I had my Trek 3900 since 2010 (review written in 2012) and it has Shimano Acera on it. The large plastic shell protects and covers, but isnt the best for appearence. Ive never had a problem with my rear derailler thanks to Shimano Acera. It awlays shifts smoothly, and is a lot better then my moms Sram rear derailler which lets the chain awlays fall of the teeth and is very unreliable. I would highly reccomend this product to a friend.
Bike Setup: 2010 trek 3900-aluminum frame, trek fork with 5 inch suspension travel, gray/black/silver, 27 speed, thumb shifters, v-brake, 26 inch wheels, bontrager grips, bontrager wheels, bontrager ssr seat, bontrager water cage, adjustable suspension.
a Weekend Warrior
Date Reviewed: August 25, 2011
Strengths: shifts DECENTLY but i always hear grinding,and there are constant misshifts where the chain pops off. I always wash my bikes and lube all the parts right affter i hit a trail.
Weaknesses: Today I was bunnyhopping in my neighborhood and my chain slipped to a different gear,like always i just tried to pedal and hope that it would correct itself. but this time it was different when i pedaled the whole derailer twisted and got caught in my spoke and the plastic part snapped in half.
It never worked well from the beginning. There was always rough shifting misshifts and the chain even came off several times and the final straw was when it snapped in half in my back wheel....I really expected more from shimano.... I ride on very harsh trails but at the same time i always take my time to maintain my things.
a Weekend Warrior
from Los Angeles, CA, USA
Date Reviewed: July 9, 2011
Strengths: Simple, surprisingly strong on the trail
Weaknesses: Plastic, integrated with brake lever, optical display
I bought the bike for an around the city kicker but it got me into mountain biking. For a year, this whole set has been trouble free, set it and forget it. I love it. I hate the plastic and gear display, but its an amazing value. I've jumped, crashed, ran rabbits over, and far more, nothing has happened to them.
Bike Setup: Gary Fisher 29er. SSR stem, post, bar. bb7 brakes w/ speed dial 7 levers, x9 shifters, deraillers, 980 cassette/chain, stylo crank, rock solid carbon fork
from Vancouver Island, BC
Date Reviewed: April 19, 2011
I've had this model of derailluer for over 1 year. It is obviously not a performance part but it does well.
I ride hard, downhill and all-mountain trails, pushing my limits. I've gone through 2 of these derailluers. I know that for my type of riding I should invest more, but I'm poor and I don't need supreme performance. It does the job.
My first derailluer bent just from crashes and other stress. My second one just went 2 days ago when a stick got caught in the wheel.
I often lose performance because I don't replace my cables often, and they get gunked up fast. Cable replacements and cleaning the drive-train more often would get me more out of this product.
I'm surprised how well it does for what I do. Again it's not a performance part, but it's stood up to what I've thrown at it.
a Cross Country Rider
Date Reviewed: March 11, 2011
Weaknesses: Weak hanger, incapable of maintaining a tune-up for 24 hours
I got this derailleur with the bike at a nation-wide sports store, but within two weeks of having the bike and riding it daily, it wasn't shifting properly, and in first gear it caught on a spoke of the wheel, and snapped the hanger clean off. I sent it back for the replacement as per the warrranty, and this store put another Acera back on. Again, I had problems with shifting, and I got so fed up with the problem, I took it to the store and said I needed it replaced, because I couldn't even make a tune-up last for a day on this derailleur. They claimed they had no other 8-speed derailleurs, and offered a free tune-up and cleaning/waxing of the bike. I brought it back home, the next day shifting problems again. I dealt with this for two years, and two weeks ago, the hanger snapped again after the derailleur caught on the spokes of my bike wheel (In 6th gear this time). In neither instances of the hanger snapping were my spokes damaged, not even paint scratched off. If your a non-serious biker, maybe 5 miles on the weekend, this derailleur will work fine for you, but anything more than that, you will unlikely be satisfied with the quality of the derailleur. I wouldn't recommend any serious biker purchase this product and expect it to perform even basic functions satisfactorily. I have gone through two of these derailleurs now, and both times they had the same issues. I maintain my bike very well, as I ride a minimum of 3 miles daily through every weather and road condition known to mankind, including rain and snow.
Bike Setup: Diamondback Insight 1 700x23c use as road bike
a Cross Country Rider
Date Reviewed: July 22, 2009
Strengths: Quick fast shift, was reliable and would avoid the biggest of hits
Weaknesses: Broke very easily, plastic, not very appealing due to easy scratch
i would not buy for a cheap reliable great performing rear deraillieur pick a SLX much better, this one broke for me after a year of on off riding but completely gave up in deep riding, and has now snapped and bent the hanger along with a few spokes.
Bought my bike stock, the Acera came with it. I bike to commute/workout on road everyday. I ride a basic trail (few short rocky downhills) about 5 times a week. With the everyday abuse, I thought I would be replacing my Acera sooner, but it still works perfectly. I had only tuned it once since I bought it. It has eaten sand, mud, grass, twigs, bumped rocks and curb, and it still works well. For an entry level component, not bad at all.
Bike Setup: stock 2008 Jamis X trail 3.0 24s disc with Cat Eye Velo 8 computer
Date Reviewed: April 12, 2008
Strengths: The Acera rear shifter on my Norco Bushpilot finally snapped in half, after 8 years of trail/ street/abusive riding. I plan on getting another one and repair the bike. I found it easy to adjust,with seamless shifting if properly done. As I've read, it's not the best for the exreme riders, but for what I do- streets, some trails and occasionally cross country- it worked out pretty well.
The bottom line: 8 years of riding everywhere, and a lot of abuse. Pretty good value, I'd say.
a Weekend Warrior
from Sydney, NSW, Australia
Date Reviewed: April 7, 2008
Strengths: Bulletproof, strong
Weaknesses: Heavy, front crank rings cannot be tightened nor disassembled
My comments are on the front crankset and rear cassette only.
A certain bike shop changed my worn alivio gear for this series a few years back and I didn't think much of it (I wasn't all that fussed about materials and so forth back then). Though I probably paid too much as I actually thought it was better than the original ware.
This is probably because they are made of steel and not aluminium, which explains why they have lasted longer and haven't gotten all bent and worn out like the aluminium ones did. Works well with the original STX equipment.
They've mainly been used for commuting but have held up well to the occasional bashing on kerbs and ramps etc.
The only reason I would replace them is that dirt has gotten between the rings on the front and I cannot actually pull them apart to clean them nor can I tighten them. Oh, and they're heavy.
Giving them a high value rating because they are really cheap for what they do (and how long they last). Otherwise, they are pretty average.