# Trek Roscoe 20 - Learnings and Mods



## gobo333 (Aug 20, 2018)

New here. Wanted to share my experience buying, owning and modifying a Trek Roscoe 20 kids + sized bike. 

I had scoured the internets for information on a good beginners MTB and had a few things in mind before discovering the Trek at my LBS. I have three kids and this is for the oldest, so it made sense to me to get something good, and make it great to create the best experience for all three of the kids over the next 9 years. I want them to learn to love cycling with me.

The hunt was on for a great base to start from. Light frame, and descent build would set up an easy upgrade. I like to tinker and modify everything, so simply buying the best thing I could find was no fun, but the basic ingredients had to be there, and the fit had to be right. My oldest is 6.5 years old, already has great balance and bike handling skills, and needed something to grow with.

Long story short, after much interweb research I was prepared to order the Cannondale Cujo 20, but found the Trek Roscoe 20 in person at my LBS. I had not seen a thing on this bike on the internets, but after looking at it, having her ride it, two things were obvious. It fit perfectly with room to grow, and it had a build that would allow me to mod it quickly.

The stock bike can be found online, so look for the specs there. But the big wins are the frame, it's weight, and the wheels/hubs from the factory running disc brakes and an 8 speed. This allowed me to go immediately to 10 speed and upgrade the brakes to something much better without the hassle of having to build a wheel set first thing.


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## gobo333 (Aug 20, 2018)

First Impressions

The bike weighed at the LBS was 24.48lbs with nylon pedals. It ran well when my daughter took a test ride. It turns quickly, shifted well enough, and was easy for her to climb on and off. The handlebars might be a little wide, but she will quickly grow into them.

The brakes stop the bike well, but being mechanical, they lacked feel. More than that, they lacked the ability to adjust the reach of the levers enough. There is an adjustment screw, but it just didn't go as far as my daughter needed. They would be more than acceptable for daily use, but I cant leave well enough alone.

The 8 speed Tourney derailleur and thumb shifter work well. They were consistent and didn't require too much force to shift. There was some slop, but that was expected at this level, and totally acceptable. For me, the use of the thumb shifter was a HUGE improvement over the grip-shift found on most of these 20" bikes. Another immediate observation was the incredible length of the derailleur cage and just how far it stuck out from the bike. Again, totally serviceable and worthy of riding into the ground.

The crank is noted as 32T on the website, but mine was a 28T. Two things of note here...the 28 made the gearing wonderfully low when combined with the 11-34, and interestingly, when weighed, it was actually pretty darn lightweight. Less than what I eventually replaced it with by ~100g!

The hubs and wheels are also nice all things considered. Particularly in the rear where you can swap to a 10 speed without any modification. I have yet to weigh them individually yet, as I have plans to go tubeless eventually. More on that later. But I am sure they weigh a bit with huge 2.8 CST tires, requisite tubes, and budget rims. One thing to note was what might be sloppy spoke build. It looks like some of the spokes are bent and wonky. Nothing seems loose, and the wheels spin true, but they don't look right to my eye. I'm going to guess they could easily withstand anything my daughter can throw at it, but I am committed to swapping them eventually to be sure they are right, and to use in better hubs. Of note, the front wheel appears to be true, but off center by about 10cm. Need to fix that.

One final note on running gear, the bottom bracket was crunchy from the start. I tried to adjust a bit, and found it to have a major lack of grease, but nothing could make the improvement I was looking for. Due for replacement.

Overall, for a $500 purchase, it is well composed and ready for some fun adventure directly from the showroom floor. I would HIGHLY reccomend that you go through the bike, loosed the overtightened hardware and running gear, lube and grease where necessary, and put it back together with care and a torque wrench. I can't help but believe these are not being assembled by passionate weathered Italian men like your Pinarello, but instead with power tools in Asia and by ham-fisted mechanics looking for their next break. It's performance and longevity are up to what you do when you first get it home.


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## gobo333 (Aug 20, 2018)

Modifications

Objective - make it lighter, more durable, and fun/easy to use.

First to go were the brakes. I swapped with Shimano BR-M396. They were super easy to install, have much better feel, and have fairly significant reach adjustment. They come preassembled so they require you to shorten the tubing, but have the parts needed in the box. You just need mineral oil. Immediate and significant improvement.

Next was swapping the rear cassette to a Shimano 10 speed 11-36. Pick up a couple extra teeth on the far end, and more importantly, a couple more cogs to even out the jump from gear to gear. This was also easy as going from 8 to 10 speeds requires no change to the rear hub.

