Race tires 250 ducati

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Kthomas
Posts: 28
Joined: Sun Apr 26, 2015 12:24 am

Race tires 250 ducati

Postby Kthomas » Thu Dec 06, 2018 12:29 am

What is everyone using these days ? I haven’t raced in a couple years and need new tires . Anyone using Continental Conti Road Attack 2 ?

double diamond
Posts: 415
Joined: Thu Apr 28, 2011 1:20 am

Re: Race tires 250 ducati

Postby double diamond » Thu Dec 06, 2018 7:53 pm

I’ve seen the Conti’s on vintage superbikes but not on smaller vintage bikes. Conti doesn’t offer a size small enough for a Ducati 250. Your alternatives for race compound tires are Avon and Heidenau. Avons are well regarded and very expensive. I have Heidenau race tires on my 350 WC single, 100/90-18 K65R on the rear, 90/90-18 K44R front. The amount of grip they provide for a vintage tread pattern is impressive. The 100/90 rear seems about right but I think the 90/90-18 front might be too big, even for a 350. On a 250, I would say it’s definitely too big. For a 250 I would consider a 2.50-18 K40R front and either a 3.00 or 3.50-18 K65R for the rear. Heidenau also offers natural rubber tubes (good) but they are heavy (bad). I’ve spoken with racers who use various manufacturer street compound tires. Street tires give you a few more choices but you won’t have the grip of race compounds. If you use street tires, be aware of the speed rating. Small street tires suitable for a Ducati 250 might not have sufficient speed rating for racing speeds. The Heidenau race tires I'm using are H rated, which equates to 130 mph.

When I installed the tires (on alloy rims) the diameter of the bead seemed too small for the rim. They were very difficult to install but they did go on and seat with copious amounts of tire lubricant. I could not use rim protectors; there just isn’t sufficient room. I also tried installing on a tire machine but the machine I used wouldn’t work with these small tires. I ended up using tire irons and no rim protectors. If you use the Heidenau tubes (this probably applies to any tube but especially the thick Heidenau tubes), be sure that the tube does not get pinched between the tire and the rim. This happened on my rear wheel, resulting in a noticeable bulge in the side of the tire. Be sure you have the tube all the way inside the tire before seating the bead. This is difficult with the tight fit of these tires but critical for correct installation.

Matt

Kthomas
Posts: 28
Joined: Sun Apr 26, 2015 12:24 am

Re: Race tires 250 ducati

Postby Kthomas » Fri Dec 07, 2018 1:41 am

Thank You Matt.
That was very helpful. I appreciate your taking the time to give me the details. I’ll most likely order some Heidenau’s .

HMBAtrail
Posts: 21
Joined: Wed Aug 16, 2017 4:07 am

Re: Race tires 250 ducati

Postby HMBAtrail » Fri Dec 07, 2018 9:56 pm

I race the Conti RoadAttack 2 CR on my 350 Honda, my 350 Ducati, and my 250 Ducati.

You can get them in 100/90/18 and 110/80/18. They are wonderful tires.

etsjw
Posts: 5
Joined: Wed Jul 19, 2017 2:05 am

Re: Race tires 250 ducati

Postby etsjw » Sat Dec 08, 2018 2:32 am

As double diamond stated Avons are very good but expensive. I also question the age of some of the Avon RR tires offered by the various accessory retailers here in the US.
On a 250, unless you are trying to emulate Marquez, I would use a 3.00 or 3.25 Dunlop TT100 K82. These are speed rated at 112 MPH. If you are going faster than that on a 250 I think everyone on the forum would like to know your speed secrets!
I have a set of 3.25 TT100s on my NC Mk3 that I use for fast street riding (early AM only) and an occasional track day. The TT100s are very stable in a straight line and I would guess that a lean angle between 40/45 degrees is possible before you notice some complaints from the tires.
Unfortunately they don't seem to be available in the US.
I got mine from Feked in the UK. Took about a week and half from order to delivery. They were very well packaged, freshly made by Dunlop France, and I seem to recall that the total cost was around $230.
I've had them for two years and I remain very satisfied.

Bevel bob
Posts: 773
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Race tires 250 ducati

Postby Bevel bob » Sat Dec 08, 2018 7:43 am

At a previous classic TT in the 350 race a Ducati came 3rd and was doing 126mph at one point . I manged 104 mph on a roadster Mach1 some 52 years ago ,so one would expect 112 would be easy now for a 250 racer?.

etsjw
Posts: 5
Joined: Wed Jul 19, 2017 2:05 am

Re: Race tires 250 ducati

Postby etsjw » Sat Dec 08, 2018 6:21 pm

Well Bob you had one rocket of a Mk1.
All the published articles I ever saw for mid/late 60s Mk1/Mk3s reported top speeds in the mid 90s. Were you using an open megaphone on the exhaust?

Cycle World's 65/66 250 Mk3 project racer had a reported top speed of 116mph. This was a bike weighing 233 pounds with an extensively modified cylinder head and a huge 1 3/8" Amal GP carb. They estimated they had about 30 rear wheel horsepower at 10000 rpm. I really think that 30 HP is about the limit when modifying an existing 250 cylinder head - unless you are willing to keep raising revs, which has its own set of issues.

My own feeling is that unless you are racing at a track like the IOM, early, strong, controllable acceleration is more important than top speed.
Its like Rob Muzzy once asked: "What would you rather have, half a second gained off each of the ten corners or 3 seconds gained from higher top speed at the end of the straight?"

John

Bevel bob
Posts: 773
Joined: Thu Apr 15, 2010 8:01 am
Location: Bromley Kent UK.

Re: Race tires 250 ducati

Postby Bevel bob » Sat Dec 08, 2018 10:14 pm

Without doubt the Mach1 and later Mark3 Narrowcase were a bit too overtuned for the market and the top speed could only be achieved after a very long run up and 9ooo rpm in 4th before a change into top ,everything had to be in perfect tune and flat on the tank . Several American tests timed it at 105 mph and a brit test of a well used one managed a timed 97 in fourth.(with silencer). Few owners could be bothered to keep one in top tune,so 90 became the accepted figure. The bike would have been a better rider with a 27mm carb. When properly set up they could perform . In 1967 a very standard Mark 3 Narrowcase was raced by Paul Smart and Reg Everett in the then worlds premier and toughest race , approx 600 laps over 24 hours. It finshed 3rd overall inbetween the big bikes and first in the 250,350 and 500 classes, beating whole teams of works Ossas and Bultaco's.No mechanical problems going as well at the end as the beginning with brakes worn right out.


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