Difference between Vbrake posts 24/26/29"

[markz]

As far as I can tell, it might just be 56mm (5.6cm) between a 24" fork and a 26" fork brake posts.
I base it on average ERD's for 24" and 26" rims off the Sunringle pdf
Seems like a lot, but if I halve that 56mm it is 28mm which seems about right.
My online searches reveal nothing.

Making an adapter plate for a 26" fork, to use V-Brake on a 24" wheel (Picture below)
It mounts to center pivot for U-Brakes and existing 26" Vbrake posts (will be taking off) and using either a M8 or a M10 bolt for the threads on the fork that the posts thread into.


Hopefully I got it right this time :wink:

 

[Chalo]

The difference in radius between a 24" and 26" wheel is one inch-- actual, not nominal-- and the position of the bosses is one inch lower for 24" wheels. 700c/29" wheels need bosses 1.25" (31.5mm) higher than those for 26".

 

[markz]

Thanks Chalo I will use 25.4mm (1") instead of my 28mm.

The difference in radius between a 24" and 26" wheel is one inch-- actual, not nominal-- and the position of the bosses is one inch lower for 24" wheels. 700c/29" wheels need bosses 1.25" (31.5mm) higher than those for 26".

 

[markz]

What thickness of metal should I use?
1/8"
3/16″
1/4″

Hot or Cold rolled plate?

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[Chalo]

What thickness of metal should I use?
1/8"
3/16″
1/4″

Hot or Cold rolled plate?

Since the biggest forces are perpendicular to the plate, thicker is better. Most of the steel retrofit brake stud plates I've seen were about 4mm thick. They didn't overhang the studs very much from the nearest support, though.

You can probably use an existing plate and modify it by welding washers on where you want it to mount to the old bosses.

You understand that the old brake bosses will limit how wide a 24" tire you can use?