Any recommendations for tyre pressures with AO48s?
Oh you so need to do a search!
Yeah, but was being a lazy arse.
There are so many opinions and, from past experience, we’ll just end up causing more confusion than help!
Ian
Ok, so I ran 20 up front and 22.5 on the rear (cold).
These seemed to work fine but I got a lot of feathering on the outside of the rears after a couple of sessions.
After a couple more the rears seemed to melt with loads of tread coming adrift all over the surface.
Did I run too low, too high?
Could have pushed it a bit more I think (worst 49secs best 47 something secs) but felt that the tyres were “going soft”.
Any advice?
cheers
Yep, get yorself a pyrometer to measure across, as the pressure depend on:
-how hard/long you run on track
-outside/track temps
-geometry settings
Yep, get yorself a pyrometer to measure across, as the pressure depend on:
-how hard/long you run on track
-outside/track temps
-geometry settings
And springs, dampers etc …
I think you were too low though …
And as you’re a “lazy arse” steve (your words not mine ) see here for a good value pyrometer - click
What do you mean too low? Is there such a thing?
I had no scrapes on the wheel arch liners and no grounding on the curbs. How do I change the suspension settings?
So I take it I should be looking for 70 degrees on the middle/inside and 80 degrees on the outside?
I’ve so much to learn
I’m not sure the temp is important, more the consistency across the width.
As I understand it, 10o less in the middle means it’s getting less action and is sagging in the middle giving less contact, ie. pressure too low. So pump it!
Ian
Sorry I meant too low on tyre pressure
So I take it I should be looking for 70 degrees on the middle/inside and 80 degrees on the outside?
You should be looking for even temps across the tread.
Well they felt even across the tyre using my trusty manual pyrometer (i.e. hand), there just seemed to be an awful lot of tread coming off them. Perhaps I was driving very fast and I’m an undiscovered driving God?
They looked ok to me Steve, no worse than i’d have expected anyway in my very limited experience.
Pressures, I normally use are 22F, 24R cold although i’ve not done enough track time yet to know if this is particularly good or not. Feels ok to me though.
steve
i think your pressures sound not too bad… so i’d say its either 1. normal wear and your just not used to seeing it or 2. you need the geo checked.
Also I seem to remember that if you use a pyro the temp difference should be approx. 10C from outside edge to inside edge ?? no ?
Why do you think that Rox? Surely you’re then not using all of the tyre (with the outside edge working harder)? Or am I just being impractical?
Randy (and others), your opinion would be of interest.
Ian
I run 28 front 29 rear when HOT. Although I would say anything above 25 PSI is O.K
I used to run them alot lower (21/23) and they would wear at the outer edge very quickly!
Set them to about 23 all round when cold then go out and do half a dozen laps. Come in and adjust them accordingly.
Steve T
There are so many opinions and, from past experience, we’ll just end up causing more confusion than help!
Ian
Never !!!
Ther are lots of factors here, as kinetic points out.
Those pressure are waaay too high, but that would be for MY geo setting (close to 1 deg front camber, stock rear camber)
With the stock camber (<1 deg) I would wear the edges with the high (stock) pressures.
So, there you go, get a pyrometer and measure across. Adjust geo accordingly.
kinetic, I bet that if you use a pyrometer you’ll measure higheer temps in the middle and outside edge than in the inside.
Get yerself more camber (are you running stock?)
Uldis
Kinetic’s car is actually a Motorsport Elise, which he runs in the Mid Engined Series. It was prepped by Gav Kershaw (latterly by Plans), & has a race set up in terms of springs, dampers, front anti roll bar, & geo.
Gav used to run 28psi all round when he was competing in the series.
In other words, what suits one car, may well not suit another