Jump to content

Camber how much is too much ?


Recommended Posts

Sorry just realised posted on wrong area.

Hope you dont mind ?

 

You guys will have the answers Im sure.

 

Hi folks

Once a have sorted my gearbox oil leak ( unlike Roger with his 4, its too cold for me in the garage)

 

I was going to have a play with the camber of my 3a that I Sprint and hill climb.

 

I have a stack of parts from a 4 to put on the front. Including shortened (by how much I dont know !?) Top wish bones. 4 trunnions (for a bit of caster) new polly bushes etc.

 

Can you have too much ? Im thinking of going to 3 deg camber.

 

Im also going to try 420lb front springs

 

Already have uprated rear springs.

3/4 front anti roll bar.

 

Im trying for better cornering

And may be stop a rear wheel going light and spinning loosing drive.

 

As Im in for only couple hundred quid on ALL my parts I think its work a try.

 

Current tyres 185/70x15 vredestiens.

But I may consider some maxsport 185/55x15 5rb Tarmac soft rally tyres ?!?!?

Edited by Hamish
Link to post
Share on other sites

I should try 1 deg neg camber first, how will you get the tyre surface onto the floor with uprated springs and a "buqqer" off dia anti roll bar ?

 

The car will be like a go kart and cross car weight transfer won't allow the suspension to move ! "Softly softly Catchy monkey".

Invest in a practice day at your local track will provide good feedback, go with a mechanic or mate and make 1 change at a time and write it down what you do. Take a camber guage with you or make your own, make changes and judge by the stopwatch.Try and drive constant effort laps which normally means about 80% pace and use the stopwatch to define what effect the changes make. DON'T make a decision on spec upon how the car feels, to make the car quick you make it unstable, that's how you get rapid changes in car direction, the laps which feel the most comfortable where the car turns in easily are normally slower. Hopefully 3/4 of the way through the sessions you'll start to see a pattern which can define how the spec you are changing are making the car behave, then try for some hairy laps and see again how the car reacts and what you can do to make it better.

 

There are very few cars that will run over 2 deg neg camber and benefit from it.

 

Mick Richards

 

PS:

About 10mm out of the top wishbones seem to give reasonable camber which gives good results.

Edited by Motorsport Mickey
Link to post
Share on other sites

Hamish,

Something else to bear in mind.

Sorry I only know of my TR6 but I was unhappy with cornering, hard to pin down - more of a feeling that something was not right. After lots of playing and making changes which affected the cornering this “it’s not right” feeling remained. Car has a new chassis and suspension etc is all new components.

In the end I took the car and had it corner weighed. Result showed the car was thirty five kilos lighter OS front compared with NS front. OS front spring was shimmed (3mm I think) to achieve equal front wheel weighting. Car then sits on all four wheels with equal weights.

Car handling was immediately noticeably different, hard to describe but more stable. I suppose the words would be better balanced and more predictable in cornering.

Cost was £25, a real bargain considering the results.

 

 

Alan

Link to post
Share on other sites

Hi Mick

 

I do know what you mean about 1 step at a time and the sense in track time between alteration

 

But I fear my changes mean too much spanner work between test runs and Id spend more time on axle stands.

 

Last year a mate weighd my car with his car scales.

Results

Car weight/balance.

 

Aprox 1/2 tank fuel.

No tools, spare wheel, windscreen, empty boot.

Total race weight 933kg

LF. 258kg

RF. 246kg

LR. 219kg

RR. 210kg

 

We were happy with the figures and I did last season with this

Apart from last hill and sprint with the 7/8th anti roll bar rather than the original 9/16th

 

H

Edited by Hamish
Link to post
Share on other sites

Do not forget the caster!

It increases steering forces but either makes a more stable on the straight

and also makes somewhat more camber when the steering is turned in.

 

TR3 originally had 0 degree caster and later the 3B

started with the 2.45 degree what can be swapped into the TR3.

 

I found it very positive to increase that on the TR6 much

more to about 3.45 degree. High speed is no more a

problem like it was before!

Link to post
Share on other sites

Hamish,

I'd add to Mickeys wise words to invest in an IR temp gun, of better (and a lot more expensive) a tyre temp probe.

After a test session, three laps is enough once the tyres are up to temp, come in and ASAP - station them at the pit entrance - have them measure and record the temperature of the tyre treads, across the tread.

 

You're looking for a spread that is even, or even across mid to inner, to show that when the tread are working, in a corner. the traed is flat to the tarmac.

 

It'll also tell you if the pressures are right, too high will concantrate heat in the middle.

 

Bests

John

Link to post
Share on other sites

Thanks guys

 

I will keep all the advice in mind.

I have an IR thermometer but not sure 185s would show much temp hot spots.

The pics above show lots of tyre lean. Thus I am trying to straighten up the lean on to the tyre rather than have it tuck in so much.

 

Doing gearbox at the mo tho.

