Help fitting my son's new (to him) bike
 

My son has been jonesing for a full suspension MTB for a long time, so for Christmas I secretly built him one up. He loves it, but I'm concerned I goofed and I think it's too small. Any input would be great.

He is 5'6" and rides a 17" hardtail MTB w/o issue. This Giant is a 16.5" frame (hence my thinking it'd fit). According to a fit guide I just found, he's right between a 16.5 & 18.5 frame.

http://i222.photobucket.com/albums/d...ale/photo1.jpg

http://i222.photobucket.com/albums/d...ale/photo4.jpg

http://i222.photobucket.com/albums/d...ale/photo3.jpg

http://i222.photobucket.com/albums/d...ale/photo2.jpg

He rode it around today (in the snow) and said it felt fine, but I'm concerned he's too far forward/low and once we hit the trails he'll go over the bars. We do ride some technical trails (uphill and down) but no big drops or jumps.

He really likes the flat bars I put on there, but I'm thinking a steeper stem and riser bars to bring him up about 2".

Buying a new frame/bike at this moment isn't really an option without selling this one (his Christmas gift). But feedback on how to better fit him - or if it actually looks ok and I'm just being paranoid.

Thanks!

No one?

Yup, In fact if you get the right stem, you're talking more like 3+ inches lift with riser bars. Also, the seatpost is too low. He doesn't have full extension so the situation with the bars is actually worse than shown.

At 5'8" I ride 17-18" frames. Your son should have no trouble on a 16.5. My 6' son, who has short legs for someone 6', also rides a 17" frame. However all four of our current bikes have riser bars and stems with lift.

Edit: I just looked at the last pic, do you actually have two spacers above the stem? If yes, that's a half inch right there for free.
2nd Edit: You didn't say what size the cranks are. I would not use anything shorter than 170, maybe even longer. He's still growing.

My first gut reaction from looking at the pics is that it is too small. Any possibility of procuring a larger frame and switching out the components? You could maybe try to make it fit him better as is, but I suspect he's only gonna get bigger in the next few years. Good Luck.

When I bought my mountain bike (hardtail) the guy in the shop said I should be on a 23" frame but I chose the 21". The reason was simple - the 23" didn't give me enough clearance over the top tube for comfort - if I'd jumped off the saddle in a hurry it could have spelled doom for my unborn children.

A full suspension bike has a lower top tube so I would expect a larger frame would work better. If your son is between 16.5" and 18.5", and he looks to be of an age where he's not fully grown, I'd have gone for the 18.5. That said, you mentioned the only option is to sell this one so the more obvious question is how to best fit it to him. To be honest I see lots of teenagers around my area riding bikes so many sizes too small it's just not funny, so it can be done!

If you can, raise the saddle. His knees are still bent at maximum extension (i.e. the pedal at the lowest position) so he's losing energy. You may be able to slide the saddle forward and backward as well - from what I can see I'd reckon it wants to go back a bit but obviously his comfort is more important than my best guess from a picture. Just make sure you tighten it back up properly (I say that because when I adjusted my saddle I didn't tighten it enough, so it slid all the way back when I needed it all the way forward).

Depending on where you bought the frame, if it's still in resaleable condition it might be worth approaching them to see if they will swap it out for a larger frame. If not you need to tweak what you've got, but before you put any miles on it (or any dirt, stonechips etc) you might be able to trade it for something your son can grow into.

What type of riding will your son be doing with this bike?

Too me it looks like the right size for next summer but probably not for 2012. Lucky kid !

get a bigger size, unless he has stopped growing.

It does look small, specifically his hands are too low and with not enough extension. Get a longer stem with higher rise and it should definitely help, not only for comfort but for handling ability. When he stops growing or gets way too big for the frame, switch it out for something that fits him better.

Small changes in geometry can make a huge difference. If selling the frame & getting another isn't an option, try what others have suggested--scoot the seat back, put the spacers above the stem below it to raise it up, get a longer stem & a riser bar, & see how that works.

It looks to me like y'all have quite some time before riding weather hits again, so you might ought to list the frame for sale on CL or ebay, & see if you can sell it & get a larger one. That would be the best option, as the frame does look too small (unless he's using it for DJ).

I appreciate the comments from everyone. To clarify a few things:

The bike / frame was bought on Craigslist, so there's no returning it to a store. It's a 2004 Giant Warp DS1 that I got for $150. Seeing a good price I lost judgment and failed to check Giant's sizing chart. OPPS 1 - DAD 0 Pulling off the broken/not usable parts I ended up putting another $150 into it for a grand build total of $300.

I think we'll try raised handlebars and a taller seatpost (both of which I have on hand).

I'm fine fitting him on roadbikes (which he races) but when it comes to MTBs I'm not as confident. And then add to it trying to do something on a tight budget = mistakes.

All in all, I guess I'm trying to get reassurance that I'm not going to get my son killed the first time we actually hit the trails. :eek:

I don't even think it looks that small. How long are the rides? Is he a sit and spin kind of guy or a stand and pump rider? If he sits a lot or does a lot of really long rides, you can probably raise the saddle and get a longer stem. If he spends a lot of time out of the saddle...I don't think it looks that bad. I'd probably put on riser bars and move the stem above the spacers, but that would be it. He probably could ride the next size up comfortably, but it's not like he can't also ride this bike. He probably falls between sizes and could ride either one. If he goes over the bars on that bike, it won't be because it's too small.

We usually go out for a couple hours at a time. As it's almost 50/50 uphill and down. He prefers to stand and pump, but I usually fuss at him to sit and spin (conditioning for road racing). We'll probably head out in a few days (supposed to finally get over 40 degrees).

This is one of our favourite places to ride http://trails.mtbr.com/cat/united-st...0_4578crx.aspx .