Bicycle Mechanics - Part Measurments

Hi, I'm a 'noob' to bike mechanics. I ordered some parts for my old 8ball lowrider that I bought a few years ago. The parts in question are fender braces and 'fork bars' for the springer front end. Both 20 inches.
I'm wondering.. are these parts exact dimensions? I'm sure my bike is a "20 inch lowrider".. when checking the forks, the main bars are 20" long but curved so it comes out to more like 18".
The fenders are about 20" from end to end but measuring the full brace length is around 23 & 1/2"

The problem is I can only find 16", 20" and 26" fender braces so I'm hoping they round down the numbers, same with the 'fork bars" 16, 20 and 26.

Basically need someone to tell me that I screwed up and ordered the wrong size parts or that I got lucky this time:D

All of the parts you got should be listed by the size wheel they're meant for, so should probably be correct. Depending on what tires you put on, the wheel diameter with tire may not even be 20"

The fork blades being only 18" seems odd to me. Have you tried putting a wheel in it? That almost seems like it's made for a 16" wheel.

Fender braces being 23.5" sounds like it's in the neighborhood for fitting 20" wheels.

Careful not to confuse Diameter and Radius .. r x2=D ... so 20" wheel has a 10" r [generalizing]

Ahhh Yes! Glad someone's thinking around here.

Now fork blade dimensions seem good for a 20" springer, but I can't really tell from your description what you're measuring on the fenders.

Thanks for the replies! the actual fork bar is only 18" long, from end to end. The bigger curved part is 20" but since its curved, it's really only 18" from tip to tip. Do they measure them weird like that or do I really have a 18" springer?

The wheels including the stock tires are just under 20", about 16 & 1/2 not counting tires. Its the 72 spoke wheels and tires it came stock with.
If I put a measuring tape as if it was the fender brace(or if i was to unbend it) its about 23". The back fenders inner diameter is 20".

EDIT: wheel dimensions are diameter too just under 20"

Thanks for the replies! the actual fork bar is only 18" long, from end to end. The bigger curved part is 20" but since its curved, it's really only 18" from tip to tip. Do they measure them weird like that or do I really have a 18" springer?

I doubt many springer fork manufacturers will give precise numbers for specs like some other forks will. These numbers are typically center of axle to crown race in millimeters. The average springer fork manu will just tell you what size wheel it's made for. In this case you don't even need to worry about that so much unless you're gonna run a front brake, if there are any lowrider springers drilled for brakes. I'd imagine your 20" wheel will fit just fine. You could probably roll a 24" up in there, if you wanted too, but then it wouldn't be much of a lowrider anymore and you'd never get your fender on.



If I put a measuring tape as if it was the fender brace(or if i was to unbend it) its about 23". The back fenders inner diameter is 20".


Measuring the arc (that sounds like what you're measuring from this description) of your particular fender doesn't tell me a whole lot. If your vender said it was for 20" wheels, it probably is.

If you have all the parts, a quick "dry fit" should pretty much tell you if it's gonna work.

My only real concern is that the screw holes line up with the curved part that attaches to the frame and crown. The actual bars being 18" just kinda threw me off. I think I get it now though.

The fender braces sound like they should be right.. I guess worse case i can flex the fender a bit and maybe add a spacer, theres still a few inches room from the tire.

Everything seems like it should be good, thanks a bunch for the help!:thumb: