# Our MT 220 mods; I am very happy with the lighter bike



## jgiedt (Jun 7, 2011)

Three weeks ago I began lurking here to help find the best value for my 10 year old son's first geared bike. I found a Trek MT220 on Craig's list that was in decent condition and did my best to lighten it and make it fit him better. It is a big jump from an 18" single speed BMX style to this 24" geared mountain bike, so I wanted to give him an equipment edge without breaking the bank.















My first job was to create a 1 x 7 transmission. I drilled out the big and little ring off the stock crank and removed the front derailleur. The crank had dual pedal holes. Since he is also pretty small and should probably be on a 130mm crank arm, I went ahead and utilized the inner pedal holes and cut off the end of the crank. This gives him 128mm arm length and more ground clearance.

It worked well for him, but he was losing the chain often. After trying to build a chain retention device to hold the chain to the top of the ring, I settled with reattaching the big ring. First I ground down the teeth making it a bash ring. It is just bolted together now, but I hope to find some proper chain ring bolts at the local bike store since I had already drilled out the stock rivets. On the inside, I utilized an old front derailleur I had laying around, using it similar to a Third Eye type device. It is all working well now, but this crank will certainly be replaced with a lighter one once he grows in size and skill.









I picked up a new 7 speed freewheel with a 34 tooth cog to help him with climbing since he has no small ring up front. This has proved to be very useful, giving a 1:1 ratio that gets him up most hills we've encountered so far.

I slammed the stem and twisted the handlebars towards the seat as much as I could. Today, a 30mm 7° stem arrived from Hong Kong, an inexpensive ebay purchase, saving even more weight from stock and providing a better fit.

My biggest ebay score was finding an old Terry bikes 24" rigid fork with brake bosses. I spent a lot of time looking at options, rigid or modifying a lighter 26" suspension fork. I really wanted rigid, figuring this would lighten the bike the most. That stock fork is a hoss! The problem is that 24" rigid forks with brake bosses are pretty rare. I was thrilled to find the rigid worked perfectly and had just the right amount of steer tube for my situation. This saved several pounds.









I had an old carbon seat post laying around and slapped that in. A seat rail is bent, but I'll just grab something at a local Walmart or Target to replace it soon.

Going with Bontrager XR1 tires, currently available at $24/each from Trek, saved another 1.6 lbs. of important rotational weight. I'll keep the wheels as-is for now, but know that is an area that can be improved if ever needed.

Right now the bike is weighing in at somewhere between 21-22 lbs. This is significantly lighter than stock and makes his transition into a bigger bike much easier for him. I couldn't be more pleased with the way this has worked out.

Thanks to all who helped with sizing questions or made valuable posts in the past that guided me on this project. I found this forum a huge help in picking the right bike and wading through options.


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## DucatiRider (Oct 1, 2014)

Very cool project! I bought an MT200 for my son and am looking to change a lot of the same things. His is already a 1 x 7 with a rigid (but heavy) fork.

Is that a new bar? Do you have a link to the stem? How did you determine the stem length/specs?


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## jgiedt (Jun 7, 2011)

The bars are stock. The stem was just one of the smallest I could find. There were certainly some others to choose from, but this one looked good enough:

Bicycle Stem 7 Degree 32 x 25 4mm 31 8mm MTB Bike Cycling Road Bike BMX | eBay

It comes in colors and the two main handlebar sizes. 'Hope that helps. Make sure you have a 1 1/8 threadless fork and check what size your handlebars are.

Good luck with your bike!

-jg


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## DucatiRider (Oct 1, 2014)

Thanks!

The OEM fork is threaded but I can get a quill adapter from ebay for lack of a better option.


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## Fargo1 (Oct 19, 2012)

Very nice. I too prefer a rigid fork for early learners. They are very hard to find. I recently purchased a raleigh Scout because it has a rigid fork. Now I am trying to decide if I build the Scout or look for a better bike and swap the fork. I paid $105 for the Scout, so its not a cheap fork if thats all I use on it.


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## melchionda (Sep 25, 2012)

Very cool project and nice results. Looks totally Legit! 
I'm doing the same thing for my son's MT60 and so I'm dealing with similar parts.

The only other changes that I would recommend you look into are:

-Change out the crankset - IF its the same crankset that came on our MT60 then its really heavy. Take off the left side crank arm and you'll be surprised at how unnecessarily heavy it is.

- Get a Tioga Spider Tec Seat. Cooperdrummond on this forum recommended that seat to me and we are pretty happy with it. ITs light and cheap.

I also changed out our rear derailleur because we wanted to go with trigger shifters, however going with an XT rear derailleur didn't save much weight compared to the plastic SRAM rear derailleur, so no need to rush into that.

Nice work!


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## softbatch (Aug 19, 2014)

Do you know the weight of the Bontrager XR1 24s?

Edit: Nevermind Bontrager's site lists them at 482g and 554g, 60 and 30 TPI respectively.


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## Fargo1 (Oct 19, 2012)

softbatch said:


> Do you know the weight of the Bontrager XR1 24s?
> 
> Edit: Nevermind Bontrager's site lists them at 482g and 554g, 60 and 30 TPI respectively.


Just for comparison, because I was looking at tires earlier today, the Schwable Rocket Ron that I see put on a lot of 24s weighs in at 445 g. So that Bontrager is a pretty light tire.


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## jgiedt (Jun 7, 2011)

Looking into Tioga Spider Tec Seat. Honestly, I found it so hard to shop for a kids saddle online that I just gave up. Good to have some direction.

On the tires, I did look at the Rocket Ron too, but hard to beat the price the Bontragers are going for right now. It got the job done on low dollar budget I'm sticking to.

Thanks!


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## Fargo1 (Oct 19, 2012)

Where did you get the Bontragers from? Which did you get and how much are they?


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## indianadave (Apr 27, 2010)

I did the same thing to the rings on my daughters 24" Gary Fisher. The outer ring got mangled, so I drilled out the rivets, intending to leave it off, but ended up grinding the teeth off, and putting it back on as a bash guard also.
Check out my daughters 24" Mt220 for some more ideas... particularly running half the spokes and cheap QR hubs.
Her bike is 24lbs with the Marin suspension fork... Couldn't go rigid, as she insisted on a "grown up" bike with front shocks.
Hey. Gotta make her happy if she's gonna ride with me.
I am thinking about one of those Tioga spider seats... Wish I knew someone local who had one for her to try out.
http://forums.mtbr.com/families-riding-kids/trek-mt220-goodwill-find-build-mt-8-year-old-daughter-907008.html


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## jgiedt (Jun 7, 2011)

I've read that post a couple times Indianadave. Thanks! Good stuff. As my son proves he is interested, I'll certainly look at a lighter wheel build, going to cassette and 8 speed, decent crank and all. Right now he has more than enough to get his feet wet. With my personality, I could go and never stop on this project! :-]

For Fargo1, I got the Bontragers direct from Trek: 
Bontrager XR1 Comp Tire - Trek Bicycle Superstore


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## GrayJay (May 16, 2011)

Fargo1 said:


> Where did you get the Bontragers from? Which did you get and how much are they?


You can get them online directly from Trek at
Bontrager: XR1 Kids' (Model #11456) or try another LBS or web shop

The awsome schwalbe rocket rons are NLA, these XR1 are probably best bet for a lightweight 24" tire, they are just a bit narrow at 1.85".

Incase anyone has missed it; the 20 pound, front suspension equipped, limited budget MT220 I built for my daughter is detailed at; http://forums.mtbr.com/families-riding-kids/trek-mt220-24-mod-build-894279.html


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