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1

General Discussion Area / Re: Wim

« on: 03 February 2017, 10:21:29 »

Reading the WIM forums, Im not sure Tony does anything day to day due to his health

That is somewhat true i'm sorry to say. Nevertheless i'm 10 miles and a phone call away if needed. I do however pop in and pull geometry reports from the machine to ensure standards remain and i attend any complaint if only to learn what and why it went wrong.

That's good to hear Tony 

As I plan to bring my VW CC up to you guys when it needs new front boots and a geo setup.

They are quite adjustable actually, just be sure to contact me direct.

2

General Discussion Area / Re: Wim

« on: 02 February 2017, 09:10:06 »

Reading the WIM forums, Im not sure Tony does anything day to day due to his health

That is somewhat true i'm sorry to say. Nevertheless i'm 10 miles and a phone call away if needed. I do however pop in and pull geometry reports from the machine to ensure standards remain and i attend any complaint if only to learn what and why it went wrong.

3

Omega General Help / Re: Full Geometry setup done - Nigel Langs Bolton - WOW WHAT A DIFFERENCE

« on: 07 May 2014, 09:29:07 »

Lang's are very good, nice to see they use the revised geometric positions i wrote for the Omega and gave them. Pete is top of his game in regard to customer care and never to ashamed to call me if he has a problem outside of the box.

4

General Car Chat / Re: Zero toe

« on: 17 March 2014, 10:29:36 »

Polly's and rose joints historically run zero toe regardless of drive. Nevertheless the toe tendency needs to be witnessed during the camber curve and that tendency will differ between suspension modifications and general compliance. 

Ackermann has nothing to do with toe.... Ackermann is the geometric steering radii differential during yaw whereas toe is the longitudinal position measured static, calculated for a dynamic condition.

Ackermann/ toe has nothing to do with lock angles. The lock angle will support Ackermann disparity which is assumed globally at 1 degree 30' measured on a 20 degree lock. Agreed if the lock angle was increased the Ackermann would/ could hold the lock position but this event would be very unusual.

Point to note and this may come as a surprise all geometric settings suggested by the manufacture are nothing more than that "suggestions". There is no absolute law the suggestions will work for everyone? Chris has issues with tyre wear so the complaint and live geometric measurements need to be correlated in order to evolve totally new positions.   

5

Omega General Help / Re: Wheel Alignment

« on: 14 March 2014, 11:24:10 »

There are distinctive clues when it comes to vibration, the clues are not the law but offer direction.....

Vibration under 20mph suggests a distorted tyre or wheel
Vibration at say 60mph that disperses at a higher speed suggests a wheel balance frequency
Vibration at the seat suggests the rear is the focus and at the steering wheel the front is the focus
Vibration under torque suggests a drive-train problem
Vibration under braking suggests brake pad matter contamination or drive flange problem. Don't be fooled it's near impossible to warp a brake disc. 

6

Omega General Help / Re: Wheel Alignment

« on: 13 March 2014, 13:46:09 »

The vibration is a wheel balance problem, the steering position is geometric.

Regarding the wheel balance the wheels need to be mounted on the machine by the stud holes, not the wheels centre hole. Reason for this is the centre hole is cosmetically central....... Sad to say this is why French cars have solid centre wheels meaning there's no option other than balance them via the stud holes.

7

General Car Chat / Re: Rear camber adjustment theory question

« on: 17 January 2014, 11:18:53 »

Most have been an attempt at some point to adjust the camber. Does the cam have a ledge to push against?

8

General Car Chat / Re: Rear camber adjustment theory question

« on: 16 January 2014, 10:51:40 »

Yep it's for the toe, not the camber...... The off-set D-cam washers have a tooth that fit into a female cut out in the through bolts. When turned the washers push/ pull against the horseshoe surround. 

9

General Car Chat / Re: Tracking..... What is it and why is it?

« on: 19 December 2013, 12:09:06 »

so whilst youre on can I ask how much youd charge to correctly align my car based on the image of my current readings? pm me if you prefer

I need to be careful here because the forum has given me great leverage over the years but in this case i feel a real image of realistic pricing might help members know what to expect elsewhere.

I can't quote for the entire country but i would like to offer a smattering of knowledge....

If you are told a "free alignment/ geometry check" then that's hook so ask what is any adjustment fee in advance?

MD will offer a total fee. This is regardless of the corrections made so top dollar.

We offer members a worst-case fee of £60+ vat including adjustments assuming the front subframe doesn't need moving, if it does then it's £95+ vat ( worst case )

Now in my tiny little mind the adjustability of the Omega doesn't command more than the normal discounted £60+ vat. Data positions are established so to me the calibration is fire-and-forget type of thing.

Thank TheBoy for this because he is the one who's helped me maintain the price structure without change for the last five years.... Think i might need to send him a letter bomb for Xmas 

10

General Car Chat / Re: Tracking..... What is it and why is it?

« on: 19 December 2013, 11:46:40 »

Chris has raised some good, valuable points that members need to heed before spending a penny on wheel alignment.

