I'm new to the Lakes area and thought you might be able to help me find some good natural downhill riding. I mean the kind worthy of hauling heavy big-travel bikes up just for the descent.

I know it's asking a lot but a grid reference (top and bottom) would be good.

Appreciated.

I think the Helvellyn range lends itself to big travel bikes,Starting from Glenridding(Ullswater Lake) its a Heck of a climb/push but well worth the decent if you dont mind peddaling a bit.

Glenridding to Greenside mine,to the Zig Zag climb up Keppel cove,Lower Man, to Helvellyn summit.
This route means a lot of carrying pushing but your going to do that on any bike so it might as well be a big rig to maximise the fun on the downhill!!. Dollywagon is very steep and technical to Grisedale Tarn and then more flowey into the Patterdale Valley back to Glenridding,enjoy,be warned though its "full on" 😉
Max Cousins Dollywagon decent on Saturday 😯

Garburn, both directions as well as Walnar Scar

You might want to consider that the Dollywagon descent is also VERY popular with walkers. Just be aware of that when caining it on a DH bike.

Scared the shit out of me.

Interestingly some of the walkers were using the grass on the side of the stone pitching,the said it was too difficult to walk on the stones…lol 😯