SR4 Owners Manual

[splitpin]

Good news is that one can now actually open it up online, no longer being rewarded with that for the SR8!

Not so good news is that it seems to be exactly the same as the old one with a new cover.........low downforce tyre pressures still shown - fine those are still applicable to LD Sr4s....but strangely (and worrying?) no mention of the considerably higher ones recommended for high downforce spec cars, without which (according to that Bulletin a few months ago) there could be dire/dangerous consequences.

Mmmmn

[ScottHughes]

I assume you don't know the right pressure's for higher downforce cars hence your post? I didn't think it was different? I would be interested to know if I will need to run higher pressures when I fit a wing and front diffuser etc to my clubsport?

[Simon T]

start with 23-24 psi cold

Simon

[ScottHughes]

Thanks Simon... is that for radials? and would crossplys be different? I not sure what I am going to run this season yet?

[SportsLibre]

That must be for Radials, Crossplies should be much lower, I wouldn't go for much more than 15 (cold), on the hillclimbs and sprints I have used as low as 10, now use about 12 or 13.

[splitpin]

ScottHughes said:

I assume you don't know the right pressure's for higher downforce cars hence your post? I didn't think it was different? I would be interested to know if I will need to run higher pressures when I fit a wing and front diffuser etc to my clubsport?

No, it wasn't that; It was mainly to let people know that Radical have finally got the SR4 OM back online - someone was after one a while ago (nick997 kindly bailed him out) but others might want to download.

My additional point about the tyre pressures (omissions as I see it) is exactly that; with an SR4 (sorry don't know about any other Radicals) they are different (very different) according to whether or not it's a HD or non HD spec car; it relates back to an old thread about Radical (Dunlop) issuing a Bulletin about tyre pressures on HD Cars: unfortunately, I didn't save it, but 21lb cold I recall (can't recollect hot but I think it was 28lbs) whereas the OM's still gives the pressures as 14/16lb Cold, 20lb hot; as I confirmed with Radical themselves those lower pressures do still hold good for non HD Versions and the Bulletin only applies to HD Cars. My surprise is that given it was in effect a high priority Safety Bulletin when it was issued, that the latest version of the OM still doesn't make this clear.

To my mind, this lack of precision could mean that if someone with an HD car just looks at the OM and doesn't know about the Bulletin, there's a chance they'll run with way too low pressures and have a tyre come off etc, whereas someone with a non HD car who knows about the Bulletin (but hasn't looked at the OM) and thinks it applies to his car could run with way too high pressures and quickly say hello to the gravel etc!

[Simon T]

Scott, yep for Radical Dunlops. For anything else depends on the car, the tyre and the track/air temp. I've never run Xplys so no idea but for a small sports proto on radials I would start at 20 psi cold and dial the pressures in based on tyre temp when hot

Hope this helps

Simon

[ScottHughes]

Cheers Simon.. Probably going to use Dunlops anyway so thats a great help thanks