Let's try this..... There you are in the tyre shop wanting the front wheel alignment checked/ adjusted would you dare to ask what they are aligning the front wheels to?

I bet my left nut they say each-other......"WRONG!"

The front wheels don't actually know where forward is, is it \ \ there or / / or | |? The front wheels point of reference is the middle of the rear, called the Thrust angle.

The Thrust angle is a geometric law despite the drive formate. The Thrust position is generated by each rear toe position. In an ideal world both rear wheels would have the exact toe position and within the tolerances permitted, but it's not an ideal world.

Globally a tolerance displacement of the thrust is 10', this has been downgraded from the 30' permitted some years back. The Thrust position establishes an imaginary centre line that's projected to the front wheels forward direction. From that data each front wheel can be adjusted to the forward direction born from that reference point.

It's from that i say to you "front wheel alignment" is a con, reason i say this is on it's own there's no reference point so.... What are they aligning the wheels to?

11

General Car Chat / Re: Tracking..... What is it and why is it?

« on: 19 December 2013, 11:17:15 »

+1.

Very informative.... especially regarding the toe as I was led to believe it's this that is the most aggressive tyre wearing angle! And also that it can't create pull! 

That's the tyre industry talking to you.... Reality is the toe displacement offers lateral scrub to the tyres. In the event to toe position is wildly out then you as a driver would definitely know with the car bolting on/ off bump and white lines.

The front toe is the only angle that's shared between the front wheels. Since it's shared it's also symmetrical so of an equal force... Can't pull.

12

General Car Chat / Re: Tracking..... What is it and why is it?

« on: 19 December 2013, 11:12:03 »

But an out of line thrust centre(combined rear toe) can. (Make the car crab)

So given the desired rolling toe setting is zero, that's alot of rolling resistance to give +0.10 mins static. Would poly give less deflection from rolling resistance? Given the comparatively soft oe bushes.

Yes polly's or rose joints would be set to a static zero toe front and rear.

13

General Car Chat / Re: Tracking..... What is it and why is it?

« on: 16 December 2013, 10:51:12 »

Well you all seem very clued up on the topic so well done team....

As said the toe is a compliance angle.... Compliance as in the expected movement in the bushings under thrust/ tyre rolling resistance and braking force. The globule desire for the collective forces is a dynamic 0 toe.... This is the geometric law no matter what form of drive the car has albeit rear/ front or all four.

The suggested differences in the toe position over the marques is due to the bushing size and configuration. The downside is the variables? These suggested settings are all well and good for a newish car with lovely fit bushings but our cars live most their lives in the realm of worn........ Not new and not knackered but worn.

As an instructor i know operators/ calibrators in the field cannot work in an ideal world where the suspension and bushings are lovely and new so there has to be a realistic compromise..... How?

An initial visual check of the suspension, bushings and running gear like steering box and so on. Measure the chassis ( before the car is jacked up ) so that a "rested reading" is taken before the suspension/ bushing positions are violated.

Once proved the car sits happily in the realm of worn they can then simulate the tyres dynamic rolling resistance by installing a spreader rod? This is a sprung loaded bar that fits under the car and pushes the front tyres apart ( rolling resistance )

Once done and with live readings on the screen the toe tendency needs to be found?

Toe tendency what's that?
Remember we are in the realm of worn! Well every cars actual toe setting with differ depending on the level of worn. So with the spreader rod fitted a bounce on the suspension ( bump ) and a lift on the suspension ( droop ) within the expected range of travel they should be able to calculate the toe tendency.... Once read the static adjustment should be made at the centre of that tendency.

Example
Lets say the manufacturers suggested toe setting is +2mm total for the front wheels. I use mm because most tyre centres measure in mm although this is not really the correct way to measure the toe position! Anyway 2mm toe total, meaning a collective measurement between both front wheels.

If the cars bushings are tired and the steering linkage a bit "energetic" lets say, then with the spreader rod fitted and the tendency calculated the actual static toe position might need to be +6mm, giving that car a dynamic 0 toe.

Sad thing is after reading this you will know more about the toe angle than most tyre shops, and it's for this reason i post in great forums like this so that you get a heads up in the industry i work in and embarrasses me constantly.

Final note..... The toe angle is the least damaging, least influential regarding tyre wear and it CANNOT make the car pull!

14

General Car Chat / Re: Tracking..... What is it and why is it?

« on: 15 December 2013, 11:03:12 »

Q is why is there a toe in/out position and why does this vary between marques.

Remember team this is not designed to be a test nor is it designed to belittle any answers.... It's simply designed to help understand what your £30 or £40 quid is paying for.

15

General Car Chat / Tracking..... What is it and why is it?

« on: 15 December 2013, 10:38:12 »

Born from another post i thought i could add a little understanding on this topic which is actually under the realm of chassis geometry....It's not a grey art so don't run away.... 

If we just concentrate on the front wheels for now and the toe position AKA
1: Alignment
2: Tracking
3: Four wheel Alignment

Historically the manufacture offers a static toe in or toe out position with a given tolerance.... Question to you is why?