So, I have my 56 road bike in the classifieds. I’m 5’11.5.

Junior likes to do 4-5 Triathlons a year. Mrs K has said, why don’t you keep it for him as a Triathlon bike?. He’s 14 and 5’5 currently.

Will he fit? You see kids on too large a bike all the time, what could go wrong?! Have I missed something without trying to overthink her logic?

My kids spent a lot of time racing on bike they were going to grow into. Sounds like he is not too far off now.
The only question that springs to mind is – is your plan to put clip on aero bars on? Will they be too far forward?

There is a change coming for British cycling (so not triathlons) where they have removed the need for junior gears – which simplifies what you want to do.

what could go wrong

Clems to stem interface possible.*

Clems to top tube interface highly likely.**

Are you bothered about bloodline continuation? 😳

* experience of this as a kid prior to going over bars.
** experience of this as a kid, using feet as brakes, real brakes didn’t work, to stop me going under a bus.

I still wince now and my eyes are welling up 😢😢😢

Do you apply the same logic to shoes?

Mine road a beautiful Trek 3400 which was basically 2/3 scale with 105 groupset and 650C wheels. When it was stolen, it was replaced by an XS Giant Defy and an XS Giant hardtail (both now enjoyed by smaller ladies, since Son2 is six foot). Buy a cheap Defy/TCR frame and move the parts over. Will cost about £150.

XS and S frames and bikes are hard to find. You should get away with a small, and I’d probably look for a TCR, for triathlon a smaller bike will be better with aero extensions. A 56 frame will be far too big for someone 5’5″. The 700c wheel size is not a big problem. But that Trek just looked so RIGHT.

Are the 14 year old Trust on road or grass? My boy is 12 he uses Mrs Anagallis gravel bike

30mm stem, 165mm cranks and it would probably work.

Yeah, I’d get a smaller frame and transplant the parts (assuming you can get one that uses same standards).  Then keep the frame ’til he grows more

Might want shorter cranks but would probably be “OK” depending on what yours are

Wiggle flogging brand-x road framesets (inc 50, 52) for £120

Having been a kid who had a road bike as a present that I would grow into what I can say from experience if it doesn’t make a great bike to ride until you have grown into it (around 3 years later in my case)

Are the 14 year old Trust on road or grass? My boy is 12 he uses Mrs Anagallis gravel bike

Similar, he uses his MTB currently, this was about keeping the bike until he needs to use it, rather than buying another. Hence, I should be less worried about the sizing perhaps.

I’ve just a bee in my bonnet about the price of bikes vs the speed the kids grow out of them, having been lucky enough to recycle all the bikes to his younger sister, it saves money.

Why don’t you borrow a 60 or 62 for a few weeks to see how it feels?

Just bear in mind that in Triathlon U16 has gear restrictions, can you achieve those with the set up on the bike?

622mm wheels (25c tyres) use 52T chainring and 16t sprocket for U16’s/Youth*

Will he fit? You see kids on too large a bike all the time, what could go wrong?! Have I missed something without trying to overthink her logic?

Handling could well be terrible along with the ability to turn corners, saying that it’s triathlon so cornering with finesse and ability isn’t something that many other in the field will possess 😀

I have a 53cm road bike I need to get rid of. It’s not modern but nor will it be expensive, but it is quite quick. DM me.

this was about keeping the bike until he needs to use it, rather than buying another. Hence, I should be less worried about the sizing perhaps.

I’ve just a bee in my bonnet about the price of bikes vs the speed the kids grow out of them, having been lucky enough to recycle all the bikes to his younger sister, it saves money.

What are the odds of him growing another 4~5″ in the next 12-18 months?

I’m 5’10” and ride a 56 with a shorter stem, inline post and 170mm crank, a lot of the sizing charts show me at the bottom of the recommended height range for a 56 and top of the height range for 54, so if he’s going to shoot up to 5’9″+ in the next 12-18 months it’s possibly worth hanging on to it.

Also what’s the specific bike? if it’s a TCR or something with sensible stand over that helps, if the TT is a bit high and he’s going to struggle to throw a leg over it maybe look at What will it fetch used Vs the cost of potentially buying him a similar bike again in a year or two?

I see the quandary, I’d be prepared to change stem and/or Crank and shunt the saddle drown/forwards possibly to get a bike fitting my kids, but they’ve got to be able to get on/off comfortably. nothing puts a kid off riding a bike like it not being easy enough to get mount or dismount.

I have spent a lot of time (and money to be honest) sorting bikes to fit kids at all sort of different sizes. Go to any under 12 road race and you’ll see an array of flipped seatposts, negative stems, narrow bars and short cranks. It’s quite a mazing what you can sensibly get to fit, but it’s only worth doing if the bike is worth doing it for (vs just getting a bike that fits).

Shorter cranks make the biggest difference – can completely change the saddle to bar drop possible, and on a recent MTB build switching to 165mm cranks made the difference between being able to fit a dropper or not. Negative angle stems are great for getting a better position on the road or track (track bike specialists like Velodromeshop are good for those). Seat posts you can flip to have a forward offset are great (and probably just right for a tri bike) – also helps avoid fitting to short a stem that can screw up handling a bit.

So if it’s a nice enough bike to go to the effort on then it should be perfectly doable.