 

Cheers

H

Edited by Hamish
Link to post
Share on other sites

" but not sure 185s would show much temp hot spots. "

 

I'd suggest that they will indeed show an amount of temperature spread, although from past experience following a similar procedure to John's recommendation then only the first tyre tested with the thermometer can be reliably assessed - the remainder will be experiencing heat equalisation by the time you get to them.

 

The quick and reliable way is to have two thermometers and operators available, and measure the two tyres of one axle simultaneously. It works, and it's the sort of small incremental advantage that wins championships . . . . been there etc !

 

Cheers,

 

Alec

Link to post
Share on other sites

Alec's wise words are a demonstration of how competition is the best way of making a fortune - for parts and tools suppliers.

 

So, if you're in mind to spend some more of your fortune, here's an interesting article, about measuring tread temperature across the tread on the track and in real time.

Three remote IR sensors on each wheel, connected to a datalogging system that can be downloaded at a pitstop, and analysed in concert with all the other suspension and engine data.

How much? Don't ask! Although I think this is a Formula Student project, even those have a budget in five figures.

 

https://www.micro-epsilon.co.uk/press/publication/pub-uk--2008-04--Monitoring_tyre-temp.pdf

 

And for those with a budget in seven figures, you may have seen the short sequencies on F1 TV of an IR camera focussed on the front tyres.

Here's an equally short video, that clearly shows how the high negative camber causes the tyres to ride on their inner shoulders on the straight, where that is the hottest part of the tyre, allowing the whole tread of the outer tyre to be evenly pressed to the road and heated in a corner.

 

 

 

John

Edited by john.r.davies
Link to post
Share on other sites

The F1 tyre temps in use are mesmerising ever since they've been shown over the last decade but the real epiphany when you watching the changing colours is that the springs actually work.

You can see the tyre temp react microscopically as the cross car weight transfer is controlled meticulously being fed in and let out with the spring compressing and the camber change allowing the tyre to contact across the entire surface increasing grip. A real rap on the wrist to those drivers who set up the handling by altering the tyre pressures, changing the tyre pressures from the determined amount which allows best temps across the tyre is compromising the grip by one end or the other and changing the handling. You make the car as whole handle better by degrading the grip at one end, far better to increase the grip at both ends and balance the grip between them to increase the grip as a whole.

There are too many cars where the suspension is set so it is only correct maybe a couple of times a lap, normally those cars where their basic sports car suspensions behave so poorly the drivers set them impossibly hard so to limit the suspension change and the negative affects. Like a stopped watch which at least then is correct twice a day.

Always run with the softest suspension settings you can use.

 

Mick Richards

Edited by Motorsport Mickey
Link to post
Share on other sites

 

Result showed the car was thirty five kilos lighter OS front compared with NS front. OS front spring was shimmed (3mm I think) to achieve equal front wheel weighting. Car then sits on all four wheels with equal weights.

 

 

 

 

That's not usually how it works, Alan. Actual wheel weights will seldom be the same. Look at Hamish's quoted wheel weights. Nearly a fifty kilo spread. Now go online and punch the numbers into one of the many available online corner weight calculators. In terms of what matters the results are very good. It's all rather counter-intuitive and impossible to sum up in a single post even if I could.

Which I can't.

I seem to remember going through this exercise many, many moons ago along with Mick on the TR7V8. We didn't have corner scales. We had a lever device that lifted the wheel rim and gave a reading on a scale. The readings were seemingly a bit various until we worked things out on paper. No online trickery in those days! Results were within a few percent of ideal so I think we just left things alone.

And in relation to the OPs question...

I can't believe that we have a thread discussing TR handling and no-one has mentioned bump steer!

Tell him Mick!!

Link to post
Share on other sites

That's not usually how it works, Alan. Actual wheel weights will seldom be the same. Look at Hamish's quoted wheel weights. Nearly a fifty kilo spread. Now go online and punch the numbers into one of the many available online corner weight calculators. In terms of what matters the results are very good. It's all rather counter-intuitive and impossible to sum up in a single post even if I could.

Which I can't.

I seem to remember going through this exercise many, many moons ago along with Mick on the TR7V8. We didn't have corner scales. We had a lever device that lifted the wheel rim and gave a reading on a scale. The readings were seemingly a bit various until we worked things out on paper. No online trickery in those days! Results were within a few percent of ideal so I think we just left things alone.

And in relation to the OPs question...

I can't believe that we have a thread discussing TR handling and no-one has mentioned bump steer!

Tell him Mick!!

Link to post
Share on other sites

Micks been great with advice.

Inc bump steer. I have the revington Ackerman steering arms fitted etc.

 

H

Link to post
Share on other sites

Alec's wise words are a demonstration of how competition is the best way of making a fortune - for parts and tools suppliers.

 

 

It's very easy to make a small fortune in motor sport. All you need to do is start with a large fortune!

 

Pete

Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

Please familiarise yourself with our Terms and Conditions. By using this site, you agree to the following: Terms of Use.