[Added_flavor]

Originally Posted by ashkamath

It is raining intermittently in the coast and I had a short ride to Gokarna for a ceremony. while returning after entering Goa, I chose the twisty coastal route via Agonda-Betul to Vasco because it is devoid of any traffic.
the road was wet and I was riding at a fairly comfortable speed as traffic was sparse. I have been using engine braking as much as possible (while approaching humps or while approaching a sharp turn). If I may say so, I was controlling the speed mostly with the gear shifts.
so there I was in 5th gear and ahead is a sharp right downward gradient turn and I down shift to 4th, sensing the speed is still more and down shift to 3rd ( back to back) and viola, my rear wheel just tails out. (It was sort of tail out when one uses the rear brake hard on Non ABS bikes). The bike corrects itself immediately in a sec or two and I was wondering out loud. what the heck was that? It never happened in my bike earlier.
So then only engine braking does not appear to be a safe bet afterall at reasonable speeds on wet roads?? Any idea what is the safe tread depth of the tyre for safe usage / wet roads? I checked the tyre pressure before leaving in the morning (Front 25 and rear 29) so guess pressure is alright.
Another issue is I need to crank the bike at least 5-7 times to start every time.

And reg tyres, yesterday I inquired at the local Ceat guy with regard to Ceat Vertigo Sports. he says the manufacturing is stopped and it is no more available??? So Ralco or Michelin Pilot sport or Ceat Vertigo Sports???(for the hill ride of course)

I can think of multiple possibilities here.

1. At the speed you were in, you were too fast for 3rd gear. Hence your rear wheel lost traction for a second or two before regaining it - This was amplified due to wet conditions.

Remember, the first three gears are shorter on the 390 compared to the last 3, both 5th and 6th being overdrive.

Lastly, engine braking is definitely recommended but coupled with progressive braking.

2. Rear tyre is definitely nearing it's end of life - Quite obvious. This point is linked to the above.

3. Remote Possibility: Due to the known issue, engine stalled momentarily when you depressed the clutch resulting in rear wheel lock, but started again when you released the clutch - thus regaining lost traction.

IMO, option 1 is most probably what has happened!

Regarding the tyres, I would any day go with Michelin Pilot Sport or Michelin M45/Sirac (if you are fine with 120 section) over the Ceats.

[ebonho]

Originally Posted by Ricci

Mebbe this Sunday, doc? Karizma was sold off long back in 2008, my 2007 Pulsar 220 FI soldiers on , though now the 7 year itch is demanding a scratch!

Sure buddy. Lets meet up. Maybe a short rain ride too if you're up for it. Am PM'ing my cell number to you.

Originally Posted by john doe

Does the ABS work when the rear wheel locks due to engine braking?

It does in my Storme. See no reason why an ABS bike should be different.

[Added_flavor]

Originally Posted by ebonho

It does in my Storme. See no reason why an ABS bike should be different.

I don't think so. I believe the ABS system reads signals only from the wheel sensors. I do not think it will kick in during engine braking.

[ebonho]

Originally Posted by ashkamath

And reg tyres, yesterday I inquired at the local Ceat guy with regard to Ceat Vertigo Sports. he says the manufacturing is stopped and it is no more available??? So Ralco or Michelin Pilot sport or Ceat Vertigo Sports???(for the hill ride of course)

Ashok as I whatsapped you, its simply an issue of equalizing revs for smooth gear transitions. No biggie. But yes, do change your Metz's for the Ladakh ride for sure.

My pick would be for a tubeless tyre with the hardest rubber and the deepest block/button tread you can find. Don't bother about the make or brand or the tarmac grip. Its not Moto GP you're going to be doing up there. You will bless the off road grip and ride within the limits of the tyre when and where you get tarmac. I am assuing you are not riding the bike to Delhi of course .....

Originally Posted by Added_flavor

I don't think so. I believe the ABS system reads signals only from the wheel sensors. I do not think it will kick in during engine braking.

If the engine braking causes the rpm to shoot and suddenly surge to the extent the wheel locks up and skids, the ABS should (and does) kick in. The feed comes from the wheel only.

[john doe]

Originally Posted by Added_flavor

I don't think so. I believe the ABS system reads signals only from the wheel sensors. I do not think it will kick in during engine braking.

Originally Posted by ebonho

If the engine braking causes the rpm to shoot and suddenly surge to the extent the wheel locks up and skids, the ABS should (and does) kick in. The feed comes from the wheel only.

Giving it a little further thought, I think that the wheel sensors will certainly sense that the wheel is locked, but cannot change this condition by rapidly "pulse-braking" ( since the reason for the wheel lock is the engine).

That is why the ABS cannot change anything, even if it does kick in ( IMHO).

[ebonho]

Originally Posted by john doe

Giving it a little further thought, I think that the wheel sensors will certainly sense that the wheel is locked, but cannot change this condition by rapidly "pulse-braking" ( since the reason for the wheel lock is the engine).

That is why the ABS cannot change anything, even if it does kick in ( IMHO).

How does it make a difference what causes the wheel to lock - Brakes or Engine?

The dynamics remain the same. And the sensors would kick in automatically.

And it does make a difference. Between the wheel stepping out of line and not. Which is what I experienced on my Storme when I once absent mindedly shifted to second insted of fourth.

[sandeepmohan]

Originally Posted by ebonho

If the engine braking causes the rpm to shoot and suddenly surge to the extent the wheel locks up and skids, the ABS should (and does) kick in. The feed comes from the wheel only.

I am sure abs does not work this way, even on your abs equipped car. Abs comes in to play only when there is a braking attempt by the brake lever or pedal. If it works the way you say, then the system needs to have some control over the clutch as well, which it does not.

