Bicycle Mechanics - SRAM X.4 front shifter, how to put it back together?

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chimpanzee
12-21-08, 09:29 AM
I have a 2005 Schwinn Super Sport flat bar road bike. Has SRAM SX4 paddle shifters.

I have 1000 miles on it, & have had minimal service on it (free lifetime adjustment at Performance Bike, local store).

I began to experience some shifting problems:

1) rear (8 cogs)
when I shift to bigger sprocket..it slips back to the original (smaller) sprocket

2) front
can't shift from medium ring to small ring.


Does 1) mean that the shifter is at fault?

I played with the front derailleur for 2), & seemed to make some progress by adjusting the H & L screws on the derailleur. Then, I got greedy & thought I could take apart the SRAM SX4 front shifter..while it was still on the handlebar. BIG MISTAKE. When I unbolted the lever, a round clip fell out. When I tried re-installing the lever..it wouldn't shift.

I then took off the shifter, & disassembled it by removing the 3 small Philips screw. Pieces fell out everywhere (see picture). I couldn't figure out how to put it back together.

Anyone know of an assembly diagram?

I was amazed at the amount of nylon material (which holds the cable). Am I better off just buying a better set of paddle-shifters? REI sells the X.4 for only $26.00:

http://www.rei.com/product/777369

$8.95 for the front X.4 shifter
http://www.dp76.com/products/sram-x.4-trigger-shifters/

I could buy a X.4 replacement set, or upgrade to a better set. Can someone recommend a good brand/model?

TIA for any help/advice.


PS

I found a manual here, but no assembly instructions:

http://www.sram.com/_media/pdf/sram/...MTB_MY05_E.pdf


joejack951
12-21-08, 05:46 PM
I could probably figure it out if I had all the parts in my hand but I certainly can't help much over the internet. It's highly unlikely that you'll find an exploded diagram of something that SRAM never intended someone to take apart.

As to your problems, for 1) if you aren't getting a "click" when trying to shift from a smaller to larger gear then something is likely up with the shifter. The ratcheting mechanism is either jammed or worn out. For the former, flushing the assembly with WD-40 could possibly restore normal performance. For the latter, replacement is your only choice as I don't think individual components are available for those shifter.

For 2), something is preventing your FD from fully retracting. If the shifter is releasing the cable then all that's left is the low limit screw, the cable, or the derailler itself. If you loosening the low limit screw does not give the necessary movement no matter how much you loosen it, the problem is either the derailler or cable. For the cable, just replace the cable and housing and be done with unless you are in a bind and don't have parts in which case you might improve things by lubing the inside of the housing. For the derailler, clean it up as best you can and use some chain lube on the pivots. Work it through it's motions by hand until it moves as it should.

And next time, only attack those deraillers once you are sure the problem lies there :) Luckily, yours are pretty cheap to replace.

chimpanzee
12-21-08, 06:15 PM
I removed everything from the handlebar, to my shop bench.

Way better to tinker with it.

After messing with it, I figured out how things go back. I got to the point of making the ratchet work: go up in gear & down. However, I still haven't figured out how the that dang "u-shaped" spring goes in.

I realized now why it didn't shift after I took that bolt out initially..I tightened it too much!! This led to disassembling the other 3 screws, which spelled CHAOS!!


I went out to REI, & got a SRAM X-5 for 40.00 less 20% (Xmas discount, expires 12/24). It seems to be better than the SX4.


JanMM
12-21-08, 08:22 PM
When I thought there was "something wrong the the trigger shifter" (shimano) on our KHS tandem, it turned out that the cable/housing needed replacement. Shifts fine now. Never seen the insides of the shimano triggers or the SRAM trigger shifters (sx5 and x9) on my two 'bents. Usually, problems indicate need for adjustments relating to the cables and/or the stops of the derailleurs. I, too, wouldn't had any idea how to make whole what you took apart.