Racing Tires for Commando and other Nortons

Road tyres these days are much better than anything we raced on in the 1960s.

Not sure the roads are, though.

SteveA said:

And.....I have absolutely no idea what this means:

.....you could walk it into a tight turn & catch it on the power.....

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Well , I guess most of em call it ' backing it in ' , K R & assoc .

Super Keen Types . . . Hard Brakeing , as you counter steer / start to lean , if youve got a controlable rear wheel brake / pedal ,
a touch of excess brake at that moment gets the ass end walking out , Just . So , getting the rpm's right , and the throttle leading ( ON )
a correct amount , the rear drift is maintained into the entry by throttle . Though the bikes at the ' crossed up ' initial point .
A Commando there tends to lean and go into a full drift . Both ends together balanced . Where it'll ' steer on the throttle .
Like P.W. , Mert Lawill & others are exponents of .
NOTE : Laer Commandos have ' improved ' swing arm & location . NOTE : Lateral rotational ( swing arm twist , pivot to axle , going ' out of plane ' to each other ,
tends to spit you off .
WARNING : Not for adshearants whow havnt explored the tecnique on unsealed / backroads / dirt , beforehad . WARNING . High Side . = Vehical Wt / Your Wt. + Mech Adv. in favour
of the equipment . RESULT . ? Ever been fired out of a cannon . Tecnically it could , if it dug in drifting , amplify your bodys mass / acceration two fold . Hence Tyre Choice . And chassis tune .

QUOTE , From Pete williams . " Oh No . Theyre Not the Same Thing At All " Ref : F- 750 compared P.R. ( Commando chassis ) Norton . Undulating bumpy track will tend to steer the machine
as the stresses twist the running gear . Bad idea . the F-750 were more ridgid . I believe they even used rear racing tyres . NOT recomended on a Commando ( or Triumph ) Prod. racer .

When ' the Slicks ' came out - the whole game changed . a modern highly sticky tyre could easilly twist up the running gear , going real hard on a uneven track .
YOU WANT THE REAR O SLIP ABOUT A LITTLE , so as not to overload the chassis .
On a dead smooth track , with a cautious riding style , it might not bite . Much better to have a machine in a CONTROLLED DRIFT , at the limit . rather than stuck fast then gone .

The Variations in chassis load are more even / less uneven . IF it twists under load , widely flutuating loads will wildly fluctuate chassis twist . ( like a H2 or std Z1 kawa on slicks )

Pretty much like on the dirt . To powerslide / drift it through the full bend ,youve got to get the back out & pushing the machine inward ,
Most Triumphs will ' steer on the throttle ' - most bikes maybe run wide / push / understeer . If you back the thorottle much , cranking right over round a turn .

Dirt Track ( flat track ) the tecnique BEFORE any brakes ( NO back brake . Or Front ) was to hold outward till say 3/4 down the straight , then Gas & Flick over
into the bend . This is why K R , that little aussie git , er , STONER etc etc , who were brought up in the dust have refined developed throtle & balance control.
Theyve had a bit of practise .

then theres the Olde School , Hailwood - tidy extreme exact throttle modulation . The film of him being held up by the jappers is evidance of ' smooth is fast '
IF you have a copetant chassis .

HOWEVER a Ducati Chassis is vastly more stable dimensionally under severe wqorking loads , than a Std. Commando Chassis !

This was vastly more evidant in production class machines , in the I. o. M. before it was debumpified . Where it had shown production roadholding and rideability assets & defects .

You can get Lotus 40 syndrome with overstickey tyres . ( a light 1600 ' sports ' class racing car ( 30 ). fitted with a racing V8 . One or two achived Chapmans ' " If it disintigrates as it
crosses the finish line in first place , its optimally stressed " prematurely . One is said to have left the driver seat & steering wheel in the center of the track at brands . the rest dissapateing in all directions .

Getting to the point , a pre war Indian , with the " Use the stickist tyres you can get " started pogoing then tank slapped , then the pilot woke up in hospital . Concussion produces perceptuall delays .
THEREFORE if you follow suit , on a scrawney mild steel Commando Chassis , a bumpy / undulateing track , unless the suspensions set up full travel , and even then . Youll FEED MORE LOAD INTO IT
than it is capeable of absorbing without deflection . It'll start to develop a mind of its own , as to where it goes . If youre striving to use the fancy tyres full adhesion . As in its OVERSTRESSED .

BALANCE is far more important than a mega sticky grip turning thhe chassis into a rubber band , Like a series one Suzuki TR 750 . Though some are brought up on uglu brute handling jappers
are better at resolving the problems .

