Here at Pinkbike we get inundated with all kinds of questions, ranging from the basic "Can I have stickers" to more in-depth, soul searching types of queries like if you should pop the question or what to name your first child. Ask Pinkbike is an occasional column where we'll be hand picking and answering questions that have been keeping readers up at night, although we'll likely steer clear of those last two and keep it more tech oriented.
Carbon or Aluminum YT?
Question: @wrymn asks in the All Mountain, Enduro & Cross-Country forum:Is it worth spending more money for carbon MTB over an aluminum one? The advantage would be 800 grams lighter and some vibration resistance, and a tiny bit better parts. The cost difference is 800 Euro. I have not ridden full suspension, nor any carbon bike, so I seek advice of more experienced users. I ride XC and trails several times a week (20km+). The choices: YT Jeffsy CF One (carbon) or YT Jeffsy AL One (aluminum).
Buy the carbon version if you have the expendable cash. If there were no price difference between carbon and aluminum frames, aluminum mountain bikes would be extinct, except for those built by bike makers, or for customers who adhere to religious beliefs about the cosmic virtues that steel and aluminum bestow upon otherwise ordinary fabricated structures. There is also a real need for designers to quickly cob up test mules to try new geometry or suspension configurations, and metal makes that an easier task.
Inflammatory statement, perhaps, but carbon's immense strength-to-weight ratio over steel or aluminum alloys provides frame designers more options to build in durability, strength, stiffness and yes, impact resistance, than are available when using metals at similar weight targets. Top designers who work in both mediums will tell you that they can make an aluminum chassis that will approach the performance of a carbon version, but the cost to construct that metal wonder would also match its carbon sibling. (Liteville furnishes an excellent example.)
Carbon requires more up-front engineering and testing, but once it is in production the frames come out of a mold perfectly aligned and close to completion. That accurate alignment is paramount for suspension components. If a weakness appears, extra carbon can be layered in that area, or the mold can be altered to provide strength. And, if a lighter version is desired, less material can be used. Carbon composite is wonderfully resistant to chemicals and weather, and when stored, it sits in rolls in a freezer.
By contrast, aluminum frames are assembled from a number of forged, bent, butted and manipulated pieces which must be pre-manufactured for each frame size, which adds to delivery times. And, the parts are melted together, barbecued in a furnace, and then bent into alignment, which creates production variables. Aluminum frame makers err towards heavier weights because, if a problem arises or a change is required, new tubes or forgings must be manufactured, and lead times for a fix often exceed the effective model year of the product.
There are places on a mountain bike where aluminum or steel are better applications, but apples to apples - comparing two high-end frames from a reputable bike maker (like your YT Jeffsy) - the only reason to buy an aluminum framed version is to spend significantly less money, knowing that you will be riding the same geometry and enjoying nearly the same performance as the carbon version delivers. Aluminum is the better value. Carbon is the better performer. — RC
Carbon framed YT Jeffsy CF One 29
Aluminum framed YT Jeffsy AL One 29
Norco Optic or Sight?
Question:@tomerzaz asks in the All Mountain, Enduro & Cross-Country forum: I'm looking to buy a new mountain bike and I've always been a Norco guy. I'm weighing my options between the Sight or the Optic. I've tried the 29er Optic but didn't love it so sticking with 650b and most likely aluminium rather than carbon. I mostly ride technical, man made, rooty, North Shore type of riding. Anybody have experience with either? Any opinion is much appreciated.
Although they may look similar from a distance, there are several key differences between the Norco Optic and the Sight. The amount of travel is the most obvious one – the Optic has 120mm of rear travel that's paired with a 130mm fork, while the Sight has 140mm of rear travel and a 150mm fork. Will the Sight's extra 20mm of squish be noticeable out on the trail? Absolutely. It'll help smooth out some of those rooty, technical trails you mentioned, and there will be extra travel in reserve to help out on those really big hits.
Of course, both bike can handle technical trails, but for the type of riding you described I'd steer you towards the Sight. The longer travel and the slacker head angle (66.5 vs. 68-degrees) help create a bike that feels more stable and composed at higher speeds and on steeper terrain. You might lose a little bit of liveliness when you're poking around on flatter trails, but the Sight's still a very well-rounded bike that's doesn't sacrifice too much on the climbs or the descents. — Mike Kazimer
The 27.5" Norco Optic has 120mm of rear travel and a 130mm fork...
...and the 27.5" Sight has 140mm of travel and a 150mm fork. The carbon models are shown, but there are aluminum versions of both.
Have some unresolved tech questions? Jump in the Pinkbike Forum and we'll look to answer it for next time.