Lewis’s bike update – new tyres

Kids bike tyres can be pretty awful with poor tread patterns, hard rubber compounds and hefty weights.  There are very few 507 etro tyres that you might consider putting on a kids mountain bike for serious off roading.

The popular choice is schwalbe’s rocket ron in 24×2.1 flavour weighing in at ~445g. depending on the OE tyre & tube  you could save anything from 1-2lb by mounting these tyres tubeless.  The easiest way is to use DT swiss valves and gorilla tape with stans sealant.  The downside to this weight saving is thin side walls, lack of grip and tread that gets damaged easily

Tread damage on rocket ron

 

As Lewis develops his skill the tyres were starting to show weakness and I decided to fit rubber more suited to the trails he is now ridding.  Maxxis make a 24 inch version of their highly respected high roller but these wouldn’t fit lewis’s bike and they weigh close to 1100g.  Another alternative is the 24×2.35 Kenda kinetics which comes OE fitment on the 24 inch Transition Ripcord but I’m not sure they would have fitted the RST fork.

I eventually choose the relatively new 24×2.0 Hutchinson toro hardskin but as they are not being imported into the UK I had to source a pair from France (£20 each incl postage).  They come in 200g heavier than the RR but are wire beaded and have a stronger sidewall.  The toro is significantly more aggressive but still has good rolling resistance.

Hutchinson toro left – Rocket ron right

It was a slight effort to set the front tyre tubeless as there was a kink in the bead from being squashed in the packaging but a couple of days with a tube, lashings of fairy and my ghetto compressor got it inflated.

Feed back from Lewis is positive with more grip from the toro easily present over the RR.  Unless your Kid is cycling on fairly smooth hardpack I wouldn’t bother going with the rons.  Lewis doesn’t have the weight to push the tread into the ground and the low tyre pressure required for more grip either burps the tyre or would burst the tube.

 

 

Kids Cranks

Crank length should be considered when buying a child’s bike as this can have a major effect on cycling. The Carrera blast came spec’d with 165mm cranks which for Lewis was far too long (I use 165mm XT’s). This was noticeable as he would bob when spinning under light load. Long cranks also affect saddle height which in turn affects body position over the bars. There are a number of pages on the internet to provide the information about leg and crank length to what is suitable. I recommend reading this page on bike dynamics and this one on highpath.net

The Carrera comes with a 22/32/42 triple crank with a 12-28 7sp cassette and is fitted with a no-name cone and cup bottom bracket – 68 X 122.5 square tapper. I fitted a SRAM 12-32 cassette at the same time as the new crank to give Lewis lower gearing.

Kids suspension forks

For adult mountain bikes, its the norm for the bike to come supplied with a suspension fork. At the cheap BSO end of the market these are often basic coil sprung forks with little or no damping. Should you wish to upgrade there are many forks the rider can choose from. However, for kids bikes (24) there is very little in the way of choice if you want a decent fork. There are 4 current air forks that are available that you could consider. These are 1 1/8 steerer size