Typical Fork Tube Spacing?

[Blackout]

Hello 3WheelerWorld!

I'm doing a custom front setup (custom triples and hub) using a 23.5 x 8 - 11 tire. While I certainly can figure out what fork tube spacing works for brake clearance and such, I am curious what the typical spacing for 3 wheelers is. A search did yield that a 200x is 11" center to center, but I wanted to confirm. The measurement does not need to be exact, thanks!! Please measure from center to center.

[big specht]

Yep they are 11” but the 83-5 200x’s have rack build into the triples. The steering stem angle is different than the fork tubes.

[Blackout]

Cool, Thanks for the confirmation!!

My triples will have zero rake since I will be using a leading axle fork. My calculations show with 21.5 degrees of frame rake and 1.48 inches of triple offset, I will have 1.5 inches of trail.

[El Camexican]

I’m using an 8 inch wide tire with my custom clamps which are 11-7/8” O/C and it’s a tight fit. The inverted fork tubes are 48mm. Just trying to say that if you plan to use larger than original fork tubes you’ll want to consider the extra space they’ll need. On my setup an extra 1/8” might have made it possible to R&R the brake caliper with the wheel mounted, but the way it is I have to mount the caliper with the wheel. It’s not impossible, but it is a PITA.

Good luck with your project.

[Blackout]

I’m using an 8 inch wide tire with my custom clamps which are 11-7/8” O/C and it’s a tight fit. The inverted fork tubes are 48mm. Just trying to say that if you plan to use larger than original fork tubes you’ll want to consider the extra space they’ll need. On my setup an extra 1/8” might have made it possible to R&R the brake caliper with the wheel mounted, but the way it is I have to mount the caliper with the wheel. It’s not impossible, but it is a PITA.

Good luck with your project.

Thanks for the info! I'm using 41mm RSU forks and YZ250 brakes. I'm looking into wheel/caliper clearance as I type.

[Red Rider]

I’m using the OEM 23X8X11 Dunlop front tire on my setup with 43mm inverted forks, and my fork tubes are spaced 10 5/8” apart on center. Once you’ve decided on what wheel, tire, forks, fork protectors, and brake caliper you are going to use, that will dictate what your minimum fork spacing needs to be. Also, the wider apart your forks are, decreases your lock-to-lock turning radius.

[El Camexican]

Exactly. I ended up going to 2.5” offset in order to retain a decent steering radius without having to dent my rads.Fortunately, my frame came with adjustable steering stops, so I am able to maximize my set up.

I used cut outs to finalize my dimensions, I would recommend that to anybody taking on this kind of a project.

[Blackout]

Anyone know what steering angle I should be shooting for? It's a custom frame, so my options are open. Thanks!

[El Camexican]

Anyone know what steering angle I should be shooting for? It's a custom frame, so my options are open. Thanks!

That’s a question you probably won’t get a straight answer on. Too many factors in play. Swing-arm length & angle, ground clearance, fork length, trailing or leading axle, etc. Having gone though this once my suggestion (which may differ from others) is to try and copy a proven design. A 1985 250R would be one suggestion (which may differ from others).

By all means, read up on the topic, but don’t expect to find a definitive answer to your question.