SRAM CX1 chainset with ultegra groupset

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eliflap-scalpel
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by eliflap-scalpel

i am using Garbaruk since october ! worth the money
http://eliflap.it/

by Weenie


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9x12man
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by 9x12man

Thanks for the input @eliflap-scapel. I should say that I will build up 2 sets of wheels. One for flat, one for more varied off road. The first wheelset is for flatter rides.

I did use a gear calculator and based it on my current road setup. This is 50-36 with a 12-25 rear. This is what this setup gives me:

KPH at 80RPM

Chainrings: 36t | 50t
12 = 31.0 | 43.1 km/h
13 = 28.6 | 39.8 km/h
14 = 26.6 | 36.9 km/h
15 = 24.8 | 34.5 km/h
16 = 23.3 | 32.3 km/h
17 = 21.9 | 30.4 km/h
18 = 20.7 | 28.7 km/h
19 = 19.6 | 27.2 km/h
21 = 17.7 | 24.6 km/h
23 = 16.2 | 22.5 km/h
25 = 14.9 | 20.7 km/h

Essentially a 14.9km/h to 43.1km/h range at a reasonable 80rpm. I use this setup in the southern alps (on road of course).

This would be my setup with my flat course cassette on the new rig:

Chainring: 46t
11t = 43.2 km/h
12t = 39.6 km/h
13t = 36.6 km/h
14t = 34.0 km/h
15t = 31.7 km/h
16t = 29.7 km/h
17t = 28.0 km/h
19t = 25.0 km/h
21t = 22.7 km/h
23t = 20.7 km/h
25t = 19.0 km/h

So I appreciate I'm loosing the 36t 21, 23, and 25 gearing. However I do still get a 19.0 - 43.2 km/h range. For flat to bumpy this should be fine. I will take your advice on the 11-34 range though. This gives a range slightly greater than my current road setup:

Chainring: 46t
11t = 43.2 km/h
12t = 39.6 km/h
13t = 36.6 km/h
14t = 34.0 km/h
16t = 29.7 km/h
18t = 26.4 km/h
20t = 23.8 km/h
22t = 21.6 km/h
25t = 19.0 km/h
30t = 15.9 km/h
34t = 14.0 km/h

A 14.0 - 43.2 km/h range.

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eliflap-scalpel
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by eliflap-scalpel

it's not only a matter of mathematic, although gear calculators are ok.

.... your legs will talk to you about right choice.
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9x12man
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by 9x12man

@eliflap-scalpel - I'm sure you are right. My legs will find out before I do, followed by my wallet...

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eliflap-scalpel
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by eliflap-scalpel

i used and currently i am using 10 speeds RD and shifters/disc brakes for the easisest way to find right cassette from MTB world.


i prefer XX cassette from SRAM , it's on 11-12-14-16-18-21-24-28-32-36T, better for my legs

XTR Shimano 11-36T instead is 11-13-15-17-19-21-24-28-32-36T

i tried Leonardi 9-38T with 9-11-13-15-17-20-23-27-32-38T too but with my custom rear derailleur hanger i had some issues with 9T cog

11 speeds cassette on MTB buids are only 11-40 XTR and 10-42 from XX or XX1 Sram ... and maybe i will go with a XX1 cassette in my CAAD10 disc build as second bike
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9x12man
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by 9x12man

@eliflap-scalpel you are right. I'm going to run 2 sets of wheels. One with 11-25 (flat course) and one 11-36 / 11-34 (anything other than flat). Was riding at the weekend and the 11-25 works, but not on the steeper hills and definitely wouldn't when its muddy.

Quick review of the gearing setup. The SRAM CX1 crankset works great with Ultegra Di2 RD and the R785 shifters. Did a 25km course and rode aggressively to see if I could mess with the setup. No jumping or dropped chain. Smooth shifts. The setup worked as well as I had hoped.

Image

Image

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rasmussloth
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by rasmussloth

Thats a great setup.

Do you use both shifters?

I am thinking doing the exact same but with 11-28 cassette or 48t chainring and 11-32 cassette.

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eliflap-scalpel
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by eliflap-scalpel

9x12man wrote:@eliflap-scalpel you are right. I'm going to run 2 sets of wheels. One with 11-25 (flat course) and one 11-36 / 11-34 (anything other than flat). Was riding at the weekend and the 11-25 works, but not on the steeper hills and definitely wouldn't when its muddy.

Quick review of the gearing setup. The SRAM CX1 crankset works great with Ultegra Di2 RD and the R785 shifters. Did a 25km course and rode aggressively to see if I could mess with the setup. No jumping or dropped chain. Smooth shifts. The setup worked as well as I had hoped.



and how did you manage the 36T cog clearance ?
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rasmussloth
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by rasmussloth

Can the RD "manage" a 36t cog?

9x12man
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by 9x12man

Ahhh. Apologies. I have only run the 11-25t so far. I can only put a 32t on the back with an Ultegra 6870 Di2 RD. I have not put this wheelset together yet, so will have to use an 11-32t. Its the GS version of the RD.

9x12man
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by 9x12man

@rasmussloth. I have it setup as standard, but will change this to utilise the left and right shifters. One shifter going up, one going down the cassette.

ihs0yz
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by ihs0yz

Mind if I ask how are you going to take a 36t cog when you do switch to it?

Nefarious86
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by Nefarious86

Scrap that idea.
Using Tapatalk

9x12man
Posts: 63
Joined: Sat Sep 08, 2012 8:48 am

by 9x12man

9x12man wrote:Ahhh. Apologies. I have only run the 11-25t so far. I can only put a 32t on the back with an Ultegra 6870 Di2 RD. I have not put this wheelset together yet, so will have to use an 11-32t. Its the GS version of the RD.


It was my mistake. I'll be running 32t at the back max.

by Weenie


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Jengaback
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Joined: Thu Jan 29, 2015 9:17 pm

by Jengaback

You could try using a Goatlink to get the 11-36. It's designed to allow mtb derailleurs to take a 42t sprocket but I assume it would allow a road derailleur to take a 36t?
http://www.wolftoothcomponents.com/products/goatlink

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