Northern California - Good East Bay route for LT HR measurement?

I think I need to reassess my LT HR number. I previously used a ride up Diablo NGR from April or May this year to do this and pegged it at ~178bpm. This worked well for a while, but I'm thinking that my LTHR has gone up as I seem to be able to ride at that level with less effort than I used to (a good thing). I'm wondering where else might be a good candidate for the 30mins TT effort that I see mentioned a lot. I was wondering about the 3bears loop, but that's probably too varied to be useful. Any other thoughts from the BF East bay cognoscenti?

Mt. Hamilton. It's a good steady 6-7%. Just enough that you have to give a good effort but not so hard that you redline 30 secs into it.

As an alternative, my coach took me out to the flats of North Livermore. We made a loop out of Highland, Manning and Carnellian. There are stop signs, but you are making rights onto mostly low traffic roads. We went out and messed around the first day, looking for a heart rate I could sustain for 20 minutes, then came back the next week and did the field test.

JB

Thanks guys - Mt Ham is on the list, but it would be tough to call it east bay, N. Livermore sounds intriguing. Might have to look into that a little more closely.

If you're going to do this on a relatively flat course, it helps to have someone else out there with you. I did the ~3 mile loop clockwise, she did it counterclockwise - that way she was able to keep tabs on me. When I showed signs of really struggling, she hopped on my wheel and "encouraged" me for the last few minutes to keep the effort up.

JB

Mines rd would work. The first part is a long gradual climb.

Mines rd would work. The first part is a long gradual climb.

I was just going to say that.

+1

Cheers, Mines Rd is good to know. JB's suggestion is a little closer to me, so I might check that circuit out first.