Front wheel size

Chris Launders

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I've just been out for the first time this year and my twin, I've been using my Norton Atlas for several weeks and my first impression was "What a pile of rubbish" the steering felt really heavy and uncertain at low speed, and this is with the modified steering stem etc and a steering damper on it's lowest setting with 27" bars.
Now I have a 19" rim on the front with a 90/90 Roadrider at 28 psi (I've just blown it up) would changing to a 21" lighten it up much ?
 

vibrac

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That should start a deluge!!! pop out and have your tyre pressures to hand as you are bound to be asked! :D
 

davidd

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Tim is right on both counts! I would try working the air pressure of the front tire up a bit to reduce the size of the contact patch. It could have a positive result.

The resistance of the front end turning goes up with the square of the diameter of the circumference of the tire. I would tend to stay with the 19" tire. (A low profile tire also helps out.)

Because tire and wheel changes tend to be expensive, you might consider trying the Reg Bolton mod. It will speed up the steering by steepening the rake. The lovely thing about this mod is that it can be easily removed. It is also easy to alter if you wish to experiment.

Altering the rake has always been an important mod to Vincent road racers. David Tompkins has used my steering stem and variation of the Reg Bolton mod on his racer. He felt that it improved the handling considerably at Laguna Seca. The "corkscrew" requires some pretty quick turning.

David
 

Chris Launders

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Davidd, I have a vague recollection the Reg Bolton mod involves lifting the middle of the bike to steepen the head angle, that's a no as I find the bike too high as it is, even with a reduced thickness seat, I'm one of the short fat brigade.
 

Peter Holmes

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I think you may be suffering from unrealistic high expectations, after all at its very youngest your Vincent will be 65 years old. I have related this story before on this forum, but I will retell it in as short form as I can, my Son, now 45 years old, cut his teeth on Japanese four cylinder missiles, but one day for reasons I cannot recall his Kawasaki was off the road, and he was desperate to go somewhere on two wheels, so I lent him my Rapide, with the conditions don't thrash it or crash it, thankfully he did neither, but on his return I asked him how found the experience, his reply was somewhat less than complimentary, his appraisal went something like this " they really should not be allowed on the public highway, the engine is gutless, the brakes, well there aren't any, and the suspension is a bit like when I was a kid and used to bounce around on a pogo stick"
It was all said a bit tongue in cheek, I think he likes it really, but the point is an awful lot has changed with motorcycle design in 65 years, in my opinion not all of it for the better. But the reality is if you want to ride a fantastically fast motorcycle with neck braking acceleration and brakes, fast steering and great suspension, you probably don't want a Vincent.
But I digress, I think it well documented that the best steering is to be had with a 20 inch front wheel as opposed to a 19 inch front wheel, but the variety of tyres are just not available, so perhaps 21 inch is the way to go, but then you get increased height, as I am finding now, dilemma.
 
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Chris Launders

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Hi Peter,
I'm not new to this, I've been riding it for about 10 years now, but been mostly riding pre- war stuff as well, the last few weeks on the Norton must have coloured my perceptions of what it was like I presume.
I will try upping the tyre pressure and see how that is, maybe try it without the steering damper as it's so stable with the steering mods.
I can always dig my Norvin out and have the best of both (he said ducking)
 

vibrac

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Pot Holes !, What Pot Holes :D .
Exactly what i said when I added the Brampton and rear of my Comet with coil overs (19" wheels) the only caveat is that I had just been over the same bit of road on my 52 ridged Trophy with knoblies:D
 

Chris Launders

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Well I upped the front tyre to 32psi, went to wheel it out, into a thunderstorm, maybe later then.
I know what T.T. said about the steering damper, it would only be to see what was the difference at up to a few MPH, although I have to say once above dawdling speed the handling is really good, hands off anytime.
 
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