Sjtaylor

I have a 14 year old great nephew who is excited about bike touring. We’ve done a couple of organized rides together and we’re planning our first short bike tour to see how it goes. Great nephew has a mountain bike and a couple of family bikes but nothing suitable for making miles with gear. Today I CLed an early 2000s Trek 520 for him. The angled top tube and dropped seat stays fooled me and the frame is larger than I had guessed. The frame measures 580mm and he is a wirery 5’4” and hopefully growing (his dad is 6’4”).

Is it feasible to size down that frame until he grows into it? I have $300 into the 520 so far and I’ll purchase parts to refresh the consumables. He’s really excited that we’re meeting up to overhaul his new dropbar bike but I worry I may have mistakenly purchased a bike that won’t fit him.

any thoughts? Thanks.

BTW the proposed bike tour includes and ferry boat ride and a cycle across the Golden Gate Bridge.

Ross520

I'm sure you could make it work, but it will definitely be sub-optimal. I'm your nephew's father's height and I ride a 58 (could go 60 but I like a good saddle-bar drop).

CliffordK

How big of shoes does your nephew wear?

My 14 year old nephew wears about size 14 or 15 shoes... hopefully he'll grow into those feet soon.

Drop the seat post down to say 1", and see if the kid can ride the bike.

Slam the seat?

You can also hunt for a bit better bike/frame that you could build up. Keep the Trek frame. The kid may well be ready for it in 2 or 3 years, and simply swap the parts over.

If you hunt, you may find an old chromoly double butted hybrid that would make a nice touring frame. Or, find another Trek 520.

hermanchauw

If he can stand over it, you can do anything.

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Gresp15C

My spouse has a hybrid with a fairly small frame. Both kids rode it while they were in those in-between years -- too big for a kids bike, but not at their adult stature yet. I wouldn't pay money for a new bike that's going to be outgrown.

mstateglfr 

Does the seatpost actually measure 580mm even with the sloping top tube? If so, then its huge and way too big. If its an effective fit of 580mm, then its still too big, but perhaps you can kludge together a fit through a shorter stem and short reach bars.

c_m_shooter

Kids are flexible. Buy a bike too big and let him grow into it. When I got my first "ten speed" I had the saddle all the way down to just reach the pedals. I think I was in 3rd or 4th grade. Standover was never a concern, we rode horses, and swung up on bikes basically the same way. He will grow that foot of height in the next year or so.

Retro Grouch 

How is the seat to handlebar reach?

I think that using seat tube length as the go-to measurement for sizing bicycles is stupid. Saddle height is the easiest dimension on a bicycle to adjust. Think about if he'd look more in control if he had a shorter stem and save the longer OE stem for next year.

RiceAWay

Absolutely not. He needs a 54 cm frame. Getting to the Golden Gate has lots of climbing for new riders of road bikes and the cross winds - especially at the towers need extreme care since there is always some brainless fool who thinks that riding fast makes him a big man. If your nephew can climb from using his MTB, the ride up the north end to Lands End is pretty exciting. While the bottom is pretty steep it lets up after about a quarter of a mile. Though the drop down the other side is 18% and you have to be cautious.

If his father is 6'4" keep the 58 around since he will be able to ride that. I'm 6'4" and my Colnago XL is a 58.