slowride454

I bought a 2011 GT Karakoram 1.0 last spring and love the hell out of the bike, but have never liked the shifting on the FD. It is 3 X 9 with X5 shifters and a X7 RD. The front is Alivio for the BB/crankset/FD. Even when everything is clean sometimes it is off a little, and when I play in the mud forget about shifting at all up front.

So I was at the bike shop yesterday talking cranks for my road bike when I brought up my MTB problem. The mechanic was surprised someone would have put these parts together because SRAM shifters do not play with Shimano parts. If this is indeed the case, then I am starting to get disappointed in GT for the build.

So I can replace the FD with a SRAM X7 3x9 FD and it should fix my issues?
If I replace the FD should I replace the remaining Shimano Octalink Alivio crankset with say a X5 or X7? Or Shimano XT?

I'm in the process of finishing the spring cleaning and changing the stem and handlebars, so now is the time since I don't want to have the bike down at all during the limited riding season here in Wisconsin.

ncfisherman

There is nothing wrong with mixing Shimano/SRAM up front -- for the rear, the brands need to match. The problem has to do with derailleur setup.

Go ahead and shift to your small chainring, undo the cable pinch bolt and turn your barrel adjuster all the way in. From there, check the front derailleur for height and alignment with the chainrings. You want the cage to be parallel with the chainrings and high enough to just clear the large chainring by 1-2mm -- you'll need to rotate the crank fully while holding the cage out to check clearance because some teeth will be higher than others.

Next, you'll want to check clearance between the inner side of the FD cage and chain, when the chain is on the smallest chainring and largest rear cog -- again, you'll want about 1mm of clearance. From there, you can pull the slack out of the cable and tighten the pinch bolt -- you don't need to pull too hard. Check the shift by pulling exposed cable from under the top or downtube -- pull the cable so the chain goes into the middle cog and release the cable to check the shift to the small chainring. You're looking for a smooth shift. Make adjustments to the low limit screw as necessary. When setting up derailleurs, you always want the "tightest" setting possible -- this will keep the adjustment longer.

After that is set, pedal forward while pulling your exposed cable to make the shift into the big chainring. When the chain is on the large chainring and smallest rear cog, you'll again want about 1mm of clearance between chain and cage. Use the exposed section of cable to check the shift from middle to large chainring. Again, you're looking for a clean shift.

To finish up, release cable to return to small chainring. Then use the shifter to shift from small to middle chainring. While in the middle up front, shift to your largest rear cog and check the distance between the cage/chain -- there should be a 1mm gap. If the gap is larger than 1mm, turn your barrel adjuster out until you have a 1mm gap.

ncfisherman

Simplified version: The bike "mechanic"(using that term loosely) doesn't know what he/she is talking about. Safe to say that GT knows which parts work together, considering they have sold millions of bikes.

slowride454

Thank you very, very much. Just shows how great the LBS in our area are. I've taken the GT back to place I bought it 3 times early last summer to fix the FD and get the tubeless conversion to seal up. I finally quit. The other shop only has one mechanic, who doesn't like to talk. And then the largest one where this guy works. that's why I am learning as much as I can and buying the tools as I need them. I built up a steel Soma Double Cross commuter over the winter. Now I'm going to tune up the MTB and replace the BB/crankset on my Specialized Roubaix Road bike.

ncfisherman

Hope you get that FD sorted out -- shouldn't be much of an issue, just proper set up. If you haven't checked it out already, Parktool.com has a pretty solid repair help section on their site.

What issues did you have with the tubeless conversion? What rims/tires?

On the crankset, nothing wrong with Alivio unless you just want a lighter option(XT with external bb would be much lighter than the Alivio). Out of SRAM and Shimano, both are good, but I prefer Shimano's attachment method. With Shimano external bb cranks, you have a preload adjustment and then pinch bolts to tighten down the NDS crankarm. With SRAM, the preload and securing of NDS crankarm is done with the same bolt.

slowride454

Thanks for the help. I have parktool.com bookmarked. It helped a bunch when building up the commuter over the winter.

What I have is not ideal. It is Kenda Smallblock 8 tires with Alex rims and a Stan's kit with the rim strip. I had the shop where I bought the bike do the conversion for me when I brought the bike in for it's free tune-up. They charged me and arm and a leg for the kit and labor. The front tire was flat and oozing juice all over my trunk by the time I got home (3 mile drive). I was not able to get the bead reseated at home. I took the bike back a few days later since both tires were flat and leaking juice. Rinse and repeat... After the third time I was fed up. I took the wheels to the large LBS and they got them to seal up and I haven't had an issue since, I just need to air them up periodically like any bike tire. The original LBS never did the tune-up either like they said they did. The shifting did not improve after taking it there.

I've become somewhat familiar with SRAM road and Shimano commuter/townie stuff, but need to learn a lot more about MTB components. I'm not too concerned with weight at this point. Yes my bike does weigh over 30 pounds, but I could stand to lose 40 myself before I start going down the weight weenie path.

mtnbiker66

Ditch the FD and go 1x9 problem solved.

roccobike

For what it's worth, the worst FD I had, on any of the bikes was an Alivio level. After one season of multiple chain suck issues, then throwing the chain, replaced it with a Deore level, never had a problem again, NEVER. You shouldn't have any problems with the front DR, if it continues, replace it and live happily ever after.
As for compatibility, NCfisherman is right, both current bikes I ride have Shimano front with a SRAM system. No shifting problems, but then as little as I shift out of the middle chain ring, I ought to take up mtnbiker66's recommendation. As for a crank, I use XT with the SRAM systems, no issues whatsoever.