Apu

Sorry, I haven't had a chance to get working on my front hub, The cones and bearings are stuffed and need replacing. In fact haven't got any where with the bike, a project going to waste really. The frame hasn't been started on, nor the components. and yes steel frames do crack but they are far less hassle when they do. very easy to repair. Sorry, I haven't had a chance to get working on my front hub, The cones and bearings are stuffed and need replacing. In fact haven't got any where with the bike, a project going to waste really. The frame hasn't been started on, nor the components. and yes steel frames do crack but they are far less hassle when they do. very easy to repair.

Keep away from second hand aluminium frames, if they are used they have probable fractures in the compound depending on how they were ridden. Bikes are only made to last 3 yrs so stick to a time frame of 1 or so used yrs of bike or just buy a heavy, steel framed bike.

I started out on a 12.5" kids bike, fully steel and everything. That got me started real well until the spokes got loose and punctured the rim tape and tires. DARN 16 SPOKE WHEELS!!! the bike had pushed forward bars and was rather comfortable. My reason for using it as a trials bike was because my mate broke the seat rail clamp which gave me the idea to cut the seat post tube down to top tube height. I plan to move up a size, all the way to 16" with a whopping 28 spokes. wheels will be replaced with light weight (and stronger) aluminium rims. small rims = stiffer wheel. I'll also use high flanged hubs.

If they made those little bike's wheels just a little stronger then I say we have a freak class of trials bikes. Maybe some of those skyway tuffs in 12 inch form would do the job. but then what about weight? oh well, back to the drawing board for me.

Ok thanks. I can tell a differnce in geometry from riding mountain bikes and bmx's over the past 16 yrs. The geometry does vary a lot from chainstay length to Q factor on the cranks. head angle doesn't bother me so much but steeper would be nicer. Because I am new to trials (and very bad at lifting my bike off the ground) I am going to build myself a bike small enough to thorw around easier than my current mountain bike. I chose to do this as an excuse to develop my welding skills and recycle my old mtb and bmx parts I have laying around. And yes the frame will be steel. I first wanted to get into trials when I had a little 12 inch kids bike with pushed foward handle bars. My friend broke the seat rail clamp so I removed the post etc. and cut the seat post tube down to top tube height. I found this a really solid little bike with excellent frame geometry but I gave up riding this because the tubes would always blow from having loose spokes and rather buckled rims. I think I am in one of those moods too, I love talking "bikes" and anything bike related. I am just an enthusiast, not a pro rider and like building my own bikes, not buying already assembled bike. Building a bike from scrap parts laying around will get me track standing and bunny hopping/side hopping away and then I will move up if I still have the patience and enjoyment for the sport.

I was looking around on the internet at 20" mod bikes and realized how much different, in size, the forks are to standard bmx forks. They seem longer, almost the same length of an non travel-corrected mtb fork. Are they actually any bigger than standard bmx forks or is it just an illusion? If so then why are they longer? does it boost the front up higher or does it alter frame geometry?

Yeah he one the Gravity cross here in Christchurch. When he was here on holiday he realized there was going to be a Slalom race going on and he wanted to enter. Little did he know he was to win after purchasing the bike from the local dump. yeah using a standard 20" frame wouldn't work because the chain stays are too long. 16" bikes are shorter in the back end.

I seem to understand because trial and error helped me. Over the years I have had numerous bikes the have been solid enough for pissing about on. It's only a fart around bike. Not some $2000 mod with top quality components. I don't even think I would be able to get a mod easily here. Haven't seen a bike shop yet to display one. Children's bikes can be very solidly built and with a few gussets here and some half decent components rescued from my scrap parts bin, it will eventually work. Remember what they used for earlier trials bikes? Haven't broken a frame yet, just a fork. And if any bike was to give way to me soon it would definitely be my "gravity bike." which is an aluminium huffy frame. Yes the rims will hold on this little machine. I haven't buckled the stock chrome/steel ones on the bike yet and I have been pretty hard on the bike so far. Smooth riding pays off if you want parts to last. It was the nationals race here in Christchurch, NZ the guy came from overseas and had no bike to race on so went and bought one second hand to have a laugh on. know one realized he was going to win, not even him.

Yea thanks. It'll work. After weighing the 16" bike I got today it happens to be less than my aluminium mountain bike. I could guarantee that once the bike will be finished it will be both strong and light with very responsive frame geometry. The bike tends to manual straight after landing a bunny hop. (the bike is bog standard at the moment) all I will really be changing on the frame/fork is the seat tube length and adding disc and v brake mounts. (disc on fork vees on frame) oh yea and the American bottom bracket shell is getting changed to European everything else is going to recycled mountain bike parts. A mechanical Shimano (gasp) disc brake is going out front. (sourced from my scrap parts bin) Cut and tapped Truvativ firex square tapered cranks. (sourced from my scrap parts bin) Chosen front disc hub (sourced from my scrap parts bin) Aluminium rims, 16 inch(yes ALUMINIUM not steel. these will be purchased new) A long mountain bike head stem (sourced from my scrap parts bin) Sealed VP bottom bracket List has changed since first post due to lack of spare parts available in my scrap parts bin. And if something breaks on the bike it isn't due to strength problems but due to the fact I am not riding smooth enough. Smooth riding is a key factor in any bicycle sport and should be considered by all. I know a guy who placed 2nd in a DH competition on a used $10 bike. All it had for brakes were horse shoes.

For me I would say 20" due to the ease of throwing the bike around. If you want a really lightweight and easy bike to throw around I would recommend a 12 1/2"

remember when using aluminium you have to use twice as much due to aluminium not being as string in the same quantities. The frame is only little so it won't require much metal. In fact I will guarantee you it will be lighter than any stock frame... XD. If weight was a problem I would just go ahead and TIG together an alloy frame. (still thinking about it.) any way due to the frame being small it won't flex.

Yeah getting a mod would be fun but shipping costs are phenomenal to New Zealand. And clearly you didn't see the last guys video. That's what I would call ALUMINIUM. kids bikes are very robust. Being an alternative person I want an Alternative bike. not something everyone has already seen.

Yeah thanks for understanding. Who the hell thought steel frames are weaker than aluminium frames? someone clearly doesn't know a thing. Why are freestyle bmx bikes steel? and earlier trials bikes? and even good dirt jump bikes? My eldest brother is a sheet metal fabricator so working with metal is nothing new to him or me. Aluminium frames have been around since 74 or something when Kawasaki made a race bmx with triples and a twin shock back end. so please anyone don't say because aluminium frames weren't around back then. This is just a novelty item really and somehow I don't think a 5yr old kid could go and ride a mod up a rock easily. He needs a bike that is small and agile. Easy for him/her to throw around.

steel frames last longer due to frame flex. Aluminium frames are stiffer meaning less give in the metal. Steel can be easily re welded with out stress on the metal. Why do you think companies like DMR use cromo? It's easier and stronger and provides a smoother ride. And yes 12" alloys would be surprisingly strong. And I never said alloy frames crack each time you bunny hop as such I said aluminium gets microscopic cracks from impact. These join up eventually and yep there goes a broken nose or cracked balls. Aluminium frames only have a 2yr warranty if you're lucky.