Correct crank length is importan; it will help your son pedal properly. A good guide is about 21% of inner leg length (crotch to floor). Whem my son was smaller we had probably about ten pairs of cranks cut down to suit him - he had both road and track bikes so always needed at least two pairs. I would go with Mark's suggestion of cut-down MTB bars for him at this age - by about 8 he will be ready to handle drop bars. Where I would disagree with Mark is over a gear - I think it is important that they learn how to use a gear properly from the start. The Shimano auto-D gear is notorious for encouraging a slow cadence which is exactly the opposite of what you want. A 5spd indexed gear would probably be ideal - if necessary you could take the outermost sprocket off a 5spd freewheel and turn into a 4spd one and just use 4 of the clicks. A 5spd shifter can certainly be found secondhand on Ebay together with a suitable rear mech. Gear low as shorter cranks reduce the leverage at the front end of the transmission. A 36T will probably be all that's necessary. These minature Italian road bikes are nearly always well designed with a suitably low bottom bracket but are often not that well made - but that really does not matter until your child is more serious. With my son that came at about 7 (he rode his first Dutch 5-day stage race at 8) and now 9 years later he is still as enthusiastic about road racing as he was back then... This year he does two Dutch 6-day stage races as well as the Youth Paris-Roubaix in Belgium and the Junior Tour of Wales.
Hilary Stone, Bristol, England
> From: Mark Stonich <mark@bikesmithdesign.com>
> Date: Mon, 03 Apr 2006 09:21:47 -0500
> To: "Harrison Magun" <harrisonm@gmail.com>
> Cc: Classicrendezvous@bikelist.org
> Subject: Re: [CR]Question/Advice on Vintage Kids Bianchi
>
> At 4/2/2006 07:03 PM -0800, Harrison Magun wrote:
>> Hi, I just purchased a vintage kids bianchi for my 5 1/2 year old. It
>> reminded me of the fuji Junior I had as a kid, except this has campy, 20"
>> wheels, and is probably older.
>> Ebay listing 7229360821
>>
>> I'd like any general thoughts anyone might have, but here are specific
>> questions:
>
> We had a 38cm Gitane that our kids, and the kids of several friends,
> went through. Years later I sold it to a guy who had me build it up
> with light 451 wheels and a 5 speed freewheel.
>
>> - can I replace the cottered crank with a modern short square taper
>> single-speed/BMX crank (and of course the bb as well).
>
> Yes but they might be too long, I don't know of any under 135mm. I
> do shorten cranks, so if he needs something shorter let me know. I
> have some 140mm Bulletproofs.
>
>> If so, what size/length BB should i get?
>
> Correct BB length varies from crank to crank and with desired
> chainline. Till you decide on what rear setup you will be using and
> which crank, it's impossible to advise
>
>> - I have no idea of the condition of the hubs/rims/spokes.
>
> Looks like alloy rims. If someone upgraded the rims they may have
> also done the hubs. Due to the age, I'd wager it originally came
> with 500A steel rims (440-37) I'd guess the Stelvios are 451.
>
> If the front hub is OK just use it, even if it's steel. The fork
> is/was probably narrower than normal.
>
>> Could I have a
>> wheel built (alas, the only thing I don't do in a bike is build wheels) wit
>> h one of the shimano internal gear hubs and ditch the derailleur. Or fit a
>> modern
>
> Chain line will be awfully short for an 8/9 speed cassette.
>
> You will probably have to spread the rear triangle to even get a 5
> speed freewheel into it.
>
>> - Value. I paid $200 US. It seems worth it to me, but I have no objective
>> form of measurement,
>
> If this bike helps your son develop a taste for physical activity and
> adventure, you can't pay to much. In the '70s we rode with the Lake
> Country Cyclists, a group of about 50 families. We would do 3 day
> camping tours, staying in regional parks and doing about 35 miles a
> day, with kids as young as 6 riding their own bikes. AFAIK all of
> those kids turned out OK. On a nice day my son will still take a day
> off, to go riding with the old man.
>
>> - Anything else I should know?
>
> Kids are usually in the wrong gear. If you can find a Nexus Auto-D 4
> speed hub, it would be perfect.
>
> I don't think really young kids do well with dropped bars. I'd
> suggest cut down MTB bars, 5 speed grip shift and bar end handlebar
> extensions.
> If you disagree, I still have a set of 32cm GB bars with much less
> drop than those on the bike, and a set of NOS Weinnman "Junior" brake levers.
>
>
> Mark Stonich;
> Minneapolis Minnesota
> http://mnhpva.org
> http://bikesmithdesign.com