Topic: V or Z rated vintage style 19" ribbed front tires?

[gschuld]

I'm looking for a 19" front tire rated for up to 150 mph(V or Z rating) in a vintage ribbed tread.  Anyone know any?  Several modern tread pattern tires to choose from, but hoping for a vintage tread. 

Thanks,

George

[Old Scrambler]

I've looked several times for 19 and 21-inch ribbed treads ..........no luck. I have seen the claims that 'shaving' an H-rated Avon Speedmaster will give it a rating for 150-mph but I don't have verification. You may want to post on the www.landracing.com site. They have a thread for tires.

[johno]

Hi George,
Just curious as to why you want to run the traditional ribbed at 150mph , is it a combo of a hot big bore sleeper with stock look ?   or classic CR look ?  Either way George I love any honda 750 that does 150mph, in oz that would get a DLRA 750 modified record currently at 149 .76 mph

I dont know of  V rated rib s only the H as your aware of. 

Scrambler This record is both good and bad for me as I have 3 sets of wheels to run,  2 x 18 inch mags,  2 x  stock 19inch honda front wheels and 2 x 21 inch laced honda front hubs,  or a combo of above.  ( special homemade rear swing arm to suit the honda front hub to make things skinny ) The tyre rating required is determined by the current record record so the V rating at 150 says I can run  V rated but only gives me 0.24 mph to go and I will have to run a Z rated tyre which is not available in 19 inch or 21 inch.     Bummer .....so I contacted the chief motorcycle scrutineer at DLRA who  base their regs on your SCTA and exchange information and safety updates regularly across the water.

He is more than familiar with two tyre issues,
1. in a bid for skinny tyres..... front only tagged on back
2. 19 inch and 21 inch tyres only available in H or V .........no Z for 150 mph plus

After an accident with rider down at 160mph the DLRA banned front tyres to back for 3 years but this year have officially revised to allow front to back and I have it in writing.    ( problem was found to be tyre valve stem found 200 metres from bike)

If the tyre treads are buffed to  x ? mm DLRA will allow H to V and V to Z rating and I have that in writing as well................. life is not easy  .......... re the tyre buffing it has been standard practice in the car racing classes particularly production classes and I have evan buffed and grooved them myself BUT I'm struggling to accept it yet as an option for me on the front wheel ............  Unfortunately I might be forced ( hopefully) into giving it a go to run tall skinnies at 150 plus.

Just for discussion Continental have just bought out " classic attacks "  in 18 inch and 19 inch , they are radials, the only 19 inch I believe rather than the 19 inch and 21 inch bias ply available.

They sound interesting george , like the idea of radials on the old bikes, only I dont think they are ribbed mate.   I tried some ribbed condoms once ......there not as good as they claim.
ciao johno

[gschuld]

Johno and Old Scrambler,

     The best that I have found so far is the Avon Speedmaster "race" version front.  It's rated at only 130mph though, and is NOT DOT approved!   I have an RC Engineering built 1000cc motor that would like to stretch it's legs at some point.  Perhaps mounted in a lighter chassis...  hence the higher speed rated tires.

I'd rather not shave tires to fudge the limits.  And I'd certainly prefer to be street legal with a decent tread depth available.  There are modern tread tires available, just not my first choice

George




Item Description


Avon AM6 Speedmaster MKII Race Front Tire

Available in Sizes:

2.75/3.00-19
3.25-19
3.00-21




Item Details

H-rated for speeds up to 130 mph
Intended for race use only
Not D.O.T. approved
Tube Type Tire
 

[Bill/BentON Racing]

What was on the triple?Sorcerer? Jr. might could help,Bill

[turboguzzi]

conti tkv 11 is rated V and is a vintage patern

http://www.conti-online.com/generator/www/it/it/continental/moto/themes/a_motorcycletyres/d_custom_touring/g_tkv11_12_it.html

[gschuld]

http://www.conti-bike.co.uk/default.asp?spid=59

Well I'd say more of a modern tire meant for vintage bikes than a terribly vintage tread pattern.   Better than most though...  thanks for the link.

George

[Retro Rocket]

GS, are you drag racing or going for speed records, flying mile type stuff, if the later use the best tire you can get, forget old ribbed designs, they are horrible at high speed and track badly....

[gschuld]

RR,

     Good to know.  Thanks.  And potentially a little bit of both.  If ribbed fronts do not perform well at speed, then this thread is dead in the water.  I prefer vintage looks, but I like being safe better.

George

[turboguzzi]

http://www.conti-bike.co.uk/default.asp?spid=59

Well I'd say more of a modern tire meant for vintage bikes than a terribly vintage tread pattern.   Better than most though...  thanks for the link.

George

agree on the rear, but the front pattern is just like conti's 70's - 80's race tire pattern

try to dig some old pics and youll see

[Old Scrambler]

Thanks TG for the Conti link...............just some more info........nothing definitive

I run the H-rated Avon Speedmaster on the front with no issues...........I run a modern-tread 21-inch front tire on the rear with a 1.6 rim.

Based on observations of other bikes running on the salt............the modern tread design has a lot of contact area and throws a lot of salt at the rear wheel.  I think a ribbed design has a lot less contact area and allows air to pass between the ribs.........my thoughts..........not scientific proof........is that the ribbed design is more aerodynamic and has significantly less friction requiring less power to 'push' it through the salt and air.  I think that loose salt hitting the rear tire can only lead to wheel-spin.

I run narrow rims to force the tread face to be rounded...........at speed the tire growth should be uniform across the tread but if not it will tend to grow in the center...........I think that is a good thing on the front but may not be good for traction at the rear.

From my reading, radial tires are not recommended for high-speed (175 mph+) because they have a stronger tendency to pull away from the rim due to the soft sidewall.  Some people run heavy duty tubes in the radials but that seems to be self-defeating because of the weight and the risk of blowing a tube from wear on the internal 'ribs' of the tire.   It also seems to be recommended to run non-wire-spoke wheels in excess of 175 mph because of rim-flex and the good potential to break the spokes.

Shaving (buffing) the tread is recommended for high-speeds because it reduces the amount of weight at the outer circumference of tire. On-board cameras have images of tires 'chunk'-ing and shredding at speed. I am told the best way to shave a tire is to use a spin-balance machine with indexed cutting blades.

Anyhow...............my effort has yet to get my Triumph Cub over 84 mph...........but I thought I would learn as I go and try to use the knowledge to apply to a faster machine.  This year the goal is 90 mph but really hoping to top 96.2 mph. 

Somewhere in my long memory I read about the 'Hardley-Davidson test of a late '60s or '70s Sportster at speed. Something about only 7 or so lbs. of down-force (weight) on the rear tire at 110 mph.  In general, at speed, the entire vehicle tends to compress the air beneath it and create lift. Lots of subsequent NASCAR and other studies lead to the creation of air-dams at the front. BTW, fan-induced negative air (suction) beneath a competitive car (or bike) is not allowed.   

Land Speed Racing is such a small part of the motors-ports world that the tire manufacturers can only afford to produce tires to fit street-machines.  Good-Year and Dunlap have tested 17-inch and other sizes at 350 mph and higher without success. The 350 mph+ streamliners are resorting to a cast-aluminum front wheel with a 'tread'-design cut into the outer surface.  Others have resorted to air-craft tires.