Spring's here, time to die

[Brian d marge]

That's not what you said in your first post.

yes it is

2 seconds means , if you cant stop within the road ahead , ( 2 seconds is a comfortable stopping difference ) then you decrease your speed

and no it doesnt mean hauling on the anchors over every crest ,

Stephen

[Crasherfromwayback]

yes it is

2 seconds means , if you cant stop within the road ahead , ( 2 seconds is a comfortable stopping difference ) then you decrease your speed

and no it doesnt mean hauling on the anchors over every crest ,

Stephen

I'm not going back to find old posts etc. But 2 secs is the rule of thumb for following others. Not a safe stopping distance.

[Brian d marge]

I'm not going back to find old posts etc. But 2 secs is the rule of thumb for following others. Not a safe stopping distance.

well It seems to work for me , ( ice and rain and mud excluded )

Stephen

[AD345]

I pity the poor sod who comes over the crest with 50m visibility and sees a truck and trailer fully across the road.

They died

Two out of the three that slammed into a milk tanker & trailer that was across the road as they came over a crest

Boom, boom, boom


be prepared

[R-Soul]

No. I know it seems counter-intuative, but maximum braking is just before the wheels lock up ... not with the wheels locked up (by then you've lost some braking force ...) ABS, supposedly, helps to maintain the wheels at just before lock up ..


Yes - because ABS maintains the wheels at just before lock up .. .

ABS detects when the wheels do lock up, and releases them again, and then brakes again in cycles again and again. In effect it pulses the brakes, but much faster than a human can, which has teh effect of almost maximum braking for most of the time. It is not as effective as a braking god, who theoretically can feeel exactly when the wheels are about to lock up, and holds braking steady there, without releasing and reapplying brakes.

Yes - it does seem fucked up - but it is true ... it's just counter-intuative.

On a locked up wheel there is more braking force acting on the brake pad and disc that causes the wheel to stop harder and lock up. But there is less actual force acting through friction on the contact patch that is causing the bike to stop, because dynamic or sliding friction of atyre on a road is less sticky than rolling or static friction of the same wheel on the road.

Maximum energy dissipation of the bikes speed comes when the friction has not progressed from (static) rolling friction to sliding (dynamic) friction, but it is just on the verge of doing so, and where the tyre is deforming to its max and just starting to break chemical bonds in teh tyre ( and it is at its hottest and stickiest).

Hmm ... maybe ... I'd think it's more about old Newton's Laws of Motion i.e. Force = Mass x Acceleration ...

In this case the amount of force being applied to a human body by friction (big friction area)as it slides down the road, combined with the minimum mass of a human body means deceleration (negative acceleration) would be quite high.

The amount of force applied through the tyres of a motorcycle (small friction area) OR the friction of the bike sliding down the road, combined with the mass of the bike plus the rider would mean that the deceleration (negative aceleration) would be much higher ...

Physics say I'll take my chances sliding down the road ... (And in all my sliding accidents I've stopped way before the bike has ...)

The friction factor of tyres on the road is far higher than leather/textiles or steel on the same road. Tyres are after by design meant to provide teh maximum friction that they can.
While theoretically diching the bike would reduce the mass, and require less braking force, there would be a problem applying whatever braking force you have to the road while sliding on your ass. You would also have a lot less control over what happens to you. From speed, staying on the bike is a no brainer.

[R-Soul]

Don't confuse car ABS with bike ABS, as far as I'm aware bike ABS is a lot harder to do because that is exactly what they try and get it to do.

The same principles apply - they detect when one wheel (front) is rotating at a different speed to the other, and releases it fractionally when this ids detcted. BUT it is a lot more difficult on bikes, as they need to make allowance for normal differences in wheel rotation (which can be a good 30% more), or if its wheelying. So throttle position must be taken into account, and/or gravity sensors to detect wheelies.

[R-Soul]

Would you have parted company with this?

This is different because tyres on grass aint gonna do much.

[bogan]

The same principles apply - they detect when one wheel (front) is rotating at a different speed to the other, and releases it fractionally when this ids detcted. BUT it is a lot more difficult on bikes, as they need to make allowance for normal differences in wheel rotation (which can be a good 30% more), or if its wheelying. So throttle position must be taken into account, and/or gravity sensors to detect wheelies.

Normal differences of 30%? Has Drew been giving you riding lessons? I'd want ABS to come in at around 10% slip, in the 0-10% slip range is where max grip is found iirc. If it is pulsed (and I'd much prefer it to be a proportional control instead), the frequency should be high enough not to unsettle the suspension, and ideally high enough to barely be felt at all.
Wheelies are kind of a non-issue, not like you'll be counting on much stopping ability from the front during a wheelie.

[Crasherfromwayback]

This is different because tyres on grass aint gonna do much.

Yeah I realize that. Had a bit of experience with various types of tyres on diff surfaces. But that wasn't the question.

[Ocean1]

If it is pulsed (and I'd much prefer it to be a proportional control instead), the frequency should be high enough not to unsettle the suspension, and ideally high enough to barely be felt at all.

I understand that pulsing the brake actually reduces the stopping distance compared to constantly maintaining a just-pre-lockup state.

[bogan]

I understand that pulsing the brake actually reduces the stopping distance compared to constantly maintaining a just-pre-lockup state.

Is that due to the practicality of a just-pre-lockup state being at a level of grip lower than what is ideal, or is there a different reason?

[Brian d marge]

I understand that pulsing the brake actually reduces the stopping distance compared to constantly maintaining a just-pre-lockup state.

no grip when locked up , more grip when rolling

Something like that

Stephen

[FJRider]

In summary, he was a nuisance.

Probably pissed off with the biker (HE believed was) following him too closely ... perhaps you should have overtaken him on (OR BEFORE) one of those crests .... (OR ... BACK OFF a bit)

And scared YOUR impatience might kill HIM ... It is the responsibility of the overtaking vehicle to overtake safely. It wasn't safe to do so ... otherwise you WOULD have ... right .. ???

[Maha]

Probably pissed off with the biker (HE believed was) following him too closely ... perhaps you should have overtaken him on (OR BEFORE) one of those crests .... (OR ... BACK OFF a bit)

And scared YOUR impatience might kill HIM ... It is the responsibility of the overtaking vehicle to overtake safely. It wasn't safe to do so ... otherwise you WOULD have ... right .. ???

Not doing to well at the guessing game today Trev?....
If this was a hypothetical situation, you may have a point (or two) but alas, it is not.
I am quite happy to sit behind someone that rides as I do, and Mr Cruiser was going fine prior.........until the dreaded crests of which we speak...da da daaaaaaaaaaa!
Thats when he and I had different ideas about what is comfortable and what is not.
Anyone who knows my riding will attest that it is not agressive in any way.

[FJRider]

It's not an issue for me. But I sure as fuck wouldn't ride with anyone that does at every crest.

Nor would it bother me. But not all riders have your ability and confidence (no I'm not taking the piss). If said rider was just getting back on the road after a serious off ... the reason for braking for each crest would be understandable.


But I guess nobody bothered to take the trouble/time ... to ask what his (her ???) issue was. We are ALL busy people ... eh .. !!!