MSRP (new) $529.99
this bike is made for commuting I have it in size 18,and in orange
the geometry so, not good for Mtb, for me, but for people with short armed and short back, this is not a bad thing, but I am about 180 cm high and i am average sized everywhere,so I get a very upright position, But when I was a teen i was not as big as I am now so it was ok.
which is too small of mountain biking but for commuting its OK, you will sit upright.
the bike is no real mountain bike, frame is way too short and the handlebar is too short too, this make the bike too responsive.
ignore the sticker that say trek mountain bikes, it just refers to the standard for mountain bike frames. it’s not a mountain bike,but it can be with some upgrades.
Seat post parts look like this:
the frame can withstand mountain biking, but the geometry is horrible for mountain biking.
- max tyre size is 2.3
- slack seat tube angle
- steep head tube angle
- horrible wheels, the rear wheel comes with a FH-M475 rear hub which has been troublesome, bending axle, possibly due to bad tolerances, this happen on all of the FH-M475 rear hubs I used.
- The Shimano Acera M360rear dérailleur is horrible, too soft spring, no clutch. the use of a nut instead of a bolt was a bad choice.
- The handle bar bends in a crash, a simple side fall will bend it.
- Steel stem with only two bolts which is also quite heavy & low quality:
You can notice the low quality part I mentioned on the inside of the stem, weird wave pattern instead of a smooth hole, there were no wall there that has been rusted away, it is just made this badly, as you can see there is paint on it,so this means it clearly was like this when new.
- The fork is a SR Suntour SF9 XCT V2, 100mm travel does not have the promised 100mm travel, but more like 20mm, the fork had play and it got even more play so when i was braking hard i felt like the fork would snap or fall apart. it also lack of adjust ability.
- Nylon Wellgo pedals, which were horrible, the plastic snapped on on side, I don’t remember how that happen, and they were very sketchy, foot coming off was a common issues for me. here is a review from Bikechanic for what seems to be the same or similar pedals:
- The all in one unit Brake & Shifters/triggers: the stock are v brake lever and shifters, shifters are horrible you need to swing the lever way too far to change gear, so changing gear becomes unnecessarily difficult. if you want the shifter to be at a good angle the brake will be at a bad angle and wise versa.
- Brakes: the bike comes with single piston mechanical brakes from Promax.. The mechanical brakes don’t work well you need to press very hard to brake. these brake are so bad that V-brakes actually are better for braking wise,not wear wise of course. so i upgraded to hydraulic & shifters/triggers.
- Saddle– saddle is way too big for me, it wears out fast because of flex in the saddle the plastic under it that have screws in it will flex too so the screws will pop out.
- Overly beefy brake mount, it’s heavy, and wide.
- horrible headset: VP-A68-TK, 1-1/8″ semi-cartridge, with horrible seal, making it a greasy rust water mess.
- The Bontrager LT-3, 26×2.0 tyres got horrible grip in the wet they are a death trap. on wet asphalt they slip and you will crash, there is not enough space between the knobs and the rubber is too hard and not sticky enough to grab on to the asphalt check out the the review by Bikechanic :
- replaceable derailleur hanger, which is a must.
- decent welds.
- stiff enough frame for a average rider for at least this size.
- the brake rotors can handle metal pads.
waste of money, unless you need a bike fast and it’s the only bike you can then at the point you are i the store.
I only used the 3900 as winter bike, plus the front dérailleur does not work in below -2 degrees for some reason, maybe due to the wear it has.
the review was originally posted 26 june 2015, but I improved the text and added pictures.