Monday, October 30, 2017

Bert's 650 plus

The stainless dropouts solved the (powdercoat build-up) tolerance issues that I had with the last plus bike. 

Much of the riding in Texas consists of creek adjacent trails, as there isn't much public property and the acreage that is spared is usually in a flood plane.

 In east Texas this means that every few years the trails get washed out and replaced by sand dunes. Bigger tires and wider rims allow us to run lower tire pressure and float through sand that would otherwise grind momentum to a stop. The mid fat bike is a compromise for sand floating and cornering ability: While the bigger 4"+ fat wheels float on sand better they can be sluggish and have an over-steer characteristic.


Wednesday, October 25, 2017

Almost there. I debated whether to use 16 or 19mm seat stays and went with 16 because they're more compliant, most of the other steel 650+ bikes have them, and I can bend them on a large radius. The little seat tube gusset was to lower the standover a little bit and keep the junction strong enough. I lathed down some bottle cage mounts with a slightly wider surface area.
Been riding skateparks on this thing with 7"s instead of the 8"s and it feels right. I have to get a disc specific lever, as the BMX lever doesn't have the correct pull ratio for street stuff (way too sticky).



Monday, October 23, 2017

trials 24 done

 "Midnight blue"
 Tensioner and tool designed for a specific trial hub.
 Removable V brakes and disc.

Monday, October 16, 2017

 Starting the little big bike: mid fat, 148mm rear. Size Extra Medium
I chose the stainless dropouts this time as the last (1018 steel) thru axle drops that I used seemed to have too tight of tolerances for any kind of coating. 

I forgot to order barrel nuts for the brake mount so I had to make a few out of stainless. The ones Paragon sells are AL or brass, so these might actually be better than what they sell.

Saturday, October 14, 2017

Trials 24"

 Finally got the 24" close to coating. Tensioners and a brake brace are next
 The first set of stays below had the bosses too narrow. At 83mm, the brake arms had to aim too far outward, even with the convex washer removed. The good ones here are sitting at 91mm apart. This wouldn't have been a big deal had I not had to make the removable V brake mounts each time (my usual sources are out of them).

Friday, October 6, 2017

The trials frame is awaiting some details on sprocket size

Brent's 17 backsweep bars are ready to go