Speed vs Revs

Fred Primmer

Fred Primmer

Joined
Jun 23, 2020
Messages
1,039
Location
Barrie, Ontario, Canada
Bike
2004 ST1300
I have had my 2004 ST1300 for a year and it seems to run and perform well, but I really don't have anything to compare it to. In 5th gear at 3750 rpm it does 70 mph; at 3250 rpm it does 60 mph. The conditions were 79 deg F, flat level highway, Shinko Verge tires at 42 psi, vstream windshield about 3 inches from full up, just me at 230 lb, givi top box, elevation 827 ft ASL.

Do those revs at those speeds sound about right for an ST1300?
 
Fred Primmer said:
In 5th gear at 3750 rpm it does 70 mph; at 3250 rpm it does 60 mph.
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Are those speedometer readings or GPS actual speed?
Those are with in 100-200 RPM of what I read on the GPS.
Now do I use RPM and GPS speed all the time to tell what gear I am in due to getting older and forgetting all the time.:oops:
 
Fred Primmer said:
I have had my 2004 ST1300 for a year and it seems to run and perform well, but I really don't have anything to compare it to. In 5th gear at 3750 rpm it does 70 mph; at 3250 rpm it does 60 mph. The conditions were 79 deg F, flat level highway, Shinko Verge tires at 42 psi, vstream windshield about 3 inches from full up, just me at 230 lb, givi top box, elevation 827
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My 2007 was always very happy at those rpm’s. Buddy of mine with an older Concours said the same thing. What say you Igofar? Are Japanese bikes around those cc’s happy?
 
I've never paid attention ... it all "feels correct" to me and have never questioned it.

I'll look next time I'm out
 
I have an 04 and that is what I see as well. Your bike is fine. For comparison to GPS. My speedo is 5mph higher at 70 mph. Meaning actual speed is 65. About a 7% difference.
 
Fred Primmer said:
I have had my 2004 ST1300 for a year and it seems to run and perform well, but I really don't have anything to compare it to. In 5th gear at 3750 rpm it does 70 mph; at 3250 rpm it does 60 mph. The conditions were 79 deg F, flat level highway, Shinko Verge tires at 42 psi, vstream windshield about 3 inches from full up, just me at 230 lb, givi top box, elevation 827 ft ASL.

Do those revs at those speeds sound about right for an ST1300?
Click to expand...
All your details are interesting, but your road speed/rpm ratio was fixed when Honda finalized the gearbox ratios in the driveline. With the possible exception of some very minor differences in tire pressure that could alter the effective diameter of the tire, it doesn't matter if you're an 80lb speedo wearing Rollie Free wanna be or towing a trailer full of beer. Your road speed at a given rpm will be the same. Change to a non-standard tire profile and you've effectively changed the gear ratio and that could also impact it.

Now your gas mileage... that's a different story.

Fun fact... My 2017 Honda CR-V has a TPMS function, but it doesn't employ pressure sensors in the wheels like my Acura. It uses the ABS sensors to monitor the relative rotational rate of the four wheels. An underinflated tire will turn faster relative to the others and will trigger a warning. My Acura reports a specific pressure in each tire. The CR-V does not. It also takes some amount of driving to trigger a warning in the system. Interesting.
 
I see what you are saying. I was thinking that the speed/rpm relationship might be an indicator of engine health/performance but as you say that is a fixed mechanical relationship.
 
STRider said:
With the possible exception of some very minor differences in tire pressure that could alter the effective diameter of the tire, it doesn't matter if you're an 80lb speedo wearing Rollie Free wanna be or towing a trailer full of beer. Your road speed at a given rpm will be the same.
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Fred Primmer said:
I see what you are saying. I was thinking that the speed/rpm relationship might be an indicator of engine health/performance but as you say that is a fixed mechanical relationship.
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Unless there is a mechanical issue that alters the relationship between the normally fixed one of engine rpm and road speed, such as a slipping clutch, which makes asking this question a good idea if you do not know what normal is.
 
Andrew Shadow said:
Unless there is a mechanical issue that alters the relationship between the normally fixed one of engine rpm and road speed, such as a slipping clutch, which makes asking this question a good idea if you do not know what normal is.
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This is exactly what I did to diagnose a slipping clutch on a Yamaha Royal Star Venture. Of course, they don't have a tach, so I had to install an aftermarket one to keep an eye on RPM.
New clutch springs fixed it (I caught it early enough to fix it before the plates burned up).
 
Sometimes a guy wishes for 6th gear or a taller ratio in the rear, but the motor is so smooth and so happy kicking along that you just forget about it and ride!
 
Sometimes a guy wishes for 6th gear or a taller ratio in the rear, but the motor is so smooth and so happy kicking along that you just forget about it and ride!
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What about the women? : )

Anyway, pretty much what I wrote, thanks for confirming ...

Speaking of riding ... who's gonna get a 'D' ?
 
STRider said:
All your details are interesting, but your road speed/rpm ratio was fixed when Honda finalized the gearbox ratios in the driveline. With the possible exception of some very minor differences in tire pressure that could alter the effective diameter of the tire, it doesn't matter if you're an 80lb speedo wearing Rollie Free wanna be or towing a trailer full of beer. Your road speed at a given rpm will be the same. Change to a non-standard tire profile and you've effectively changed the gear ratio and that could also impact it.

Now your gas mileage... that's a different story.

Fun fact... My 2017 Honda CR-V has a TPMS function, but it doesn't employ pressure sensors in the wheels like my Acura. It uses the ABS sensors to monitor the relative rotational rate of the four wheels. An underinflated tire will turn faster relative to the others and will trigger a warning. My Acura reports a specific pressure in each tire. The CR-V does not. It also takes some amount of driving to trigger a warning in the system. Interesting.
Click to expand...
ABS used to check tire pressures have been used for over a decade. But they are very sensitive. If your rear tire on the bike was low 5lbs you would not be able to tell by rpm and speed. Also when the tires on the bike get hot they can increase pressure as much as 10psi. No one has ever noticed an increase in speed over rpms that I know of.
 
GryST said:
I wish that the 1st gear was taller. I need to shift right up to second, or wind it up and go straight to 3rd. Yet starting in second is meah. From the 3rt on, it is good. But yeah, the 1st gear is just to take off a meter or two and shift up, (in a normal ride, not power riding).
The old Wing had better gearing and torque, but didn't have the feel of a bike...
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A short shift 1st gear is better for the longevity of the clutch. Mercedes have always had a short shift 1st gear. If you're loaded up with 2 up on a small incline you won't have to ride the clutch as much to get going.
 
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