
#2 rear spacing ( I think) The GRX grouppo is built for disc brakes and correct me if I am wrong, the narrowest disc brake spacing is 135mm(?) My bike is 130mm.
Here is my question..........Since the GRX crankset and front derailleur are offset outboard 2.5mm to correct chainline and to support use of bigger tires, will the chainline be all screwed up on my bike? if so, I think the simple fix wound be get a non disc 135mm mountain bike hub, lace it up to 700c rim and cold set my rear spacing to match.
Opinions please.............
07-01-21, 09:06 PM
#2
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Since your chain moves back and forth along the cassette and possibly front chain rings I find that chain line is less of a concern than with a single speed/fixed gear setup.
Am I the only one who finds the use of "grouppo/gruppo" for Japanese components a little odd?
Am I the only one who finds the use of "grouppo/gruppo" for Japanese components a little odd?
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07-02-21, 05:34 AM
#3
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Chainline is not a major issue as mentioned above. I'd even try this without buying the GRX front derailleur first, it just might swing out enough.
FWIW, I have a GRX crank on an 86 road bike with 130mm wheel running 2x8 with 600 derailleurs and friction. Works great.
FWIW, I have a GRX crank on an 86 road bike with 130mm wheel running 2x8 with 600 derailleurs and friction. Works great.
07-02-21, 06:56 AM
#4
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Modern disc brake hubs have 142mm spacing and only work with much larger 12mm thru-axles. If your frame is made for quick release hubs, it's not going to work.
https://bike.shimano.com/en-EU/produ...-R12-700C.html
https://boydcycling.com/blogs/news/hub-standards
https://bike.shimano.com/en-EU/produ...-R12-700C.html
https://boydcycling.com/blogs/news/hub-standards
Last edited by DaveSSS; 07-03-21 at 06:42 AM.
07-02-21, 06:39 PM
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Why not just go all tiagra? grx400 is Tiagra level and you are not taking advantage of the disk brakes, etc.
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Life is too short not to ride the best bike you have, as much as you can
(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
07-02-21, 08:06 PM
#7
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#1 Hydro brifters My bike is cantilever brake only so to fix that I am going to use Tiagra 4700 shifters. Problem solved.
#2 rear spacing ( I think) The GRX grouppo is built for disc brakes and correct me if I am wrong, the narrowest disc brake spacing is 135mm(?) My bike is 130mm.
#2 rear spacing ( I think) The GRX grouppo is built for disc brakes and correct me if I am wrong, the narrowest disc brake spacing is 135mm(?) My bike is 130mm.
Here is my question..........Since the GRX crankset and front derailleur are offset outboard 2.5mm to correct chainline and to support use of bigger tires, will the chainline be all screwed up on my bike? if so, I think the simple fix wound be get a non disc 135mm mountain bike hub, lace it up to 700c rim and cold set my rear spacing to match.
Last edited by HTupolev; 07-02-21 at 08:11 PM.
07-02-21, 10:06 PM
#8
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Nope. It layers ignorance on top of pretentiousness, to me.
07-03-21, 06:17 AM
#9
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