SRAM Corporation, Derailleur gears mpjumper Upgrades (Top 3 for 2021 Stumpjumper Alloy)
We are going to talk about the top three upgrades for the stump jumper 2021 alloy, so let’s make sure we start by saying this is total personal preference. These upgrades that you’re going to want to do to the bike or not are going to depend on your personal preference, what you’re trying to accomplish with the bike. For me, i started out at 35.5 from the factory on this bike. I wanted to get the weight down to something closer to around 30 pounds, so a lot of my upgrades are aimed at reducing the weight, but it’s gon na depend on your personal preference and the riding conditions that you’re in i mean so let’s talk about the Upgrades that i chose for my bike number three i’m gon na go in reverse order. Number three was the tire, so i’ll give a little bit more detail on that and talk a little bit about how to do the conversion. But my number three upgrade was the tires on this bike. Number two for me was the drive train so in an effort to reduce weight. The drive train on this bike is an easy place. You can get some pretty serious weight savings. My number one upgrade for this bike coming from the shop coming from the factory was the brakes and so we’ll talk through why i chose the brakes. What i thought about the factory brakes and a little bit about how to do that i’m – not going to do a full, install video on these things.
But i will talk just a little bit about the process. If you want to jump into that, and if you want me to do a full blown video on those things, just let me know in the comments and we’ll jump into it together, so let’s talk about the number three upgrade the tires on this bike, so you Can see here, i got the stock tire here, which is the butcher grid that’s a 2.3 29 2.3 that’s a tubeless ready tire, so it’s ready to convert from the factory which i went ahead and did right away before i ordered a new tire combo. I figured i’d try them out, but it’s tubeless ready, so you can pull the tube out and do the conversion. I’Ve got a whole nother video on that, but you can watch. But this is the tire that i went to. This is a maxis recon, 29 by 2.4, so this is a little bit actual um wider tire, and you can see the difference in the tread on these. For my riding conditions, this is just a massive amount of tread. I got into the mud a couple times and it really just sucked the mud up really poor clearance on mud. So, if you’re in an area where you’re riding in the mud a lot, probably not going to be a great tire for you, this for me a lot less rolling resistance on this tire than what the factory had and what i will tell you is.
After doing the conversion to the new tire, combo max’s tire combo, that i’m running, i got .71 pounds of weight reduction just from doing a different tire combination, and it feels like a totally different bike. What i will say on this tire is it had crazy, good grip, so, if you’re somewhere, where you’re doing a lot of downhill and you’ve got nice hero dirt that’s, not too sticky that’s going to get caught all in it and you’re not worried about doing a Bunch of climbing and not trying to get the weight of your down your bike down too much. This is maybe a good tire for you. For me, i was, after less rolling resistance, a little faster, rolling tire, something that would clear mud a little bit better here in texas. We’Ve got hard packed single track, but when it rains it gets muddy really quickly. And if you get a little bit of moisture on the trails this, this makes it really hard to clear the mud. I like something like this a little bit better but let’s take a quick look at the back tire all right. So here is our rear factory. Tire again here’s the factory here’s, my upgrade. We went from a purgatory again 2.3 on the back. This is a purgatory specialized to an icon. 29. 2.35. But again, this stock tire just has a massive amount of tread on it. If you can see that so again, i went for a little more fast, rolling um, faster tire, a little less tread on that which works well for me again: 2.
7 or i’m sorry 0.7, pounds of weight reduction on this. I i did the tubeless conversion on the factory tires just to try them out, wrote them for a while without the tubes in them. So comparison of that tire, with the tubeless setup and this tire combination with the tubeless setup, 0.75 pounds of weight reduction a lot faster, rolling a lot less tread on the tire which is perfect for me in my riding conditions, so really happy with this tire upgrade Let’S talk about the number two upgrade which is gon na, be the drive train on this bike. So for me i was trying to get the weight down, so i went to the sram dub bottom bracket setup and i focus on the front of the drivetrain. This comes with a sram drivetrain on it. You can get rid of a bunch of the weight by doing the bottom bracket conversion to dub. If you want to go the shimano route, you can do that, but you also have to update the rear cassette. So ricardo martens friend of the channel has told me that he got contact with specialized and you if you want to go, upgrade your cassette on the back beyond what comes on it to something that’s, a higher grade, gx nx, if you’re tram and then something else. If you wanted to go the shimano route, you’re going to have to update the rear hub, but if you want to update the front drive train with an upgraded tram and move to the dub, you can go ahead and do that with your rear setup.
