Bridgestone and Rossi

Rossi has defected to Bridgestone tyres for 08 and I just wondered if any Banty riders are thinking of doing the same?

I thought about following Rossi's lead, just cant work out how to get the 190 rear in

I was thinking of a slightly narrower tyre than the one you mentioned and the help of a hacksaw, some bits of metal and welding gear! Where there's a will there's a way!

Hi Mike,

Good news eh? Wont be long before he is at Ducati...

I shall be maintaining my allegance to Dunlop, because I have heard a rumour they are bringing back the KR73 and 76's (Triangulars). Of course, I wont be using one on the front, as on the TZ's I used to find the optimum was Triangular rear and rounded profile front.

Might start looking at the bike soon , now that this Christmas nonsense is out of the way!

Pete do you run a 17 or 18 on the front now? And what rim width is suggested for the 17? Thanks Mike and thx for pump details..

Mike,

I've run an 18" all 2007, having decided the 17" is too heavy. Rim size recommended was WM3 (I think).

The problem is you have 800g more weight in the rim+tyre region with the 17" wheel. Now consider that inertia forces are proportional to mxRxW2, where m = mass, R = radius, and W2 = omega squred (omega = angular velocity).

With the 17" you have higher mass, higher angular velocity (squared), and a little less radius. So inertia must be higher.

I'm too slow now to notice the difference, but I bet you would!

Would Messrs Bass and Hall care to comment?

Probably either:
a) confused by the long words, or
b) still suffering from the excess of Christmas port!

Peter & KA!
Comment on what?
Long words, Xmas port or tyres?
Stay cool,
JayBee.

James Cook could explain the theory of gysoscopic precession better than I. I`ll just say this about wheels and tyres: theoretically a very large wheel is better than a small one because when the little one drops into a hole it shakes up the rider such as to cause disturbances within the heavily laden Xmas stomach. The smaller wheel has the advantage of lesser gyroscopic effects yet some Bantam ravers actually think gyro helps them get into and around the corners (James! You are on... ). Don´t forget that being smaller it rotates quicker ...!
I´d like to make a suggestion: That is Mike Powell should use 24" wheels of 1.5" width to overcome whatever problems he thinks he has... For the 2008 season, that is. Then my favourite raver might get past him.
Re experience -- way back in the dark days -- I´d done two & a half seasons on a "Continental Sports" (or some such name...) at the front and some hideous Roadster thing on the back when the Triangulars hit the scene. Wow!
Distinctly noticeable -- the difference -- but I´d add that for sliding the top (Paddock was it?) corner at Llandow the old half-worn-out Roadster was the best.
Ah, nostalgia raises its silly head.
On the 19th May 1973 it was raining quite a bit. Mick Scutt fell off on his way to the grid... Sorry Mick! I just remember the look on your face when somebody said you ought to try buying a new tyre. Keep well.
I do hope that was of some assistance to you ravers, struggling with what sort of rubbers to wear in 2008.
Stay cool and stay on,
Aye! JayBee.

Slick reckons 16.5 is the best for short circuits. A hit with the heavier WSB lads who shove plenty of torque thro´the back wheel -- not so much (rim & tyre) inertia force and an optimum contact patch on the front... Down to the "rider feel" in the end. For myself, I dunno. Couldn´t afford to experiment with tyres -- well we didn´t have much choice 35 years ago -- but I had oxy-acetylene welding equipment and altered the front end geometry of Icarus 2 with alarming results at Brands on practice days.
How´d I get into this --- help!
Cheers! JayBee.

This reminds me of an article which appeared in one of the Bantam mags in the 80's where the author went to great lengths to explain that it is better (i.e. you are less likely to fall off) to go over a patch of oil on the track at a greater speed than a lesser one! Come to think of it.....

Rusty

just remembered - I couldn't do that one because I was swatting up for my finals - its funny how exams always used to be in TT week. Bit of a nuisance all round. But in June 1973 Kevin Scudder & I went on a "motorcycle" (weekly news paper a bit aloft from the MCN) day trip to the Senior TT.

We flew from Castle Donington on a Dan Air Vickers Viscount. the landing at Ronaldsway was a bit hairy , ooh such a short runway cos of cliffs either end.

On the Mountain upstream of kates Cottage we watched Bantam riders Chris Gregory (team Harpic - clean round the bend) , Mick Scutt?, Tony Jones? go through. Peter Williams was 2nd on the Arter wheel barrow wheels Matchless G50, to Ago. Great stuff.

Then return flight had to circle over disused airfield east of Leicester, while they cleared a "whoopsy" from the runway at Donington.

Oh, and Llandow - best bit was the Mag afterwards "Deepest sympathy for all those who fell at Llandow"

Peter!
Yeah! Mick Scutt in the Island on Robbie Winston`s Bantam with foot pegs, double battery carrier and other oddments welded on by me at
12 Cavendish Gardens, Barking. Midnight and Mick, fast asleep in racing crouch alongside the Winston machine. Wonderful memories -- like they left at around 3 a.m. and I had to go to work at Henry´s place at 08.30... Work...hmmmm?
Dunn you go saying nasty things about Llandow. My favourite track. Pull away in first and use 2nd and 3rd for the race -- on Icarus One Bantam, that was. Almost dozing off at times... On Andy´s 250, totally different -- forever forgetting which of the 5 gears I was in. But great race with John Senior. He on his Greeves Silverstone and I... were 3rd & 4th a half a wheel apart at finish. Two Jap machines ahead: water cooled an´all that fast, speedy crud... Not that far ahead either.
How did we get to Llandow? How did we get on to this slushy nostalgia stuff? We were supposed to be discussing Mike Powell´s need of a different front wheel to make him go faster -- weren´t we? And a clever
mathematician/scientist/engineer was going to give us the reasons why
gyroscopic precession helps...

