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  1. #1
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    Trek MT220 24" mod build

    I last built-up a 20" Novara frame into a bike for my daughter, Novara Pixie 20" project
    She is turning 8 yrs old this week and ready for a 24" bike so I have slowly been working on building up her next bike.

    Trek MT220 24" mod build-img_4899.jpgTrek MT220 24" mod build-img_4900.jpgTrek MT220 24" mod build-img_4901.jpg

    My philosophy is to keep it light as possible without splurging on any really expensive parts. I found the Trek MT220 frame at a bike co-op for free, it was an donated frame in great shape, undamaged but had been stripped of all parts and the co-op didnt want to bother with sourcing all the components to put it back together as a complete bike. The Trek frame is made with hydro-formed aluminum (quasi-rectanglular downtube) and weighted 1420gr, almost 1 lbd lighter than another Novara 24" frame I had previously sourced for this project. Most expensive cash outlay I made on the project was for a set of new Schwalbe Rocket Ron 24" folding bead tires, 440gr each and very supple. I re-used the Alex singlewall 36 hole rims from the Novara, 404gr and 420gr each and re-laced them to some much better quality (& quick release) non-disk hubs as I am staying with V-brakes to keep weight down. The rear hub was an older shimano with a 7-speed cassette body. THe hub itself was not particularly light (cheap steel cassette body) but the shorter 7-speed cassette helps to keep the spoke dish more even, makes for a good wheel build geometry. I laced the rear with 12 crossed spokes on the drive side and 6 radial non-drive spokes, producing a 880gr rear wheel. Front was built as a 12-spoke radial wheel using just every 3rd spoke hole. 12-spoke front makes for a completely symmetric wheel with the spokes correctly oriented in the angled rim holes to each side. I have ridden the wheels around under my own 200lbd weight and they hold up fine so I feel confident they will be reliable for my much lighter daughter as the 400gr rims are complete overkill for her weight. I used a lightweight (253gr) XT 9-speed 32-11 cassette with aluminum carrier that I shortened to 8 cogs (32-12) in order to fit on the 7-speed body. Also used a XT rear derailleur and a deore push shifter that I had all sourced cheap from a swap meet.
    I found a late 90's manitou spyder 26" fork at the co-op that was fairly easy to shorten into a 24" fork by carving up the fork tip ends, see 24" air fork . The fork has aluminum steer tube & stachions and it uses combine coil springs and elastomers and had a simple oil-bath dampener that is easy to service and tune. I re-worked the internals to provide 70mm of travel and eliminated the spring & elastomers from one side to soften the compression for my daughter. Once shortened and reworked, the spyder fork weighted 1300gr, a very nice weight savings compared to the currently available 24" forks (RST first air, Spinner, suntour). With the fork sliders shortened, the rim brakes work perfect on the original bosses and the A-C height is nice and low so the front end is not jacked up excessively.
    The crank is a 5-bolt Bulletproof brand 145mm length that I setup 1x with an outer bashguard and a 34t inner ring (581gr crank weight) on a reasonably light (270gr) shimano UN71 bottom bracket.
    Despite the good standover clearance, the frame has a somewhat long 51cm effective top-tube length so I bought a new shorty 5cm stem and found some swept-back riser bars that help keep the seat-to-bar extension reasonably comfortable for my daughter.
    The V-brakes are generic caliper arms with small tektro levers, they work great and provide a light touch with plenty of braking force and control.

    I have spent perhaps $250 altogether on the build. Most of thw parts were sourced lightly used but I did need to get a new chain, derailleur hanger, tires, cables, stem, and a cheap kids saddle ( Bell saddle from wal-mart!). As it stands now, the bike weighs 20.5 lbs ready to ride, just above my goal of a 20lbd bike. The frame, fork, tires, wheels and crank are all fairly lightweight parts that I want to keep. The inner-tubes are fairly heavy at 150gr each so I am thinking I can drop some more rotational weight by going to a tubeless setup. I didn't use any carbon fiber parts for the stem, bars or seatpost. I could likely drop another 150gr by using a lighter rear hub with alloy cassette but that would also involve re-building the wheel (again) and I like the 8 of 9 on 7 cassette & shifting.
    My daughters birthday is this weekend so I plan to give her the bike then, have her test ride it a bit if winter conditions allow but hopefully I can re-work it further to drop a bit more weight before springtime riding really starts!

