On my Clubbie I have found that the tyre presure that I run is crucial to the ease with which the wheels will lock-up. Given the fact that the physics is the same for a Morris Minor I can't help wondering what sort of tyre pressures people are running in their cars, especially when they have gone to modern radials and or wider wheels. My clubbie runs at just 18 pounds front and rear much more than this and I get bugger all traction and easy lock up, it only weighs 630 kg where as a Morris weighs what, a bit over 700kg? (according to what I've read)
Has anyone done some serious experimenting with tyre pressure to find the optimum for modern tyres to get a better trade off between traction and economy?
Disc Brakes on rear?? any ideas
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- Minor Friendly
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Re: Disc Brakes on rear?? any ideas
The fun has begun!
Re: Disc Brakes on rear?? any ideas
I use tyre temps to set my pressures. If they are too hard then the centre will run hotter than the inside and outerside edges, too soft and the inside and outer edges will be hotter.Iain Hall wrote:
Has anyone done some serious experimenting with tyre pressure to find the optimum for modern tyres to get a better trade off between traction and economy?
Re: Disc Brakes on rear?? any ideas
If I run any less than 30 psi - the handling is like driving a jelly........ But I agree that on a wet road it can be all too easy to lock wheels - but then the tyres are not exactly high tech.... I do drop the pressure to ~ 24 when I take the car for it's annual test - so they will grip the test rollers rather better. 18psi sounds very low - do the tyres not get very hot - no side wall cracking problems ??
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Re: Disc Brakes on rear?? any ideas
bmcecosse
My Clubbie weighs just 630 kg so 18 PSI works out just about right in terms of getting the right balance between reducing rolling resistance and maintaining traction, in fact the car is so light that when I have a flat I can still drive the car. I am getting two new tyres on the back tomorrow as i am finally replacing the the rubber that was on the wheels when I bought then second-hand off eBay five years ago. I expect that the tyre fitters will be as surprised as you are when I tell them that I want them set at 18psi.
The fun has begun!
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Re: Disc Brakes on rear?? any ideas
That sounds very sensible for getting optimum grip and even wear...I use tyre temps to set my pressures. If they are too hard then the centre will run hotter than the inside and outerside edges, too soft and the inside and outer edges will be hotter.
How long do you drive before checking temps and does it need to be mainly straight road?
I've seen a lot of Minor tyres worn low in the centre due to excess pressure - probably a growing trend as more people want the extra half an mpg.. Certainly the 'feel' of the Minor is more similar to a modern car when the tyre pressures are high.
Ray. MMOC#47368. Forum moderator.
Jan 06: The Minor SII Africa adventure: http://www.minor-detour.com
Oct 06: back from Dresden with my Trabant 601 Kombi
Jan 07: back from a month thru North Africa (via Timbuktu) in a S3 Landy
June 07 - back from Zwickau Trabi Treffen
Aug 07 & Aug 08 - back from the Lands End to Orkney in 71 pickup
Sept 2010 - finally gave up breaking down in a SII Landy...
where to break down next?
2013... managed to seize my 1275 just by driving it round the block
Jan 06: The Minor SII Africa adventure: http://www.minor-detour.com
Oct 06: back from Dresden with my Trabant 601 Kombi
Jan 07: back from a month thru North Africa (via Timbuktu) in a S3 Landy
June 07 - back from Zwickau Trabi Treffen
Aug 07 & Aug 08 - back from the Lands End to Orkney in 71 pickup
Sept 2010 - finally gave up breaking down in a SII Landy...
where to break down next?
2013... managed to seize my 1275 just by driving it round the block
Re: Disc Brakes on rear?? any ideas
I can not remember the exact distance (10 miles?? ) but is was the A1 which is straight enough then I could pull straight off into a layby and jump out and measure the temps.rayofleamington wrote:That sounds very sensible for getting optimum grip and even wear...I use tyre temps to set my pressures. If they are too hard then the centre will run hotter than the inside and outerside edges, too soft and the inside and outer edges will be hotter.
How long do you drive before checking temps and does it need to be mainly straight road?