The Suntour XCT cranks are some of the most common stock cranks that you find sold on entry to mid-level mountain bicycles. And, since they hold up so well, they are typically some of the last items to be upgraded on a bicycle, after you’ve upgraded the shocks and the derailleurs and the shifters.
You see this crankshaft used on a lot of bikes in the $300-$500 price point.
In this post, I want to discuss some of their more common weaknesses, the things you need to know if you are looking to put them on your ride and what you should know if you are upgrading.
It’s a short piece, but comprehensive.
The first thing is, this crankset is heavy. Weighing in somewhere around 1100 grams, this crankset was designed to offer the most strength at the least price. It does that well, but the serious rider will want to unload it to get the most speed possible on the climbs.
The weakness in these is that the left arm tends to stretch and not stay attached. I’ve seen countless arms that have come off on the trail, and when you screw them back on, they just fall off on the next ride (even when using loctite).
I never figured out why some came off and some didn’t. It always seemed like it depended on the batch. There may have been something intrinsic about their manufacturing.
Additionally, you want to tighten them properly. A Torque wrench is needed for this, and you would want to tighten it to 340 in-pounds. Getting this dialed in at the start makes all of the difference. Riding a bike with a bolt even slightly can damage the left side arm to the point it needs to be replaced.
Square taper technology is quite past its prime. There are so many reliable bottom bracket systems like the Shimano Hollowtech, that makes sense to upgrade as soon as you have the money. Race face also makes an entire line of reliable cranks that are quite affordable as an upgrade.
The other downside to these is that the chainrings are riveted on. I believe that they do this because they are made of a thinner material. I have seen the chainrings bent on these (they rarely can be bent back), but it is not a common problem, in my experience.
When you upgrade, the new chainrings will be bolted on individually, allowing you to customize your gear ratios down the road.
As an entry-level system, they can bring the price of a bicycle down, and they hold up well to some pretty aggressive riding. If you have trashed your crankshaft and can only afford the XCT V2, you will be surprised at how well it holds up, especially if you locate and tighten the bolts properly.
However, this is dated technology, and the newer bottom bracket designs do not have the same problems. Spending more money is for the rider who is avid about their sport.