Rollers and momentum

[Crankin]

Catrin, you can't improve if you don't have many places to practice what you want to do!
Besides, 6 mph is a perfectly respectable speed for steep climbs. Unless you are racing, what's the point of going so fast that you eventually blow up and have to get off the bike? I have seen this time and time again on rides; people are mashing up the hill, trying to go faster, when suddenly, I notice it looks like they have been shot backwards out of a cannon. Get in your granny gear at the bottom of the hill and stay in a mid to higher range gear on the back. Shift down as you need to on the rear, trying to keep a steady cadence. Do *not* look at your computer! I have been told time and time again that I am a good climber... but really, all I do is use the easiest gear I can, spin up the hill, and pace myself.
The best thing that ever happened to me was on our recent trip to Spain, they did not have computers on the bikes. At first, I complained. But, as we got into the "mountains," I appreciated it. DH and I just ticked the pedals over again and again. We had 3 very difficult climbs (two of them ranked climbs from the Vuelta and one 10 mile climb), as well as a few others. We made it up all of them ahead of everyone else in the group, except for the 2 people who were clearly stronger, who were trying to go as fast as possible. After riding at home for the past 6 weeks since we got back, I now realize we must have been going between 3-6 mph . I think this is especially important if you don't know what lies ahead.
Don't worry so much about this. It will come.

[OakLeaf]

Good advice here, and I'd especially listen to Indy who knows your terrain.

I don't think there's much momentum effect until you get over 10% on both the climbs and the descents... at least over 25 mph and maybe 30.

Learning your shift points and how to maintain cadence is a prerequisite to maintaining momentum. Focus on the former and the latter will come.

If you're finding yourself spun out at a relatively low speed and cadence, downhills are a great place to practice a nice circular pedal stroke. Back in the day we did downhill intervals for just that purpose. Let gravity propel you, stay in whatever gear you climbed in, and spin with just enough pressure on the pedals that you're not freewheeling, until you start to bounce. Since you don't have to put pressure on the pedals to propel yourself, you can concentrate on using the same amount of pressure all the way around.

But that's an intermediate-to-advanced drill... work first just on learning your shift points and shifting smoothly. On the steep stuff, you may find you want to shift several cogs at once, or you may want to go one gear at a time, pedal a few strokes and on to the next one. You may be lucky and find some of those ideal hills where you can just shift your chainring for climbing/descending, and stay in one of the middle freewheel cogs.