Wet Road Grip

campbellju

Moderators
Staff member
The link below is to the results of tests done by RoSPA in 2005:

http://www.rospa.com/roadsafety/info/tyre_tread_depth.pdf

Their conclusion is not very exciting, when tyres get below 3mm then wet weather performance drops off. What I thought was interesting is the graph.

Although not said, I would expect you'd get the same effect on cornering and accelerating.

If your rear tyres are 4mm and and your front tyres are 2.5mm, the difference in grip levels front to back will be significant though visually there is little in it. In these winter months you might be wondering why you car is under steering so badly and be looking to coilovers as a solution.

Check the simple things first. Tyre pressures can also change in the winter months, tread depth is something else to watch for when tweaking your car's handling.

As I'm sure you all know, if in doubt, put the best tyres on the front.
 
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Fast Guy

Moderators
Staff member
As I'm sure you all know, if in doubt, but the best tyres on the front.
The only time I put my best tyres on the front I spun it at the first roundabout I came too. Much more grip of the front than rears and the outcome is only going one way....backwards. (wasn't on my gtir btw)
 

red reading

Active Member
People never seem to keep there headlight clean in the winter months either...and in shitty weather every little extra helps!
 

fubar andy

Moderator & N/W Rep
Staff member
Funny I've just set all my tyre pressures for winter last weekend and I've noticed an increase in mpg (3-4) and a little less under steer.

Braking is still unchanged however and the fronts are around 2.5mm and rears are 4.8mm
 

Jon Olds

Well-Known Member
Mostly ice. 1/4" to 1.5" thick. some slush, some soft slush, some frozen ruts. Youtube Christmas stages 2012.
Three problems;
Turn in. Hairpins, chicanes None existent. Only way on real slow ones is to dip the clutch and coast around, then the front wheels would do something. Other wise straight on.
Power on, boost straight line. As soon as it comes on boost, the back wheels want to overtake the front. And its not catchable, easily
Medium speed , grippy ish slush. A right handful to power slide in 3rd gear (assuming you haven't lost it trying to build boost in a straight line...)
Watching the 6r4's and proper scoobies it is obvious how easily they were coping with the same corners
Obviously tyres are a massive issue, but the previous year in my mk1 golf on the same rubber, similar conditions we were flying.
In short very very little fun was had
Jon
 

PobodY

Moderators
Staff member
Studded tyres for rallying?

I was driving in Finland on the studded tyres on ice roads, and I was really impressed by the grip.
 

Jon Olds

Well-Known Member
Not allowed in MSA events. Think the diffs are partially to blame also. Ideally, plate diffs front back would be the way to go
Scarey thing is it handles, grips ok in the dry
Jon
 

PobodY

Moderators
Staff member
I can understand why they may not let you. - Not great for bitumen road surfaces, and may actually be a liability since metal doesn't provide a lot of grip.
 

Jon Olds

Well-Known Member
Think its damage to the road surface. Would love to do some ice racing with them. One day, when I get rich!!
Jon
 

The Doc

Moderators
Staff member
What suspension set up are you using Jon , ie suspension travel, spring rates, antiroll bars etc as I may be able to help...pm if you prefer to keep it of the forum.
 

Jon Olds

Well-Known Member
Great offer. Just put a set of BC's on, and to be honest they have improved it a lot. Not used it on ice/snow since. Its out at Xmas (Christmas Stages: Croft: 28th Dec) so it will be interesting if it snows.

When I get some time, I will pm you some details and would appreciate any input. Suspension and settings are not my specialist subject, by any means

Jon
 
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