Upgrading your MTB

Some cyclists are happy with their bikes the way they came. Others are keen to alter the bike with replacement parts in search of some sort of improvement; we can call this generically an upgrade. Upgrades can be installed to replace perfectly good existing parts or as part of replacing some part which has broken or worn out. Replacement parts cost money, often more than the item they are replacing, so most people wonder at least tangentially if the upgrade is “worth it”.

As noted when talking about the fit of my newest bike, changing stem and bars to dial in your position is absolutely worth it for almost any bike. The fit is everything for performance and comfort. Changing parts for fit can be the primary reason, but it often will bring some weight savings and maybe better performance beyond mere fit. So that would qualify as an upgrade. Handlebars of identical rise, sweep, etc (fit) may differ in stiffness/compliance (performance), for example. New bars and stem can be lighter in a lot of cases, and not even for all that much money. Lower cost bikes (and in the time of Covid even not so lower cost bikes) are often spec’d with really heavy handlebars and new ones can be had in the $50-$150 range that may drop a quarter pound or more.

At the other end of the scale, there’s no point trying to graft a modern wireless drivetrain onto a 2000 vintage cheap bike from Wal*mart. Not worth it.

I was once a confirmed upgrader, particularly in the 1990s mountain bike industry expansion when parts were rapidly diversifying beyond Shimano’s groups. [N.b. Shimano was really the only major game in town for sophisticated, complete gruppo MTB components. SunTour was practically kaput after having missed out on indexed shifting, Campagnolo barely dabbled in MTB parts and SRAM was not a thing yet.] In large part this was because I started with a heavy, entry level bike and I was always seeking to get lighter for racing. I also started with lower level componentry, the Shimano Exage 500 LX. Deore XT was definitely more durable, lighter and worked better. Some upgrading can be done gradually as one can afford individual components, and it may take a long time to simply save up for a better stock bike. In those days you could even just put on a better rear derailleur or shifters and get better performance. Heck, I think I remember moving up to Deore LX cantilever brakes at one point and they were better. So I perused the ad copy and magazine reviews and catalog listings all the time, dreaming of upgrades. And many of the people I was riding with were upgrading to the latest CNC machined this or titanium that. Some of this stuff ended up being really great, such as a TiTEC 118 gram titanium bar with perfect compliance I ran for about 20 years on a bike. Other stuff I purchased maybe was light but was not a demonstrable performance improvement, such as some TNT cranks I got at one point. Still more stuff was out there didn’t actually work as well as good old Shimano parts- CNC cantilever brakes and chi-chi derailleurs for example. And a lot of stuff just sucked (like the beautiful White Ti Cassette Hub I had which was incapable of holding bearing preload) and/or broke on people.

Once I could afford to start with a bike that landed in my sweet spot, my urge to upgrade faded. Both due to my earlier experiences that more expensive was not always better function and my relative lack of riding.

In between extremes we have a lot of personal preference and (bad) judgment. So here’s how I’d look at a recent test case.

Let’s take the Polygon Siskiu D7 SE as an example. Is it worth upgrading?

My initial read based on a friend’s 2022 Siskiu D7 (and also another friend’s circa 2021 Siskiu T7, the longer travel “trail” version), is yes. It is a solid package of a bike with a frame that works well, holds up, and likely will take owners a long way in their MTB journey. It is also a bargain of an entry-level bike, meaning there are places the company had to save money by specifying less awesome, but perfectly functional, parts.

I haven’t weighed all the bits on the 2022 D7 so I’m making some assumptions, and relying on web searching for supporting other ones with weight information.

Tires: I guess technically tires are an upgrade item, and they are a relatively inexpensive change to your bike. Whether you are looking for weight savings, ideal grip suited to your terrain and riding style, better durability or a unique appearance, there are plenty of options. Or perhaps once worn out, you are merely looking for a very inexpensive tire that performs well. Tires are one of the best bangs for your buck if the tires currently on the bike are not well suited to your purpose. The Nobby Nic tread on the D7 looks very good as a general purpose MTB tire to me, but of course different riders may need different things to maximize their individual bike enjoyment. Minimalist tread tires designed for XC racing really are a lot faster rolling and can be the right call if your riding is mostly on smoother trails. Beefier carcass tires may be required if you are riding through jagged rocks all of the time. Etc.