Hardly the type to be attracted to a British Bike ( SOME British Bikes , anyway ! )

So the olde period garbage in modern form , may well be quicker through CONTROLABILITY and suitability to chassis geometry . If the rides game & skilled at four wheel drifting - on two wheels .



Dunno whatits running here , but was 4.10 19 F & 4.25 - 18 R K 81 Dunlops . When it was black . Scrawny 3.60 F & 4.10 R might get good balance and drivabilty on modern rubber .

This is the old Fr racing Dunlop . Rear Racing Rubber was to stickey for production roadster chassis . Itd BEND them . Wobble weave Spit . Kapow .

A Bevel Ducati has steering geometry which suits powering around the high line on bends and in corners. It suits circuits which have high speed bends rather than tight corners - it is usually very stable.. On circuits which have tight corners, you need a bike which you can just flick into corners without counter-steering, and which does not tend to understeer as you power out of corners. It all depends on frame rake and trail - tyres are less important on a bike which is designed to take the low line in corners. But if you are out on the high line using full power at full lean, you need excellent tyres. With my bike, I just flick it into corners while braking, then almost immediately gas it hard. It usually turns tight and passes under the guys who are out on the high line.
This is something which I only learned very late in life - it is not intuitive - not something you would expect. A neutral handling bike usually needs counter-steering as you tip into corners and it will tend to run wide if you gas it when halfway around a corner - both are evidence of under-steer. If you increase the trail, you can induce over-steer. It will flick into corners without counter-steer and will tend to turn in the correct direction as you power out of the corner.
I would not change the trail on a normal Commando. My Seeley has the same rake as a Commando, but it does not have isolastics.

If you back a race bike into a corner on a bitumen circuit, you have the rear already sliding. That is asking for trouble. Once the tyre slides, it has to gain traction again. That can happen very suddenly. But you could wear a parachute.

Matt Spencer said:

HOWEVER a Ducati Chassis is vastly more stable dimensionally under severe wqorking loads , than a Std. Commando Chassis !

This was vastly more evidant in production class machines , in the I. o. M. before it was debumpified . Where it had shown production roadholding and rideability assets & defects .

You can get Lotus 40 syndrome with overstickey tyres . ( a light 1600 ' sports ' class racing car ( 30 ). fitted with a racing V8 . One or two achived Chapmans ' " If it disintigrates as it
crosses the finish line in first place , its optimally stressed " prematurely . One is said to have left the driver seat & steering wheel in the center of the track at brands . the rest dissapateing in all directions .

Getting to the point , a pre war Indian , with the " Use the stickist tyres you can get " started pogoing then tank slapped , then the pilot woke up in hospital . Concussion produces perceptuall delays .
THEREFORE if you follow suit , on a scrawney mild steel Commando Chassis , a bumpy / undulateing track , unless the suspensions set up full travel , and even then . Youll FEED MORE LOAD INTO IT
than it is capeable of absorbing without deflection . It'll start to develop a mind of its own , as to where it goes . If youre striving to use the fancy tyres full adhesion . As in its OVERSTRESSED .

BALANCE is far more important than a mega sticky grip turning thhe chassis into a rubber band , Like a series one Suzuki TR 750 . Though some are brought up on uglu brute handling jappers
are better at resolving the problems .

Hardly the type to be attracted to a British Bike ( SOME British Bikes , anyway ! )

So the olde period garbage in modern form , may well be quicker through CONTROLABILITY and suitability to chassis geometry . If the rides game & skilled at four wheel drifting - on two wheels .

View attachment 94272

Dunno whatits running here , but was 4.10 19 F & 4.25 - 18 R K 81 Dunlops . When it was black . Scrawny 3.60 F & 4.10 R might get good balance and drivabilty on modern rubber .

This is the old Fr racing Dunlop . Rear Racing Rubber was to stickey for production roadster chassis . Itd BEND them . Wobble weave Spit . Kapow .

View attachment 94273

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If you look where Hailwood was passing the other guys, he usually went around the high side on the fastest bend. The Ducati was extremely stable. With many other bikes, you would not dare to do that. It is 'horses for courses'.

TomU said:

A race tire is any tire you race on

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A race tire is any tire that gets you through AARMA tech (I think that WERA is a little more lenient). Individual variations are not something that I want to investigate early on a Saturday morning after I've driven 270 miles on Friday.

SteveA said:

And.....I have absolutely no idea what this means:

.....you could walk it into a tight turn & catch it on the power.....

