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Getting Your Knee Down... On An Old Bike.


Wippersnapper
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Hello again! I have an old 1984 Honda VF 1000 Interceptor. Being a more "out-dated" bike the rear wheel is not a radial like all the newer bikes. I have ridden my dads GSR1300R with the radial rear and have felt a major difference. It was in the corners, I immediatly felt like I could lean the bike further over and it was SOLID when going through the corners. I did not try to touch down on a bike that was not mine but this planted the seed of a naggin question deep inside my head. Is it safely possible to get your knee down on a bike with the old style tyre? I have looked at my rear and it is pocked all the way to the sides on both. Also, when I have been fairly far over (what I think might be the max of the bike) it seemed to want to fall over on its side. Not the side of the tyre but completly just fall over. I have been able to pick it up with the throttle when this happens but is this the bike riding near/on the eadge of the tyre or is it a sensation I am just unfamiliar with? Thanks.

 

~Wip

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During the early 1990's I raced an FZR400 on both radials and bias ply tires. I started with Dunlop Sportmax radials and also ran the Dunlop and Metzler bias ply. Honestly, the bias ply tires felt more "planted" most of time to me. The stiff carcass had way less flex than the radials and I felt the bias ply compounds also had a more predictable or progressive slide than the Sportmax compound. Though the Sportmax's definitely had more overall sticky grip. There was a big difference in the profiles as well. Obviously, the Sportmax had a lower profile with shorter sidewall just being a radial, but the front was sorta squeezed on which gave it a pointier shape if that makes any sense. Although, maybe once the radial settled in so to speak, how can I say, it felt better? I don't know if any of this will be helpful...but to answer your question directly, there is nothing inherently wrong with a bias ply tire for leaning over. There might be other factors contributing to your comfort on your dad's bike like the shape/profile, or the condition of wear. Are your tires worn? In any case, maybe someone else has more specific knowledge of these makes and models or more recent tire tech? Sorry, I'm probabaly confusing you more.

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No, no confusion at all. I can see how comfortable the rider is with the bike effects the overall performance. Yes, my tyres are worn but not completly. So what I think you are trying to figure out is the sensation I was feeling as I was leaned over? As far as I can tell I was not sliding really or emm scrubing that part of the tyre, the whole tyre had be gradually broken in by myself before any serious riding had taken place. I am going to try to take some picture of myself in a hard corner and see if I am close to the ground or if my body position and style would even allow that on my bike. Thanks, everything helps.

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In a nutshell, the bulk of street riding is done on the crown of the tire. Even if one spends alot of time in the twisty's, unless you are riding ONLY in the twisty's, the percentage of wear will be greater as you move toward the center of the tire. Even a tire with "good" tread to pass state inspection can have horrid riding characteristics. Essentially, the profile "squares off". If you can imagine a cross section view, the smooth rounded transition from straight up to leaned over becomes less smooth or gradual over time. The zone from a little leaned over to alot leaned over becomes an abrupt change. Hence the feeling of falling over. And, IMO, also the sudden shift of stresses to the edge can overcome traction. This is my theory based on experience and observation. So, this is why I ask how worn the tire might be. If there is deeper tread on the side than the crown...maybe you'd feel better on a new set of rubber.

 

BTW...when I used the word "planted" to describe bias ply tires, I mean more solid or connected than the typically "squirmy" feeling of radials fifteen years ago. During the process of leaning over, one lost the feel or sensation of the road and connection while the tire deformed and reshaped to the new lean angle. Sort of a feedback limbo that could be a little scary while flicking into a fast tight corner and not really knowing what the front was gonna do till it did it. It took a little time to get familiar with these "new tech" tires. I imagine that motorcycle radial technology may have progressed since then. I can't be this old.

 

In any case, there is nothing inherently wrong with your bike being OLD-er per se. There are many things that could affect handling that could be cleared up with some typical high mileage maintainance and TLC. Many things, like tires, that will pass a street or even race track inspection can still be worn enuf to need replacing. Steering head bearings, rear monoshock and linkage bearings, swingarm bearings to name a few. Not to mention the more common fork oil and chain/sprockets combo. It's amazing how all these lilttle things will add up to turn a wonderful bike like an Interceptor into a shyte handling machine. Just some thoughts. I don't mean to imply that this is your case, but, I am constantly amazed at the number of riders I meet who don't even think about maintaining their machines beyond an oil change, so, I just thot I'd use your thread here to get on my soapbox about it.

 

Cheers.

 

Something else that just caught my attention as I read your original post again...do you mean to imply that your front tire is a radial and your rear is a bias ply???

 

Um...I don't know what the gurus might say these days if radial tech has come a long way, but, IN MY OPINON, due to drastically different performance characterics, this would not be desirable. Unmatched tires in any way is never a good idea in my mind. But, someone else may have a different opinion re the bias rear/front radial combo.

