Ideal RPM Shift?

[HappyHighwayman]

So since I'm new to higher-revving bikes, and my SECA II can go to 10k before redlining, what is the ideal short shift range? I know it's no sports bike that an do 14k rpm redline, but for me it's still plenty for the city.

I've been mostly going by sound and feel, but would beewen 4500-5500 RPM make sense?

I want to program my Trailtech lights to indicate when to shift.

 

[VtownMac]

It really depends on conditions and intentions. You should be able to feel the bike complain if you shift too early, tho. ie, chugging clattering. I'd never give it lots of stick at rpms lower than 3-3.5krpm, but I've never ridden a SecaII, so that's just a safe estimate.

 

[strega]

Honestly, you shouldn't be relying on lights to indicate when to shift, do it by sound, eyes on the road...

 

[afm199]

5467.904 rpm, on warm days 5428.258

 

[CaptCrash]

Honestly, you shouldn't be relying on lights to indicate when to shift, do it by sound, eyes on the road...

Odds are you were shifting by feel/sound on your old bike. Thing to remember is that an inline 4 isn't gonna grunt off the bottom like a single or twin, you'll want rev's for passing or acceleration. Keep doing what you're doing--riding, testing, refining your technique...take your time and build.

Mostly? Have fun with it!

 

[Squidly McSmearstain]

5467.904 rpm, on warm days 5428.258

Remember to adjust by .0325798 RPM per .000025687 difference in average pug gap (averaging across all 4 cylinders, but weighting the inside two cylinders 2.48% higher in calculating the average).

 

[rritterson]

You want to shift when the next highest gear will have enough power for you at the speed you're going, if you want to maximize fuel efficiency. Of course, you want enough power not to just keep going at the current speed, but enough to also accelerate quickly out of the way should a car go motorcycle hunting.

For example, on my R6, that means shifting between 8-10k RPM for city riding, 12-14k in the twisties.

 

[AbsolutEnduser]

I knew a guy who may or may not be reading this forum, he had a toyota corolla and always shifted it between 1500 and 2500 rpm, barely ever going higher. He was basically afraid not to break the car.. Needless to say he accelerated like a slow snot.

So then he got a 600cc Japanese 4-cyl bike and kept shifting up until 4000 rpm... never revving it any higher. (until he learned.) (and the redline was an obvious 14000 or something).

That just shows that people with manual transmissions should really learn where their engine makes its power and when to shift

 

[HappyHighwayman]

Cool, I wasn't looking for an exact #, just an idea if I was doing it properly. The Obsessive Compulsive in me just wants to program the shift lights for fun.

 

[Jack the Smack]

If you want to know specifically when to shift for maximum accelleration, you'll need to:

Dyno every gear.
Match the speed to each gear's RPMs
Calculate when the horsepower delivered in one of the gears crosses below the amount of horsepower delivered in the next gear up.

Then you have to adjust based on wind.


I would suggest looking up generic torque graphs of your bike model and experimentation with that. If you live in the Sco the Great Hwy along the west side of the city is the best place. It's like a drag strip with no cross traffic and perfectly timed lights.

 

[AbsolutEnduser]

basically, let's say for a SECA II, it probably makes 25hp at 4000rpm and 60hp at 8000rpm.

so if you find youself always shifting at 4000rpm that means you need only 25hp in your everyday life. Which I think is the case. In that case you really should've bought a 250 Ninja, b/c it also makes 25hp.


Some bikes basically won't even let you ride with lower than 3000rpm .. ( I think some italian bikes) .. they try to stall .. so that's the "low" point you have to watch out for, that's all.

the high point to watch out for is if you find yourself going too fast..

 

[afm199]

Remember to adjust by .0325798 RPM per .000025687 difference in average pug gap (averaging across all 4 cylinders, but weighting the inside two cylinders 2.48% higher in calculating the average).

I was using the LaPlace Vernier formula weighting and integrating the differential across the entire range of output, leavin out of course, the minimal mechanical distortion due to retrograde buffering.

 

[Blankpage]

Ask a silly question you will get silly answers.
But if you have to ask question then you may have bought the wrong bike.

Might want to check out one of these.

 

[Burning1]

Most of the time, your owners manual will include a minimum speed for each gear. Use that as a lowest safe speed for each shift. Generally, where you short shift will depend entirely on the situation and what you are trying to accomplish. But, the minimum shift speed will provide some good guidelines.

 

[larry kahn]

They run best when you get them in the red part.

 

[Burning1]

Most of the time, your owners manual will include a minimum speed for each gear. Use that as a lowest safe speed for each shift. Generally, where you short shift will depend entirely on the situation and what you are trying to accomplish. But, the minimum shift speed will provide some good guidelines.

 

[mosquito]

Like they said, what's ideal depends on what you want to optimize, acceleration, fuel economy, or something else. If I'm just tooling along on the street, I shift at about 4000 or 5000 rpm. If I've got to get up to speed fast, I'll spin my little motor up over 11k (14.5k redline).

Not that it'll really help you -- because optimal depends on conditions, desires, etc. -- but you can take the generic marketing performance charts and speed : rpm ratios and chart out a decent indication of what you can do:



I went to all of trouble 'cause I was curious about how fast my bike could accelerate, what the top speed would be, and to have some indication of the best mpg vs speed *theoretically*. My interpretation says that the greatest acceleration could be if I shifted at:

-- 48 mph / 14.0 krpm
-- 67 mph / 13.5 krpm
-- 82 mph / 13.5 krpm
-- 94 mph / 13.5 krpm
- 104 mph / 13.0 krpm

I never got the best mpg / speed worked out. (That's what the light blue curve was for.)

 

[HappyHighwayman]

I find I barely can get into 4th gear in the city. I use 2-3 mostly. I just don't need that speed for puttering around SF.

 

[Junkie]

I just shift when it feels right, although since I've had issues with 4th gear a couple times I try to stay out of it. That can mean anything from redline all the way down to shifting at 4k, depending on how I'm riding.

 

[planegray]

5467.904 rpm, on warm days 5428.258

Remember to adjust by .0325798 RPM per .000025687 difference in average pug gap (averaging across all 4 cylinders, but weighting the inside two cylinders 2.48% higher in calculating the average).

I was using the LaPlace Vernier formula weighting and integrating the differential across the entire range of output, leavin out of course, the minimal mechanical distortion due to retrograde buffering.

YOu guys are messed up !

PLUS: you didn't include the "stiffy factor"> bulge in pants automatically adds 1K rpm to shift point