Phyxt!
If it wasn't for OT background chatter, most threads on this forum would be about 2 posts long. - Fred W
Going to the Dark Side
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Phyxt!
If it wasn't for OT background chatter, most threads on this forum would be about 2 posts long. - Fred W
I received a PM on this topic that brought up some good questions and I feel is worthy of the main thread. I've edited out the ID of the sender. They can post, or not, as they wish.
Eric (OCfjr)
-------------------------------------
I'm inserting my answers as the questions go.
Now that I know I'm happy with the CT, I may spend a little more next time and go with the Bridgestone Potenza RE92A. Link It has a 40k mileage rating, as opposed to the no mileage rating of the 019 Grid, which should last ~about 20k on a car. It's $100 more than the 019 Grid though, so I didn't want to start there. It also has a section width of 8.2", which may, (should), be narrow enough to use the stock tension arm, not that it matters for me any more.
I chose the tire based on wanting an all season tire with symmetrical tread design that wasn't specifically hyping stiff sidewalls and performance handling. I ride all year, so didn't want a tire compound aimed at summer use that might change characteristics dramatically in the wet or cold. (I've experienced this with summer sports car tires and it's scary enough there) speed rating wasn't really a factor for me, but generally, higher speed rated tires do have stiffer side walls, as you mention, so I was not specifically looking at those.
I honestly don't believe a tire with a lower load rating would have made mounting any easier. It was more the issue of keeping the wide tire's bead in the narrow valley of the wheel to allow the movement necessary to get the second bead on that was the difficult part.
Second part - While the sidewalls do flex, you never really ride on one of them exclusively. You might get 2/3 of the tire off the ground during extreme lean maneuvers, but you're still riding on that 1/3 of the tread, possibly stressing that sidewall more, but not so much that I believe it's an issue. At those lean angles, the back of the bike is lifting too. You've exceeded the amount of flex available to maintain full tread to the ground, so now the tire is going over on partial tread, but the sidewall has reached maximum flex. It might actually be stressing the sidewall less in this condition, since the tire has now gone over/lifted up and become slightly more round as it's come up off the ground.
From reading and talking with the Wing dark siders, it seems that for the heavier bike, (900+ lbs), the stiffer side wall is beneficial and allows them to run lower pressures, (26-29 psi), and still get good life. they are running the low pressures to get sidewall flex and decrease turn in effort. However, the FJR is much lighter at 650 or so and IMHO doesn't need the uber stiff sidewalls of a run flat tire, and I believe it's not desirable in regards to allowing flex. I want flex so that more tread stays on the ground during cornering, AND because this part of the lean/turn is pretty easy, requiring less effort at the bars than the turns where we need to start lifting the outside of the tire off the ground.
I have the experience of having tried a stiff sidewall summer rated tire, (the Cooper Zeon), and a significantly less stiff sidewall all season tire, (the 019), and can tell you that the stiffer sidewall caused more turn in effort, especially at low speeds, and kept less tread on the ground than the softer sidewall all season tire. For this reason, my opinion is that for the FJR, a less stiff sidewall is more optimal. If you run high speeds for significant periods of time, or intend to really flog the bike in the tight corners most of your riding, (probably wouldn't be looking at CT options), then stiffer might be better.
FWIW - even flat, (zero pressure), the Cooper didn't flex enough to rub more than with air pressure. I suspect even the 019 tire will effectively be a run flat on the FJR. Our light weight, combined with the narrow wheel seems to minimize the issue. I don't think you'd want to ride fast on a flat tire, but I bet you could get where you wanted to go w/o difficulty.
Eric (OCfjr)
-------------------------------------
I'm inserting my answers as the questions go.
I agree, but as you have discovered, different brands sometimes have different specs. The 25.1 diameter makes my FJR speedo and odo perfectly correct, (verified by GPS on the odo for a 40 mile run.) It read faster than actual before, by 3-5 mph. The 7.1-7.4" widths are tread widths. These can be helpful in comparison, but the value you really want to look at is the section width. Most of the 205 tires will have a section width of 8.4" or close. As you probably know, specs are posted, but there are tolerance variations, both wider and narrower. The tire I first tried, a Cooper Zeon, was spec'd at 8.43" and just barely rubbed on the tops of the letters. The Bridgestone Potenza 019 Grid I have on now is spec'd at 8.3", but is wider than the Cooper, at least on the bike, and required a modified brake tension arm, whereas the Cooper didn't.
