I see a lot of crapola about tire sizes here. As for matching diameters, unless you are riding on the rims, matching overall diameters with 19" front and 18" rear is easily achieved, as John pointed out. As far as widths, I'd take my cue from the racers. Most street riders don't even come close to finding a tire's potential. Here again, check out the racers. Another thing I see posted here often is rim widths and tire combinations that are out of tire manufactures' specification . Evidently some of you were tire engineers in another life.
Handling with 18" rear wheels.
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But it was only Eighteen . E E E Eighteen . :shock:
advice-needed-t12512-15.html?hilit=thruxton#p147016
in mah book you can read ' 18 ' on the rear tyre of the 72 JPN F 750 too , not that that means it was before it was restored , but mayve been .
advice-needed-t12512-15.html?hilit=thruxton#p147016
in mah book you can read ' 18 ' on the rear tyre of the 72 JPN F 750 too , not that that means it was before it was restored , but mayve been .
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Mentions the KR 83 ?? rear on the Rawlins Mods too , necesary then for TRACTION for the astounding Quater Mile times . :wink:
though we have to be honest and say thisis leant over on a race circuit .
:lol:
though we have to be honest and say thisis leant over on a race circuit .
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" Most street riders don't even come close to finding a tire's potential. "
but at 2 am when its fair precipitateing and a possum attempts harekare under your wheels , youll appreciate that big rear as you hit the anchors .
Remember the 16 in tyre craze of the 80s , for improved turn in. They finally settled on 17 in ( like a 3TA ) as the bump steer with the 16 in.
FRONTS was a bit gruesome . The old Avon 5.00 x 16 rears were a good cruiseing / touring set up . plety of rubber on the deck , popular with T.C.
they say . Prefered Option even .
but at 2 am when its fair precipitateing and a possum attempts harekare under your wheels , youll appreciate that big rear as you hit the anchors .
Remember the 16 in tyre craze of the 80s , for improved turn in. They finally settled on 17 in ( like a 3TA
) as the bump steer with the 16 in.FRONTS was a bit gruesome . The old Avon 5.00 x 16 rears were a good cruiseing / touring set up . plety of rubber on the deck , popular with T.C.
they say . Prefered Option even .
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Rain has cleared grit from ice storms off leaving fresh sun exposed crystalline edges on all the hard particles embedded in asphalt which also seems to collect or charge up static electricity polarity oppositely to the rubier compound for a sense of duct tape like traction to mess your birches the good way. We have sections with curves enough one after another ya can experiment with a little more of this & that - this side then that side ditto ditto as tires heat stabilizes, bone-muscle memory begins to work from brain stem animal level w/o thought so ya just know what will work best and happen the next instants into the future. Regardless of sizes a new set of tires is always a treat with some feeling out like this track shoe or another. Who knows what yo'll like till ya try it so get 19 & 18 and see.
Breaking loose in public to me is more about learning what not to ever do again any where and to never ever forget how close we all are with just the wee bit of traction missing in the shade or insect migration trails etc. Slow leaks are other handling teaser. When i feel a wiggles like wind gusts before pressing a turn I'll glance at rear to make sure.
I'm very curious why so many barn finds have 16" rears and shocked to head cocking states seeing Hogslayer TC's 16" beef, before he headed out on another leg from Ohio rallly to Orgegon on it while the dragster followed in a chevy van. I must try the dark side if even possible.
New 16 inch Sizes
http://www.blockleytyre.com/page2.htm
Our latest project has been to produce a range of 16 inch tyres incorporating a new tread design. After much work and testing (both on the road and at Goodwood track) the new range has been available since December 2003, starting with the 600 x 16" size suitable for cars such as XK and C type Jaguar, 250 Td F and Testa Rossa Ferrari etc. Many vehicles appear to be fitted with incorrect fitment radials (one well known manufacturer even recommending the fitment of their taxi tyre!) which these handsome new tyres will correct.
650 and 550 X 16 Tyres have also been tested and produced.
Breaking loose in public to me is more about learning what not to ever do again any where and to never ever forget how close we all are with just the wee bit of traction missing in the shade or insect migration trails etc. Slow leaks are other handling teaser. When i feel a wiggles like wind gusts before pressing a turn I'll glance at rear to make sure.
I'm very curious why so many barn finds have 16" rears and shocked to head cocking states seeing Hogslayer TC's 16" beef, before he headed out on another leg from Ohio rallly to Orgegon on it while the dragster followed in a chevy van. I must try the dark side if even possible.
New 16 inch Sizes
http://www.blockleytyre.com/page2.htm
Our latest project has been to produce a range of 16 inch tyres incorporating a new tread design. After much work and testing (both on the road and at Goodwood track) the new range has been available since December 2003, starting with the 600 x 16" size suitable for cars such as XK and C type Jaguar, 250 Td F and Testa Rossa Ferrari etc. Many vehicles appear to be fitted with incorrect fitment radials (one well known manufacturer even recommending the fitment of their taxi tyre!) which these handsome new tyres will correct.