This required a new derailleur and thumb shifter. For the shifter I splurged the $45 to use an XT version, opting for the metal components and smoother action. It's well worth it. And on the far end, I swapped with the Shimano Zee short cage, also $45. This is Shimano's budget downhill derailleur, but it has an incredibly short cage, is tucked into the frame, both making it less likely to be hit and damaged. And it has a clutch as well! Win win win. Combined with the XT shifter, it runs through all gears quickly and efficiently. One thing I have observed and you should keep in mind is that small hands can and will have a tough time pushing thumb shifters. They DO get more skilled with time and practice though.

I wanted to change out the crank to be able to run a narrow-wide chainring, and possibly shave a few grams in the process. Low and behold, the stock crank was actually 28T (not a narrow-wide but stamped steel chainring) and it was alloy, adding up to something actually very light in stock form! But I ordered a Spawn 127mm w/NW in 32T. It is heavier than the stock unit, has 4 more teeth, and is SO nice. Dang kid.

This takes me to that crunchy bottom bracket. I planned on a simple swap to a Shimano UN55. It was not that simple. First, to take the hard work out of aligning the chain-line, order the 113mm 73. I did the measurement and the maths and there you go. The stock BB is 133mm due to the construction of the crank. I'm sure you could make a 127mm crank work if you wanted to run the stock crank, but it was way out of line for the Spawn. Be sure you either copy this setup, or take the time to buy the crank, mock it up, do the maths, and order the right crank. And if you are between two measurements, go to the smaller one. All of that yielded a buttery smooth BB for less than $20.

Connect the rotating bits with an XT 10 speed chain.

At this point the major functional components have been upgraded and the bike rides outstanding. She can grind up hills, through loose sand, smooth streets, and even ride directly over parking blocks like they aren't there. We did a few cosmetic things to personalize the bike.

Lizard Skins Moab Lock on Grips
Rant Hella PC pedals

She is happy. Dad is happy.

Next upgrades...Chinese carbon bars, Kenda Slant 6 tires, and tubeless setup.


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## GSJ1973 (May 8, 2011)

gobo333 said:


> Next upgrades...Chinese carbon bars, Kenda Slant 6 tires, and tubeless setup.


Nice! We found the Zee 10 speed shifter and rear derailluer (clutch off at first) operated a bit better than the XT. Our daughter was having problems shifting with XT, for whatever reason, I think it has slightly longer "throw" in the upshift lever if you will.

Curious on the crank upgrade. 28 to 32 tooth, most are looking for lower climbing gears, not harder. Was your daughter spinning out the 28t on flats? Also, I think you are going to be adding more weight with the Kenda Slant 6's. They are 600g as I recall. Would be interesting to hear what the CST (Maxxis' parent company) weigh. The CST is actually a fairly good tire.

Thanks for the great writeup and have fun with the mods! This is a bike we've not seen much of posted here.


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## gobo333 (Aug 20, 2018)

GSJ1973 said:


> Nice! We found the Zee 10 speed shifter and rear derailluer (clutch off at first) operated a bit better than the XT. Our daughter was having problems shifting with XT, for whatever reason, I think it has slightly longer "throw" in the upshift lever if you will.
> 
> Curious on the crank upgrade. 28 to 32 tooth, most are looking for lower climbing gears, not harder. Was your daughter spinning out the 28t on flats? Also, I think you are going to be adding more weight with the Kenda Slant 6's. They are 600g as I recall. Would be interesting to hear what the CST (Maxxis' parent company) weigh. The CST is actually a fairly good tire.
> 
> Thanks for the great writeup and have fun with the mods! This is a bike we've not seen much of posted here.


Interesting on your Zee shifter. That's outstanding to hear, and only $20! It's truly amazing what they produce. If this XT becomes a bother, I'll give that a try for sure.

I had thought all along it came with a 32T as advertised. Only after counting did I discover it was 28T. So far, she has plenty of gear with the 32T. Her spirit gives out before her legs right now! But I have plans to get a 30T when she needs more. That is as small as the Spawn crank will go. Fortunately the 11-36 helps on the back end too. ??

Tires. Agree the 2.8 CST seems to be a good tire. Even with tubes, I run under 20lbs. I plan on taking one tire off and weighing it after our Labor Day mountain trip. I couldn't find its weight anywhere online, nor could I find documented success at converting to tubeless. In my research, the Slant 6 is tubeless ready, and is the lightest of the plus tires. I'm interested to hear more opinions/experience on the matter, but I want to stay plus size ultimately. To go down would be much lighter of course. Below are the numbers I accumulated...

Tires
CST Fringe (on bike) - 2.8 - xxxg - $28
Specialized Big Rollers - 2.8 - 670g - $25
Kenda Slant 6 - 2.6 - 574g - $35
Kenda Kaos Sport - 2.8 - 732g - $35
Kenda Kaos Sport - 2.6 - 686g - $35
Maxis Creepy Crawler - 2.0 - XXXg - $28
Spawn Brood Maxton - 2.2 - 440g - $40
Schwalbe Little Joe - 2.0 - 290g - $20

I'll get some photos up soon. Hopefully this give others another data point as so little is avail on this bike right now. Thanks for the notes!