It’S already got a tram cassette on the rear and that is compatible with whatever you want to do. Sram wise in the front, which is one of the things i love about, the tram drivetrain. Is you can mix and match gx nx sx it’s all compatible. The only thing that you have to make sure of is that you’ve got a a hub that is compatible a free hub, that’s compatible with the cassette that you want to put on there. So if you want to swap out to shimano you’re going to have to get the shimano freehub and if you want to go above, the factory graded, install, which is probably like whatever’s below sx or below for the cassette you’ll, have to get an xd hub, which Will allow you to jump up to the nx gx cassettes on that, but you can do like. I said: i’ll walk you around the bike in a second, but you can do the gx front, setup or nx front setup bottom bracket. You can change that to a dub and it’ll be compatible with the rear cassette that comes on from the factory, so let’s take a look at that all right. So quick walk around on this drivetrain. I went to the dub bottom bracket in the front with the gx crank it’s a 170 just like the stock was you got a 165 a 170 or 175, depending on your height again i’m, like five, nine, so i’m good on the 170.
. I went to the oval. I took off the the front sprocket that came on this set and put on a absolute black oval, which is pretty cool. I like the oval. I talked about the paint on the bike in my full review, which you can check out, but got a few chips on this thing already. I think that’s from the chain sucking in right there um from what you guys have told me, so i think that’s, what chipped at versus a rock so dub on the bottom. I showed you how to pull out the um the crank set to do that. Install it’s easy, you guys can do it. You can totally do that install if you want you’re just going to make sure you get the right size, it’s, the 73, 65 73 threaded bsa, dub bottom bracket bracket bottom bracket. For that and then moving on to the back here, i’ve got the stock derailleur. I think that’s probably going to have to get upgraded. A lot of you guys have told me this is like snapped off or that you can’t get it to shift right and that you just aren’t having good luck with it. I know i’ve banged it around a little bit already and it’s it’s kind of hard to get it um back where i want it. I’Ve struggled a little bit to get it adjusted and fine tuned, but that’s, probably a future upgrade to go from this sx to a gx.
The thing i love about the sram drivetrain is that you can mix and match. If you wanted to do a gx front crank set with an nx derailleur, you could do that if you guys are going to run shimano on this, you’ll have to update the free hub to the micro spline on this. But you can do that without replacing the whole wheel, so that’s a pretty easy upgrade from what i understand, and so i left the stock cassette stock rederailer with an upgraded dub, bottom bracket and gx crank set all in all that saved me about a pound ditching. The stock bottom bracket and crank set, so i was pretty happy with that upgrade i, like the current look, the way the cranks look and it all works together, really really well so i’ve got the factory drive, train here or bottom bracket and crank set. You can see that’s a sram sx and what i’ll tell you about this, is you can see i’ve got it on the scale. I think you can probably see that on the video it’s like two pounds: 4.6 ounces. What i’ll tell you is the dub bottom bracket and crank set that i put on there gx and then you want the um bsa threaded dub bottom bracket 73. I think it’s 65 to 73 mil i’ll link to that in the description all the parts you need to do the conversion, but this is sitting at two pounds.
Four point: six ounces: the the tram dub system is sitting at one point, five, so i’m. On the 170, this factory is a 170, so i went from 170 length crank arm to 170, so you might choose to go to a 175 or a 165, depending on your height, i’m, five nine. So i like the 170 that’s what the factory comes with you. So it’s a good comparison on the weight, but basically a pound of weight savings. What i’ll tell you is this power spline um is just super heavy. This thing is super solid, super heavy it’s made by sram, but um it’s an easy place. You can really shave some weight and i really like the the bottom bracket system. Some of you guys also have asked about getting off this factory crank i did want to share. This is a simple tool you can get it on. Amazon super cheap, but basically what you do is you use the allen wrench and you back this bolt out, and then you screw this bolt here in and then screw this into that and basically what it does is it pushes the crank set off of the bottom Bracket so super easy to do if you have the right tool but again i’ll link to this in the description, so you can pick one of these up if you don’t have it, but just put this in here you break that you put this in. You got ta kind of crank on this because it it’s, probably in there pretty tight, so don’t, be afraid to really really crank that to get it to break, and then this crank arm will just slide right off and then um.
