Skinny vs fatso tire cornering

True, It's 1939, ..drum brakes, 4 speed box, crude forks and solid rear.plus no fairing. topped off with 40 odd b.h.p...yet a lap of 90 on the I.O.M...not to mention the most basic of tyres...but which Norton 500 rider was it? ...answers on a post card.. and the track was no where as good ...yet 180 bhp R1 new comers .with super fat tyres only just beat that 1939 record...The old boys must have flown Spitefires!!

Seeley920 said:

swooshdave said:

Seeley920 said:

I remember a few years back, one of my mates took a manx, still on 19" tyres to a modern trackday at Cadwell park, out with big Dukes, 7/11 GSXRs etc.......he was 4 secs a lap quicker than anything else there!!

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Rider, not bike.

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Both....I've been racing for 30 years, I should know!! Manxes are capable of higher cornering speeds than lots of modern bikes, Supermonos, Rob North Tridents etc.....try coming to a race meeting. The fastest lap of the weekend usually goes to a 500 single, not an unlimited bike....same rider before you come back with some response!!!

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Danno, you brought me up to speed on flat track. I must watch some vids of modern flat track. Hobot was talking about motocross technique where they often slide the rear accelerating off the exit of a turn. I was thinking he could adopt the same technique on his Commando! :mrgreen:

JRB — was it Freddie Frith? Ireland's own Stanley Woods wasn't bad either...and both Norton works riders.

Rather timid run on fatso race tires 120 & 170 Perelli's so soft pebble stick to em cold but not enough to keep up with any narrow tire Commando in same conditions.
[video]http://www.youtube.com/watch?v=Sx0oUUY--iI[/video]

Off 40 miles on fat tire bike appliance now, till I get a real motorcycle between my legs again.

hobot

Try some Perrelli MT6os on those rims for a little better traction. Came stock on my supermoto. Don't last long on asphalt. Those are great roads for the likes of Husky 610-630 or KTM 690.
Yesterday I rode 2 hours of Mountains + passes, about half on single lane dirt. Getting the 990 a little sideways out of the turns. Lots of fun, clears the head.

Why Will you're beginning to sound like a brother in grit.
Your MT60 report backs up my own tests. I was very pleased/surprised by tarmac performance of Dunlop Trail Max. I have never cornered harsher so far on any other tire. SuperVenoms arrived after over rev event took the steam out of Ms Peel so couldn't test them on the power loads I crave.
These street first off road 2nd tires texture only matters in dirt, sand, mud or grass. Pure soft slicks work best on loose Gravel layers on hard pack or good smooth tarmac. If tire can't really dig a trench in base surface, slicks are best when surface is dry. Clay tracks can use some grooving grip help.
I suspect some advantage in lean by narrow tires that have more round profile.

They look about identical to these here MT60's.


Narrow 19-18" Dunlop TrailMax


I can get my factory Combat skid marks about a foot wide before its freaks me out. I can get my suspension upgraded SV650 almost 18" wide before its a floppy terror. I've gotten Ms Peel over 22" apart still enjoying it but ruing out of slide room to go much farther apart. I never put a foot down as tends to jerk it under peg or tire and on tarmac leans there is no room. Like the video shows I know better than press my modern on grass, grit or tarmac - dozen+ bar levers, half dozen peg/shit/brake levers and signals, 3 radiators and caps, 2 gas tanks and epoxy'd a few times dash mount that just lost it grip on a tack chrome cover today.

Narrow tires seems to allow me to focus spikes of adhesion while the fat ones seem to smear reaction out too long to take much advantage of.

When ya go out supermotarding again and kinda kicking up heels, note that some times you are tossing bike to lean and letting bars straight steer to follow rather than a counter steer to initiate the lean. Depending on condition you innate control sense is cycling in/out of steering phases. Glance at bar angle to tank next time. If ya dare the extra speed involved tarmac is even easier, safer to ski.

hobot

hobot said:

Why Will you're beginning to sound like a brother in grit.
Your MT60 report backs up my own tests. I was very pleased/surprised by tarmac performance of Dunlop Trail Max. I have never cornered harsher so far on any other tire. SuperVenoms arrived after over rev event took the steam out of Ms Peel so couldn't test them on the power loads I crave.
These street first off road 2nd tires texture only matters in dirt, sand, mud or grass. Pure soft slicks work best on loose Gravel layers on hard pack or good smooth tarmac. If tire can't really dig a trench in base surface, slicks are best when surface is dry. Clay tracks can use some grooving grip help.
I suspect some advantage in lean by narrow tires that have more round profile.

They look about identical to these here MT60's.

Narrow 19-18" Dunlop TrailMax

I can get my factory Combat skid marks about a foot wide before its freaks me out. I can get my suspension upgraded SV650 almost 18" wide before its a floppy terror. I've gotten Ms Peel over 22" apart still enjoying it but ruing out of slide room to go much farther apart. I never put a foot down as tends to jerk it under peg or tire and on tarmac leans there is no room. Like the video shows I know better than press my modern on grass, grit or tarmac - dozen+ bar levers, half dozen peg/shit/brake levers and signals, 3 radiators and caps, 2 gas tanks and epoxy'd a few times dash mount that just lost it grip on a tack chrome cover today.

Narrow tires seems to allow me to focus spikes of adhesion while the fat ones seem to smear reaction out too long to take much advantage of.

