Are all square taper bottom brackets created equally?

[SmileyBoots]

My other half (or should that be quarter?) ain't very tall.

I have a Dahon Vitesse which adjusts fine for her but with 170mm cranks she struggles to stay seated.

I've found the Pinnacle Kids Bike Chainset at Evans Cycles and was wondering if it would fit the Dahon bottom bracket?

I've tried asking Evans but thought I'd try here for an explanation I could understand.

The Dahon had a square taper spindle in the BB. The chainset says it fits a square taper BB.

Is that it?

Will it fit or is it going to be an impossible task? The guy at Evans wanted me to measure the length of the spindle. but I don't see why this would matter.

Please enlighten me.

 

[Smurfy]

There are three standards for square taper BBs.
http://sheldonbrown.com/bbtaper.html

 

[cyberknight]

http://www.ebay.co.uk/itm/THORN-BIK...sure_cycling_bikeparts_SR&hash=item4627ff67d5

 

[RecordAceFromNew]

The guy at Evans wanted me to measure the length of the spindle. but I don't see why this would matter.

Please enlighten me.

It matters because e.g. JIS square tapered bb spindle lengths of 103mm to 127.5mm are common, so the position of the chainring and the pedals will be different dependent on the spindle length. Chainsets are designed to operate with specific spindle lengths. Ideal chainline (the distance between the single ring or middle of multiple rings to centre of frame) is driven by the position of the sprocket or cluster of sprockets at the back, roughly speaking, and standards exist for single speed, double chainset, triple chainset, road, mtb etc. Also using a spindle that is too short can cause the chainset to clash with the frame.

You might want to be aware that the issue of using a shorter crank for the bike is that the saddle has to be raised, so that the pedal (at 6 o'clock) to saddle distance continues to correspond to the height of her seatbone, and she might not be comfortable with having a higher saddle initially.

According to the Q&A of the chainset it is for 1/8" (i.e. single speed) chain. You might want to check with Evans that the Dahon's chain (likely 3/32" if it has a derailleur) will be ok with it.