RustyKipper
100 W
Hey guys, My daily commuter suffers from pretty bad fork flex ie. if I waggle the handle bars quickly or hit a pothole I can build up a fair bit of death wobble, although it doesn't continue it doesn't inspire confidence and makes the bike feel like a blancmange!
I think this is mainly due to the fact that I have to use stupidly thick and heavy inner tubes (3mm thick rubber) to cope with the broken glass and shrapnel covered roads where I work, this builds up huge gyroscopic forces plus I have quite heavy aluminium hand formed mudguards and a handlebar bag containing my waterproofs so a lot of weight hanging of the steering.
So I figured I might have a go at engineering a solution, the flex appears to be centered around the bridge at the bottom of the steerer tube so I figure a good step would be to effectively carry the stanchion tubes right up the the handlebars, not so easy as there are controls on top of the stanchions so I would have to fabricate some sort of joint. So I ordered up some 30mm thin wall stainless tubing to make the tube extensions, and some alumininium tubing and spent a few evenings in the machine shop.
View attachment 2
View attachment 1
Most of the time was spent machining weight out of the parts.
The parts were then painted and fitted to the bike with heavy duty stainless hose clamps.
The flex was reduced by a good degree but can still get the front wheel to oscillate.
In an ideal world I would swap the standard MTB type forks (Rockshox silver) to a triple clamp set but they are around $1000 plus when the rear mounted hub motor fails I want to go awd and fit a mini hub motor in the front to help with weight balance and triple clamp forks with drop outs seem to be rarer than hens teeth.
The fork extensions seem to be reasonably successful, the forks rarely bottom out unless I land really heavily from jumping of a kerb or speed bump, steering angle is quite reduced but is only an issue when negotiating cycle lane barriers where I have to turn the bars nearly 90 degrees and have added about 1.4Kg of weight.
I'm currently looking at a mark 2 version with the joint between the lower stanchion tubes and the upper tubes from carbon fiber to reduce weight and increase the steering angle and do away with the hose clamps that have some rather sharp edges that will cause a fair bit of bleeding when I come off in the mud.
It has to be said I'm quite pleased with how this setup looks.
I think this is mainly due to the fact that I have to use stupidly thick and heavy inner tubes (3mm thick rubber) to cope with the broken glass and shrapnel covered roads where I work, this builds up huge gyroscopic forces plus I have quite heavy aluminium hand formed mudguards and a handlebar bag containing my waterproofs so a lot of weight hanging of the steering.
So I figured I might have a go at engineering a solution, the flex appears to be centered around the bridge at the bottom of the steerer tube so I figure a good step would be to effectively carry the stanchion tubes right up the the handlebars, not so easy as there are controls on top of the stanchions so I would have to fabricate some sort of joint. So I ordered up some 30mm thin wall stainless tubing to make the tube extensions, and some alumininium tubing and spent a few evenings in the machine shop.
View attachment 2
View attachment 1
Most of the time was spent machining weight out of the parts.
The parts were then painted and fitted to the bike with heavy duty stainless hose clamps.
The flex was reduced by a good degree but can still get the front wheel to oscillate.
In an ideal world I would swap the standard MTB type forks (Rockshox silver) to a triple clamp set but they are around $1000 plus when the rear mounted hub motor fails I want to go awd and fit a mini hub motor in the front to help with weight balance and triple clamp forks with drop outs seem to be rarer than hens teeth.
The fork extensions seem to be reasonably successful, the forks rarely bottom out unless I land really heavily from jumping of a kerb or speed bump, steering angle is quite reduced but is only an issue when negotiating cycle lane barriers where I have to turn the bars nearly 90 degrees and have added about 1.4Kg of weight.
I'm currently looking at a mark 2 version with the joint between the lower stanchion tubes and the upper tubes from carbon fiber to reduce weight and increase the steering angle and do away with the hose clamps that have some rather sharp edges that will cause a fair bit of bleeding when I come off in the mud.
It has to be said I'm quite pleased with how this setup looks.
I did try a pair of Nukeproof wide handlebars but after hitting my arm on a lamp post and then getting stuck trying to get through a gate and finding it impossible to extract by bike from the company cycle rack I ended up cutting a good 6 inches off. Most people round this way use racing type drop handlebars.