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## HEMIjer (Jul 17, 2008)

Nice thread post some pics...might pick up a 24 soon still on the edge for my youngest daughters next bike.


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## gobo333 (Aug 20, 2018)

I'll get some images of the bike posted this weekend.


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## gobo333 (Aug 20, 2018)

Some better images...still happy with the results  Will put it to the test in Big Bear next weekend!














































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## Biggs427 (Dec 8, 2017)

Thanks for the post, this is great stuff!

I'm on the fence of buying the Roscoe 20 for my younger daughter and knowing that I can swap the spare 11-36 cassette I have laying in my part bin is great. I looked at the Riprock but I didn't like the weight, grip shifter and freewheel at the back.

With 2.8 tires I plan on bringing her ride with me during winter as for a 48lbs girl the tires should be ok on groomed trails. Might want a tire with better grip though.


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## Judsky (Sep 21, 2018)

Thanks so much for this detailed post, this is exactly the kind of stuff I'd look to do when I pickup a Roscoe 20 / 24.
My kids are a little on the short side, so I was wondering what mods I could do to shorten the reach.
The Trek website does not seem to list the stem length (it just says 31.8mm - which is the diameter no doubt). Would you be willing to post the stem length for your Roscoe 20?

I could also roll the handle bar a bit, to make use of the rise, but that alters the sweep too, so I would not be able to get very far with that.


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## Charlie Don't Surf (Mar 31, 2017)

Good stuff, just ordered my 6 year old one in lilac! I'll be matching a few of your ideas like the 10sp (but with a NX cassette) the short cage Zee mech, narrow/wide ring, Shimano MT500 hydraulics with XT rotors, tubeless, 30mm stem w/ cutdown 1" riser bars and might even build some new wheels!


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## Steve-XtC (Feb 7, 2016)

> Shimano MT500 hydraulics with XT rotors


If I was splurging on anything it would be the brake levers for something that can be used 1 finger.

Ultimate kids shifting is probably 11 speed SLX M7000 as it has 20% less force required at both ends than XT M8000... however the main thing in our climate was actually using full length good quality cables and outers and swapping reasonably regularly.


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## Charlie Don't Surf (Mar 31, 2017)

I already have then as take offs! I should be able to get 1 finger braking with her


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## Steve-XtC (Feb 7, 2016)

1 finger braking was by far the biggest challenge/habit we had to break ...


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## TimTucker (Nov 9, 2011)

Steve-XtC said:


> 1 finger braking was by far the biggest challenge/habit we had to break ...


Definitely a challenge -- I'm still working on it myself!

Looking ahead, what size bars does it start to become feasible on kids' bikes? On the 460mm wide bars on our Spawn Yoji 14, there's not enough room to even move the levers far enough inward for it to be possible.


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## Steve-XtC (Feb 7, 2016)

TimTucker said:


> Definitely a challenge -- I'm still working on it myself!
> 
> Looking ahead, what size bars does it start to become feasible on kids' bikes? On the 460mm wide bars on our Spawn Yoji 14, there's not enough room to even move the levers far enough inward for it to be possible.


Of course it's one of those annoying things  it sorta compounds that the smaller they are and their hands and bars (and the old diameter bars/stem).... and size of the grips. 
More than anything I think its a combo of what you can get on the bike... if you can swap the stem and put on different bars etc. (once you do this the stems at least get reused.. so his stem on his 20 started at 35mm, then 50mm then 80 for a short time.. then onto the 24" with the 35mm... etc. The bars also saw some reuse... but obviously you can't put length back but he now has a XC bike and DH bike and the XC bike bars are the longest from the 20"... and the DH bars came off my XC bike ...

The first variable is levers so a SLX/XT lever designed that way doesn't need to be as far inboard as the lower end ones... We skipped this right until he was big enough for the 24 because he had rim brakes...

*I wish I hadn't.*... because even when the brakes got swapped for something his pinky could lock up his habit was grabbing a handful... he even accepted he didn't need more than one finger but when it comes down to panic it's one thing to know and another to react. He persisted for a long time... and in that time he was riding stuff that was just crazy to ride without ... especially given limited fork travel etc. (which he had by that time) but obviously even worse rigid.

Nothing else even comes close in terms of breaking habits to braking habits... 
He's now just turned 9 and has 90mm grips ... something you can at least buy.(if not easily) .. but previously it's been a case of sacrificing a set with single lock-on and just cutting down .. so the brakes could be moved in... and to an extent also put the shifter OUTSIDE the brake...


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## shaudy (Feb 24, 2006)

has anyone here with a Roscoe 20 managed to set up tubeless? I've spent hours trying with the original CST tyres but cannot get the tyres to take air!