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In a nutshell, the bulk of street riding is done on the crown of the tire. Even if one spends alot of time in the twisty's, unless you are riding ONLY in the twisty's, the percentage of wear will be greater as you move toward the center of the tire. Even a tire with "good" tread to pass state inspection can have horrid riding characteristics. Essentially, the profile "squares off". If you can imagine a cross section view, the smooth rounded transition from straight up to leaned over becomes less smooth or gradual over time. The zone from a little leaned over to alot leaned over becomes an abrupt change. Hence the feeling of falling over. And, IMO, also the sudden shift of stresses to the edge can overcome traction. This is my theory based on experience and observation. So, this is why I ask how worn the tire might be. If there is deeper tread on the side than the crown...maybe you'd feel better on a new set of rubber.

 

BTW...when I used the word "planted" to describe bias ply tires, I mean more solid or connected than the typically "squirmy" feeling of radials fifteen years ago. During the process of leaning over, one lost the feel or sensation of the road and connection while the tire deformed and reshaped to the new lean angle. Sort of a feedback limbo that could be a little scary while flicking into a fast tight corner and not really knowing what the front was gonna do till it did it. It took a little time to get familiar with these "new tech" tires. I imagine that motorcycle radial technology may have progressed since then. I can't be this old.

 

In any case, there is nothing inherently wrong with your bike being OLD-er per se. There are many things that could affect handling that could be cleared up with some typical high mileage maintainance and TLC. Many things, like tires, that will pass a street or even race track inspection can still be worn enuf to need replacing. Steering head bearings, rear monoshock and linkage bearings, swingarm bearings to name a few. Not to mention the more common fork oil and chain/sprockets combo. It's amazing how all these lilttle things will add up to turn a wonderful bike like an Interceptor into a shyte handling machine. Just some thoughts. I don't mean to imply that this is your case, but, I am constantly amazed at the number of riders I meet who don't even think about maintaining their machines beyond an oil change, so, I just thot I'd use your thread here to get on my soapbox about it.

 

Cheers.

 

Something else that just caught my attention as I read your original post again...do you mean to imply that your front tire is a radial and your rear is a bias ply???

 

Um...I don't know what the gurus might say these days if radial tech has come a long way, but, IN MY OPINON, due to drastically different performance characterics, this would not be desirable. Unmatched tires in any way is never a good idea in my mind. But, someone else may have a different opinion re the bias rear/front radial combo.

 

 

No no no, they are both bias ply. I was just concerned about the rear, I have not been sliding the front much at all, so no worries there. I undersand what you are saying about the edge on the tyre and that might be exactly what it is. I have put 5k miles on these tyres and most of that was a long ride down to cali/oregon twice so I could see where the wear would be a lot more in the center.

 

About the maitnence, my dad used to be a mechanic so the bike is well maintained, new rings and cams at 45k (the bike now has 95k). It is my first motorcyle besides a 125cc dirtbike (two strokes rock), and being a begginner I tried to ride it at first like the dirt bike using massive clutch slippage to get it going fast, faster and what do ya know, a burnt clutch. Also, shifting was new, being new to motorcycles (this all was about a year ago) so I believe that in one of my clutchless shifting adventures I bent the 1st/2nd shift fork. We took the bike apart and found out that the shift fork was slightly worn but what falls out the bottom but a pice of the shifter drum... ooppss. Luckly my dad could only find an entire transmission on ebay and had ordered it because trans parts are no longer available for this bike, so we went throught all the gears and forks and put the ones with the least wear back in. Anyways, in short, thanks to my dad I have been through the entire engine (with exception of the cylinders but big whoop), cams, crank, clutch, valves, all the wireing and cooling devices, etc... Right now the bike needs a new chain and it is burning oil. We have replaced the shifter seals and countershaft seal but it still leaks/burns. So a new set of heads are waiting in the garage (again picked up from e-bay). I/we think the problem is the valve seals but with a whole head just sititng there the plan is to re-cut the valve seats, replace the bearings, etc.. then pull the engine out and sort-of "hot-swap" the heads out. Anywho, there is a little maitnence story for ya.

 

~Wip

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Wow! 125cc to 1000cc. Talk about the extremes. Cool beans on the rebuilds, dude. Lucky you can find stuff on ebay. If you are getting oil smoke out your tailpipe, the rule of thumb...lemme see if I can remember...smoke under deceleration is rings, smoke under acceleration is valve issue...I might have that backwards. I'll have to think it thru and get back to you. Sometimes leaky valve seals will drip into the combustion chamber overnight and give blue smoke cloud out the tail pipe upon cold start in the morning.

 

Good luck.

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Yeah, motorcycles just feel natural to me. I can't wait to attend a CSS class and start racing some day. Thanks about the tip about the smoke, I will pay closer attention next time I start the bike. That makes sense (leaking/cold start) because the oil loss is not consistant. You can ride it 200 miles and it will not burn more than 50ccs and a few days later (casual use in between) it might take 3/4 a quart! Thanks for the help.

 

~Wip

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