XXLHardrock

I have 3 daughters, 8, 10 & 12. They are very good swimmers and make it to provincials every year. Now they want to do Kid's triathlons and I just don't have a lot of cash to pour into this.
I'd like to do everything I can to promote fitness in their lives so I want to make it happen for them if I can. I'm not an athlete and haven't really got a grasp on all of this. So...

Swimming is covered.
Running doesn't seem like much of an investment, equipment wise.
Cycling, on the other hand, has me seeing $$$$$$$.
Do they need shoes, pedals and proper road bikes at this age?

MRT2

How long is the bike riding part of a kid's triathlon?

gazelle5333

I would say not right away. While a basic kids mountain bike isnt ideal, they can get away with it. Having to mess with shoes off and on, if not practiced enough can take time away from the overall and without worrying about that, the time lost by having the mountain bike that they probably already ride is just cancelled out by the time lost in transition if they had to swap everything. I dont think a few seconds is going to matter, but thats my opinion

Though if they start winning races and getting to the higher levels of competition you are SOL and will need to get the proper gear

mstateglfr 

A bike with gearing and a rigid frame will work.
No suspension. No knobby tires.

Your girls will do just fine if they like to ride. Making the swap from knobby tires to smooth isn't much- there are Kenda tires in 20" for $12 on Amazon all the time.
Used Specialized Hardrock, Hotrock, or other rigid mtb frames are great, they are used all the time around where I am for kids tris. Another option is the Fuji Ace 24" and 650. Those two models are made for kids and are cheaper than most all other kids road bikes. My brother in law picked up a 650 size a couple months ago for $150 for his 10yo. Its only 6 years old and works great. Craigslist craigslist craigslist. Kids are going to outgrow the bikes, no need to buy new if good used options exist.

https://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1 - good cheap smooth tire to replace 20" knobby MTB tires.

mel2012

My 6-year old did a kid's triathlon last year, and I was surprised to see that about 90% of the kids in the 24"+ bike size had bona fide road bikes, either flat bar or drop bars, many of them with clip-in pedals, etc. This was for a 4-mile bike ride, so it seemed like a bit of overkill. This particular race was a 4 mile ride, 1 mile run, so it seems like any incremental difference in speed between a real road bike and a slightly heavier bike could easily be made up by faster speeds on the running part. I'd try to find the lightest used bike you can find and put road bike tires on it.

I was talking to one of the other dads with older kids and he said he found all of his daughters' road bikes used on Craigslist.