Author & Automotive Expert James D. Halderman



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Halderman newsletterSeptember 2012

Welcome to the September edition of the Halderman newsletter.


For many of you, school is back in session. I hope you enjoyed your summer break. Time certainly flew by, didn't it? I hope the rest of the year finds you well, and for those educators, I hope you are ready for another successful school year. In this issue, I've got some helpful information, and I wanted to let you know that all of my titles are now correlated to the 2012 NATEF standards for MLR, AST and MAST.

As always, I want to hear your feedback, and encourage you to visit my website for learning tools, study aids and helpful information.




Straight Talk
What's new?

Now all Halderman titles are correlated to not only the older NATEF standards (2008), but also to the new 2012 standards for MLR, AST and MAST.


The correlation charts are on the Halderman website now and ready to view or download. Click on the title you are using and then click on the correlation chart you need.


Is There a Rule-of-Thumb for Rim Size?


According to the Tire and Rim Association, Inc., the answer

is no. Each tire size has a designated rim width on which

it is designed to be mounted so as to provide the best

performance and wear. The width of the specified rim also

varies with rim diameter. A 235/45 X17 tire may require

a 7.5-in. rim but a 235/45 X19 tire may require an 8.0-in.

rim. A rule-of-thumb that has been used is to multiply the

width of the rim by 33.55 to determine the approximate tire

size for the rim. For example, consider the following:


Rim width 5.0 in. X 33.55 = 167.85 (165 mm) tire

Rim width 5.5 in. X 33.55 = 184.50 (185 mm) tire

Rim width 6.0 in. X 33.55 = 201.30 (195 mm) tire

Rim width 6.5 in. X 33.55 = 218.00 (215 mm) tire

Rim width 7.0 in. X 33.55 =234.90 (235 mm) tire

Rim width 7.5 in. X 33.55 = 252.00 (245 mm) tire

Rim width 8.0 in. X 33.55 = 268.00 (265 mm) tire

Rim width 8.5 in. X 33.55 = 285.00 (285 mm) tire

Rim width 9.0 in. X 33.55 = 302.00 (305 mm) tire

Rim width 10.0 in. X 33.55 = 335.60 (335 mm) tire


Always check with the tire manufacturer as to the specified tire rim width that should be used.

ASE Sample Question

A driver complains that the vehicle darts when traveling over rises or dips in the road. Technician A says that bump steer caused by an un-level steering linkage could be the cause. Technician B says that worn rack bushings could be the cause. Which technician is correct?


a. Technician A only

b. Technician B only

c. Both Technicians A and B

d. Neither Technician A nor B





The correct answer is c. Both technicians are correct. Technician A is correct because if the steering linkage is not level, it will cause a force that steers the front wheels when the suspension moves up and down. Technician B is correct because worn or damaged rack bushings can cause the steering rack to be un-level creating a bump steer condition. Answers a, b, and d are not correct because both technicians are correct.

Straight Talk

From the August 18, Wheels section in the Dayton Daily News:



Reader asks about what size vehicle is large enough



Wheels: J.D. from Cincinnati asks:


"I am looking to downsize my daily driver yet I want to retain some passenger carrying capacity and still be able to carry groceries home. I see the specifications for the vehicles I am looking at but can you help me by providing some sort of guidelines that might help me select a small vehicle that can still be useful?"



As you are finding out, it is difficult to visualize the size of the vehicle from the specifications alone. The best approach is to actually see and test drive each vehicle that you are considering.

Some guidelines include:

Trunk- From my experience, I think that 8 cu. ft. is about as small as you should select to be practical with most full size cars having 12 cu. ft. to 14 cu. ft. of trunk space. A car with 20 cu ft. is a huge trunk and not likely to be used to its full extent.


Interior space (volume) - Here is the vehicle size class as defined by the Environmental Protection Agency (EPA) who uses this information to rate similar vehicles for fuel economy comparison purposes. The volume is a combination of the interior volume in cubic feet and the trunk volume, both in cubic feet (cu. ft.) together. Subtract the trunk volume from the total interior volume to determine the volume of the interior alone.

Mini-compact- less than 85 cu. ft.

Sub-compact-85-99 cu. ft.

Compact- 100-109 cu. ft.

Mid-size- 110-119 cu. ft.

Large- 120+ cu. ft.

Vehicles within the same class may not look or feel the same as the interior volume could include space over the dash or behind the rear seat, which could make the interior look and feel cramped, whereas another vehicle within the same class may actually feel much larger.



Length and width - I use this information because I want some room in my garage to get around. If the vehicle is longer than about 200 inches in length, then it a very long vehicle. I prefer a vehicle that is less than 190 inches long so it is easier to park. Width makes a vehicle feel small or roomy so a car that is over 72 inches wide will tend to feel roomy, whereas if it is less than 69 inches, it is likely to feel small or cramped.  



Find more Straight Talk columns here 


Please let me know what you think of the newsletter. I would love to include any of your automotive news or any tech tips you might have. Send me your suggestions! 
You can email me here or visit my website. You can connect with me on Facebook, Twitter and LinkedIn too (links above). And I encourage you to visit this website for great car reviews and more of my Straight Talk columns.
Jim Halderman
James D. Halderman writes automotive technology textbooks for Pearson Education. He is an ASE-certified Master Technician with more than 20 years instructional experience.