  2. #2
    Havok
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    Very nice work. That's really cool that you built that for only $250

  3. #3
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    Awesome build! Thanks for recording the steps and the weights. I have the identical MT220 that I picked up cheap. Same year and everything. I am very interested in doing a similar build. I want to utilize as many stock parts as possible to keep the cost down, but get the weight down as economically as possible. I have another year or so before my daughter grows into her bike as she is small for her age. She is riding a 20" Hotrock with 7 speed Megarange cassette and alivio shifter.

    Your wheels are really interesting. I have a question for you. Could I go through the wheel and remove all the spokes except the ones that you left without having to totally rebuild the wheel? If I actually buy new hubs, I will have a bunch more questions for you. I am interested in knowing the weights of the stock Trek rims.

    I would have never thought of cutting the bottom off of a fork. That was a slick mod. Looking at old models currently available on ebay, I don't see many that are designed in a way that they could be cut off like that.

    Again, congrats. Very cool. I thought about stripping my daughters Trek down to aluminum and then putting some cool graphics on it. Cheap and easy to dress it up, otherwise I will find a cheap, basic powder coater.

  4. #4
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    Sorry, I dont have trek rims that came stock on this frame to get weight, I had to re-use rims harvested from another bike. It does look however like trek used 32 hole rims instead of 36 hole, so exact same 12 and 18 spoke lacing patterns cannot be replicated on 32 spoke rims. Best bet for for a low spoke count pattern on 32 hole rims/hubs is to drop 1/2 the spokes, so go to 16 spokes each front/rear, see recent thread for further example;
    Kid specific Wheel Build for 40lb rider NEED HELP

    I dont think you can simply remove 1/2 the spoke from an existing wheel however, the new pattern requires that the remaining spokes to be located in different rim/hub holes in order to get an even lacing pattern. There are actually two slightly different pattern choices that can be used for a 16 spoke wheel. You can lace all the spokes into every-other rim hole fore equal spacing between spokes but this requires that the spokes for one side to be put into rim holes that are angled to the opposite side. This is not a huge problem but can be remidied on a singlewall non-eyelett rim easily enough by using a drill to elongate those rim holes toward the side being used for better spoke alignment.
    Other option as in the thread above is to use paired spoke spacing so that original rim holes face correct direction. See Tig's excellent paired spoke lacing tutorial at; FAQLoad - Paired spoke lacing

  5. #5
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    Nice bike! Would love to finf a frame like that.
    The Trek MT220Ihave is an older one. It's black with gray flames. It has a 1" steerer, which might make it more difficult to find a short stem for it. It's got that funky, heavy adjustable height stem on it now. Gonna get it rideable and go from there.

  6. #6
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    Finding a decent short 1" quill stem shouldn't be too much trouble. Having the ability to easily adjust stem height as kid grows is very convenient for a kids bike. Check ebay but beware of BMX stems that use small diameter 21.1mm quill shaft. I used an old road stem on our 20" bike and shimmed the 26.0 bar clamp down to 25.5 for MTB bars) using strip of beer can). A bit heavier and more expensive solution is that you can also use a quill adapter Dimension Quill Stem Adaptor > Components > Handlebars and Stems > Stems | Jenson USA Online Bike Shop to be able to use 1-1/8" threadless stems, this might make sense of you already have a short threadless stem.

  7. #7
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    there is a RECALL on the TREK MT220.. you may wish to look it up

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  9. #9
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    Quote Originally Posted by Black Pearl View Post
    there is a RECALL on the TREK MT220.. you may wish to look it up
    THanks, looks like the recall was specific to the girls model which the top tube was not connected to the headtube. The frame I built was a boy's model, standard top-tube so not recalled. http://www.trekbikes.com/pdf/recalls...220_recall.pdf

  10. #10
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    Cool, just saw it and thought you might want to check it out.

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