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## gobo333 (Aug 20, 2018)

Before I committed to trying tubeless, I decided to see how low I could drop the pressure with the stock CST/tubes setup. Granted my daughter is small, and not a hard core shredder yet, but I’m running them at ~8lbs and have yet to experience a flat. She rides straight up and over curbs and parking blocks like it ain’t no thing. You might be past this point already. 


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## gobo333 (Aug 20, 2018)

Charlie Don't Surf said:


> Good stuff, just ordered my 6 year old one in lilac! I'll be matching a few of your ideas like the 10sp (but with a NX cassette) the short cage Zee mech, narrow/wide ring, Shimano MT500 hydraulics with XT rotors, tubeless, 30mm stem w/ cutdown 1" riser bars and might even build some new wheels!


Want to see! Lilac with mods!

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## shaudy (Feb 24, 2006)

I just wanted convert to save a bit of weight and have the extra puncture protection from the sealant since we have a lot thorns around here .. I think the only chance I have is building the inner of the rim up with lots of Rim Tape, unless someone has had success another way!


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## OREGON85 (Nov 14, 2018)

The Roscoe 20 is an awesome bike. I searched diligently over the spring/early summer for the right bike. I was in the local Trek dealer to order one before they had even heard about its release. 

I made the factory brakes work by adjusting the reach screw all the way in and letting a little cable out so they engage where he has more strength. The brakes are certainly the low point in my opinion, but they get the job done. I am frequently back and forth on replacing them. My wife keeps saying "you want to spend how much on brakes for a $400 kids bike?!"

We've been running about 8 psi in the tires since day one without issue.


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## PaulInMarin (Jan 8, 2019)

Thanks for the upgrade tips.

For anyone considering the Roscoe, my 6.5 year old has been riding this on our trails in Marin for the past 6 months. We ride twice a week, usually 8 to 10 miles per ride with anywhere from 500 to 1000 ft of elevation gain. The terrain varies from easy fire roads to single track and rocks.

The bike has been absolutely fantastic. He's learned great climbing and downhill skills on it and because it's full rigid he's learning how to pick good riding lines.

My only advice is to upgrade the brakes right away if you plan to have your kiddo ride long downhills. The stock mechanical brakes are hard to reach, hard to pull, and build bad grip and breaking habits. Once that upgrade is made... this bike is hard to beat.

I put a set of XT Hydraulic brakes on the bike. I got them on sale. It's almost like those brakes were made for small hands


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## Biggs427 (Dec 8, 2017)

I second that for the brakes. The mechanical are hard to activate for a kid. Even entry level hydro brakes are easier than mechanical. Only problem is now my kid is spoiled and could never go back to mech brakes... :lol:

For those who would want tire with more grip, Vee make the crown jewel in 20 x 2.80:
https://www.veetireco.com/listings/plus-size-crown-gem/

I might give them a try as the CST are too slippery in snow. Only problem is that they are hard to find in Canada...


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## gobo333 (Aug 20, 2018)

Oooooh! Look nice!


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## mintydip (Mar 25, 2008)

I just ordered my son a Silver Roscoe 20!

It will arrive at the LBS in a few days.

Based on everyone's recommendation, I would like to upgrade the brakes to hydraulic as well.

Are the rotors reusable?
Just need to swap the lever and add caliper/line?


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## shaudy (Feb 24, 2006)

yes, I've got the original rotors on with slx brakes. Had to face the frame so the rear caliper would align up.

Would love to get it tubeless, has anyone managed it?


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## ProjectBomber (Jun 9, 2008)

Just bought one in Pink for my daughter... I have Richard over at Stikrd making up some custom stickers in turquoise for it to make it hers. Then I've got a Zee 10sp drivetrain for it with some Shimano Deore brakes and the Tioga Dazz lite pedals. Want to try and cut some weight from there but not really sure where I'll start other than tubeless.


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## Steve-XtC (Feb 7, 2016)

Brakes seem the way... either sell the mechanical as new or keep them until they outgrow the bike and swap them back to sell.


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## DaveX (Feb 10, 2004)

Just picked up a Roscoe for my daughter. Some new Jr size levers should be here Friday to replace the stock levers. This got me to thinking, instead of hydraulic brakes how about Avid/SRAM BB7 mechanicals to replace the stock calipers? I had BB7s on a bike years ago and I recall them being quite good and almost comparable to hydros. What do you all think?


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## TimTucker (Nov 9, 2011)

DaveX said:


> Just picked up a Roscoe for my daughter. Some new Jr size levers should be here Friday to replace the stock levers. This got me to thinking, instead of hydraulic brakes how about Avid/SRAM BB7 mechanicals to replace the stock calipers? I had BB7s on a bike years ago and I recall them being quite good and almost comparable to hydros. What do you all think?


