Commando Top Speed? (2010)

pommie john · Dec 27, 2010

Has anyone got access to these records? Links to websites maybe where the official records are held? Magazines are notoriously unreliable at checking facts. It would be nice to see the info from the horse's mouth.

Rohan · Dec 27, 2010

pommie john said:
Has anyone got access to these records? Links to websites maybe where the official records are held? Magazines are notoriously unreliable at checking facts. It would be nice to see the info from the horse's mouth.

I think we will be extremely lucky if any of that stuff is on the web.

You may be referring to modern magazines rehashing old ground, but all the old numbers and figures are likely to be stored in old magazines.

For example, I have in front of me the 1959 issue of the TT Report in "The Motor Cycle".
It records that John Surtees won the 7 lap senior race on an MV Augusta, in 3 hours and 13 seconds, at an average of 87.94 mph. Best lap was 101.18 mph. And records each of his lap times, and for each competitor.
2nd was a Manx Norton, at an average of 85.50 mph.
4th was a G50 Matchless.
All fully faired, of course. With pics.
No speed trap numbers.

So its probably a matter of finding the individual magazines that hold each race report, and getting the numbers from there.

I don't have any problem with believing a Commando Racer can do those speeds - A TZ700 Yamaha at Daytona in 1974 is only listed as having 90 bhp, and they were near 200 mph that year - or the next when they became a 750, and had 105 bhp.

Which is what killed the Commando as a racer....

ML · Dec 27, 2010

Horsepower is NOT the final factor in what gives any motorcycle its ultimate top speed. Power to Weight Ratio is equally important as is Streamline Coefficient.

Race bikes are geared to achieve a balance of acceleration and top speed via selection of cams and matched inlet and exhaust tracts. The legendary Vincent Black Lightning achieved 150MPH / 240kms on roughly 70HP with snail pace acceleration but with a large flywheel intertia, tall gearing, modest weight and slim profile it could do it with reasonable consistency. There is a difference between "quick"and "fast"".

Comments in this thread about needing 105 HP to achieve 150MPH on a Commando are not accurate. I have witnessed Steve Maney on his excellent 750 do this comfortably many times over and he's getting 90HP peak.

In the mid 1950's NSU Germany achieved remarkable high speeds on small motors i.e. sub 250cc on cigar body streamliners. Put a IOM TT "dustbin" fairing on a Commando, drop 10Kg in weight and be surprised what it could achieve on high gearing i.e. 24T, but at the end of a very long flat road on a cool day!

Mick

Chris · Dec 27, 2010

Hi
Brilliant thread. Keep finding those magazine articles. My Seeley has a Steve Maney 750 engine that Steve said ran 140 on the banking at Daytona.
Steve runs a fairing on his Seeleys that surrounds the engine & the bottom / side pieces go beyond the footrests. He also has a seat & screen that you can see he has spent ages streamlining. I cant see that I have ever got over 125 on my naked bike. 17 1/4 stone sees to that. BHP bullshit & all are not the full story.
As Mr Landsdowne told me your bike is as fast but they exit the corner on to the straight 30 plus miles an hour faster than you.(thanks John)
ps even with the full Dunstall engine exhaust mods etc niether my mate John (Atlas) or my Commando have ever got near Norman Whites time with a standard Commando!!!!
Chris

Carbonfibre · Dec 27, 2010

Interesting that an old 1950's Moto Guzzi race bike was able to lap MIRA at 187mph...........maybe modern MotoGP teams need to take a very close look at this particular bike? As well as old pushrod twins apparently able to produce well over 100bhp per litre, and with 170mph top speeds......................

Carbonfibre · Dec 27, 2010

If there is no need to have BHP to provide good performance, then in the case of the Norton Commando how are 170mph top speeds possible?

pommie john · Dec 27, 2010

ML said:
Horsepower is NOT the final factor in what gives any motorcycle its ultimate top speed. Power to Weight Ratio is equally important as is Streamline Coefficient.

Mick

No. Power to weight ratio has nothing to do with ultimate top speed. It affects how quick you get there, not top speed.

Streamlining is very important, but i go back to my graph, were the JPNs and Vincents really that much better streamlined than modern race reps?

Maybe tomorrow I'll plot these claims on my graph and see if they fit the trend.

pommie john · Dec 27, 2010

One last thing before I retire for the night.

Race teams say things to psych out the opposition and magazines print things to keeps their advertisers happy.

I know this because I race and I work for magazines.

ML · Dec 27, 2010

Carbonfibre said:
If there is no need to have BHP to provide good performance, then in the case of the Norton Commando how are 170mph top speeds possible?

You miss the point. You need 3 essentials - BHP at the rear wheel, Weight reduction and Air Resistance reduction. And what do you mean by "performance"?
Ultimate top speed? Drag racer acceleration? You cannot achieve 170MPH on a Commando equipped for general road use. Anything remotely capable of doing so must have a specially built transmission, race tuned engine, hi octane race fuel and all enclosed streamlining. The motor would need to put out around 90BHP, a rolling weight of less than 160Kg and a CD half of the stock frontal area / resistance. (rough estimate).

For comparison, examine the Burns & Wright record setting Vincent with similar characteristics at 185MPH on July 3rd 1955 in New Zealand.

Mick

ML · Dec 27, 2010

pommie john said:
ML said:

Horsepower is NOT the final factor in what gives any motorcycle its ultimate top speed. Power to Weight Ratio is equally important as is Streamline Coefficient.

Mick

Click to expand...

