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SQUARING UP YOUR TIRES & CHASSIS


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Thanks, Doc!! Did you get the blocks from micromark, and are they 2"x2"? Also, how about running a metal straight edge between the blocks to make sure both tires on each side are pointed in the same direction? Seems i can either get the camber right, or them pointed the same way, but rarely both.

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Only one comment: Bear in mind that the front wheels of almost every car ever made have a bit of positive camber to them (tops of the wheels are farther out than the bottom (the part that touches the road). This is very noticeable if you look at pics of say, any Bugatti, or certainly any solid front axle Ford, but trust me, positive camber is a feature of virtually every independent front suspension as well!

Art

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For my squaring duties I purchased a couple of adjustable squares and by adding one to the other I have a quick and easy way get things aligned. This works a treat on getting the rear wings on F1 cars squared up too.

IMG_1568.jpg

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  • 2 weeks later...

are you 100% sure about that Art?

Model Factory Hiro has this,

http://www.hlj.com/product/MFHBC-323

a little expensive maybe, but any good tool should never be cheap.

James, yes I am sure. There are three angles from vertical that are a part of any automoitive steerable front end: Camber, Caster and Rake. Now, rake can be seen on the front fork of any bicycle, motor scooter or motorcycle--just look at how the front fork angles forward from the pivot point to the front axle. That has the effect of making the bike or scooter steer predictably. Caster is just as the name implies--it's the ever so slight "spacing" of the centerline (think spindle here on an automobile front suspension, be it independent or a beam or solid front axle) slightly to the rear of the center line of the front kingpins or side-to-side pivot point of the front uprights--caster aids in making the steerable front wheels "self centering". Caster is exactly what the front wheels of a grocery shopping cart have, but much more pronounced!. Camber is almost always used as "positive camber", that is, with the front wheels pointed straight ahead (any automotive front end will have the wheels slightly "toe'd in", or seemingly steered slightly toward each other), the tops of the wheels will be farther apart than the "bottoms" of the wheels--this also makes steering easier, and helps minimize tire wear.

You can easily see positive camber in almost any 2wd car or truck, particularly any Model T through 1948 Ford passenger car or pickup--very prominent on Model A's and even the '32 Ford--the front end, when steered straight ahead will have the tires appearing almost "bowlegged". This is even more pronounced on any Classic Era Bugatti. But even a car with independent front suspension will show it as well. Take your own personal car, crank the steering wheel hard over either to the right or to the left, all the way to the limit. Now look at the two wheels: The wheel on the "inside" of this turning car will show as leaning over, well out of vertical--the opposite wheel will seem standing straight up and down.--that's camber--and it may well vary from car to car.

Only a few model car kits ever got this at all right--the best examples I can think of are the Revell '29 Model A Ford Pickup, and their '31 Model A Ford 2dr Sedan/Woodie Station Wagon--Revell's designers actually managed to get both camber and rake tooled into the front axle and radius rod assemblies; and assembled carefully, you can see it clearly when you pose the front wheels cranked all the way to one side or the other, to the limit. Monogram's '27 Bugatti Type 35B and the Italeri Bugatti Type 41 Royale also show the severe positive camber that is so characteristic of those old, solid-front-axle Bugs. Not likely that it shows in the Lindberg Bugatti Royale, or any of the Heller Bugatti kits though.

Hope this helps!

Art

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  • 2 weeks later...

Dr Cranky you said you got the kit that includes the 2x2 blocks and 8 magnets but I was checking the website and the description of the item didn't say the blocks are included. Am I wrong? :) let me know thank u and keep on creating

Edited by Hedgehog
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  • 3 weeks later...

Art... camber is the departure in angle of a tire from vertical....not toed in or out. In other words...if you look at a tire from directly in front of the car and the tire is perfectly straight up and down...a perfect 90° ..it has 0° camber. If the top of the tire leans inward slightly, then you have so many degrees negative camber. If the top of the tire leans out you have so many degrees positive camber. Camber is not toe. Toe is the parallelism of the front tires when looking down on them from the top. If the front of the tires are leaning slightly inwards as viewed from above you have toe IN. If the front of the tires are bowed slightly outward you have toe OUT. I've done a lot of front end alignments and rake never comes into play on a car except in the fact that rake and caster are the same thing....simply the angle from vertical.. As you said, the rake term is used predominately in motorcycle front ends in conjunction with measuring trail....which has a heckuva lot to do with how the bike handles!!!

Like you said.. we usually build in a very slight degree of toe IN on a front end because at speed, the front tires have a natural tendency to spread in the front...or...toe out. So with the slight built-in toe IN...at speed...the tires actually track more parallel....just like you said...but that's not camber.

I've attached a few illustrations so those fellas who are interested can see a reference graphic to make it easier to understand

Here's an illustration of camber. This is looking at the tires from directly in front...

camberexplanation-vi.jpgHosted on Fotki

And this is Toe...looking down on the tires from above...

toenew-vi.jpgHosted on Fotki

And this is caster...looking at the vehicle from it's side.

caster-vi.jpgHosted on Fotki

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Exellent description of alignment angles, Terry. I've been in the alignment and front end business myself for 20 years. I will agree with Art on the vehicles he listed as having noticable positive camber, and even add one to the list; the '88-'98 GM 4x4 full size trucks, especially if they're lifted any. The camber is very noticable, even though it's on .2-.5 degrees.

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There are three angles from vertical that are a part of any automoitive steerable front end: Camber, Caster and Rake. Now, rake can be seen on the front fork of any bicycle, motor scooter or motorcycle--just look at how the front fork angles forward from the pivot point to the front axle. That has the effect of making the bike or scooter steer predictably. Caster is just as the name implies--it's the ever so slight "spacing" of the centerline (think spindle here on an automobile front suspension, be it independent or a beam or solid front axle) slightly to the rear of the center line of the front kingpins or side-to-side pivot point of the front uprights--caster aids in making the steerable front wheels "self centering". Caster is exactly what the front wheels of a grocery shopping cart have, but much more pronounced!. Camber is almost always used as "positive camber", that is, with the front wheels pointed straight ahead (any automotive front end will have the wheels slightly "toe'd in", or seemingly steered slightly toward each other), the tops of the wheels will be farther apart than the "bottoms" of the wheels--this also makes steering easier, and helps minimize tire wear.

I think you have your caster, camber and toe muddled up a bit.

Caster and camber involve the degree of offset from straight vertical, toe in (or out) refers to whether or not the front tires are parallel to each other (when viewed from above). Caster, camber and toe are all independent of each other.

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  • 3 months later...

Dr. Cranky, it appears that one could make one of these very easily. Why couldn't one just use a ruler to obtain the same thing ? Keeping costs down for me is a huge deal so being for real, would a ruler do the same procedure ? Or the gentleman with the double square on a ruler ? I really like that idea and the squares arn't really that much at per say Harbor Freight. The amount of valuable information and knowledge that I'm receiving in my two short weeks from you guys is just unreal. I'm having a hard time remembering it all to the point I'm starting to take notes in a note book I bought specifically for model building lol.

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