I put on a TRP Spykes for the front brake on my son's bike, which are a step up from the BB7s since they actuate the pistons from both sides.

Braking power is good, but the force to pull the lever is still a little greater than a hydraulic brake.

The only reason I went with them was to keep front & rear levers the same, since the rear was a v-brake.


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## JeremyFXDWG (Aug 4, 2004)

gobo333 said:


> Interesting on your Zee shifter. That's outstanding to hear, and only $20! It's truly amazing what they produce. If this XT becomes a bother, I'll give that a try for sure.
> 
> I had thought all along it came with a 32T as advertised. Only after counting did I discover it was 28T. So far, she has plenty of gear with the 32T. Her spirit gives out before her legs right now! But I have plans to get a 30T when she needs more. That is as small as the Spawn crank will go. Fortunately the 11-36 helps on the back end too. 爛
> 
> ...


Just had the tire off my sons bike and the CST tires were 552g.

The tubes were 340g so I am looking for lighter tubes. I am hoping the Schwalbe AV7 will stretch enough to work as they are only 145g.

Also the cassette was 440g which is kind of crazy.


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## FuzzyOptics (Oct 15, 2014)

Late to the party but stoked to have found this thread. Had been planning on buying a new bike for him for his birthday, to size up from a 16" wheeled Redline Pitboss, but jumped on a used Roscoe in good condition via Craigslist, for $250. Aside from cosmetic scrapes, only really concrete degradation from new is tire wear.

So glad to have this thread as a guide as his birthday present will now be cycling gear and upgrades to his bike.

Really look forward to upgrading him to hydraulic brakes and expansion to 10 speed, maybe a smaller chainring. 

He's practically just over the bare minimum size to ride the bike and also has only ridden on the street and a BMX dirt track, so gonna take a little bit for him to develop ability to climb. 

I'm a recent convert from road to dirt, so he can come along at his own pace and I'll be happy to ride whatever he can handle.


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## Rafa145! (May 19, 2021)

has anyone here with a Roscoe 20 managed to set up tubeless?
Any problems using a 10 speed chain?


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## JeremyFXDWG (Aug 4, 2004)

I tried multiple times and could not get them to seat. I ended up using schwalbe lightweight tubes.


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## philibuster (Apr 28, 2021)

I'm in the process of upgrading/lightweighting a craigslist Roscoe to 1x10. So far I've done the bare minimum of things: 

Replaced brake levers with Avid speedials and longer reach adjustment screws. Power and modulation are not bad with this setup. 
Replaced shift and brake housings and cables with compressionless, polished stainless cables, 
New alloy flat bar for narrower controls and lower rise (I might go to chinese carbon here, but maybe after he stops dropping the bike on its side). I also moved the shifter inboard of the brake lever to get him to 1 finger brake. 
Used carbon seatpost, 
New pedals to replace grindy nylon pedals

Parts on order:

Prevelo Heir 120mm cranks. I'm a little concerned about chainstay clearance but I emailed them and they said as long as I have 140mm of clearance at 120mm behind the BB I'm OK. For reference, the chainstay has a nice little squish at 120mm, and width there is 123mm. Q factor on the stock crankset is ridiculous. I measured at something like 180mm+. The kid looks like he's doing the splits. These have 151mm Q factor and shorter cranks are probably better for his hip angle. 
XT BB, 
Zee derailleur (freeride version) and shifter, 
Wolf Tooth CAMO Bashspider. I'm really mostly worried about the little brother putting a finger between the ring and chain. Probably worth the extra weight and $$. Plus less grease on the calf is always good.
Wolf Tooth CAMO Oval 30T NW chainring. He's been having a tough time on the starts getting his cranks aligned so he can start riding. Hopefully this means he can spend less time in the low leverage areas.
XT 10s chain,
XT M771 11-34 cassette.

Here's my concern:
Short chainstays with the 1x10 drivetrain means pretty extreme chain angles. I'm wondering if I should stick with the recommended big-big+1" chain sizing rule, or add another 2 links to ease out the lateral tension on the cage in the big gear. 
Weight is pretty high, especially on the wheels. I'd love to get tubolitos or another TPU tube, but Tubolito only goes to 20x2.5. I'm wondering if I can stretch them and still have any kind of durability. The tires have the middle knobs worn down pretty well, and I want to run him at low (~10 psi) pressures. I was thinking of doing split tube tubeless, but these tires look pretty baggy on the rim, and sidewall is pretty thin. 
The backstory on the drivetrain upgrade started from the grindy BB. It's old-skool cup and cone, 131mm square taper. Trek Roscoe Kids' Loose-Ball Bottom Bracket | Trek Bikes It's got like 9 balls per side and a super thick ball carrier. I cannot, for the life of me, find a drop-in cartridge bearing replacement. There are some 68x131mm bb out there, but then chainline would be off. I'm also a believer in shorter cranks for biomechanics. He's only 45" or so, so 10% of his height is 111mm. Q factor is also an issue. Prevelo shipped the cranks yesterday, so I haven't been able to test fit them, but I'm really looking forward to it. Stated weight is 523g without chainrings. HEIR Direct Mount Crank Chainring setup is 135g. Bottom bracket is 82g. The new setup is probably going to weigh slightly more than the one that it replaces, but I'm hoping the better biomechanics and smoother bearings outweigh the weight penalty.


