Going to the Dark Side

[Padre]

For those who are wondering what the rubbing looks like:



This is a light rubbing, which I really haven’t felt. The tire is a 2 year old BF Goodrich g-Force Comp-2 A/S with 33,361 (s)miles on it. I have no complaints, in fact I’m getting another one to replace it. 
 

I did have to repair a nail hole early on at EOM in Maggie Valley. Needless to say I had PLENTY of supervision for that.

Here is the sticky string repair after two years of trouble free riding:



This is what it looks like on the inside:



And yes, I still change my own tires:



With rainy season coming up I’m taking advantage of the good weather to change it, and perform other services to my primary transportation. 
 

Brodie

Hi Brodie, 

your bike support, is that 1 1/4 pipe? 1 1/2?

 

[RossKean]

your bike support, is that 1 1/4 pipe? 1 1/2?

Here is a version with instructions.  Don't know if it is the same as Brodie's or not.  (His might be heavier tubing)

FJR1300 Front End Support Stand

 

[Padre]

Here is a version with instructions.  Don't know if it is the same as Brodie's or not.  (His might be heavier tubing)

FJR1300 Front End Support Stand

Thank-you! The pipe he has is definitely bigger than the 1" in the link you gave. I've put together more of that stuff than I care to remember. That said, it seemed to me that 1" would do it, and sure enough, it does. This forum is such a great resource! Cheers. 

 

[Brodie]

Padre
I used 1 1/4 pipe because I figure the bike is heavy enough that I don't want to stress that top bar while I am underneath working on removing the swing arm and such. 

One thing... Do not rely on just this stand when picking up the rear of the bike. When you remove parts back there the center of gravity changes. My straps were hooked into where the exhaust pipe hangers attach to the sub frame rails. Draw a line from this point forward to the front tire contact patch and you will get a sense of just how much weight is carried above this. I have seen an FJR on just such a pipe stand, which toppled over on it's side. Whenever I use mine I have the front wheel firmly placed into a wheel chock. This picture shows it on the center stand, however there are times I lift the bike high enough to pull the rear wheel straight out. A dark sided wheel will fight you more because the tire sidewall protrudes way beyond the edge of the rim.

No Way am I going to let this pig fall over on me!

Brodie

 

[user 213]

@wfooshee - Dude, it was your turn to bring the cookies.  @101stpathfinder I can not believe it took you this long to get with the program.  You are Darksider #93 and it's your turn to bring the cookies at the next gathering.

We no longer do initiations after the hot mess we got into with the Nevada House of Hoes and the ensuing brawl with the Jenny McCarthy School of Chrome Removal girls.  We lost our Vegas privileges. 

 

[Brodie]

^^^ Too many Burn Outs in the parking lot; that's what got it started.

Brodie

 

[garyahouse]

Getting ready to sell the FJR. Should be another month or so. Was talking to my buddy Mark who's going to buy it. He's ridden it many times and seems happy with leaving the car tire on there. Guess he'll be a "transfer" DS rider.

 

[infrared]

Okay, more miles per dollar, I get that.  Since I have no experience with car tires on a bike, I have a few simple questions, which I have not seen addressed. 

From 'way back in the day, I remember car tires with nicely rounded profiles, not exactly bike tires, but much better than any CTs I have seen proposed for motorcycle use lately.  These old-design tires were bias-ply, with polyester belts (if any), not steel-belted radials.  As I understand it, steel-belted radials were intended to keep a lot of tread flat on the roadway, but that is NOT what I would want there.  With a little over-inflation, the bias-ply tire edges did not touch the ground.  This option looks much better to me, for motorcycle use.  I use bias-ply Pirelli Sport Demons on my 1985 FJ1100, and I see no problem with using bias-ply tires on the (similar) FJR.  I would not mix a rear bias-ply tire with a radial front tire on a bike, but I may be overly-cautious there.

I believe that a tire-truing machine (before balancing) could safely take off much of the shoulders of a CT, making CTs even better for motorcycle use.  New tires may or may not be round, but they can be made so.  The natural "give" of a bias-ply tire should keep more tread on the road when leaning, also.  In this case, the CTs we might want are probably tires with low ply counts, such as 2-ply rather than 4-ply or 6-ply.  Stiff sidewalls may be the wrong choice, there.  Any thoughts?

My US$.02 worth . . .

The prices of such low-tech light weight bias-ply tires and the lack of steel belts should keep the price low, which to me is the major draw of CTs anyway. 

From a safety standpoint, I would use an inner tube, to avoid any possible leaks at the rim when cornering at speed.  CTs and MC rims are not a good match at the bead. in some cases.

Advice welcome, here.

 

[rbentnail]

Okay, more miles per dollar, I get that.  Since I have no experience with car tires on a bike, I have a few simple questions, which I have not seen addressed. 

