parrothed

I have a question about the proper inflation for childrens bike tires. My son races in triathlons on a 650C road bike. He weighs around 88lbs(The bike including his training clincher wheels weighs around 19lbs) and has a training wheelset and a racing wheelset.

Question 1: The training set is aluminum clincher with tires rated to 100-145 PSI. I used to inflate them to 140 PSI, but have heard that is way too much for his weight so I lowered this down to close to the minimum listed PSI or around 105. Does this seem right / any thoughts suggestions?

Question 2: Also, I just got his racing wheelset. They are carbon and he has 19mm tubular tires that are rated up to 170 PSI (Conti competition black chilli tires). There is no minimum tire pressure listed for these. I have no idea what I should be inflating these to as I have heard that you should go higher with tubulars. Any thoughts/insight/suggestions would be appreciated.

I am a bike newbie that has just started to get into this because of my childrens sporting interests. They have started to get me hooked as well. Thanks in advance.

JonathanGennick 

Props for supporting your kids like that.

parrothed

Thanks. I spend a lot of time trying to cost effectively build a nice setup for him by utilizing our LBS/Amazon/Ebay/Craigslist. The tires and used carbon rims were a find on eBay that I have been looking for for over a year. Finally found the right deal, just cannot find good information on what pressure I should be using for tubulars for a 85-90lb 10 year old. Was hoping someone on here had a little insight. The carbon rims are about 10 years old, but with minimal wear.

JonathanGennick 

I wish I had enough experience on tubulars to offer good advice.

Generally speaking, I put enough air in my tires so as not to pinch flat. I aim more for the min possible than the highest possible.

You are racing though. So maybe there is some optimal trade off between pressure and speed.

CliffordK

There are quite a few discussions about tire pressure for adults. 19mm is pretty narrow, which is good for your needs.

Apparently there are two problems with too high of pressure. Less gripping on corners, and the bike tends to bounce too much, and looses energy with the bounces.

Here is a page/chart on tire inflation.
Problem Solvers | Optimal Bike Tire Pressure

When one goes to the spreadsheet...
https://docs.google.com/spreadsheet/...X3BMVGc#gid=20

And plugs in the numbers.
108 lbs total.
19mm tires

One comes up with:
56 psi front
88 psi rear

I was thinking more around 70 - 100 psi, so the low numbers were surprising, especially on the front.

It may also depend a bit on what the kid is doing with the bike. Mainly on roads... the lower pressure may be fine.
Lots of off-road, and bumps... Perhaps a little higher.

Homebrew01

70-80 psi