Enfield tyre sizes

[Smithy]

Hi

The standard rear tyre size on the mighty Enfield was 110-80-18 which always felt a bit under-tyred to me so when I changed to knobblies I put on a 120-80-18 Heidenau K60 Scout which fitted beautifully but still seemed a bit skinny to me. The bike handled well enough in both wet and dry conditions but it only lasted about 4000 miles.

I decided to try a Mitas E07 in a 130-80-18 size and I'm glad I did. I have a new chain on the bike which meant that the wheel sat about as far forward as it gets and as the swinging arm narrows along its length the tyre did rub on the arm  and chainguard. However it was such a small amount that I thought it worth altering the swinging arm to make the tyre fit.

I removed the swinging arm taped a 32mm socket to the point where the tyre rubbed, put the whole lot in a vice and squeezed a shallow dimple into the arm about 1-2mm in depth. The chainguard I rested on a roll of tape and indented it with a hammer. Voila the tyre no longer rubs.

Because the tyre has a greater diameter the gearing is slightly raised and the bike now cruises much more smoothly at A road speeds. Handling is not affected. In my opinion it also looks better.

Ian

[Propellor]

Must admit my first impressions of the avon road riders fitted as standard were very reassuring steering but a little under tyred, as in the contact patch feels small. Not had any issues with grip in the dry, the peg goes down on the left and the brake lever on the right. But in greasy conditions I've had a few occasions where the tyres slide, especially the front. That's when you notice the small contact area.

Having clocked up 2800 miles I've got used to it.

[Moto63]

Even Ian, "ONLY lasted 4000 miles" blimey wish I could have got that kindda mileage outta my old trumpet speed triple tyre.... I was lucky if I got 1800 miles. Expensive hobby. 😁👍
Cheers, Michael

[Smithy]

Ayup Michael

Blimey 1800 miles at the rate of my current mileage I would have had to change tyres 7 or 8 times a year! I think when I had CZs I only changed tyres when I got bored and had nothing to do.

Ian

[Moto63]

Ha ha.... yeah I used to go thro three or four tyres a year at one point..... didn't have kids then tho 🤣🤣🤣🤣

[Propellor]

Was the CZ the one where the gear lever doubled as a kickstart?

[Smithy]

Yes that's the one, JAWAs did it too. They also had a version of Triumph's slickshift gearbox where holding the gear lever down (or up) would disengage the clutch. Very handy if the clutch cable snapped.

Ian

[iansoady]

I'm not convinced big tyres are necessary. My Guzzi V50 is perfectly happy on a 100/90 x 18 Roadrider on the back. And the Norton only has 3.25 x 19 both ends (although I admit I don't ride it like I stole it.....)

[Propellor]

Wonder what the continental gt 535 runs? And wheel rims...? (Cog whirring sounds in my head 😂😂)

[Smithy]

I'm not convinced big tyres are necessary. My Guzzi V50 is perfectly happy on a 100/90 x 18 Roadrider on the back. And the Norton only has 3.25 x 19 both ends (although I admit I don't ride it like I stole it.....)

I agree they're not necessary as most Manx Nortons etc raced successfully on what would be called skinny tyres today. The truth is when I say I decided to try a 130 80 18 I decided to try it only after ordering it by mistake! However as I say it was a happy accident as the bike seems to run smoother with the slightly raised gearing it has brought.

Ian