[naylon]

I could not find Hill descent control system on G30.

Hill descent control system is like an autopilot bringing the car safely downhill.
Driver backs off brake pedal, car is braking all 4 corners individually and closing throttle body. This helps to go downhill without slip, slide.

(tested on E46 330xi, HDC worked fantastic)

HDC is an excellent feature. It was available on F10 and had its own button, next to gear lever.

Is there HDC on G30 x-drive?

[timmahh]

Originally Posted by naylon

I could not find Hill descent control system on G30.

Hill descent control system is like an autopilot bringing the car safely downhill.
Driver backs off brake pedal, car is braking all 4 corners individually and closing throttle body. This helps to go downhill without slip, slide.

(tested on E46 330xi, HDC worked fantastic)

HDC is an excellent feature. It was available on F10 and had its own button, next to gear lever.

Is there HDC on G30 x-drive?

I would think if it had it there would be a way to control whether or not it's on/off. If you've got your foot on the brake I assume nothing is on the gas pedal -- the throttle body should be closed. You can also drop the transmission into manual mode and use that to help keep the vehicle at a predictable speed, while minimizing the amount of brake force required by you.

[saporitj]

I'm going to say no. The owners manual talks about using the lower transmission gears to avoid brake overheating. That is it, no other comments. It does seam like useful safety option.

[AP]

I'd say no as well.
Even the speed limit function will not brake to maintain your speed down a hill ( it just warns you you've exceeded the set speed)

[Zap-xpilot]

Hmm...

Is it really needed? This is not meant to be an offroad-capable vehicle?

Also, shouldn't the DSC+ABS combo sort braking individual wheels while maintaining course? I know that DSC has at least one gyro as a sensor, so it should very much understand that the car is in "descent"?

[naylon]

Found a BMW Technical Bulletin, it says HDC is no longer available on G30.

Is HDC needed? 100 % of drivers who have tested HDC on a steep, ice and slush covered downhill wouşd say "YES". It is amazing. We as drivers can not imitate HDC hence all 4 corners are braked individually, not at the same time, allowing the car to go downhill under control without slip or slide.

I will email BMW AG and ask them to add this feature.

[SteveinArizona]

Originally Posted by naylon

Found a BMW Technical Bulletin, it says HDC is no longer available on G30.

Is HDC needed? 100 % of drivers who have tested HDC on a steep, ice and slush covered downhill wouşd say "YES". It is amazing. We as drivers can not imitate HDC hence all 4 corners are braked individually, not at the same time, allowing the car to go downhill under control without slip or slide.

I will email BMW AG and ask them to add this feature.

And you expect them to pay attention? Good luck!

[HighlandPete]

Originally Posted by naylon

Found a BMW Technical Bulletin, it says HDC is no longer available on G30.

Is HDC needed? 100 % of drivers who have tested HDC on a steep, ice and slush covered downhill wouşd say "YES". It is amazing. We as drivers can not imitate HDC hence all 4 corners are braked individually, not at the same time, allowing the car to go downhill under control without slip or slide.

I will email BMW AG and ask them to add this feature.

HDC is no substitute for the wrong tires.

I've closely watched an X3 trying to descend a steep slope on snow, using HDC, was fitted with summer tyres. HDC was easily overwhelmed, if the grip isn't there to start with, can soon go into a slide.

No match for xDrive with appropriate tires. My RWD on winter tires had total control on the same slope.

Something like the G30 required the right tires, for all driving conditions in winter. Not simply HDC, just for one driving condition.

[naylon]

Originally Posted by HighlandPete

HDC is no substitute for the wrong tires.

I've closely watched an X3 trying to descend a steep slope on snow, using HDC, was fitted with summer tyres. HDC was easily overwhelmed, if the grip isn't there to start with, can soon go into a slide.

No match for xDrive with appropriate tires. My RWD on winter tires had total control on the same slope.

Something like the G30 required the right tires, for all driving conditions in winter. Not simply HDC, just for one driving condition.

Did you go descend a steep slope on snow tires with the foot on brakes and without sliding?

[HighlandPete]

Originally Posted by naylon

Did you go descend a steep slope on snow tires with the foot on brakes and without sliding?

On my RWD, yes could stop and control the car simply on the brakes. Whereas the xDrive struggled with HDC, no issues modulating the footbrake on my car to stop on the same slope.

XDrive was quite impressive, how the individual wheels were trying to keep grip, but the limitation of the summer tires clearly showed up as the weak link.

The particular slope we experimented on, had a sharp bend part way down. That also highlighted how important tires are to car control.

[naylon]

Originally Posted by HighlandPete

On my RWD, yes could stop and control the car simply on the brakes. Whereas the xDrive struggled with HDC, no issues modulating the footbrake on my car to stop on the same slope.

XDrive was quite impressive, how the individual wheels were trying to keep grip, but the limitation of the summer tires clearly showed up as the weak link.

The particular slope we experimented on, had a sharp bend part way down. That also highlighted how important tires are to car control.

Ok, winter tires + HDC system work awesome.

If you test once, you will be amazed.

[HighlandPete]

Originally Posted by naylon

Ok, winter tires + HDC system work awesome.

If you test once, you will be amazed.

I agree winter tires and HDC is the business.

What I'm highlighting, HDC is no substitute for winter tires. Will enhance their performance, but HDC is not really necessary for typical road use including quite steep slopes.

[naylon]

Originally Posted by HighlandPete

I agree winter tires and HDC is the business.

What I'm highlighting, HDC is no substitute for winter tires. Will enhance their performance, but HDC is not really necessary for typical road use including quite steep slopes.

I do not think that drivers can do what HDC does on a steep descending hill.

We as human beings can not turn on/off brakes on 4 corners individually.

[HighlandPete]

Originally Posted by naylon

I do not think that drivers can do what HDC does on a steep descending hill.

We as human beings can not turn on/off brakes on 4 corners individually.

HDC uses ABS, similar to how it would be functioning, if we are controlling speed on the gears (engine braking) and applying the brakes on slippery surfaces.

xDrive will help a user to control speed downhill without HDC, but it must be done on the gears, to be similar to HDC. It is a reason I prefer RWD vs. FWD, can select low gears to use the rear wheels to retard the vehicle. Leaves the front to steer and brake where and when necessary.

Whatever way we look at it, safe hill descent is only as good as the grip the tires can provide. HDC won't save us sliding, if there is not enough grip from the tires.

[naylon]

Originally Posted by HighlandPete

HDC uses ABS, similar to how it would be functioning, if we are controlling speed on the gears (engine braking) and applying the brakes on slippery surfaces.

xDrive will help a user to control speed downhill without HDC, but it must be done on the gears, to be similar to HDC. It is a reason I prefer RWD vs. FWD, can select low gears to use the rear wheels to retard the vehicle. Leaves the front to steer and brake where and when necessary.

Whatever way we look at it, safe hill descent is only as good as the grip the tires can provide. HDC won't save us sliding, if there is not enough grip from the tires.

I agree with you. Summer tires, steep descending hill, 5" of snow:

HDC does the job. I tested many times. You can test and see the benefits of HDC "even on summer tires".

HDC + winter tires are the best combination.