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## philibuster (Apr 28, 2021)

I was worried about the derailleur hanger getting bent so I put this on the through bolt quick release. Amazon.com : M-Wave Quick Release Light Holder, Black, 1.8 x .5 x .5 : Sports & Outdoors I put a rubbery bar plug in it. With the tire and peg touching the ground it keeps the derailleur off the ground.

The stock bottom bracket weighs 329g, crankset is 487g.

The prevelo heir did not have the necessary clearance for the chainstays. I asked about putting extra bb spacers in but they recommended against it. I ended up filing the backs of the cranks to gain the necessary clearance. I also ended up having to file the backs of the pedal spindles. It's super smooth and 68g lighter on the front end of the drivetrain.

I was also ended up with a chainline around 54mm, so I ordered a 2.5mm direct mount spacer.

The chain was also ghost shifting to a larger cog on the smallest cog and down on the largest cog when backpedaling. I'm pretty sure this is due to the short chainstays and small tolerances of the 10s cassette and 10s chain. I tried a 12 speed eagle chain and it works great now. It sometimes drops with the largest cog but it takes many revolutions to trigger it.

I'm going to try to go tubeless with a set of 20x2.25 rocket rons and the split tube method. They're going to be at the limit of what's sane in terms of rim width at 43mm external and carcass at 57mm.


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## philibuster (Apr 28, 2021)

I mounted up the rocket rons split tube tubeless. They seem like they're going to be ok profile wise. They measured 57mm external maximum width. The sidewalls protrude a little from the outer side knobs but they look like they have good crown still.

Going tubeless on these rims was not bad using the yoga mat and split tube method. Yoga mat in the spoke valley was necessary to begin to inflate them. Too much yoga mat (coming out of the valley) meant the beads never fully seated and the tire was not round. I couldn't manipulate the tire to get the bead to seat if it was hung up. Either burped it or just didn't want to move.


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## TrekWarMachine (Jul 26, 2017)

Thanks for the upgrade tips! I got my son a Roscoe 20 (Rage Red) this spring. I upgraded my brakes to Shimano XT M8120's (4 piston), so I put my old brakes Shimano MT420's (4 piston) along with Shimano SLX RT66 (160mm) rotors on my son's Roscoe! Now I'm just waiting for his Chromag Radar pedals to come in.


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## rafa145 (Oct 6, 2009)

11-40 cassete, if back pedal chain drops... Otherwise working good








New pedals, 
Schwalbe av7 tubes.


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## TrekWarMachine (Jul 26, 2017)

Update: Chromag pedals arrived and my son loves them.


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## 778lai (11 mo ago)

WOW, this is a great post. Thank you for sharing.
I am a new member here and just got into MTB last summer with kids. We are picking up his new Roscoe this Sunday and this post saves me lots of time. (more time to ride with my kids) 
Does anybody replace the front fork to air suspension fork yet?


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## TrekWarMachine (Jul 26, 2017)

No, the point of the of the bike with having a rigid fork (no suspension) is to keep the bikes weight down, which is crucial for kids.


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## 778lai (11 mo ago)

TrekWarMachine said:


> No, the point of the of the bike with having a rigid fork (no suspension) is to keep the bikes weight down, which is crucial for kids.


My boy is slowly riding more technical trails (blue trails) and we will ride more bike park this year so I thought very I need to change to a suspension fork.


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## Chi81 (8 mo ago)

Man I hope this thread is still I’ve as I too, am late to the party. Our son has the same 20” Roscoe and he loves it. Swapped out to a suspension fork. Although a bit heavier, he feels more control on the trails. One thing that has me stumped is making it tubeless. I have tubeless tires but they just won’t seat. Gorilla taped the rims with and without the factory spoke strip. Tried split tube method. But still nothing. 
Would appreciate any tips you have and explain further this yoga mat method. Thanks!


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## Chi81 (8 mo ago)




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## rton20s (Aug 27, 2010)

There are some rim and tire combinations that you are just never going to get a good seal on. Neither the wheels nor the tires you have on the Roscoe are designed for tubeless installation. It is possible that all the tape and sealant in the world wouldn't get the beads to seat and tires to seal.