650 and 550 X 16 Tyres have also been tested and produced.
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Good Link . But Id only put on square tyres if you stop & put your feet down at the turns . 
or are fitting a sidecar .
these things were suitble for dirt roads perhaps , or learning throttle steering . Like the dirt track Perrelis or knobblies , Crank it over an iota & bring up the throttle & the back walks out .
Likely do it under brakeing , lent over , too . Most inconveniant at times . Well You Should Slow Down , Shouldnt You . Or fit tyres suitable to the task . :wink: :lol:
Offered the remains of a XK 120 / 140 once too , rusty 120 body 7 good 140 chassis . $ 1.000 . in early eighties . :lol: :x
or are fitting a sidecar .these things were suitble for dirt roads perhaps , or learning throttle steering . Like the dirt track Perrelis or knobblies , Crank it over an iota & bring up the throttle & the back walks out .
Likely do it under brakeing , lent over , too . Most inconveniant at times . Well You Should Slow Down , Shouldnt You . Or fit tyres suitable to the task . :wink: :lol:
Offered the remains of a XK 120 / 140 once too , rusty 120 body 7 good 140 chassis . $ 1.000 . in early eighties . :lol: :x
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On my Seeley I use an 18 inch WM4 rim (120/90 tyre) on rear, and an 18 inch WM3 rim (100/80 tyre) on front. My rake is 27 degrees and trail is about 92mm the handling is extremely quick and it self-steers under power when laid over. That doesn't help you much because the handling is probably too quick for a road bike. If you have a look at a modern bike with the huge tyres, you will see that the rake and trail are radically different to what I've just said. The bigger tyres seem to make the handling slower, and most riders of modern bikes use the 'point and squirt' riding technique and don't rely on outriding others in and around corners. They are simply committed to a wide line in corners.
With the big tyres, the difference in profile affects the steering and your commando doesn't have much provision for adjustment of it's geometry. To fit bigger tyres you probably need to slightly reduce the trail. Skinny tyres are usually better.
With the big tyres, the difference in profile affects the steering and your commando doesn't have much provision for adjustment of it's geometry. To fit bigger tyres you probably need to slightly reduce the trail. Skinny tyres are usually better.
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Matt Spencer said:But it was only Eighteen . E E E Eighteen . :shock:
advice-needed-t12512-15.html?hilit=thruxton#p147016
in mah book you can read ' 18 ' on the rear tyre of the 72 JPN F 750 too , not that that means it was before it was restored , but mayve been .
Nice pic. 18 rear with 19 up front?
I have not seen a wm4 recommended much for a commando frame.
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Yea 18 acording to old MCMech. mag . 4.25 18 R & 4.10 19 F , id go WM 4 R & WM3 F , as who wears the sides of the tyres first ? .
Sure it ran in P. R. in the I.o.M. in 78 & 81 or some such . :?
Sure it ran in P. R. in the I.o.M. in 78 & 81 or some such . :?
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Craig said:
I do recall.
I just hit the button!!
But unlike the green one on my MkIII auto start, nothing happened!!
Might be a wiring problem somewhere. I'll get back to you.
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Don't listen to me I'm very old fashioned. I was brought up racing on rock hard T1 triangular Dunlops so today, even with decent tyres I am almost vertical in corners. I love racing in the wet, it freaks the young guys right out. It all depends on steering geometry and power delivery. When I raced regularly - if the rear tyre moved even slightly, you crashed. Manx Nortons were always better than Tritons.
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Matt the corner cripple cycles vintage to modern can not lean over far enough or hook up much power compared to Ms Peel could - so they have concerns not to break free while turning but I want rear to break free completely digitally at some point and past Peel simply ran out of power to do so, so I had to go in harsh enough every apex was a controlled crash to catch and I could not bring myself to go the speed I wanted d/t the 9 ft wide lanes with 10 mph warning signs in public with school busses to logging trucks taking up both lanes and crushing inner guard rails escape routes down too. Peel was too boring to do long sweepers leaning, so most the harsh acceleration through sweepers was done upright straight ahead for more traction lifting forks to full 6" [ extra 2"] extension [if not a bit of aire], then tip a bit off bolt upright to cause rear to spin and snatch us down. This is where Peel ran out of power to do over 70-80 mph in 2nd entering turns while all the cripples hard on brake lights getting in my way. I think Peel might be best with pure flat drag slick but I must cross grass with hidden cow paddies so want some texture like flat tracker or those bocking vintage sports car tires. The 16" rim may help Peel in my-her preferred rear squat front wheelie chopper cornering stance and only hook up much when about full upright. Fitting extra wide tire on extra narrow rim may bend the sharp corners some so still normal 1.5" wide patch to 45' lean, which to Peel-me is when much turning sense and skill begins.