[ebonho]

Originally Posted by sandeepmohan

I am sure abs does not work this way, even on your abs equipped car. Abs comes in to play only when there is a braking attempt by the brake lever or pedal. If it works the way you say, then the system needs to have some control over the clutch as well, which it does not.

Well I could be wrong. Trying to look up on the net for related links. I'm describing what I've experienced on my Storme. No brakes. Just a mis-downshift.

[Added_flavor]

Doc what you are saying makes sense but I don't think it is performed by the ABS. ABS comes into picture only during braking and not under any other means of controlling the speed of the vehicle.

Perhaps other systems like Vehicle Stability Control or Traction control systems will do this. Although at this point I don't have any links to substantiate this.

[ebonho]

Originally Posted by Added_flavor

Doc what you are saying makes sense but I don't think it is performed by the ABS. ABS comes into picture only during braking and not under any other means of controlling the speed of the vehicle.

Perhaps other systems like Vehicle Stability Control or Traction control systems will do this. Although at this point I don't have any links to substantiate this.

I was thinking of Traction Control too But I am pretty sure no version of the Storme (not even the top one) is similarly equipped.

I know what the pedal feels like when the ABS kicks in. And the sound as well. And the ABS kicked in when I mis-dowshifted. My foot was nowhere near the brake pedal at the time.

[john doe]

Originally Posted by ebonho

I was thinking of Traction Control too But I am pretty sure no version of the Storme (not even the top one) is similarly equipped.

I know what the pedal feels like when the ABS kicks in. And the sound as well. And the ABS kicked in when I mis-dowshifted. My foot was nowhere near the brake pedal at the time.

You are absolutely correct that the ABS will kick in when the wheel locks ( thanks to the wheel speed sensor). Hence you will feel the brakes pulsate.

But the ABS module cannot change / rectify the wheel lock condition since the module only controls the brakes and not the clutch or any part of the engine. So the tail skid will continue, despite the ABS.

[Viju]

Not sure if this is relevant to the D390 discussion, just adding my humble point to the ABS discussion.

ABS will work only if the driver presses the brake pedal (the Brake Light Switch signal is one of the triggers for ABS) - if the wheels lock due to engine braking, ABS can of course sense the wheel lock, but cannot do anything as there is no pressure applied in the wheel brakes.

In many new generation cars, an additional function called "Engine Drag Control" (just one of the names given by different suppliers for this function) is provided (E.g. new Swift). In such cars, when the ABS senses a wheel lock due to engine braking (that is, no brake pedal effort from driver), the ABS ECU sends a "request" via CAN to Engine ECU to reduce the engine torque so as to enable the wheel to start rotating again.

Hope this does not create more confusion!

[sandeepmohan]

This is a case of the wheel locking due to dropping down to a lower gear, maybe too low a gear at a said speed and poor traction availability. It would have been quite different if the roads were dry. In a condition of dropping down a gear, even in dry conditions, you still experience a wheel lock for second and a sudden reduction of speed as you get in sync with the engine rpm. However, the impact of a dangerous skid is less as traction is achieved much faster on a dry surface.

Traction and vehicle stability controls are usually found only in automatics cause the system needs full control of the clutch, differentials and a whole bunch of other stuff, else it can't regulate power or braking.

[ebonho]

Originally Posted by john doe

You are absolutely correct that the ABS will kick in when the wheel locks ( thanks to the wheel speed sensor). Hence you will feel the brakes pulsate.

But the ABS module cannot change / rectify the wheel lock condition since the module only controls the brakes and not the clutch or any part of the engine. So the tail skid will continue, despite the ABS.

Originally Posted by Viju

Not sure if this is relevant to the D390 discussion, just adding my humble point to the ABS discussion.

ABS will work only if the driver presses the brake pedal (the Brake Light Switch signal is one of the triggers for ABS) - if the wheels lock due to engine braking, ABS can of course sense the wheel lock, but cannot do anything as there is no pressure applied in the wheel brakes.

In many new generation cars, an additional function called "Engine Drag Control" (just one of the names given by different suppliers for this function) is provided (E.g. new Swift). In such cars, when the ABS senses a wheel lock due to engine braking (that is, no brake pedal effort from driver), the ABS ECU sends a "request" via CAN to Engine ECU to reduce the engine torque so as to enable the wheel to start rotating again.

Hope this does not create more confusion!

Love to learn new stuff all the time. Thanks guys.

So what exactly was the "ABS type" judder I felt and sound I heard in my case? Since the brake was not being pressed, was it the ABS module just "blank firing" the brakes with no effect on the whel lock? Or as Viju explained, was it the ECU cutting torque in milisecond bursts?

P.S. Mods could shift this part of the discussion to a relevant thread as we do seem to have moved some distance away from Ashok's original issue!

[basuroy]

Duke ABS doesn't have the added feature of traction control so it won't help with any situation where one wheel locks up due to reasons other than brakes . It will sense the lock due to difference in speed of both wheels and it will actuate the valves to release pressure (even though there is none applied at the lever/pedal) from the brakes but that won't affect the condition of the wheel .

Traction control shares the same sensor as ABS when present but does it job by controlling the fuel injection in a motorbike if I am not wrong . While I am not sure , I think it is normally taken for granted that an ABS equipped 4-wheeler will also have traction control , please correct me if am wrong .


BTW my test ride is scheduled for either friday or sunday , I am not used to a bike capable of this power and ride a cast iron bullet 350 . Borrowed a pulsar 220 to be absolutely comfortable with the conventional gear shift and braking patterns but still feeling slightly intimidated . If all goes well , will order it on the way back itself .

I want to check out ABS , riding upto say 60kph(or 80 if traffic permits but I doubt ) and then braking hard by depressing the front as hard as I can ( that is not how I brake but that is how I might when panicked so... ) a good idea ? Anything else I should check or test ?