From 'way back in the day, I remember car tires with nicely rounded profiles, not exactly bike tires, but much better than any CTs I have seen proposed for motorcycle use lately.  These old-design tires were bias-ply, with polyester belts (if any), not steel-belted radials.  As I understand it, steel-belted radials were intended to keep a lot of tread flat on the roadway, but that is NOT what I would want there.  With a little over-inflation, the bias-ply tire edges did not touch the ground.  This option looks much better to me, for motorcycle use.  I use bias-ply Pirelli Sport Demons on my 1985 FJ1100, and I see no problem with using bias-ply tires on the (similar) FJR.  I would not mix a rear bias-ply tire with a radial front tire on a bike, but I may be overly-cautious there.

I believe that a tire-truing machine (before balancing) could safely take off much of the shoulders of a CT, making CTs even better for motorcycle use.  New tires may or may not be round, but they can be made so.  The natural "give" of a bias-ply tire should keep more tread on the road when leaning, also.  In this case, the CTs we might want are probably tires with low ply counts, such as 2-ply rather than 4-ply or 6-ply.  Stiff sidewalls may be the wrong choice, there.  Any thoughts?

My US$.02 worth . . .

The prices of such low-tech light weight bias-ply tires and the lack of steel belts should keep the price low, which to me is the major draw of CTs anyway. 

From a safety standpoint, I would use an inner tube, to avoid any possible leaks at the rim when cornering at speed.  CTs and MC rims are not a good match at the bead. in some cases.

Advice welcome, here.

Everything you ask about has been addressed dozens of times but for the inexperienced:

Steel belts, bias ply, all makes no difference.  I've done both.  Running with a radial front or not makes no difference.  I prefer medium sidewalls to stiff- stiff is too harsh a ride to me, softer feels like the ass end is sloshy.  Car tire tread never leaves the road surface and never does the car tire "roll up on the sidewall" like people think- proper sidewall for riding type and likeable inflation pressure are key to this.  No rounding of edges required, the car tire is fine.  No inner tube required, just something else to dick with when a nail or screw is acquired.  I know of no FJR using a tube.

All that said, based on the general tone of your post I highly discourage you from going Darkside.  You have to be more willing to set aside unfounded overthunk concerns of "safety" and "matching tires", "non-matching bead", etc., etc.  If you can't simply chuck a well-proven car tire on and ride without overthinking and (probably) stressing about it, it probably ain't for you.  I also say if you're a riding "purist", one of the people that can feel the difference in one click of fork adjustment, or if you're a person the absolutely requires aftermarket rear suspension "to tune it in just right for the twistes" then I think you should probably look the other way when a car tire rolls by on a motorcycle.  If you're the "purist" type, for any riding other than slabbing for long distances, you will not be happy with a car tire.

 

[user 213]

@@infrared - You might want to read the Darkside FAQ

No, mixing bias ply and radial tires on a motorcycle is not a problem.  A lot of people do it, I've done it many times because bias ply rear tires last so much longer.

Regarding DS, no, just no to shaving the edges off tires to make them more rounded.  Some radial tires are more rounded than others.  LIke all tires, each brand/model handles differently.  Some tires are more bike like than others.

 

[infrared]

@@infrared - You might want to read the Darkside FAQ
No, mixing bias ply and radial tires on a motorcycle is not a problem.  A lot of people do it, I've done it many times because bias ply rear tires last so much longer.
Regarding DS, no, just no to shaving the edges off tires to make them more rounded.  Some radial tires are more rounded than others.  LIke all tires, each brand/model handles differently.  Some tires are more bike like than others.

OCfjr,

Thanks, that is helpful.  I expect to deal with some issues if I do this, but it is not realistic to hope I can track down every possible old post on this topic.

It's hard to take "advice" from a guy who tells me that my safety-wired oil drain plug is a fix for a non-issue, until his own oil drain plug falls out on the road, dumping his engine oil.  He also said (above) "Car tire tread never leaves the road surface and never does the car tire "roll up on the sidewall" like people think" and then I find this picture:

I have never considered a car tire on any previous bike I had, but I think it may be possible to nail down the uncertainties and pull off the job safely.  I am happy to learn all I can here, before rushing into the project.  For myself, I am a disabled Vet, and I have no desire to do any more damage if I can avoid it just by asking a question.  Thanks again.

 

[user 213]

There are a lot of misconceptions about CT use on a motorcycle.  In regards to rolling up on the sidewall, NO, it does not do that.  That is a common misconception by people that look at a pic like you show and mistakenly assume that is on the sidewall.  It's not.  I've been over this a lot with people in person.  In a nut shell, the tire starts out with all the tread on the ground.  As you lean, the tire starts to take an oblong shape, (something that also happens on cars, think of extreme cornering like skid pad testing or autocross), flexing and still maintaining all the tread on the ground.  At some point, as you lean more, the tire carcass can no longer flex and returns to a round donut shape.

Two things then happen simultaneously.  The tire shifting back to round stands the rear of the bike up, which quickens steering, (which is why you don't feel any hesitation then), and the outside edge of the tread lifts off the pavement, but this is a car tire, not a bike tire, you're not "rolling over" onto the sidewall.  Look at any CT on a bike.  You will never, ever see sidewall wear.  Ride aggressive enough and you will wear the corners of the tread faster than the center, but you really have to be pushing it and using a lot of throttle to get that effect.  If you are smooth and not a whack a mole throttle users, the tread will wear evenly for the life of the tire.