You need one other tool that goes right inside the bottom bracket. That also comes in the set that just has teeth on it, that unscrews that for you, but super easy to do once you have the right tool, so don’t be afraid of doing that bottom bracket. Conversion, you can totally do it it’s an easy conversion to do don’t be afraid of it. So let’s talk about the number one upgrade for my money and, in my mind on this bike. It’S got to be the brakes so, depending on what you’re coming from, i was coming from a 2014 stump jumper competition alloy with slx brakes that were great coming to the tecturo brakes that are factory on this bike. You’Ve got a 203 millimeter disc in the front and then you’ve got a 180 in the back, but for me the brakes were really underpowered. I was used to a lot more stopping power and that’s important to me. So i like to do a lot of charging. The downhills and going really fast so for me, it’s really i like to go fast and i like to stop fast and so the factory brakes just weren’t adequate for me now, if you’re riding around your neighborhood, maybe do some light doing some light kind of trail, Riding they may be fine for you and you may be able to get some serious miles out of those brakes, but if you’re doing some serious trail, riding or you’re a pretty experienced mountain biker, that’s coming from a decent bike already with some higher end brakes, it’s.
Something that you’re going to want to put the money into so let’s jump on the bike. Do a quick walk around i’ll talk you through a little bit of the install and show you what brakes. I went to all right so let’s, uh let’s talk through the upgrade that i did and some of what you’ll want to think about. So you’ve got a 203 rotor in the front. It comes with the spacer that you need. So if you want to upgrade your brakes, you don’t need to worry about a spacer or anything. If you’re going to shimano, you can use the spacer that’s on the bike, so you’re just fine there. If you took that spacer off, you could go to a 180 rotor instead of a 203, if you wanted to shed some more weight the 203. This is the stock rotor with an xt brake. So i left the stock rotor on here and went to the xt brake. You can do that if you don’t want to upgrade your rotors right away. I figure i’ll run these for a while and then upgrade them when they get a little lower. The other thing i’ll tell you, is there and this may some people may find this strange, but i run a four piston brake. So this is the xt4 piston brake for a little more stopping power, but with a 203 rotor in the front and a 4 piston. Some people may think that’s overkill, but i like a lot of stopping power, so that’s what i went ahead and did so here’s your xt rotor or levers in the front here and then let me talk to you a little bit about the cable routing.
So you can see here there’s an entrance point right here on the front of the bike and then for your cable routing, it’s kind of neat on this bike. I don’t really like the way it looks, but you’ve got a compartment here that you can open up and you can bring your cable down through this compartment. And then you run it through there’s, a there’s, a plastic piece here and here that you take off and then you can run it through right through this arm and then you pop out right here for the rear, brake and so it’s pretty easy to do these Brakes will come with a little rubber nipple that you put on the end of the cable. So you can pull the new cable through, which makes it kind of easy. So i’ve got a two piston or two pot for you guys across the pond in the rear and then a four piston here in the front. I really like the shimano xt, but really, i think all you need is slx. Those are really really solid breaks. If you didn’t want to go to a 4 pot, 4 piston in the front, you could certainly save a little bit of weight if you didn’t do that, and if you really wanted to go after the weight, you could take this down to a 180 and do A two piston which, depending on your riding conditions, you just take this spacer out.
If you want to do that, to account for the little bit smaller rotor and you could shave some more weight, but that was a place. I was willing to absorb a little bit of the weight difference so and then in the back here, you’ve got a 180 and again i’m running the stock. Tecturo rotors with my shimano dior xt brakes and it works just fine there. You have it that’s, our top three upgrades for the 2021 stumpjumper alloy. Those are the ones that are the best investment for me, based on trying to get the weight down in my preferences and the riding conditions here in texas. I would love to hear about what upgrades you guys have planned and if you would do things in any different order, drop those in the comments. If you have questions about any of the installs or anything that i did on these top three upgrades, please shout i’ll cover those.