Talk Morgan Forums Morgan Sports Cars Morgan Three Wheeler & Super 3 air pressure and bump steer

I have never had an issue with bump steer in my M3W. Until today. This morning I checked air pressure and found it say 5 lbs. light so pumped them up to 22 lbs. went on a drive and felt bump steer for the first time. I think I will let some air out tomorrow and try something around 20lbs. Just sayin!

You've got your work cut out for you if you want to experiment. My first encounter with really bad bump steer was hitting a pothole that didn't look deep (lower seating = not great perspective) two weeks after delivery. Inspected the wheels, fearing the worst. All was well but one tire at 17 psi, one at 27 psi, 27 psi rear. So much for PDI. Anyway, played with the psi a bit, settled on 34 psi front, 37 psi rear. Works for me, may or may not for you. The fronts max at 42 psi, but I wouldn't go higher than 34 psi in the front. Always a bit higher psi in the rear tire.

Hi
I found 18psi to be optimum for reduced bumpsteer good grip and long tyre life.Of course the comfort pack sorts out any bumpsteer.
Regards David

How did the factory come up with the recommended 22 psi front & 25 psi rear? I assume it was more scientific than a wet finger test or picking them out of a hat. Is it not an offence to run tyre pressure much lower than recommended?

Tim.

After I found that my car handled better with lower tyre pressures I told the factory of my findings when my friends car was returned after some work by the factory we found that it had 18 psi in the front and 25psi in the rear.
The M3W is still in development.

David

As far as I know, not a specific offence in the UK*, but running any motor vehicle in a dangerous state is both prosecutable and may invalidate insurance. But I'd be surprised if anyone was stopped for 17.

* I think running pressures other than the recommended may be an offence in some parts of the world

I ran my Avons with 19 psi unknowingly as my air gauge was wrong. It resulted in the outside wearing fast while the middle looked almost new. Have since found two accurate gauges, one digital and the other analog. The tires were replaced at around 8,000 miles with Blockleys along with the 'comfort steer' kit.

Bump steer is gone and I'm running the front end at 24 psi with great improvement.

Personally I found with the Avons that running them even a couple of psi lower than the factory 22psi was very noticeable, led to unpleasant steering, added understeer and a real feeling of the tyres trying to leap sideways off the rim.
But each to their own...

Have you seen those videos of the M3W taking a hairpin turn and the front tires looking like they would fold right over the rim? Not good. I think it was the so- called comparison with the Caterham 3. or something

My car came back from Service yesterday - just checked the TPs ....NS 22psi OS 21psi