Wiwider swinging arm for Norton slimline featherbed

t ingermanson said:

Slimlines (as far as I know) always ran 11.9" shocks. Dave could be compensating for the 18" rear wheel with his advice. It would be good advice.

19" front wheels are stock.

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tyre dimensions are useful to discover, particularly diameters, though not always easy to find. Avon is one of the easier ones.

I have the orriginal size rims and tyres on my 600 and 650 and they steer beutifully . The Atlas has wider than std tyres ( not by much!) and it steers like a loaded truck. But then your loaded up bike will probably feel like that anyway. Dont go too mad.

Im pretty confident in going with 90/90 18 WM2 on the front and 100/90 18 WM3 on the rear. I may also get a 110/90 18 WM3 rear tyre for comparison. Ideally all Avon. And yes we should work on a tyre circumference reference document!

I haven't got time at the moment to search, but have you tried McIntosh Racing (NZ)? http://www.manxnorton.co.nz/catalogue/

EDIT: Actually, just did a quick search - http://www.manxnorton.co.nz/catalog...8A93C33909D700D5E43B8E1?m_id=1&c_id=2&p_id=10

ryan_carter said:

Im pretty confident in going with 90/90 18 WM2 on the front and 100/90 18 WM3 on the rear. I may also get a 110/90 18 WM3 rear tyre for comparison. Ideally all Avon. And yes we should work on a tyre circumference reference document!

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Avon has a great chart.

18s lower the trail on an otherwise stock Norton, slowing the steering.

t ingermanson said:

Avon has a great chart.

18s lower the trail on an otherwise stock Norton, slowing the steering.

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Depends which you choose.

I run the 100 90 19 front and 4.00 18 rear. They have exactly the same 671mm / 26.4” diameter front and rear.

Fast Eddie said:

Depends which you choose.

I run the 100 90 19 front and 4.00 18 rear. They have exactly the same 671mm / 26.4” diameter front and rear.

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True. I have 18s that measure the same as 19s in diameter as well, but the ones @ryan_carter mentioned are not the same ratio.

Whether it's enough to notice or care is up to him. I like mine slowed a bit.

When I get on the Featherbed 650ss after riding one of the other old bikes here, I tend to head for the ditch when turning onto a different street.
The bike takes very little effort to turn, so the standard effort creates too much turn and too early of a turn. After a near miss or two, riding adjustments are made and the Featherbed provides a wonderful ride.

Glen

If you have a look at the swing arm in the Barry Shene / Fred Walmsley Manx, Roger Titchmarshe used to make them.

One of my mates had built the first bike I raced. When I started racing it, it was impossible. It had 4 inch megaphones and the motor was an inch back in the framt. It had 19 inch wheels. I fitted a 2 into1 exhaust, made new engine plates to move the motor as far forward as possible I then started getting respectable lap times - the bike was almost competitive.
I then got smart and fiited 18 inch rims with better rubber. The bike did not corner any quicker, but whenever I got off it after a race I was always completely buggered. Copying Japanese bikes was not clever. Smaller wheels reduce the trail, so the bike becomes less nimble. My mates 650 Triton has 18 inch wheels, but the motor is that inch further back in the frame. It is neutral handling, but not as fast in corners. My bike was a short stroked 650 of 500cc capacity. It created anxiety.