Fender stays from bicycle forks

This could be the best "Non automotive product used as an automotive product" idea I've ever seen.

 

Theres a law where i am, but its not really enforced. But if you are gonna do a channelled late fifties look,cycle fenders are essential.

 

If I was making these I would leave more space between tire and fender, in case a piece of debris off the road got stuck in there. The old cars that had this style fender seemed to have at least a couple of inches of room.

 

That doesnt worry me so much. I'm more uneasy about welding the horizontal stay to the vertical stay.

 

There's a gusset there and the joint is close to the bolt. I'm going to heat treat the backing plate and the stays to relieve the welding stresses and de-brittle.

We'll see how it works in practice. The fenders were about $30 and the bike forks were pennies - if it starts to crack then they'll have to be made again. If that happens I might cut the same shapes out of a single sheet of 6mm stainless plate and radius and polish them. I have that arrangement on an O/T car that has done 800000 miles with no cracking.

 

Very clean and fuctional design. Patent worthy.

 

I will take pictures of the construction of the next one. The way it is made is that the flat strap bit that goes from the fork and bolts to the fender goes inside the fork tube about 3". The fork was split open down its length about 3", flattened and shaped to fit behind the flat strap. I then drilled a series of holes and rosette welded the parts together - then edge welded the fork metal and the flat strap together. It was all then ground and smoothed.

I could strengthen it more by making the strap go deeper into the fork and drilling and rosette welding front and back of the fork. I might do that for the passenger side and see which fails first ;-) I might also take some 10mm tube and curve it to the same radius as the wheel rim and then weld it between the two stays. I'll have to see what that looks like.

I was keen to avoid any agricultural look to the fender mounts and I wanted to do something a little different. I'm reasonably pleased with it so far.

The rears will be easier because there are less compromises to be made with mounting locations (there's a lot of stuff going on behind those backing plates) and fasteners can go up to M10 or even M12.

BTW - my O/T cycle fendered car has fenders very close to the tyres and I have never had any issues with debris being caught in there over the last 80,000 miles. That may be to do with UK and European road conditions though.

 

I am definately gonna borrow this idea, already got a few people on the look-out for bike forks. I am thinking I will attach the two stays to the backing plates independantly. I want to hunt up fenders without the raised rib in the center, nothing wrong with it, I just want a little bit different look. I am thinking re-popped late fifties Triumph trophy fenders. Those will be a little more pricey, but I really think I want a smooth fender, with an un-interrupted curved contour across the top. I'd be after something like this. I'd have to work out the dents for the fork tubes.
Just a thought, aluminum fenders would save some stress on the stays. They may tend to crack more easily where they are attached to the stays though. maybe 6 of one, half a dozen of another? Has anyone tried aluminum cycle fenders on thier hot rod? Hell, can it REALLY vibrate more that a triumph twin? Can ANYTHING vibrate more than a Triumph twin?

 

I like what you've done but what happens if you get a flat ? With the fender that close the tire will tear it apart.

 

Don't worry if you can't get them all matching. I got 4 different forks for my four wheels so I'm using mixing them up and using different ones for the upper and lower stay and matching them across the car on each axle.

I'd like to see how you mount them - please post pictures when you get into to it.

I know what you mean about the smooth fenders.... Here's a set on my O/T car;

 

The car above has done 80,000 miles with fenders much closer. I've had several flats in that time and no damage to the fender. Even if it did cause damage, they're cheap to replace and/or easy to repair and paint.

 

Those skirts on the insides of the OT trike are neat. Better pic of the skirts? Seems like a stable setup, and it looks cool.

 

Yes - it works very well. Will do some close up pictures in the morning as it's midnight and bloody cold here ;-)

 

Great tech article. I think a lot of us would like to see how you made the ones with the skirts too as those are sharp looking units.

 

Just what I was planning to do. Use one pair of forks for the verticals, the other for the horizontals. Hope you can wait a while, my project is just in the process of morphing into a big steaming heap of rusty parts at this point...

 

I'd like to know more as well. What fenders did you start with there?

 

Killer idea

 

I'd never thought of it, but as soon as I read the title, I knew what he'd done. Its one of those ideas where its "DAMN! Thats so OBVIOUS! Why didnt I think of it?!"

 

Picture of Avion fenders and stays;

 

^^I REALLY like the shape of the leading edge on those.

 

As promised, here are some pictures of the fabrication. The bottom of the fork is bolted to the drilled backing plate using and M8 bolt through the drop out. This then allows me to position it correctly to drill through the fork using an appropriately positioned hole on the rim of the backplate. I then open that hole to 11mm and weld in some mild steel tubing to reinforce the fork.

I mount the tyre and sit the fender on top and decide where to cut the fork. I cut half way through and then down the length to give a tab that will be drilled in four positions so that I can rosette weld in the flat strap that will go under the fender. I will show this tomorrow.

 

Here's the rears;



This bracket will be welded to the rear spring perch mounting plate - I will use more appropriate fasteners.



The leading edge of the fender will be at about 1 o'clock (to match the fronts). I've yet to trim the stays to the correct length and make the extensions that go under the fenders from 25mm x 4mm flat bar.

I think I will weld in a link between the two stays made from round bar and matched to the curve of the wheel rim.

 

While reading the first post, I imagined that the fat end of the fork would be at the backing plate

 

I tried it both ways and this looked best. This was also the way it was orientated in its intended use. They are very strong and stiff.

 

Finished up the rear stays now - I remade the rear brackets in 8mm x 50mm x 125mm angle. Much, much stiffer than the first ones. The thicker material also allowed me to tap the holes so I can use studs with dome nuts to secure the stays.

Going to move on to drilling the rear back plates and rebuilding those brakes now. While the backing plates are off I will weld the fender stay brackets to spring perch brackets and that will be called done. Just need to file and sand all the edges and welds to a pleasing shape before paint.