But why should Mike go faster? The way he trounced the Butler 250 Ducati at Lydden in `05 looked to be about as quick as any Bantam
might go. Mike -- with his head on backwards -- was truly frightening.
Keith Webb said, as I was nicking his chipos, "Cor! Did we really go that quick!"
Stay cool and stay on. Go well and keep well,
Aye!
JayBee.

Come to think of the dates: Welding bits on Robbie Winston´s Bantam must have been in 1970, or even earlier. 17/5/73 was my great day at Llandow. I know that `cos the pot is sitting on my computer...
`Stick with it´ as the actress said to ...
(To whom? A ten pound note to accompany answers...)
Cheers!
Get cracking with bike prep...
Aye!
JayBee.

Doesn't unsprung weight also come into the equation ?

Hi Ned!
Yup it does. Until you spoke of the `Equation´ I was enjoying this...
I´m backing off... It is time for James Cooper to take the stand. Or isn`t it up to the bloke who started all this to tell why he needs a different front wheel? Inertia, gyroscopic effects, front end geometry, contact patch and rubber mixes -- and now Unsprung Weight? All solved if Mike Powell uses a normal bicycle wheel -- 26" by 1& 1/4", should do it: low inertia, small gyro effect and all that ... the front wheel ought to be off the ground anyway!
I am crawling back in...
Keep well and don´t trip on the local pub´s front door mat -- better to fall over after your pint.
Take care,
Aye!
JayBee.
PS -- How long have you been living in Rayleigh?
JB.

Talking of wheels and tyres - Nearly everybody has 18" wheels on their banties, Mick and Ted being the only current 17" runners? Why haven't other riders rushed and jumped on the bandwagon of 17" wheels and more choice of tyres? If i went 17" would i lap quicker? Martin n Mick Nash both had 17" fronts as has Peter (06). I can see a problem with the rear tyre being too wide (Mick runs a front on the rear i think?) to accomadate in a standard(175) swinging arm and also the rear chain run would need to be moved as i suspect so would the engine?? But 17" may be the future.......?

Hi Mike!
Motorcycle road-racing is like that -- you are always looking at the other fellow´s bike and wondering why yours is different -- and should yours not be the same?
If one tried to be scientific about the vast variety of factors effecting handling during fast cornering the realisation would strike that any positive conclusion would become prohibitive regarding time & cost. Bike-and-rider are so unique to each other that the word "subjective" crops up... You can only make a guess based on what others have done and then try your own thing.
I´ve looked at your riding style -- in the mags and I see that yours is unique!
Regarding the basics a good book often helps.
Millhouse Books must be just down the road from your place -- give them a buzz and ask for "Motor Cycle Chassis Design -- the theory & practice" by Tony Foale & Vic Willoughby. It is dated -- 1984 -- but there´s sound stuff in there!
Last word (promise!) -- way back, Slick reckoned he was at Daytona when riders were offered a ride on Freddy Spencer´s ex GP bike and there were no takers. One of those who´d refused, was asked why... He said "Just look at the front end -- the steering geometry´s all wrong." Slick said you could not see what was wrong, by eye. It must have been rumours that had spread around.
Take care!
Aye! JayBee.

Mick you're the top 17" runner, so what do you think ? are 17" radial's better than 18" crossply's ? I'm thinking 17" may be better and that explains your silence on the topic ....... ?? or are you going 18 for this coming season ...... ?

Hi Mike
The reason Ted & I use 17 inch rims is all down to my powers of persuasion. The compound of the rubber is the same in our 17's as your 18's, but as the rolling circumfrence is almost identical in both sizes the 17 inch tyre theareticly will have a larger cotact patch when on the side of the tyre. My main reason for prefering 17's is my belief that 18 inch tyres are not beeing developed anymore whereas 17 inch tyres are the size of choice for the current racing 125's and therfore (hopfuly) these tyres will be avalable to us mere morlal's (at club leval) in the near future.

captain cook thinks he will have trouble getting a 190 in his bike I see no problem with the front as the forks should be able to take most tyre size's has he considered getting in touch with valentino, he will probably give some good advice on getting it in the rear.

Tut tutt Ted!
Did you want to hear about MOMENTS -- Rossi has had his, a skinny little Ozzy has taken over...
Keep well,
JayBee.
Who dares wins! (with apologies to SAS).

Ted our chat at the do and then me buying MCN post do, i was alarmed to see the camp way Rossi was skipping away from his mount after a fall??
Anyway when I spoke to him on the phone he told me to stick to 18s or go to 19s on a 125 as the contact patch on 17s was way to large ??

Mick start that new tyre topic you mentioned?

im moving from michels to dunlop ?