Common Beginners Mistakes
It seems to me there are a few things that people commonly do when building their first cartie which, with the benefit of hindsight, they probably wish they hadn't done. Here are a few of the common "learning opportunities" I've spotted;
- Wheels too big. It may be that "bigger wheels roll better", but that's only true when they are circular. As soon as you've taken your first serious corner with those 26" wheels you nicked off a bike you found a the tip you'll find that their newly configured "pringle profile" will be a lot slower than you'd hoped. 20" BMX wheels work well.
- Centre of gravity too high. Get as low as you possibly can, as it'll help with stability. Tall carties tend to be very top heavy and have a high risk of rolling over. Get your bum as close to the road as possible.
- Too narrow. A similar problem to the high C of G (above). Wide carties are much less likely to roll over.
- Wonky steering. I've you're going for conventional "kart style" steering (i.e. simple push rods), read up about king pin inclination, king pin camber and ackerman angle. Don't just make every joint a right angle, or it won't work very well.
- Twitchy steering. You do not need anywhere near as much lock as you think you do. Keep the steering slow (i.e. big inputs and small outputs), otherwise it'll be very difficult to control at speed. Read up about steering ratios. Also - it is worth considering fitting a steering damper. these can be acquired second hand from eBay for around £20.
- Chassis too soft. You don't want too much flex in your chassis. This, coupled with twitchy steering, is a recipe for the dreaded speed wobbles. Also make sure there is minimal flex inyour wheel mountings.