Winter tyres vol 2

[Munter]

Pica-Pica said:

It was always said that a locked wheel and a ‘snow-wedge’ building up in front of the tyre was best.
However the ABS concept was to allow steering while braking.

What we need is a test in normal UK winter commute conditions.

~4 degrees C.
Damp/drizzle.
Salt from last night.
Potholes/failing "manhole" covers.

What's best then for a "surprised and unprepared" average driver who will mash the brake pedal as hard as they can until the car stops?

[anonymous-user]

MikeStroud said:

300bhp/ton said:

Some useful videos here that everyone should find informative

ABS takes longer to stop on snow/ice:
https://youtu.be/fge_m9u864k

Wow that was an eye opener for me.

I thought modern ABS systems were meant to recognise that they were on a very low coefficient of friction surface (snow) and allow the wheels to lock up, but that's a pretty recent model and it is as pants on snow as ABS has always been.

Where is Max_Torque when you need him

[RicksAlfas]

Pica-Pica said:

It was always said that a locked wheel and a ‘snow-wedge’ building up in front of the tyre was best.

The original Audi Quattro had a switch for this very reason, so you could turn the ABS off.


My first car with ABS you could just pull a fuse out. Things have become a lot more complicated since then!
There is nothing worse than the ABS kicking in on a snowy descent though. The car feels like it's running away.

[300bhp/ton]

Munter said:

What's best then for a "surprised and unprepared" average driver who will mash the brake pedal as hard as they can until the car stops?

I wonder, in such situations with such Average Jo's, how many would actually steer when equipped with ABS or would they just mash the brake pedal as hard as they can until the car stops/hits something?

[jon-]

stickleback123 said:

MikeStroud said:

300bhp/ton said:

Some useful videos here that everyone should find informative

ABS takes longer to stop on snow/ice:
https://youtu.be/fge_m9u864k

Wow that was an eye opener for me.

I thought modern ABS systems were meant to recognise that they were on a very low coefficient of friction surface (snow) and allow the wheels to lock up, but that's a pretty recent model and it is as pants on snow as ABS has always been.

Where is Max_Torque when you need him

Most ABS systems will start locking once below ~5mph where steering isn't as big a factor

[300bhp/ton]

jon- said:

Most ABS systems will start locking once below ~5mph where steering isn't as big a factor

Is this a recent change? Don't think I've driven any knowingly that do this. Haven driven plenty that don't. Although in snow (or off road) 5mph is too slow for this to happen IMO.

Edited by 300bhp/ton on Wednesday 11th December 11:36

[Pica-Pica]

300bhp/ton said:

jon- said:

Most ABS systems will start locking once below ~5mph where steering isn't as big a factor

Must be a recent change. Don't think I've driven any knowing that do this. Haven driven plenty that don't. Although in snow (or off road) 5mph is too slow for this to happen IMO.

Yes, I used to brake to a halt outside my old house, and the wheels would lock as I came to a halt on the wet muddy leaves, in late autumn, the ABS was ineffective/inactivated. The first time it took me a bit by surprise, after that it was fun. In my old E36 as you pulled away you would hear a whirr sound as you went past 4 mph.

[Speed addicted]

300bhp/ton said:

Munter said:

What's best then for a "surprised and unprepared" average driver who will mash the brake pedal as hard as they can until the car stops?

I wonder, in such situations with such Average Jo's, how many would actually steer when equipped with ABS or would they just mash the brake pedal as hard as they can until the car stops/hits something?

I tend to brake hard, then get off the brakes to turn. I think this is due to driving only cars without ABS for the first few years after passing my test (while I was making more bad decisions about appropriate speed for the conditions) as well as riding motorbikes, a lot of which also don't have ABS.

So even though my current car is 4 years old and has modern systems, and my main bike has ABS (the other 3 don't), I'm hard wired not to attempt to swerve while hard on the brakes.

There were studies done that showed people often don't brake as hard as they possibly can to avoid accidents, hence the brake boosting tech that senses imminent interaction with other vehicles and assists in the braking effort.

