How do you measure wheel base

[rdc]

Not too sure, do you go front of the front tire to the back of the rear tire or what, just trying to find out how much of a wheelbase i have on a single cab short bed 1999f-150

[rdc]

Look on the inside of the drivers side door

[rdc]

Or if you don't have a sticker that tells you. Then measure from the center of the front hub to the center of the rear hub.

Tony

[Jack]

Somtimes it can be hard to get the center, you can measeur front of tire to front of tire.

[rdc]

Look! It's very simple. You measure from the center of the of the hub "front wheel" to the center of the rear axle "rear wheel" both sides. Thats how you measure wheel base! NOT TIRES.
Art "The TECH DUDE" Savedra

[rdc]

Actually Art, there is more than one way to measure the wheelbase and you can measure the tires because the front of the front tire
to the front of the rear tire is the same distance as center to center.

[Jack]

Unless the wheels are not round. Then Art would have a point.

[Bob_Sheaves]

Hi Art!

I would have to disagree with your method of measuring wheelbase IF ANY of the following conditions are met:

1. Dissimilar track widths comparing front to rear.

2. Dissimilar measuring points relative to the vehicle centerline plane (laterally)

3. Bent or sprung frame

Wheelbase is defined as (paraphrased here) the longitudinal distance between the lateral, normal (meaning mathematical "normal" or at 90 degrees to base) centerline of the front hub and the lateral, normal centerline of the rear hub, taken parallel to the vehicle centerline (See the SAE standard definitions for complete definition). This is the spec the FIA, NASCAR, SCCA, etc all use to define the measurement. If measuring by your procedure on a wide front or rear track (condition number 1 above) vehicle (wider track in front increases front "bite" in a corner, wider track in rear increases the "looseness" of the front end in a corner) by:

"...measure("ing"-added by RWS) from the center of the of the hub "front wheel" to the center of the rear axle "rear wheel" ("on"-added by RWS) both sides"

...your are getting a false measurement, one that represents the hypotenuse of a triangle, and not the base (parallel to the vehicle centerline plane). This number will be some amount LONGER than the actual wheelbase, depending on the height of the triangle (offset between measuring points, or condition number 2, above), possibly leading to a disqualification in a wheelbase limited class, due to a "too long" situation. The wheelbase MUST always be measured parallel to the centerline of the vehicle.

In condition number 3, above, the act of loading a frame will introduce variance into the suspension geometry, "moving the tire"' with relationship to the design position. For this reason the 2 sides must be averaged together to determine the actual "wheelbase" OR a vehicle layout (NOT a drawing, but a "string, plumb bob, and chalk" layout) must be done on a flat surface to determine, at the VEHICLE CENTERLINE, the distance between the 4 measured points, representing the wheelbase.

Best regards,

Bob Sheaves

[rdc]

Bob, you make some good points but I don't think any of us will be running our trucks in the indy 500 anytime soon. Thanks for the very fasinating information, your posts are always fun to read!!!!

Tony

[Junior]

I would also have to add that measuring from tire edge to tire edge will not work if the front and rear tires are not the same size or if the front and rear rims are not the same size. Other than that I concur with Bob, generally.

Junior
EJR Racing #244