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It means stick it up your backside. If you were doing 20 MPH, you might be able to walk a bike into a corner by stepping the rear wheel sideways. Smooth is always better than idiocy. With my bike I approaxch the corner from the middle of the track, then flick it in while braking. The bike stays more upright, so tyres are not so critical . I raced on T1 compound triangular Dunlops for about 8 years. They taught me how to stay alive. These days I am faster in the wet than in the dry. I have crashed under both conditions and I know what hurts the most.
New tyres give riders a psychological advantage which is probably not reality. Nobody in their right mind flies into the first corner in a race and relies on the tyres having grip when the bike is on full lean. But most more modern bikes are set up to corner with extreme angles of lean. A Manx with 19 inch wheels does not usually corner with much lean, and they oversteer under power, as they accelerate.
If you watch the video 'Tribute to Bob McIntyre' on Youtube. The second part shows Bob riding a Manx on Oulton Park with triangular tyres- he died on that circuit.

Avons could be in short supply in the future as the owners, Cooper Tire are shutting the Wiltshire factory down.
I don't know what the future plans are, but TGA have just ordered a shed-load in while they're still available

I believe he’s ordered a thousand ?

Fair play to Andy, that’s a huge investment.

B+Bogus said:

Avons could be in short supply in the future as the owners, Cooper Tire are shutting the Wiltshire factory down.
I don't know what the future plans are, but TGA have just ordered a shed-load in while they're still available

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To add a little, Cooper Tyres have kept Avon open since they purchased it, however Cooper themselves have now been purchased by Goodyear.

Goodyear is moving the production capability out of Melksham and closing it. It seems as if the most likely alternative site is in mainland Europe, maybe France!

In doing so, Goodyear shows no interest in low volume specialist racing tyres. Indeed, they will be increasing the price of any they do make.

Even if they decide to remain in the business of race tyres, various very low volume tyres will disappear, like for example 16" race tyres.

Andy Molnar and his son Richard have made a very significant commitment, which one hopes will convince Goodyear that the continuation of this low volume business has the potential for significant good will benefit beyond the financial return.

For what it’s worth, and cognizant that they are only available in 18” sizes- I have been running these for the past two seasons:


I really like them, having previously run Avons. The Contis feel more consistent as temperatures change and warm up quickly- they also feel less “squishy” than the Avon race tires and the bikes stability (1979 rd400) has improved. Grip is excellent and feedback is very direct.

On this bike

Elfix said:

For what it’s worth, and cognizant that they are only available in 18” sizes- I have been running these for the past two seasons:

ContiRoadAttack 3 CR Classic Race | Continental Motorcycle UK

ContiRoadAttack 3 CR - The Ultimate Classic Race Radial! Huge increases in wet weather performance thanks to a brand new compound and re-designed tread pattern.MultiGrip Technology combines wear resis

www.conti-bike.co.uk

I really like them, having previously run Avons. The Contis feel more consistent as temperatures change and warm up quickly- they also feel less “squishy” than the Avon race tires and the bikes stability (1979 rd400) has improved. Grip is excellent and feedback is very direct.

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They must be good, some fast lads over here use ‘em. I’ve been told they’re better in the wet than Avons, have you also found that?

Our track is a WWII airfield in the middle of nowhere- Tok is the closest town and is 11 miles away, nearest real hospital is 150 miles.

….so we don’t ride in the wet, and our “racing” is really time trials- all an effort to reduce the fall risk a bit and still have fun.

The pavement is of local aggregate and was put down in before the AlCan highway existed- all in order to ferry B-25s and P-39s to Russia.

And, as you might expect, it’s terrible. But it’s what we have.

Ive fitted Conti road attack 3 to my Dresda triple but have not ridden it on track as waiting for an alloy fuel tank to be made.
Mind you ive just ordered 3 new Avons, New rear for the big girl & a set for the Jim Lee. £595 plus £15 delivery plus 20%vat

Tyres make no difference to me, as long as I have some which are not cracked in the sidewalls. If you have steering geometry which creates a lot of lean in corners, you need grippy tyres. My bike stays more vertical. I would be faster on better tyres - the main advantage would be psychological. When you are racing, the best way forward is often by going under other guys in corners. If your bike has neutral steering, you usually join the others, out wide on corners ar full lean. If it oversteers when you gas it, you stay in tight in corners, at less lean. Most guys do not accelerate much in corners. I can ride at full blast from the moment I enter a corner, as long as I brake before entering the corner. When the back of the bike is down, it steers in the correct direction. The setting of the rear springs adjust the rate of turn.

acotrel said:

Tyres make no difference to me......I would be faster on better tyres......

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Right Al....whatever you say!

SteveA said:

Right Al....whatever you say!

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To be fair, it could sit on bare rims, for all the difference it would make.

If only HRC had access to acotrels experience and knowledge, maybe they could turn out a MotoGP winning bike that doesn't need to be leaned over to go underneath everyone else