Un-related to this thread, I've never seen an oil drain plug come loose that wasn't operator error.  Have you?

 

[RossKean]

and the outside edge of the tread lifts off the pavement, but this is a car tire, not a bike tire, you're not "rolling over" onto the sidewall. 

+1

I would add that the contact patch area on the CT remains at least as large (if not larger) than the contact patch of a motorcycle tire.  Traction in cornering is excellent.

I've darksided a couple of times for over 50,000 miles using two different of the "favored" tire brands and a variety of air pressures but ended back on motorcycle tires.  Nothing to do with perceived safety or control or concern about traction etc. - just didn't like the feel of the ride.  Awfully good for long highway runs but not my cup of tea for back roads or rougher road surfaces.

Not an expensive or (IMHO) dangerous experiment.  Just need the modified brake stay, the right tire and a shop willing to mount it if you don't do your own.

 

[infrared]

There are a lot of misconceptions about CT use on a motorcycle.  In regards to rolling up on the sidewall, NO, it does not do that.  That is a common misconception by people that look at a pic like you show and mistakenly assume that is on the sidewall.  It's not.  
Two things then happen simultaneously.  The tire shifting back to round stands the rear of the bike up, which quickens steering, (which is why you don't feel any hesitation then), and the outside edge of the tread lifts off the pavement, but this is a car tire, not a bike tire, you're not "rolling over" onto the sidewall.  Look at any CT on a bike.  You will never, ever see sidewall wear.  Ride aggressive enough and you will wear the corners of the tread faster than the center, but you really have to be pushing it and using a lot of throttle to get that effect.
Un-related to this thread, I've never seen an oil drain plug come loose that wasn't operator error.  Have you?

OCfjr,

Yeah, I would agree, the tire is not on the sidewall, when cornering.  Not a lot of rubber on the ground, though.  My first thought was from back in the day, seeing car tires before belted technology was common.  They were often more like doughnuts (or MC tires) than what we see now.  Only the correct tire pressure would put all of the road tread on the ground, for those old tires.

Man, I wouldn't touch that last line with a stick . . .      :no:   

I come from an aviation (maintenance) background, and safety wire is one of my best friends.
 

 

[RossKean]

Not a lot of rubber on the ground, though. 

Still as large (or larger) contact patch compared with a MC tire...

Good discussion if you go to the YouTube link.

 

[user 213]

@infrared - Tire pressure will always have a role to play.  I used to autocross in DMod long ago.  I typically ran 32 psi in my CT on the FJR, about the same as I would for similar load in a sports car.  As RossKean said and showed, contact patch is still greater.  More important, the tread design on the CT with more tread blocks has a secondary feature of grip/release of those tread blocks that allows better grip on marginal surfaces like tar snakes and loose conditions.  The CT doesn't step out like a typical moto tire will under hard cornering when you hit tar snakes or a little sand or gravel loose across the pavement.  That has saved me a couple of times pushing hard in the twisties and hitting a tar snake that was nasty.

Safety wire has it's applications and I use it.  But not on motorcycle drain plugs, for me.  Aviation is a different world in terms of vibration impact to fasteners.

 

[infrared]

@infrared - Tire pressure will always have a role to play.  I used to autocross in DMod long ago.  I typically ran 32 psi in my CT on the FJR, about the same as I would for similar load in a sports car.  As RossKean said and showed, contact patch is still greater.  More important, the tread design on the CT with more tread blocks has a secondary feature of grip/release of those tread blocks that allows better grip on marginal surfaces like tar snakes and loose conditions.  The CT doesn't step out like a typical moto tire will under hard cornering when you hit tar snakes or a little sand or gravel loose across the pavement.  That has saved me a couple of times pushing hard in the twisties and hitting a tar snake that was nasty.

OCfjr,

Interesting video.  The camera tells the tale.  Good to see that.

Thanks.  Still learnin', here.

 

[Brodie]

I’m curious…

Just how accurate is that infographic? What were the parameters? Bike? Tire? PSI? Load? Speed? Who did the research?

I didn’t see any name attached to it as having compiled the research data. 
 

It is a cool graphic though, coupled with the video of the V twin dragging its hardware. 
 

Brodie

 

[RossKean]

I’m curious…

Just how accurate is that infographic? What were the parameters? Bike? Tire? PSI? Load? Speed? Who did the research?

I didn’t see any name attached to it as having compiled the research data. 
 

It is a cool graphic though, coupled with the video of the V twin dragging its hardware. 
 

Brodie

Doubt it was a "peer-reviewed" study.  It is, however, reasonably representative of what goes on - even if the graphic is a bit exaggerated.  While I never loved the "feel" of a CT in a sharp curve, I never felt it was about to slip out from under me.  I would say that the contact surface area remains much more constant cornering with a MC tire vs a CT.  As does the geometry of the contact patch.

 

[Brodie]

^^^^^^ I need that sticker!!!

Brodie