400H Downhill On Ice - Help!

[acabucca]

Hi

Newbie, just picked up a 400h and taken me 4 hours to do the 45 minute journey home as the roads are like an ice rink.

I have done an initial search, but heres my question...

How, with a CVT box do you control your downhill descent without breaking?

I have just come from an audi Tiptronic and kept in "manual" and changed down to 2nd or even 1st to control descent.

With the Lexus it has been pretty scary on the way back down hill.

I am not sure if the "B" position is supposed to help?

Any assistance would be greatly appreciated, before I venture out into the ice rink again!

Thanks

[lexynik]

Hi

Newbie, just picked up a 400h and taken me 4 hours to do the 45 minute journey home as the roads are like an ice rink.

I have done an initial search, but heres my question...

How, with a CVT box do you control your downhill descent without breaking?

I have just come from an audi Tiptronic and kept in "manual" and changed down to 2nd or even 1st to control descent.

With the Lexus it has been pretty scary on the way back down hill.

I am not sure if the "B" position is supposed to help?

Any assistance would be greatly appreciated, before I venture out into the ice rink again!

Thanks

Hello and welcome , no idea on your question but im in south east and youre right its bloomin icy out there

[acabucca]

cheers, Im in east sussex too.

Done some more research on the "B" position and it may help with engine braking.

We'll see

[lexynik]

allways a good idea to read the owners manuals as well , they usually give tips for the cars features in driving in adverse conditions

[acabucca]

lol, having the owners manual would help.

was not with the car and on order from lexus, found a PDF but it's USA/CANADA

[lexynik]

aah i see , thats a shame , if you have a previous owner on the logbook you could try contacting them and see if they kept it "by mistake" - im sure someone will be along to help pretty soon if you check back in every now and again - or find some members with the same model as yours and send them a private message - an email should go to them and alert them to help you out if theyre nice , which near enough everyone on here is

[PCthug]

Yeah B stands for braking and is designed for controlling a downhill decent.

I have used it and it did slow me down.

I think the steeper the hill, the better it works.

I didnt try it on a very steep hill, and i was already going slow, so not sure if it applies the brakes or just uses engine/gear braking.

I know on a Land Rover Discovery it will apply the brakes as well.

All you do is put it into downhill assist and dont touch anything but the steering wheel.

[ihpj]

Can't imagine the 'B' offers any great assistance in such conditions - still its better than nothing!

[acabucca]

thanks for the replies, not been out since.

[PAD]

thanks for the replies, not been out since.

B stands for engine braking but it is very limited in effect. Tyres on the RX400 unfortunately are not very good in the snow, you have to just be very, very careful and use limited braking on down hill snow and ice. If you get going too fast you won't stop it!

[Ben Rose]

Keeping it in B will help but won't be perfect. Gentle application of the brake is the only way.

If you can't stop sufficiently, you're going too fast. The hybrid is very smooth at slow speeds, use it to your advantage and drive within your own limits.

[JBPRX400h]

See my other post regarding our recent trip to the Alps. http://www.lexusownersclub.co.uk/forum/index.php?showtopic=70376

The 400h did cope with a 12% (1 in 8) descent that was very slippery. The road had previously been cleared and gritted but it was snowing heavily with about 3" of fresh snow on the previous packed snow that was a bit wet and slippery as the temperature had had only just dropped below freezing. However, not wanting to put on the chains just to cover the last half mile down into the village, we tip-toed down at walking pace as the hill was dead straight. Even going this slowly when I experimented with the brakes the car slid in a straight line for about 10 - 15 yards before coming to a halt.

The B setting does assist by utilising the engine braking but just feathering the brakes to use the regenerative braking of the electric motors provides the best control.

The best advice when the going gets icy is to do everything smoothly and gently. No hard acceleration, no hard braking, no sudden movements of the steering wheel and keep a suitably sized "safety zone" all round your car and watch out for everyone else!

Happy motoring

JBP

[paolo137]

Rx is a very heavy car, and you just can't beat Mr. Newton.

Downhill, winter tires are the only safe way.

[fabben]

I don't do a lot of driving in these conditions but when I've been out and about (fresh show - night time black ice) The 400h has never given me a problem. The yellow warning light only flashes now and again to let me know that there's no traction - but that's only for a brief moment.

When everyone is staying on the gritted main roads, with massive congestion, I just go through the "back doubles" on ungritted roads, up and down hills. The only problems I have had is getting stuck behind someone else on a hill. Even starting on a hill, going up it, has been fine.

I've had no real issues driving in snow and ice. Obviously in these conditions I drive more cautiously but I don't use "B" anymore that I usually do. So I have nothing but praise for the 400h's handling.

[daveyboo]

The RX is great in the snow but as with any car it simply will not stop on ice unless you are being very careful. The 'B' setting helps a bit but is not fail-safe, just take it easy.