The rest of you are spot on for what works best in too stiff or too floppy corner cripples, but that just ain't the crazy making path Ms Peel&me's is on and no one else is following close, so nothing I say applies to anyone else. If this sounds like a put down to rest of motorcycling word, You Betch Ya and having fun working up the power plant to enjoy it way More. I do not feel separate from Ms Peel flinging her around, No Sir Ree Bob, we are tightly mated as one, so I do not move myself off locked down close low posture, no shifting no body English no knee fouling air flow blocking ground effect inducing funny business - there is simply no time - faster than a blink direction changes tripping out with full bike/pilot mass rear. The isolastics and over lapping power unit rider/horse frame geometry has giving Peel another secret weapon of mass destruction that sounds as silly as a cartoon to rest of the world.
The rest of you are spot on for what works best in too stiff or too floppy corner cripples, but that just ain't the crazy making path Ms Peel&me's is on and no one else is following close, so nothing I say applies to anyone else. If this sounds like a put down to rest of motorcycling word, You Betch Ya and having fun working up the power plant to enjoy it way More. I do not feel separate from Ms Peel flinging her around, No Sir Ree Bob, we are tightly mated as one, so I do not move myself off locked down close low posture, no shifting no body English no knee fouling air flow blocking ground effect inducing funny business - there is simply no time - faster than a blink direction changes tripping out with full bike/pilot mass rear. The isolastics and over lapping power unit rider/horse frame geometry has giving Peel another secret weapon of mass destruction that sounds as silly as a cartoon to rest of the world.
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acotrel said:
Here, here. Those modern fat tyres give a dull feel to steering, compared to the 4.10's on my MkIII. No doubt good riders with bums half or all off seat get them cranked right over. But they just don't feel right to me. Also, I hate the modern cornering style hanging off the side of the seat. You never saw Ron Toombs ride like that. And you won't see me either!
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When I bought my first bike at 17 in '81, I didnt feel like it was a good ride unless there were sparks coming from me tapping the footpegs in corners (not a Norton). I quickly learned I could get more corner in moving more quickly with some body english as well. Nothing wrong with that, even for me as an "oldie" (as my teen daughters call me).
Nater_Potater
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Okay, so it's not a Norton, but at least it's Brit; I converted my '72 T150 Trident to an 18" wheel in the early 80's due to the total lack of suitable 19" tires for the rear, allowing the use of a Dunlop 4.50-18 Sport Elite. It didn't change anything perceivable in its handling (at least, not by me), and I did push it pretty hard on a regular basis. We have some really cool canyon roads out here in the West! The Norton also received the same treatment for the same reasons, and, up until the Isolastics went the way of all men, handled just as well as with the 19", although I don't tend to ride it as aggressively as I did the Triumph.
On a side note, the Trumpet would, in fact, break 130 mph, and never once thought of shaking its head. An absolutely rock-solid bike. Now, if it just didn't have problems with the nasty buzzy vibration, bad rockers, grenading clutch, wiring issues, three Amals, and... where was I going with this?
Based on earlier perceptions of when the rear was swapped to 18", I see no reason to go back to 19" on the back. I'll let y'all know how much better (if any) it works once the isolastics swap-out and link head-steady are done. Maybe next week?
Nathan
On a side note, the Trumpet would, in fact, break 130 mph, and never once thought of shaking its head. An absolutely rock-solid bike. Now, if it just didn't have problems with the nasty buzzy vibration, bad rockers, grenading clutch, wiring issues, three Amals, and... where was I going with this?
Based on earlier perceptions of when the rear was swapped to 18", I see no reason to go back to 19" on the back. I'll let y'all know how much better (if any) it works once the isolastics swap-out and link head-steady are done. Maybe next week?
Nathan
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phil yates said:
Back in the 70s I helped Mike Hailwood have a ride at Winton Motor Raceway with the Manx owned by the Dunsters from Canberra. I didn't expect to see anything spectacular. What impressed me the most was the way he tucked into the bike and was super smooth. In those days we had just got gumball tyres, and the guys were letting it all hang out. The difference with Hailwood was extremely noticeable. About Ron Toombs, I watched him race many times with the Henderson Matchless and the Kawasakis. I was talking to him a few minutes before he was killed at Bathurst, he wasn't so much the super smooth rider, just relaxed and competent. I've seen him win the three major races at meetings in the one day. I once watched him run off at the hay shed near Lukey Heights on Phillip Island at very high speed and kept it all wicked up even while he was off the bitumen. He was exceptional, yet went nowhere until he was over forty years old. Turn one at Phillip Island backs a lot of guys off, myself included. Ron never backed off going around there. Ron was exceptional, however I believe Hailwood was a small step higher
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acotrel said:
I refuse to do it. I only want a bike that will go around corners with me sitting properly in the saddle, longshoreman"s cap on and smoking a pipe!
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The only time I would climb off the side of my Seeley would be if I really got out of shape in a corner, perhaps due to brake fade. Normally I just sit there like a dodo, and it all happens extremely easily. As I've said, it depends on how you've got the geometry set up and how much power you are playing with. It's a bit of a fallacy that you need heaps of horsepower, with about 65 BHP you can still do yourself a big mischief.
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acotrel said:
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