When ya go out supermotarding again and kinda kicking up heels, note that some times you are tossing bike to lean and letting bars straight steer to follow rather than a counter steer to initiate the lean. Depending on condition you innate control sense is cycling in/out of steering phases. Glance at bar angle to tank next time. If ya dare the extra speed involved tarmac is even easier, safer to ski.

hobot

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I agree that the steering goes through phases of counter-steer- straight-steer according to traction, angle of slide, etc.
Dirt riding for me is second nature. I learned to ride on antique country back roads, Coach trails, and grated secondary roads and this is where I have some of my best times even today on my big modern.
I posted the MT60 comment because they will fit your SV. They will give some stick but are as useless as all 17's in the marbles. I actually had a set of 19"-18" made for the 640. 19" X 2.75" running Contis or Metzeler Karoo in 110-80 and
18" X 4.25" running Metzeler Karoo 150-70. The rear probably would have been better at 3.25" with a 140-80 for the dirt but they were a nice compromise that allowed good dirt road fun without being squirrel y on asphalt.
It is one thing to have the rear out and another to have the front pushing beyond traction with ditches, cliffs, and barb wire fences looming beyond the radius of the corner. Once the slide goes beyond a certain point the foot goes down, not necessarily touching but ready to take the weight if need be until the front catches . I know the riding position on the SV doesn't lend well to foot out, but try it while dirt drifting. It could save you on bike parts by giving the front a little more time to catch instead of ending the Ride.
Someone also commented on getting rid of the interstate tank and going with the S/highrider tank to allow you to get your weight forward, and I have to second this. With all the potential you have going into Ms. Peel I think this would allow you to better enjoy the dirt aspects you have previously mentioned, even if it's at the expense of range. Plus they look a lot cooler and go better with the paired down aspect of your soon to be reborn Peel. Easy tank/seat swap for high mileage days. Just sayin.

Ride safe 8)
Will

I have learned some interesting things reading this thread, and got lost on some of the posts, so I may have missed it...

Wheel base is going to impact the required lean angle to negotiate a given radius. I don't have the math to back that up, but that is what my experience tells me.

Russ

If you look at pics of older flattrackers, that's how they did it, but since the Springsteen era, flattrackers have "railed the turns, only breaking traction long enough at the entrance to the turns to get the chasis set. The days of the broadslide are gone as this only slows you down.

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True, It's 1939, ..drum brakes, 4 speed box, crude forks and solid rear.plus no fairing. topped off with 40 odd b.h.p...yet a lap of 90 on the I.O.M...not to mention the most basic of tyres...but which Norton 500 rider was it? ...answers on a post card.. and the track was no where as good ...yet 180 bhp R1 new comers .with super fat tyres only just beat that 1939 record...The old boys must have flown Spitefires!!

Click to expand...

Danno, you brought me up to speed on flat track. I must watch some vids of modern flat track. Hobot was talking about motocross technique where they often slide the rear accelerating off the exit of a turn. I was thinking he could adopt the same technique on his Commando!

Click to expand...

Above is both music to my ears and pensiveness to try to take on elite bikes/rider on real tracks with isolastic Commando on vintage size tyres.
Peel's tall tales are 5 yrs old now. Survival events forced my evolution of riding styles in same sequence as history. I'm familiar enough now to see each style useful in its own time, place and reason. Just not sure how much advantage is from chassis and tires vs pilot skill or fear. I knew I liked skinny but confused by racers fat extremes. What took a while to soak in -!-
IS All Else Prior Is So Corner Crippled Only Hope is Pure Springting.
PSShaw.

I think the mass and wheelbase are mostly irrelevant or insignificant for two reasons. One: if really long wheel base its got no design intentions to road race.
Two: within lean limits from foot porches it'd give anyone fits to keep up in turns. Their long low CoG allows easy controlled drifts too. Anyone who tells me they can take on a big twin cruiser with good pilot in twisties with w/o scaring them selves reveals to me they don't know what they are talking about or they have a rump rod up their hopped up lightened Commando and practiced on these places. No one else making Peel's crazy claims so I'm sticking to my facts.
Oh sure big long bikes get balky in switch backs and take more athteltics to change leans but it would be significant extra lean for same turn.
Hehe them sports bikes do too don't ya know.
Its been some weather worn 1940's model riders that helped mentor me on how to survive on THE Grave and then on tarmac glee. Hehe a biggies was not drunk.
From one of these old warts I've got supreme secret weapon, 3rd wheel trailer.
If you tell anyone I'd have to snuff ya, but shoot this is tiny close nit bunch so nil worries mate's.

Example for lean angle vs turn in heavy bike.
If ya watch close to save a low side and lift bike to snap the sharpest turns just before falling he throws in a flick of straight steering.
http://www.youtube.com/watch?v=Jt8qSoTVCy4

But you better have rear over powered when ya do
http://www.youtube.com/watch?v=pJLhSWUBnwE

What I and now I see racers discovered is that the only real corner advantage of bikes over cars is the ability to spike traction for instants and twist chassis faster on Cog for more time on straighter accelerating power.
I want to find out if narrow tires can hook up straight sprints enough not to lose what was gained when on hi powered tire edge.
Oh yeah a narrow tire can hook up a sideways wheelie near edge which makes forks and front tire edge behavior a non issue, IF the chassis can take the loads w/o rebounding osculations. THE Hinge is not unique to Cdo's just they onset it at lower loads and speeds and at lower frequency that we perceive what's happening. When it onsets in best elites its so fast and hi frequency very few recover. All the electronic help is to limit power in corners, hehe I'm looking for more more more. Do ya know how much G force into seat it takes to over come the mass of lifting front sharply toward center of a turn against 'centripetal'?
If you ain't on tire edges it flings a hi side, if you ain't hooked beyond drag racer it low sides.

hobot
Ha- if chassis can take the loads predictably, lo>hi side controlled crashing is multi orgasmic.