Part 4: Building a Kids 20inch Full Suspension MTB
Wheels, Cassette, Gears, brakes, cables, bottom bracket, gearset, pedals….
So still a lot to do to complete this bike build, so I decided to put myself on a Bike Maintenance Course. I started with Level 1, then Level 2, then did some Hydraulics all at Cycle Training Wales in Cardiff. This course taught me a lot.
Wheels
I ordered a set of 20″ wheels including Shimano disc rotors + 8 speed Shimano cassette from WheelsOn ebay shop. They arrived next day and I put on fresh inner tubes and Continental Explorer MTB tyres:
Gear Shifter
The original bike came with grip shift which the kids never got on with (why are they always added to kids bikes?). I swapped their other bikes to use trigger finger shifters but they found it difficult to thump up the gears (thumbs not big enough?). I noticed someone was using the EV Bike style gear levers SL-TX50-7R so I purchased it but they only came in 7 speed versions and the cassette was for 8 gears arggg. The shifter looked like:
Rear Derailleur
The original rear derailleur was in a bad way and also made by Sram. I was fitting a new Shimano gear shifter so I needed to change the rear derailleur too. I check what was on my kids other bikes and noticed they where using Shimano Tourney RD-TY300. However when they arrived they had different connectors that looked liked:
This was obviously incorrect as this if for older style bikes. So I went to a local bike shop and they supplied me with the correct rear derailleur with the screw fitting that looked like:
Cassette
So now I needed to remove the current cassette and install a new 7 speed version. Easy enough I thought, looked online and found a Shimano 7 speed cassette. I took the old one off using 2 tools:
Chain Whip
Shimano Cassette Removal Tool
Removed the current cassette no problem, oh but wait the new cassette doesn’t look the same:
It seems like I ordered the FreeWheel version instead of the HyperGlide so it didn’t have the teeth going all the way through the cassette. No problem, now I know so I ordered 2 more correct 7 speed cassettes….
Well that is what I thought until they arrived and although it fitted there was a gap and the cassette wouldn’t lock properly, it was very loose? Odd I thought, then I realised I needed a tiny little spacer between the hub and the cassette. So I managed to order a Hope 7sp Spacer which looked like:
Brakes
I wanted to setup hydraulic brakes but until I went on the course I had no clue what to do here so I thought I would try out cable operated disc brakes and see how the kids get on. I bought a set of Clarks CMD-21 MTB Disc brakes. Fairly easy to setup and looked quite good installed:
