Bicycle Mechanics - Rollamajig
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03-15-01, 06:01 AM
Has anyone used one of these little devices that attaches to the rear der? Does the roller action shorten the shifter cable, reducing friction for faster shifts as the product advertises?
03-15-01, 12:35 PM
i,ve used a simillar device, it looks pretty smooth on your bike,but two things;
1. the wheel may give friction instead of losing them(slower shifting), it depends on wheel design and the angle of the inner cable travelling over the wheel.
2. Your inner cable is bare, when you ride a wet and muddy track it becomes dirty.
Through shifting the dirt reaches your outer cable and give friction.
Even when the wheel is working pretty well, i,l think this ???????? about the "fastening of shifting"
Any bikers with other opinions or experiences ?
The Rollamajig eliminates the loop at the derailleur. In theory the lack of this loop results in a more accurate shift. Your return action or the downshift is dependent on the spring in your der. In shimaNO LX quality and above there is a allen screw located behind the knuckle or the big internal spring. If you were to back this out enough to disengage the spring you can adjust the tension to the next hole. This has to be done with the der. off the bike. The spring is called the "B" spring. This increases the speed and acuuracy to a degree of the rear der. shifting down. As far as cable friction use either shimaNO SLR cables and housing and grease the cable where it goes inside the housing. These are cheaper than Gore Tex and Avid Flak Jackets. You should also grease the pivots in your der. This also reduces friction. Of course with like Campy Record, XTR and XT the pivots are sealed so you do not need to do this. Also the shorter the turns are on your housing the better. I have always just turned the bars to the opposite side of the cable I am routing and match the housing up that way. This I do in case you bail and the bars get turned sideways it will not rip your cable and housing away. Of course this depends on the crash. Delta makes some real good cables as well. These if my memory serves me correct are nickel and teflon coated steel very tightly banded. They cost more than SLR in some cases but are more rugged. Dia Compe also makes or made a cable called BRS these were a great road bike application. Other than that I do not know. I also have no clue what Toolfreak was saying about the wheel messing up shifting. Unless your der collides into the spokes.
I've used these things and would say the definitely help, especially if you have bottom routed cables that require a tight bend. Grease your cables and replace them at least once a year (brake and derail.). It's cheap, easy thing to do to make everything run smooth.
Soo, if I have 10 bucks burning a hole in my pocket would a rolamajig be worth it?
06-27-01, 12:05 PM
Despite my bad expirience with this device, i should say give it a try!:D
Sure. Replace the cable at the same time if it's a little old. Also, make sure to readjust the cable after a week or so to compensate for cable stretch. You'll have nice crispy shifting after this!
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