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## Chi81 (8 mo ago)

rton20s said:


> There are some rim and tire combinations that you are just never going to get a good seal on. Neither the wheels nor the tires you have on the Roscoe are designed for tubeless installation. It is possible that all the tape and sealant in the world wouldn't get the beads to seat and tires to seal.


You’re so right. I did however swap out the stock tires for tubeless vee tire. And I believe the rim is single wall. I was thinking of trying that yoga mat method with the split tube.


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## Chi81 (8 mo ago)

shaudy said:


> I just wanted convert to save a bit of weight and have the extra puncture protection from the sealant since we have a lot thorns around here .. I think the only chance I have is building the inner of the rim up with lots of Rim Tape, unless someone has had success another way!


I’m proud to say after countless hours and my wife can vouche for that…..”you’re in the garage again?” 😂😂😂……I can say, we finally got tubeless!! 
Other than cleaning the rim and having TLR tires:
•I did three layers of gorilla tape
•screwed in the Stan’s schrader tubeless valve rather than just shoving it down.
•wrapped an 18” inner tube on the outside of the tire to hold it in placed. Ensure it’s centered and pressure is evenly distributed. 
•dry fit first with air compressor. 
•added tire sealant via valve core
•inflated to 35-40lbs to lock in the bead
•spin and rotate tire to spread the sealant. 

Prior to adding sealant and checking for leaks, I did have some leaks from the base of the valve and some spokes. I imagine the sealant will do it’s job as it’s been 2hrs now and holding.


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## gotzero (9 mo ago)

Chi81 said:


> I’m proud to say after countless hours and my wife can vouche for that…..”you’re in the garage again?” 😂😂😂……I can say, we finally got tubeless!!


That is good to know. I failed the first time attempting with Vee Crown Gem 20x2.8" I must need to use a lot more tape than I am used to.

Here is my oldest's Roscoe in current form. Brakes changed to SRAM Level (much improved reach and had them around after upgrading a bike of mine) and added Nukeproof pedals. I milled the frame to accommodate an additional line and installed the Brand-X kid's 70mm dropper, which works perfectly at her current light weight.

She has a Nukeproof Cub Scout Race for testing limits (when I added up the cost of fork, new wheel, etc. I figured I might was well go for a second bike), but overall I am super happy I got the Roscoe 20 as a first step, and plan to use it as her neighborhood bike, whole family rides, and a "fat bike" for lightweight kid. I hope to get it set up tubeless and then plan to be done with modifications unless things start breaking. I want to keep the original shifter on as long as possible because the clear gear indicator is a huge help for talking through climbs and general learning.


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## Chi81 (8 mo ago)

gotzero said:


> That is good to know. I failed the first time attempting with Vee Crown Gem 20x2.8" I must need to use a lot more tape than I am used to.
> 
> Here is my oldest's Roscoe in current form. Brakes changed to SRAM Level (much improved reach and had them around after upgrading a bike of mine) and added Nukeproof pedals. I milled the frame to accommodate an additional line and installed the Brand-X kid's 70mm dropper, which works perfectly at her current light weight.
> 
> ...


Nice. That looks great. Yeah I think the shifter is fine. Brakes as well especially when he’s learning more control than speed. I’d love to swap out the cranks to lighten the bike but I’ve only found brood cranks at spawn cycles. 
A dropper post would be interesting. But he’s a little on the short side so we’ll see.


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## blehmbo (Sep 17, 2011)

I read through this thread and took away a lot of good information. I figured it was time to contribute my mods for my daughter's Roscoe 20:

-Tires/Tubeless: I was able to mount the stock wire bead CST tires tubeless using the split tube/ghetto method. Used "sill seal" from the home improvement store to fill the valley of the rims and split 12.5" schrader valve inner tubes. I was able to seat the beads using the "dry" method with a floor pump, removed the valve cores and filled with orange seal afterward. We keep the PSI >20 on this setup for peace of mind for keeping the bead seated. I didn't expect it to work with a wirebead tire, but I was pleasantly surprised. We will likely experiment with lower pressures later on.
-Brakes: Initially upgraded the stock Tektro brakes to BB7s and Speed Dial 7 levers with 180mm front and 160 rear G2 cleansweep rotors. I couldn't get her to break the two finger braking habit until I changed her to a hydraulic setup. The Roscoe 20 inherited my take-off SRAM G2 levers & Level calipers.
-Drivetrain: Initially installed my old SRAM X-9 setup, but she had difficulty shifting to the larger cogs. Switched to a x-horizon based (lighter actuation) derailleur to alleviate the issue, which meant overhauling the entire drivetrain. Ended up with a SRAM Rival 10/11 speed medium cage rear derailleur, SRAM Gx 10 spd shifter, PG1050 11-36T cassette, SRAM PC-XX1 11 spd chain.
-Dropper Post: A dropper felt like a necessary upgrade to allow her to get to a more ideal seat height for pedaling while being able to mount/dismount comfortably. Ended up with a PNW Fern 90mm travel with a Wolf Tooth Light Action lever. Problem Solvers Stick-On Cable Guides were used for the external housing.
-Cockpit: Matchmaker X made a big improvement in cockpit ergonomics vs discrete mounts. ODI Ruffan lock-on grips for style.