No. Power to weight ratio has nothing to do with ultimate top speed. It affects how quick you get there, not top speed.

Streamlining is very important, but i go back to my graph, were the JPNs and Vincents really that much better streamlined than modern race reps?

Maybe tomorrow I'll plot these claims on my graph and see if they fit the trend.

There is a difference between "quick"and "fast - As I mentioned earlier.

mick

JimC · Dec 27, 2010

Put a GPS on those 130+ mph street Commandos, it'll slow them down considerably.

Keith1069 · Dec 27, 2010

Ain't yet found Normal White's 170 mph article yet but creeping up on it.

When I was down at his place a few years ago I was looking over his '72 race bike with full fairing and he mentioned a 170 clocking at Imola or Monza the year before , so that would have been about 1999 'ish. Of course that could have been 170km/h :wink:

Seeley920 · Dec 27, 2010

Ok, someone else can do the maths, because I haven't got time!

130/650 VB18 rear tyre,

Primary drive 38/70

Rear 19/42

7800 rpm and feathering the throttle to stop it over revving

2010 Norwich straight at Snetterton....I could have dropped 2 teeth off the rear sprocket, but it would have hurt acceleration out of 2 slow corners!

Hobot · Dec 27, 2010

MIck > Ultimate top speed? Drag racer acceleration? You cannot achieve 170MPH on a Commando equipped for general road use. Anything remotely capable of doing so must have a specially built transmission, race tuned engine, hi octane race fuel and all enclosed streamlining. The motor would need to put out around 90BHP, a rolling weight of less than 160Kg and a CD half of the stock frontal area / resistance. (rough estimate).

Yep just wait and see, after I save up for Peels gear box and coil spring clutch pack on shaved tubeliss Z rated tyres and data logger to objectify. Shooting for 230 total wet package with pilot. BTW exhaust plume aiming helps reduce drag.

Normal White did not confuse kph with mph. I will have to ask him directly for the details as can't find it online anymore.

daveh · Dec 27, 2010

JimC said:
Put a GPS on those 130+ mph street Commandos, it'll slow them down considerably.

I think so too!

ML said:
There is a difference between "quick"and "fast - As I mentioned earlier.

Very true. Which is why I suggested a better measure for a street bike is 1/4 mile speed and time, and top gear roll-on. You can spend ages accelerating with a high-geared, low-powered bike; not practical for the street.

Racing is different and on the fast real road circuits, you have to raise the gearing considerably. Clearly, aerodynamics play a much bigger role on very fast circuits, where you are tucked in behind the bubble for miles at full throttle.

The Manx Motorcycle Club publishes speed trap times on the web. They sometimes have a speed trap on Sulby Straight, which is flat and close to sea level. 145 mph Manxes were mentioned, but if I remember correctly, in 2008, Alan Oversby's very fast Manx was clocked at 133 mph through the Sulby speed trap. I will try to find the links if anyone is interested.

Hobot · Dec 27, 2010

In Peels case besides the steady Smith's speedo needle reading I ran with a number of faired moderns to compare with their over indicating digital speedo's and more realistic GPS, but none would exceed her naked speed to catch up when their speedo numbers indicated over 135 and GPS over 133 in the short straights available. Some were left jumping with glee others pissed off sulking.
OH sure Peel got out accelerated by 900''s and above in heats we'd have but not out run, mostly d/t the poor handling of moderns about to enter real turns at speed. teehe : )

Rohan · Dec 27, 2010

Rohan said:
pommie john said:

Has anyone got access to these records? Links to websites maybe where the official records are held? Magazines are notoriously unreliable at checking facts. It would be nice to see the info from the horse's mouth.

Click to expand...

I think we will be extremely lucky if any of that stuff is on the web.

Well some of that stuff is on the web - the race results for the IoM TT for example

http://www.iomtt.com/TT-Database/Events.aspx?meet_code=TT70 &era=3

And some of the later results for the speedtrap at Sulby are findable too, but modern stuff, club racing by the look of it. Anyone know what the track is like at Sulby ?

Rohan · Dec 27, 2010

JimC said:
Put a GPS on those 130+ mph street Commandos, it'll slow them down considerably.

Jim, are you suggesting the 142 and 145 mph recorded at Elvington for the FACTORY tuned bike of Dave Rawlins wasn't correct ?? I have a 1974 magazine (somewhere) which details this, and how the bike was tuned - was impressive at the time.

Mick Duckworth in his book "Norton Commando" quotes that the 750 Production Racer Commando (half fairing) that Paul Smart rode to 2nd in the 1969 750 Production Race TT, in place of the injured Peter Williams, was clocked at the speed trap at 138.5 mph - "not bad for a Commando with full lighting equipment".

Doesn't say where the speed trap was. Averaged 99.37 mph for the entire race, if you've even seen film of the "track" this is going some....

Rohan · Dec 27, 2010

The Club running the Elvington Sprints, and other stuff, since 1970 is still going

http://www.auto66.com/

but doesn't seem to have any old records online.
Anyone near there, can enquire of old records ??

Somewhere it does mention that 1300 yards on the RAF airstrip is not long enough for really fast runs........

daveh · Dec 27, 2010

Rohan said:
Anyone know what the track is like at Sulby ?

Not that bumpy, level and pretty straight for approx. 1.5 miles after you exit Quarry Bends, I don't know exactly where they place the speed trap. This would be the best place to get a good idea of top speed because it is flat and there is plenty of road to nail the thing before the braking point at Sulby Bridge.

Commando Top Speed? (2010)

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