What is the calculated top speed of an S10?

[KYwoodsrider]

There is another thread in this forum discussing the high speed stability of the S10 at speeds over 120 mph.
https://www.yamahasupertenere.com/index.php?threads/any-instability-at-high-speed-120mph.27201/

It just got me thinking about what is the calculated top speed based on gear ratio, RPM and tire size
Of course this doesn't take into account factors such as load, hills, wind, ect...
Here is my attempt at the calculation:

Per the shop manual for a Gen 2
6th gear ratio - .929
Primary reduction ratio - 1.466
Secondary reduction ratio - 2.987
From the Bridgetone tire catalog a stock Battlewing tire dia is 25.4 inches so the circumference is - 79. 756 inches
I was not able to find a max RPM so I used 7500

(7500 rpm / .929) / 1.466 /2.984 = 1845.49 rpm of the rear wheel
1845.49 x 79.756 in = 147,189.26 in/min
147,189.26 in/min x .00095 conversion to mph = 139.82 mph

EDIT - Max power of a Gen 2 is 112 HP at 7250 RPM
Using 7250 RPM calculated max speed = 135.16 mph

Some of you motorheads out there check my math

 

[Sierra1]

You're putting WAY to much effort into this. All I know is that she's fast enough for me....regardless of what the "real" speed is. And, anything in the triple digits is going to get ya' in trouble....no matter where you live.

 

[Mak10]

The speed of sound minus 10.

 

[Mak10]

Fast enough to see flashing lights in the rear view mirrors. AMHIK.

 

[KYwoodsrider]

You're putting WAY to much effort into this. All I know is that she's fast enough for me....regardless of the "real" speed is. And, anything in the triple digits is going to get ya' in trouble....no matter where you live.

You just have to appreciate all of the engineering effort it takes to build a bike like the S10
I never had mine over 85 and I go for weeks at a time without even getting into 6th gear.

 

[KYwoodsrider]

I like the math. I have hit 125mph gps reading.

Did you notice the RPM by any chance?

 

[dannyv]

You can not ignore wind forces in that calculation. The wind drag coefficient is highly significant. Without the right numbers- it is all just a bunch of ...numbers.

 

[Sierra1]

You just have to appreciate all of the engineering effort it takes to build a bike like the S10….

Trust me....I appreciate the hell out what the Yamaha engineers turned out. I was expecting just a bigger KLR. Which would have been fine. What I got was near perfect.....at least for me.

 

[Nikolajsen]

Video on youtube shows that you are not far off.
This is readings on speedo though...

 

[azb]

Video on youtube shows that you are not far off.
This is readings on speedo though...

The speedo is optimistic.

 

[Don T]

There is another thread in this forum discussing the high speed stability of the S10 at speeds over 120 mph.
https://www.yamahasupertenere.com/index.php?threads/any-instability-at-high-speed-120mph.27201/

It just got me thinking about what is the calculated top speed based on gear ratio, RPM and tire size
Of course this doesn't take into account factors such as load, hills, wind, ect...
Here is my attempt at the calculation:

Per the shop manual for a Gen 2
6th gear ratio - .929
Primary reduction ratio - 1.466
Secondary reduction ratio - 2.987
From the Bridgetone tire catalog a stock Battlewing tire dia is 25.4 inches so the circumference is - 79. 756 inches
I was not able to find a max RPM so I used 7500

(7500 rpm / .929) / 1.466 /2.984 = 1845.49 rpm of the rear wheel
1845.49 x 79.756 in = 147,189.26 in/min
147,189.26 in/min x .00095 conversion to mph = 139.82 mph

Some of you motorheads out there check my math

Your math is correct

I have had the opportunity to do a couple of top speed runs.
Both times I reached 229 km/h (142.3 mph) on the clock which equaled 214 km/h (133 mph) on the GPS.
At that point the rev counter showed 1 bar above 7.000 rpm.

 

[eemsreno]

Back when My 12 was fairly new I raced my son on his 990.
It hit 124 fast and just stayed there like it was limited top speed at 125ish.
The speedo reads about 5 or 6 fast so I would think it was 120 max speed limited.
I have not tried the 17.

 

[Nikolajsen]

The speedo is optimistic.

I know.
That's why I wrote it

 

[KYwoodsrider]

I surfed around today and found where max HP of a Gen 2 is 112 HP at 7250 RPM
Based on this the calculated max speed would be reduced to 135.16 mph.
This seems to be consistent with Don T's experience in both RPM and max speed.

As dannyv points out no wind drag coefficient is included however I have no idea how to calculate this.
I'm sure it has an impact in a "real world" situation.
Perhaps this is why Don T's bike would only rev to around 7200 RPM

 

[Tenman]

I did a punch out at 60 mph with a cbr 1000. Felt like I was going backwards

 

[Scoop47501]

Well now we know what Seirra1 looks like
Thought he did that with his bike though

 

[GreatWhiteHunter]

Brief forays into triple digits is all I have mustered to date. Glad to know there's more to be had.

Sent from my GM1917 using Tapatalk

 

[WJBertrand]

I think I got mine up to about 109 (per GPS) chasing some FJRs and ST13s. That was in the mountains around Baker City Oregon so may be 4-5000 ft. and not sure the road was level, may have been a little incline, but she seemed about topped out and only gaining slowly before having to slow.

 

[Sierra1]

Well now we know what Seirra1 looks like
Thought he did that with his bike though

So, wait a minute....the above calculations show 135 is possible....Don has seen 133 with GPS, and 142 on the speedo....and I'm the liar at 138? With the average speedo error, how is my speed suspect? I know nobody knows me, but I'm not THAT type of guy.

 

[MikeinNZ]

I work with a “motorcycle magazine test rider/ writer” who told me the fastest he has ever been on gravel was 200kmh/124mph on a S10! He explained the road as hard packed gravel, straight and slightly downhill... nuts I recon.