Toe In Tool

RichardEntrekin · December 22, 2018, 07:12:36 AM

Since this is a DIY forum, I thought I would post a link to a spreadsheet I conjured for setting the toe in using lasers or string.

https://docs.google.com/spreadsheets/d/1Uz_eF4Pa3UdK4DcuwkhxafAHxJNq8H7YftiVk7WBzGg/edit?usp=sharing

This spreadsheet is in Google Sheets, so if you download the free Sheets app to your phone or pad, then you can use the Sheet live at the worksite.

Most may be familiar with the technique, but let me elaborate on the concept. Using string or lasers mounted to the flat part of the rim, line or laser is projected in front of the coach. The first tape measure is setup close to the front end of the coach, the second tape measure is set up a distance away from the coach. I find 40 forty feet or so to give good resolution on 1/32 increments in toe in.

The laser mounted to the flat portion of the rim is self explanatory. If using string, and easy method is to put a fish hook on one end, catch it on the tire and pull across the flat of the rim, adjust the far end till the sting just barely kisses the flat. The idea is to have the taut string aligned with the flat.

I put the tape measures on jack stands at the same height as the string on the rims.

There are other techniques for using string or laser, but the two tape method significantly reduces any error introduced by runout of the jig at the wheel. However, if you use a laser, it must be parallel to the base or the results will not be usable.

Enjoy, I hope it helps you with an otherwise tedious exercise in trigonometry. Just trying to give back, since I have learned a lot from this forum.

dtcerrato · December 22, 2018, 05:10:12 PM

Richard, thanks for posting the info, unfortunately its all Greek to me. We recently had our bus front end aligned. Can you explain to me in layman's terms the attached alignment readings that were the results of our bus being aligned. Would surely appreciate it. Thanks in advance.

RichardEntrekin · December 23, 2018, 04:59:45 AM

Dan,

Dang, most printouts of before and after are much easier to decipher. When I opened the the attachment and saw Josams, I knew I couldn't help. I took my coach there a couple of years ago, and the printout made no sense to me then, and yours makes no sense to me now. I am not going to guess about their symbols and what they mean.

Sorry I can't help you.

dtcerrato · December 23, 2018, 05:14:03 AM

Thanks for the honesty Richard, thanks for the feedback.

Jim Eh. · December 23, 2018, 06:50:20 AM

First page from left to right:

LH Camber/LH Toe/Axle Setback/Total Toe/RH Toe/RH camber
Far right - Axle thrustline (Not measured)

Second Page:

LH max turning radius/LRH Toe out in turns(?)/LH KPI (Center is Caster LH + RH) RH KPI/RH Toe on on turns(?)/RH max turn radius

KPI = King pin inclination (a check for a bent axle)

lostagain · December 23, 2018, 06:58:56 AM

All Greek to me. I have always simply measured toe-in with a tape between the wheels. We are only dealing with 1/8th to 1/4" differences, which can be adjusted easily.

JC

luvrbus · December 23, 2018, 07:40:27 AM

I have used the Bosch 3 plane laser for years for alignment,but I have always owned 3 axle buses except for a MCI 5

dtcerrato · December 23, 2018, 10:48:16 AM

Thanks for the replies guys.
Wow Jim that was a fast translation to turn the Greek into usable language... appreciate that...

dtcerrato · December 23, 2018, 11:05:56 AM

One thing that I noticed & would like to mention is that the printout has much more info about the front end & bus in general than meets the eye.
Jim you must have been involved in or have direct knowledge pertaining to vehicle alignment.

luvrbus · December 23, 2018, 11:26:28 AM

Quote from: dtcerrato on December 23, 2018, 11:05:56 AM
One thing that I noticed & would like to mention is that the printout has much more info about the front end & bus in general than meets the eye.
Jim you must have been involved in or have direct knowledge pertaining to vehicle alignment.

Most bus owners just recognize the toe end there is lot more to it than just the toe end

Jim Eh. · December 23, 2018, 10:33:45 PM

We used to do all the suspension and steering setups and alignments for New Flyer whenever they had completed units rolling out of their Winnipeg facility. Everything from the "short bus" to the 60' bendy buses. We even swapped out 1/2 dozen defective traction motors on their trolley buses headed for BC. Those 300 HP electric motors are heavy.