Downshifting: how big a blip each gear needs
Corner Speed works the rev match out from gear ratios. On a Yamaha MT-07 the 2nd-to-1st blip is about two and a half times the 6th-to-5th one.
3 min readBy PitPin Desk
How big the throttle blip is on a downshift depends on the two gears, and on the rpm you already have.
The ratio sets the blip
After a downshift the engine has to spin faster for the same road speed. The new rpm is the old rpm multiplied by the lower gear's ratio divided by the higher gear's ratio. Blip with the clutch in and the engine makes up that difference itself. Skip the blip and the rear tyre drags the engine up through the driveline, while you are braking and the rear carries very little weight.
Corner Speed works this out for a Yamaha MT-07, using the published ratios of 2.846, 2.125, 1.632, 1.300, 1.091 and 0.964. From 6th to 5th the revs rise by 13.2%, about 530 rpm from 4,000 rpm. From 2nd to 1st they rise by 33.9%, about 1,360 rpm from the same engine speed. A blip learned on the motorway in the top gears leaves you well short in the low ones.
The percentage stays fixed, so the rpm you need doubles between 3,000 and 6,000 rpm. The same downshift while cruising and while braking hard from speed needs two different inputs.
A close-ratio box needs less
On a 2013 to 2018 Kawasaki ZX-6R 636, the downshifts from 6th to 2nd need between 9.3% and 18.9%, and the shift into 1st is 29.4%. A rider used to an MT-07 who gets on the Kawasaki will over-blip and feel the bike surge as the clutch comes out. The other way round, the bike lurches. Check the ratio table in your own owner's manual, because ratios vary by model year and market.
Corner Speed's practical fix is two blips: a small one for the top three gears and a bigger one for 3rd, 2nd and 1st.
The sequence on the brakes
- Brake first and get most of the slowing done before the gear changes start.
- Pull the clutch and select one gear down.
- Blip with the clutch in. While braking hard, roll the throttle with the thumb and first two fingers while the other two keep steady pressure on the brake lever.
- Let the clutch out as the revs peak, before they fall back.
- Repeat one gear at a time if you need another.
Dropping several gears in one clutch pull multiplies the mismatch. On the MT-07, 5th to 2nd in one go needs the engine to rise by roughly 95%. Get the gear done before you commit to the lean, because a driveline shock mid-corner lands on a rear tyre already using its grip for cornering.
What a slipper clutch does
A slipper clutch lets the plates slip under back torque until the engine catches up. That stops a hard downshift from hopping the rear wheel, and the mismatch goes into clutch heat and wear. Small mismatches that only nod the forks pass straight through. A downshift quickshifter does the blip for you within its working range, which usually means above a minimum engine speed, so you still blip by hand at low speed.
A drill to start with
On a quiet road, hold a steady speed in a middle gear and downshift one gear at a time with no braking, watching the rev counter as you blip. Once the bike stops nodding, add light braking, then work down to the lower gears where the blip is bigger.