Cockpit: As per the above, bars and stems are an easy place to upgrade to save weight. The dropper post as well. In the case of all three there is some hope of a performance enhancement to go along with any weight savings. It’s pretty easy to drop a quarter pound with a fairly inexpensive handlebar swap. The dropper post probably weighs about 545 grams. A popular alternative from PNW gains only about 40 grams, but hey, grams add up. It is probably too pricey to squeeze much more weight savings from the post, but some reviews suggest improving the performance a lot might be the better reason here.

Wheels: Wheels are a traditional place to upgrade a bike. In my day the search was for lighter. Dropping both rotating mass and unsprung mass from a bike is something that is likely to be appreciated, even by relative newcomers, on a pound for pound basis compared with the same weight savings on, say, the frame. Admittedly, there are going to be some who want to get a stouter / tougher wheel instead of a lighter one but for their use this is a potential upgrade in function. It’s not uncommon to dent an aluminum rim or otherwise damage the wheel, leading to a need to replace and a seductive opportunity to upgrade. With my XC riding focus and the nature of the D7 as a downcountry or XC type of ride, lighter seems like the most likely direction for most owners, however. The Siskiu D7 wheelset probably weighs about 2188 grams. It is a 32 spoke wheel with what are likely a slightly heavy non-series Shimano hub. The rim is probably not that light. An XT wheelset at 1932 (and only $430) is about a half pound lighter, and I think there are many ~1900 options. A little more cash could take this to a ~1500 gram wheelset for a 1.5 pound saving.

Drivetrain: The 2023 D7 SE comes with 11 speed Deore shifters, derailleur and a 11-51 tooth cassette. This is one of those price saving specs since the current Deore is 12 speed (introduced in 2021), and presumably Polygon worked a good deal with Shimano for the older stuff. The gearing differences are modest. The biggest 8 cogs are the same, spanning the 18-51 tooth range. Differences are at the small end, with the 11 speed running 11-13-15 and the 12 speed running 10-12-14-16 teeth. Among other things this clues you in to the fact the 12 speed requires the Shimano Microspline freehub, instead of the standard hyperglide. Upgrading to 12 speed is therefore an involved proposition, i.e., expensive. Shifter, derailleur, cassette, chain and (probably) a new rear wheel with a Microspline compatible hub. The only real gain in range is the 10 tooth cog, which would maintain a higher top gear if you wanted to drop the chainring from the stock 32 t to a 30 t. This is pretty esoteric gear geekery for an entry level enthusiast rider, if you ask me. Most folks will be fine with the 11-51 tooth cassette range and may possible want to adjust the chainring for a lower lowest gear, but would live with the corresponding drop at the top end. Is it worth it just to get a performance upgrade? Maybe. I thought the quick test I had of the 11 speed Deore when brand new was very good in the shifting feel. My XT is only slightly better, at least under parking lot conditions. It might be more obvious after equivalent wear or under high stress shifting conditions. Maybe that cheaper SRAM electronic shifting system would be worth it?

Fork: One Facebook group devoted to the Siskiu line is filled with upgraders of the over-fork variety. Upgrading a fork for better performance is one thing. Premium forks probably work a lot better than entry level ones, and the fork has a LOT to do with ride quality. There is also some talk that fork upgrades can save up to 2 pounds of weight. That is a lot. The trouble here is that it may cost a lot of cash to get a fork that feels significantly better, or weighs a lot less, than the Raidon fork ($390 aftermarket price). Premium forks run about $1,000-$1,200 and it does not make a lot of sense to put that on a bike that cost $1,400. Would a $500-$700 fork offer an improvement in performance? maybe? You’d have to do some direct comparison to find a perfect, but affordable, upgrade. However. The over forker upgraders are not just looking to swap a fork with identical travel and better feel- they want more travel.These folks have a different consideration. In theory more travel for roughly the same quality spring / damper / action / stiffness is a useful thing. The D7 is spec’d with a 120 mm fork and owners are asking about going to 140 or 150 mm. The problem is that this will change the geometry of the bike significantly and changes to effective head tube angle, bottom bracket height and fork trail will seriously alter the ride. These changes may be an improvement for a given rider’s desired use of the bike…or they may really screw up the handling. There is a reason bike designers make frames specific to fork travel instead of just slapping a range of forks on the same frame design. I’d say stick to within about 20 mm of added travel max, and do your homework about offset and trail.

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