Wheelbase measurements

[scalelover]

Here's a newbie question. When your figuring out wheelbase length on a tandem setup, do you measure from the center of the back axle, the center of the front axle, or the center point the suspension on the chassis mount???

I have the 1:1 WB measurements but it does not specify where they were taken from, and I have no way to measure one myself. Any input would be GREATLY appreciated. I've been gathering info for ages on this build and I'd like to finally get started on it but this is holding me up on setting up the chassis.


--Dan

[TRUCKMAKER]

Dan- Wheelbase is measured from steer axle center line to rear suspension center line. On a standard tamiya tandem it would be the long pivot bolt that goes through the frame side to side. Hope that helps.

Kent

[scalelover]

Sorry if my description was a bit unclear. When I was describing the axles I meant both rear axles --front tandem and rear tandem. I knew the front measurement was from center o the steering axle. But yes this does help very much, I just was not sure at which point I should measure in the rear. So knowing that its at the center point of the suspension I can finally start setting it up.

--Dan

[doodlebug]

Originally Posted by scalelover

Sorry if my description was a bit unclear. When I was describing the axles I meant both rear axles --front tandem and rear tandem. I knew the front measurement was from center o the steering axle. But yes this does help very much, I just was not sure at which point I should measure in the rear. So knowing that its at the center point of the suspension I can finally start setting it up.

--Dan

Depending on your local bridge formula ( that legal >>>>) tandem axle's are spaced 52" to 72" spread. Centerline to centerline.
On twin steer tandem axle's, 54" is minimum, and I've seen spread's of 120"+
http://www.raydanmfg.com/?page=products&ProductId=5 see this page for more info. The gallery page show's all kind's of tandem steer spread's. http://www.raydanmfg.com/?page=media&section=gallery Or you can search thru Hank's Truck Picture's http://www.hankstruckpictures.com/ma..._emotions.html


Hope this help's, Neil.

[scalelover]

Thanks for the links Neil. Ill definitely be spending--wasting some otherwise useful hours looking through those, I've been on hanks site many o times prior but not the other one.

Is one way of measurment more common than others? I know every state is different in law, but if someone was wanting to stay 50 state legal would they use a certain setup over others?

The build I'm working on is based off a military version International cab but it also has civilian bases as well, which were actually used first before it was upgraded and modified for the good ole USA military.

--Dan

[Lil Giants]

What is it you're building? ..a few millimeter either or that rellevant?

[ihbuilder]

Dan , for wheel base measurement , Truckmaker is right on the $ . Bridge law only specifies the min distance between axles for a specific weight to be carried . I'm not sure how the manufacture figures the twin steer set up . I think it is still from the front most front axle . IIRC from pics of what I saw your building , I don't think you need to worry about that unless it's different . If your going military , I don't think they worry about bridge law .

[Exthood359]

Dan,

Are you wanting the overall wheelbase of the vehicle or the axle spacing between axles.

Here is both measurements.

Overall wheelbase is from the center of the steer axle to between the tandem axles gives you overall wheelbase. For example 265" wb.

Axle spacing is measured from the center of the front drive axle or trailer to the center of the second drive axle or trailer.

Most configurations are what we call closed tandems will be 50" from center of the front drive to center of the second drive.

On trailers a closed tandem will be the same 50" and when you get into a spread axle like you see on flatbeds or some reefer trailers the min is 10'-2" and up to 12' or 144".

Ok the picture below is a closed tandem and the measurement is from the center of the axle cover to the center of the second axle cover.


This shot shows overall wheelbase which is measured from the center of the steer axle to between the drive axles. In this case the overall wheelbase on this truck is 303" wheelbase.


This truck the overall wheelbase of the tractor is 331" wheelbase of the truck with a 53' trailer with a 12' or 144" spread on the trailer.




I hope this answered all your questions.

Good Luck
Wade

[Exthood359]

Dan,

If you are wanting to do dual steer then the same applies on the steer.

[doodlebug]

Originally Posted by ihbuilder

Dan , for wheel base measurement , Truckmaker is right on the $ . Bridge law only specifies the min distance between axles for a specific weight to be carried . I'm not sure how the manufacture figures the twin steer set up . I think it is still from the front most front axle . IIRC from pics of what I saw your building , I don't think you need to worry about that unless it's different . If your going military , I don't think they worry about bridge law .

Only in the communist state of kalifonia, that I'm aware of!
The M919 concrete batch truck has to be hauled empty on a lowboy trailer in kalifonia, something to do with not recognizing lift axle's.

Cheer's, Neil.

[ihbuilder]

Originally Posted by doodlebug

Only in the communist state of kalifonia, that I'm aware of!
The M919 concrete batch truck has to be hauled empty on a lowboy trailer in kalifonia, something to do with not recognizing lift axle's.

Cheer's, Neil.

yea figures

[scalelover]

Originally Posted by ihbuilder

Dan , for wheel base measurement , Truckmaker is right on the $ . Bridge law only specifies the min distance between axles for a specific weight to be carried . I'm not sure how the manufacture figures the twin steer set up . I think it is still from the front most front axle . IIRC from pics of what I saw your building , I don't think you need to worry about that unless it's different . If your going military , I don't think they worry about bridge law .

I was looking for overall WB measurement, because the truck I'm basing my build off of is currently used in the military, full specs are very difficult to come by for it. I have some measurements for pieces parts on the truck so I can just measure off of those and scale up to figure out what the actual WB measurement is.

but I also wanted the tandem setup measurements because the size tires I'm running don't allow me to use the basic Tamiya configuration. I figured because I'm making the tandem mount I might as well get as exact as possible to keep it scale with the rest of the build.

As you figured I probably don't need to worry about it with this truck but it's technically not a full military truck, it is available to the private sector as well. The other build I'm doing is full on military so I really wasn't worried at all about that one.


Thank you very much to all who chimed in on this, all the info was very helpful.

--Dan