Total cost? ...
I go back and forth on upgrading the stock pedals. I'm worried that shin strikes or scratched calves from pedal pins would detract from her enjoyment of the bike.


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## Mcfarton (Oct 18, 2021)

blehmbo said:


> I read through this thread and took away a lot of good information. I figured it was time to contribute my mods for my daughter's Roscoe 20:
> 
> -Tires/Tubeless: I was able to mount the stock wire bead CST tires tubeless using the split tube/ghetto method. Used "sill seal" from the home improvement store to fill the valley of the rims and split 12.5" schrader valve inner tubes. I was able to seat the beads using the "dry" method with a floor pump, removed the valve cores and filled with orange seal afterward. We keep the PSI >20 on this setup for peace of mind for keeping the bead seated. I didn't expect it to work with a wirebead tire, but I was pleasantly surprised. We will likely experiment with lower pressures later on.
> -Brakes: Initially upgraded the stock Tektro brakes to BB7s and Speed Dial 7 levers with 180mm front and 160 rear G2 cleansweep rotors. I couldn't get her to break the two finger braking habit until I changed her to a hydraulic setup. The Roscoe 20 inherited my take-off SRAM G2 levers & Level calipers.
> ...


I upgraded the pedals on both of my kids 20 inch mtbs. I have already put the stock pedals back on one. And the other one has asked for the same. It’s the beginning of summer here and they like to ride in shorts. The pedals would have probably stayed on if I switched them during pants season. Oh well I tried.


Sent from my iPhone using Tapatalk


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## CJB123 (9 mo ago)

few days ago moved up to a 20” bike for my 7 year old. Went with a giant XTC 20 but the chain was ultra tight andthe drivetrain was crunchy even after setting it correctly. Took it back for another one and the replacement made just as much noise as the first one. 
took it back and paid the different for a roscoe 20. Million times more solid bike. Kid loves the shifting.. can climb, pedal through weeds. So happy.. and dad is too. Well worth the difference in price. Appreciate my LBS for being so willing to work things out.


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## Chi81 (8 mo ago)

Has anyone used a smaller tire for their treks? I was thinking 2.6 or smaller, but want to avoid potential pedal strike. 

and as an FYI, we did mount the Suntour XCT jr suspension fork. my son def has more control of the bike, but the fork is significantly heavier than the stock one. Right now, we put the stock one back because he’s been hitting pump tracks and working on jumps. The suspension fork is just too heavy for him to pull up.


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## 778lai (11 mo ago)

778lai said:


> WOW, this is a great post. Thank you for sharing.
> I am a new member here and just got into MTB last summer with kids. We are picking up his new Roscoe this Sunday and this post saves me lots of time. (more time to ride with my kids)
> Does anybody replace the front fork to air suspension fork yet?


It has been eight months since we got this Roscoe. I did a few upgrades to the bike, fork, brakes, and handlebar within the first few weeks. Why I choose this fork because this is probably the lightest fork out there and it is worth every penny. In the beginning, he can feel the extra weight from the fork but in no time he got used to it.

The Brood Bike Co. Eldorado Fork.
Magura MT4 Brakes
SDG Slater Handlebar & Jr. Grips
Ride Alpha Kids Pedal 
Kenda Tire 20 X 2.6


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## Duct_Taper (1 mo ago)

New member here, wanted to jump in and say this thread was super helpful for me in deciding on my son's Roscoe 20... no huge mods so far, just hydraulic brakes (Shimano MT200) and tires (currently on Crown Gem 2.6, also got some Specialized Big Roller 2.8s on clearance to try out).

My main point to contribute was for anyone looking to get rid of the crunchy, unsealed factory BB - the original spec is a 73mm x 131mm, which is nearly impossible to find. I did some measuring and suspected you could get away with something shorter, and realized I had a random 73x124.5mm with sealed cartridge bearings kicking around, so I figured I'd give that a shot with the factory crank. Worked great, and now the bike has a silky smooth cartridge BB for zero cost (since I had the BB in the parts bin), plus the chainline is moved in a bit to favour the higher torque climbing gears and the Q factor is reduced a bit as well. Tightest clearance is between the chainstay and the crank inner guard, but there still looks to be ~3mm clearance so I'm not concerned.

Anyway, TL;DR a 73x124.5mm BB works with the factory crank (mine is a Feimin brand, others are probably the same measurements but YMMV).


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