Vibration during brakeing (but only w/engine brake)

Hi,

I though I'd ask what you guys might think this is.

When I'm riding at approx. 60 mph - no matter what gear - I sense a minor (fast) vibration in the handle bars. It's not that noticeable at lower speeds.

It 'goes away' when I drop the hammer and double the speed. I guess it's there, but I suspect the vibration is pulsing so fast that it's not that recognizable anymore. (Or I'm just to focused on the road ahead)

Also, when I brake from speeds between 100 - 40, I feel the vibration pulsing clearly in my brake lever, until it’s not recognizable anymore at around 20-30.

The other scenario of this is if I pull in the clutch (= no engine brake) while riding at 60 - 100, and then brake - strangely, the same vibration in my brake lever is near inexistent.

I have had the wheel checked for correct weights, and I’ve checked the air pressure. All good.

The previous owner said he put on new tires last summer, so they should have around 2000 miles on them. Should have.

At first I thought it might be faulty brake discs, but since they don’t vibrate during braking without engine brake – I ruled that out.

I’m running out of possibilities here, but my nearest conclusion is that I new front tire (even though there is still 'good' tread), as the vibration in the brake lever multiplies when I brake with engine brake, but almost disappears when I pull in the clutch and brake.

Fire away guys with advice, if you’d like.

Regards, Rune