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Bg Racing Digital Castor Camber Gauge

Motorsport Wheel Alignment Fundamentals

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Hi all. I apologize in advance if this is hard to read.

I recently purchased a BG Racing Digital Castor gauge and 3 pin frame but I'm looking for a bit more information as the details provided are non existent when it comes to measuring castor. I've used longacre bubble gauges previously without an issue.

The issues I'm having is once I've taken the reading (steering 20 degrees one way, zero gauge, 20 degrees the other way) I'm getting a fairly low reading to what I'd expect (2.2 degrees). Searching online BG does not have any videos on using that gauge for castor measurements and does not state anything in the user manual either. Looking at the manual for the same gauge but in a magnetic hub adapter similar to the more common bubble gauges it says you have to multiply this reading by 1.5. Is this correct in both applications? The only difference between both setups is that on the magnetic adapter the gauge is faced upwards, whereas with my frame the gauge is offset 90 degrees, facing towards the front of the car. Asides from the plane both gauges are on, everything else is the same. Being a dual axis gauge am I correct in saying that it wouldn't make a difference and that multiplying by 1.5 should be done in both orientations.

The other Issue I am having is I can't tell if it is reading a positive or negative castor angle.

Any advice would be greatly appreciated.

Here is a link to my gauge and frame: https://www.bg-racing.co.uk/B-G-Racing-Aluminium-Camber-Frame

(I do have the additional 3 pin adapter not shown

Link to gauge with magnetic adapter: https://www.bg-racing.co.uk/B-G%20Racing-billet-digital-camber-castor-gauge-with-magnetic-adaptor

Kind Regards

Tom Daly

Hi Thomas,

First I think asking BG directly would be a good idea, they will know their product the best. I also went through for a look on their website, to be honest, I struggled to get much useful information from it so contacting them directly seems like the best idea. I'll give you my thoughts anyway-

Looking at the product images for the dig, it looks like both the magnetic and the frame (your type) are intended to be used with the screen facing to the side. What I mean is you would be looking at the screen from the front or that back of the car, if you looked from above you would not see it. I'm not sure what you mean about your digital gauge being rotated by 90 degrees, as that would make the screen face up/down instead, but maybe I am misunderstanding you.

This factor of 1.5 you mention, does your measurement of 2.2 include this already? Obviously, it depends a lot on the application and car, but 2.2x1.5 = 3.3 which may not be unreasonable in some applications.

Re. with is being positive or negative, one sanity check on this is to simply look at your suspension in side view. The steering axis should be sloping with the top leaning back towards the rear of the car if you have positive caster. Hopefully, this should be pretty easy to eyeball.

Again, I think clarifying with BG is probably best! Let us know what you find!

As Tim said. There is a link to the manual on the second link, where is clearly says to multiply by 1.5 for the caster. It also shows the led marker for positive and negative values although, as Tim said, that's usually pretty clear to the Mk1 eyeball.

Some of these types of guages will have the correction built in, with selectable settings, others will have two separate scales - the first one I used, many years ago, had bubbles for the values, with rockers for adjustment. Very similar (been a long time) to this https://www.wish.com/product/599ea84b0dbda835e5501336?hide_login_modal=true&from_ad=goog_shopping&_display_country_code=NZ&_force_currency_code=NZD&pid=googleadwords_int&c=%7BcampaignId%7D&ad_cid=599ea84b0dbda835e5501336&ad_cc=NZ&ad_curr=NZD&ad_price=162.00&campaign_id=9973252488&exclude_install=true&gclid=Cj0KCQjwna2FBhDPARIsACAEc_XHpln6lnydXcsUSZJ1J-2Tix1MlTvOUUBMbrxtFEEJUo3k6sn9POgaAmpcEALw_wcB&share=web

As an aside, as the relationship between the camber and KPI is fixed, it's a good idea to note it when first fitted and check it is the same for every alignment, especially if the suspension is stressed or it's had an impact, as any variation will be due to it being bent and potentially going into failure mode.

Thanks all for your help, got onto BG Racing and after a lot of back and forth it appears my gauge was faulty. It was causing the +/- not to show up and was reading on the wrong axis which was causing me to have to rotate it 90 degrees to the way it was suppose to read. A replacement showed up yesterday and have been using it today and all is good.

Thanks all

Hi Thomas,

Wow, that's pretty unlucky! I can see how confusing that would be if the while gauge was offset by 90 degrees. Glad you got it sorted.

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