SRAM Rival/Force jtek shiftmate released

thewalrus · 12-31-2006, 10:17 AM

http://jtekengineering.com/shiftmate.htm

Use a Force/Rival shifter set with Campagnolo RD and cassette

OR

Use a Force/Rival shifter set with Shimano rear derailleur

OR

Use Shimano shifters with a Force/Rival RD (silly!!!)

There is of course no need to adjust the positioning on the cassette for the SRAM/Shimano combination, since the SRAM cassette has the exact same spacing as Shimano, and is spline compatible with Shimano hubs. I have a CS-6600 on my Force equipped bike because I wanted a 12-27.

Ninja · 12-31-2006, 05:45 PM

I think this is a gimmick. I might be wrong but, wouldn't you need two pulleys to change the amount of cable pull.

nouseforaname · 12-31-2006, 07:24 PM

Quote:

Originally Posted by Ninja HP Sauce

I think this is a gimmick. I might be wrong but, wouldn't you need two pulleys to change the amount of cable pull.

a single pulley has been used for years - since the arrival of v brakes - to convert a non v lever to "work" with a v brake.

XXX_er · 12-31-2006, 09:26 PM

I used the shiftmate (or something that looked exactly like the picture)on both XT and XTR deraillers and it did make for nice consistant shifting for longer periods of time on a mtn bike (I recommend it) but I am not really understanding how differnt pulley sizes are gona change cable pull since all the pulley does is act as a replacement to some cable housing

toycdn · 01-01-2007, 09:29 AM

I dont get it either, i'm sure it works. It just looks so much like a sram rollamajig, and that didn't change ratios? However a using a pully with a rope to lift objects makes it easier, so maybe it will work. I'm confused.

DeltaRider · 01-02-2007, 01:18 AM

Quote:

Originally Posted by Kye

I dont get it either, i'm sure it works. It just looks so much like a sram rollamajig, and that didn't change ratios? However a using a pully with a rope to lift objects makes it easier, so maybe it will work. I'm confused.

The cable wraps completly around the device and one groove is deeper than the other. This is the manner in which they alter the cable throw. The cable comes into the device and wraps around the pulley at a large diamter and then transitions to a smaller diameter spiral (second groove); in this manner the amount of cable pull on the exit side of the device would be less than on the input side. It is kind of like a physics question where you have two gears or pulleys of different sizes attached to a shaft.

This is similar to some of the devices made to use V brakes with center pull style levers. However, in this device the two cricles appear to be concentric whereas many of the travel agent devices are more of an eccentric design.

Ninja · 01-02-2007, 01:21 AM

Well there you go. I guess that would work.

XXX_er · 01-02-2007, 10:19 PM

ok so an eliptical pulley makes sense , the original shiftmate I had and the avid rolamajigs just have a round pulley

wouldnt the cable have to be somehow secured to the pulley to make this work reliably?

12-31-2006, 10:17 AM	#1
thewalrus Human Join Date: Nov 2004 Location: Bellingham/Vancouver/Central Asia Posts: 2,941 Rep Power: 2847546	SRAM Rival/Force jtek shiftmate released http://jtekengineering.com/shiftmate.htm Use a Force/Rival shifter set with Campagnolo RD and cassette OR Use a Force/Rival shifter set with Shimano rear derailleur OR Use Shimano shifters with a Force/Rival RD (silly!!!) There is of course no need to adjust the positioning on the cassette for the SRAM/Shimano combination, since the SRAM cassette has the exact same spacing as Shimano, and is spline compatible with Shimano hubs. I have a CS-6600 on my Force equipped bike because I wanted a 12-27. __________________ "Bicycling is a healthy and manly pursuit with much to recommend it, and, unlike other foolish crazes, it has not died out." - The Daily Telegraph (1877)

12-31-2006, 05:45 PM	#2
Ninja Hey, who farted? Join Date: Sep 2004 Location: Vancouver, Posts: 3,825 Rep Power: 3294716	I think this is a gimmick. I might be wrong but, wouldn't you need two pulleys to change the amount of cable pull. __________________ "X is for x-ray. If you've been bikin' and you haven't had an x-ray, you ain't goin' hard enough." - Bob Roll

01-02-2007, 01:21 AM	#7
Ninja Hey, who farted? Join Date: Sep 2004 Location: Vancouver, Posts: 3,825 Rep Power: 3294716	Well there you go. I guess that would work. __________________ "X is for x-ray. If you've been bikin' and you haven't had an x-ray, you ain't goin' hard enough." - Bob Roll

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12-31-2006, 09:26 PM	#4
XXX_er Registered User Join Date: Nov 2002 Location: central B.C. Posts: 10,979 Rep Power: 6350181	I used the shiftmate (or something that looked exactly like the picture)on both XT and XTR deraillers and it did make for nice consistant shifting for longer periods of time on a mtn bike (I recommend it) but I am not really understanding how differnt pulley sizes are gona change cable pull since all the pulley does is act as a replacement to some cable housing

01-01-2007, 09:29 AM	#5
toycdn Registered User Join Date: Nov 2002 Location: Port Moody Posts: 2,843 Rep Power: 269701	I dont get it either, i'm sure it works. It just looks so much like a sram rollamajig, and that didn't change ratios? However a using a pully with a rope to lift objects makes it easier, so maybe it will work. I'm confused.

01-02-2007, 10:19 PM	#8
XXX_er Registered User Join Date: Nov 2002 Location: central B.C. Posts: 10,979 Rep Power: 6350181	ok so an eliptical pulley makes sense , the original shiftmate I had and the avid rolamajigs just have a round pulley wouldnt the cable have to be somehow secured to the pulley to make this work reliably?