losing weight on a Scott Jr Spark 20" full suspension mtn bike
I have a Scott Jr Spark 20" full suspension mountain bike for my son. He loves it and we ride a lot on it. The bike is great, but it is pretty heavy especially when compared with his BMX race bike. I've been looking around trying to find parts to swap out on the bike to reduce weight but it's really difficult to find high end, low weight mountain bike parts in smaller sizes for the jr bikes. The bike has 20" wheels and I'd like to build up a new set with lower weight but can't find good 20" mountain bike wheels. It has 140 cranks, and I can't seem to find anything good that small. Same thing goes for handlebars, sprockets, chainrings, headset, and everything else.
Does anyone have any idea where I can find smaller sizes in good, light weight parts? And then any suggestions as to things I could/should easily replace to save on weight on this bike?
It is hard to find quality lightweight parts for smaller bikes. You're pretty much stuck with making or modifying stuff yourself.
I've done stuff like modifying an XT rear cassette to put gears on my youngest daughter's BMX and shortening a Manitou fork for 20" wheels.
There are a few quality cranks in 140mm (and shorter) but they are mostly of BMX origin so will be single ring in 110BCD. You could also shorten a set of adult cranks. Shimano hollowtech's will not work though.
Like Tig said, its hard finding light weight parts for kids bikes, especially 20" wheels.You may want to ask this over in the Family and kids forum.Besides wheels & cranks I would get a Thompson Elite seatpost ( they come in 26.8) replace the top cradle with KCNC style yokes & Ti bolts = 150 grams.Carboncycles 25.4 x 60mm stem with Ti bolts is approx. 116 grams & dirt cheap.Easton low riser carbon bar cut down - don't go narrower than 24", it really helps handling on the little bikes.Foam grips.X-Fushion air shock with adjustable rebound from the Scott Spark RC 24", X-Fushion USA has these in stock.Wellgo WR-1 pedals with Ti axles.You can check out these mods on a Spark RC I built for my son here Scott Spark RC 24 with mods
Torontocycles.com is a good source for bolts,etc.