isitafox Posted May 9, 2011 Report Share Posted May 9, 2011 Right I'm after a few opinions and maybe alternative suggestions from those of you who have kids who ride, those who have kids who'd like to ride and bike manufacturers/retailers. My son is 3 yrs old and loves riding his bike and coming out with me. When he does come out with me he enjoys trying to ride up and down large steps/kerbs and sometimes over small rocks here and there which he started doing on his balance bike as it had good, err, BB clearance?! Now he's riding a Specialized Hotrock (pictured below) which is basically a 16" BMX type of bike, mainly as it was the best thing available at the time in his size and at a very reasonable price. To the point, with the bike being BMX style and a kids bike it has 1 piece cranks, high rise bmx bars and a large front chainring with big plastic chainguard. As he still wants to come out with me and ride up and down steps he usually resorts to going on his old bike instead as it's better suited for the job so I thought I'd look into modding his Spesh to make life easier for him. I already plan on getting some new wheels, as the rear has a coaster brake which is a pain in the arse, and fitting a rear caliper brake to match the front so while I'm at it should I make the crank area a bit more trials friendly? I've seen Truvativ do an adaptor from American style 1pc crank setup to fit standard Euro 3pc cranks, I could fit that along with some 140mm Monty cranks and a suitable freewheel and sprocket setup and maybe a bash? My only concern would be the gearing and losing general rideability though he still uses his feet when getting up big steps so could I use a large rear sprocket to retain a good gear ratio? And if I do all this could I change the forks for a set to run an 18" wheel like the Monty 205 to raise the front end and swap the BMX bars for some normal riser type or would that kill the geo?? Sorry for the massive post but I can't quite decide and buying a 205 new (2nd hand ones are like hens teeth) or even buying the frame and building it on a budget would cost far more than the above, plus at the end of the day if he changes his mind I can always return his to standard spec. My brain hurts Quote Link to comment Share on other sites More sharing options...
roadflasj Posted May 11, 2011 Report Share Posted May 11, 2011 Hi Isitafox, Trials specific bikes for kids are very difficult to nail down as every child has there own riding style, just like their respective parents. I think a drivetrain is overkill for such young kids as they usually don't have the power, technique or speed to use it properly. I decided to build a modified department store bike to keep things simple/inexpensive as this helps build good balance and rolling skill before introducing pedaling/drivetrain use. As you mentioned previously, BB and crank clearance is at a premium especially with low bikes paired with short little legs. Good luck with your build. I think its the best thing a parent can do for their kids is to learn early and get excited about the sport. I know my 3 year old is trials crazy already. Cheers Just to give you a few idea on possible specs: Frame/Fork: All brake, seat clamp and chain cover mounts cut off, dropouts shortened, shaved and speed holes drilled. Painted gloss black with thunderbolt graphic taped off and given smoky finish. Weird thing in the BB is a silver balloon to keep out water/mud. Wheels: Internal coaster brake cut out and rims drilled w/chrome tape. Running about 5 psi until he gets used to new higher set up. Bar/Stem: Used a quill/threadless converter to put on my old Titec set up with the bars cut to 16.5". Engraved name in top cap and sanded to soften edges. Seat/Post: Refinished with a leather purse from a thrift store. Stock welded seat clamp cut off and machined a low profile aluminum bmx unit to fit. Measurements: Wheelbase - 568mm Chainstay - 216mm (8.5") BB height - 189mm (7.5") BB Rise - +40mm 1 Quote Link to comment Share on other sites More sharing options...
isitafox Posted May 12, 2011 Author Report Share Posted May 12, 2011 Cheers for the reply, he's already got a balance bike which looks just like the pics you've attached so pedals is the way to go. First job is to get some new wheels to ditch the hub brake and then I'll price up some shorter cranks so I can go FFW and lift the clearance a little whilst retaining some rideability! Quote Link to comment Share on other sites More sharing options...
thispartisrequired Posted May 12, 2011 Report Share Posted May 12, 2011 (edited) As the bike has the old 1pc crankset (the old BMX standard) why not get the smallest non nano drive front sprocket (i think halfords do a 22t or 24t salt one) and throw that on the front. Take the coaster apart (pads out/arm off etc), just as a temporary measure like, then get a new rear wheel Edited May 12, 2011 by thispartisrequired Quote Link to comment Share on other sites More sharing options...
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