# differences between the Shimano GRX RX400 and RX600 groupsets?



## Erik_A (Sep 14, 2008)

Other than 11 vs 10 speed, what are the other differences between the Shimano GRX RX400 and RX600 groupsets? Are the brakes basically the same?


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## Lombard (May 8, 2014)

I could be wrong, but I believe the RX400 is comparable to Tiagra, RX600 to 105 and RX800 to Ultegra.


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## Srode (Aug 19, 2012)

Lombard said:


> I could be wrong, but I believe the RX400 is comparable to Tiagra, RX600 to 105 and RX800 to Ultegra.


Yep, that's my understanding - with that the parts are heavier and less durable as they go down the range of groupsets. Example, the 600 series crank is 100 grams heavier than the 800 series.


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## Lombard (May 8, 2014)

Srode said:


> Yep, that's my understanding - with that the parts are* heavier and less* durable as they go down the range of groupsets. Example, the 600 series crank is 100 grams heavier than the 800 series.


I wouldn't necessarily say this. After all, the 105 series isn't called the "work horse" for nothing. I'm not sure if there is any validity to this, but my bike shop claims the alloys used to make 105 hold up better than Tiagra while Ultegra is no more durable than 105, it just sheds a bit of weight. Can we assume the same about 400 vs. 600 vs. 800 or does that put the @ss in assume?


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## Erik_A (Sep 14, 2008)

Do all three (RX400, RX600,and RX800) just use the exact same "rebranded" flat mount road calipers like these Ultegra BR-R8070:


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## Srode (Aug 19, 2012)

Lombard said:


> I wouldn't necessarily say this. After all, the 105 series isn't called the "work horse" for nothing. I'm not sure if there is any validity to this, but my bike shop claims the alloys used to make 105 hold up better than Tiagra while Ultegra is no more durable than 105, it just sheds a bit of weight. Can we assume the same about 400 vs. 600 vs. 800 or does that put the @ss in assume?


There are differences from what I have read between Ultegra and 105 that would deliver difference in durability. The Chain siltec coating is an example, as is the type of fiber used in the plastic components, and the quality of bushings/bearings in the rear DRs. I'm sure there are others, and it could well be argued that they are minimal differences but that's the game of incremental gains that groupset differences are all about.


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## Lombard (May 8, 2014)

Erik_A said:


> Do all three (RX400, RX600,and RX800) just use the exact same "rebranded" flat mount road calipers like these Ultegra BR-R8070:


It appears so, but I'm not sure. It appears that the only difference between the GRX series and road groupos are a clutch RD and different cranksets and cassettes.

Maybe CXWrench can chime in here. The Shimano website sucks for providing useful information.


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## Srode (Aug 19, 2012)

Lombard said:


> It appears so, but I'm not sure. It appears that the only difference between the GRX series and road groupos are a clutch RD and different cranksets and cassettes.


There are quite a few differences between the road and GRX groupsets but the calipers appear to be the same as the Ultegra road groupset. Shifters, front and rear DRs, cranks, are all new and specific to the GRX groupset. The most difference comes with the new Di2 shifters which have the hidden button moved to the inside by the thumb, and has servo-wave technology in for braking which closes the free travel in the brakes quicker. What's pretty shocking to me is the mechanical 810 and the 815 Di2 shifters are the same price!

There are differences between road caliper groupsets though, 105 are painted vs Ultegra anodized and the 105 are heavier.


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