[Elroy Blue]

Just got my four 16” steel wheels to replace 17” alloys. The website said I can use existing wheel nuts. Not sure they’re suitable though. They are correctly torqued and appear tight, but they don’t recess into the lug holes like they do on the alloys.
Are these OK
com/cPR6FJS4][/URL]

[300bhp/ton]

Picture is a bit small to see. Often alloy wheels are hubcentric (they centre on the hub) and the wheel nuts are just there to hold the wheel on. And they have a flat face.

Whereas many steel rims are nut centric and centre on the wheel nuts, in such cases the wheel nuts are beveled and the steel rim is thicker and raised around the holes for the nuts, to allow this centering to happen.


But it will depend on the make/model of vehicle and isn't 100% universal.

[RicksAlfas]

The image is a bit mangled.

Does your car have a steel spare wheel? The manufacturer would expect you to use the same nuts for each, so check the holes in your spare against the holes in the winter wheels. It's all to do with the shoulders of the nuts and holes. What car is it?

[Elroy Blue]

It’s a focus. Not sure what happened to the image. The bevelled nut is sitting somewhat proud of the hole and doesn’t fully seat into it
Edit: Better pic

Edited by Elroy Blue on Wednesday 11th December 14:48

Edited by Elroy Blue on Wednesday 11th December 14:58

[ATM]

Look fine to me.

Try driving it and then check they have not come loose.

Years ago I ovaled the holes for the nuts (well bolts if were being an-al) on a steel wheel on a Fiat because I hadn't tightened them up enough. Once ovaled the wheel was scrap as the nuts would never stay tight.

If your nuts stay tight how can the wheel just fall off - it cant unless it splits into pieces or the nuts sheer off.

[Elroy Blue]

Not too worried. They been torqued to the correct setting. They just don’t look ‘right’

[RicksAlfas]

Those look fine. It's made worse by Ford using those weird nuts with an integral cover and washer like an old Range Rover.
Give them another check after 100 miles or so.

[FiF]

Agree they don't look right. How much of the conical part of the nut is engaged into the similar surface of the wheel. It's almost as if the very tip of the cone is rammed only into the first part of the cup on the wheel.

This looks a bit like a lost wheel incident on a lorry I investigated. The maintenance department had put the wrong wheels on the vehicle and fitted those which were designed for a hub using lightly smaller diameter studs than the vehicle used. The nuts on the wheels still attached looked a bit like that. OK the design safety margin on heavy vehicle wheel fixings is much smaller than light vehicles which are generally over engineered ie massive safety margin thankfully. You may get away with it however.

[C7 JFW]

RicksAlfas said:

There is nothing worse than the ABS kicking in on a snowy descent though. The car feels like it's running away.

It does an incredible job of hauling my Subaru STI, on winters, to a full stop in those circumstances. There's no way I could beat the ABS's performance.

[300bhp/ton]

C7 JFW said:

RicksAlfas said:

There is nothing worse than the ABS kicking in on a snowy descent though. The car feels like it's running away.

It does an incredible job of hauling my Subaru STI, on winters, to a full stop in those circumstances. There's no way I could beat the ABS's performance.

So you can defy physics. Impressive

[RicksAlfas]

C7 JFW said:

It does an incredible job of hauling my Subaru STI, on winters, to a full stop in those circumstances. There's no way I could beat the ABS's performance.

Yes, on winter tyres, because you have the grip, so the ABS won't engage until much later.

I once made the mistake of turning down a snow covered country lane with a steep hill on it. I was on wide summer tyres and the moment I touched the brakes the ABS kicked in and away we went. I had to run up against the kerb to stop. Blew the tyre and scraped the wheel. (And had to change my underpants).

[BaldOldMan]

There's so many different circumstances.....

Locking up the fronts isn't the answer either unless the snow is very deep - look at the video posted a few pages back of 4wd vs 2wd stopping to see that.......