This is my take on speed ratings, in this application. Heat is a factor of load, speed, and inflation. We are running far less load than a car would. Our speeds, while capable of being up to 150 or so, mostly will be below the uprated specs and well within the normal range for cars. inflation generally will be on par with the load we have the tire under, or comparable to a car's load/pressure differential. I have had the CT up to 140+, but I wasn't going to be cruising there for any serious length of time. I personally, don't see a need for a speed rated tire, like V/W/Y or Z. Those speed ratings are for sustained running at those speeds, not the occasional bump up to them.
I am using a Bridgestone Potenza 019 Grid. Tire Rack link
Now that I know I'm happy with the CT, I may spend a little more next time and go with the Bridgestone Potenza RE92A. Link It has a 40k mileage rating, as opposed to the no mileage rating of the 019 Grid, which should last ~about 20k on a car. It's $100 more than the 019 Grid though, so I didn't want to start there. It also has a section width of 8.2", which may, (should), be narrow enough to use the stock tension arm, not that it matters for me any more.
I chose the tire based on wanting an all season tire with symmetrical tread design that wasn't specifically hyping stiff sidewalls and performance handling. I ride all year, so didn't want a tire compound aimed at summer use that might change characteristics dramatically in the wet or cold. (I've experienced this with summer sports car tires and it's scary enough there) speed rating wasn't really a factor for me, but generally, higher speed rated tires do have stiffer side walls, as you mention, so I was not specifically looking at those.
I'll answer the last part first, then talk more about the first part. Yes, sidewall stiffness does play a part in difficulty of tire installation, however, with a tire change machine, that wasn't really a factor, it was the width of the tire on the motorcycle wheel that made it difficult to keep the first bead in the valley of the wheel while trying to get the second bead over the rim. The stiff sidewall didn't help, but it wasn't the main factor there. The relatively short sidewall of the 50 series tire was also part of what makes things more challenging. For this reason, I suspect a 45 series sidewall tire may not be mountable on the FJR's wheel.
I honestly don't believe a tire with a lower load rating would have made mounting any easier. It was more the issue of keeping the wide tire's bead in the narrow valley of the wheel to allow the movement necessary to get the second bead on that was the difficult part.
Second part - While the sidewalls do flex, you never really ride on one of them exclusively. You might get 2/3 of the tire off the ground during extreme lean maneuvers, but you're still riding on that 1/3 of the tread, possibly stressing that sidewall more, but not so much that I believe it's an issue. At those lean angles, the back of the bike is lifting too. You've exceeded the amount of flex available to maintain full tread to the ground, so now the tire is going over on partial tread, but the sidewall has reached maximum flex. It might actually be stressing the sidewall less in this condition, since the tire has now gone over/lifted up and become slightly more round as it's come up off the ground.
From reading and talking with the Wing dark siders, it seems that for the heavier bike, (900+ lbs), the stiffer side wall is beneficial and allows them to run lower pressures, (26-29 psi), and still get good life. they are running the low pressures to get sidewall flex and decrease turn in effort. However, the FJR is much lighter at 650 or so and IMHO doesn't need the uber stiff sidewalls of a run flat tire, and I believe it's not desirable in regards to allowing flex. I want flex so that more tread stays on the ground during cornering, AND because this part of the lean/turn is pretty easy, requiring less effort at the bars than the turns where we need to start lifting the outside of the tire off the ground.
I have the experience of having tried a stiff sidewall summer rated tire, (the Cooper Zeon), and a significantly less stiff sidewall all season tire, (the 019), and can tell you that the stiffer sidewall caused more turn in effort, especially at low speeds, and kept less tread on the ground than the softer sidewall all season tire. For this reason, my opinion is that for the FJR, a less stiff sidewall is more optimal. If you run high speeds for significant periods of time, or intend to really flog the bike in the tight corners most of your riding, (probably wouldn't be looking at CT options), then stiffer might be better.
FWIW - even flat, (zero pressure), the Cooper didn't flex enough to rub more than with air pressure. I suspect even the 019 tire will effectively be a run flat on the FJR. Our light weight, combined with the narrow wheel seems to minimize the issue. I don't think you'd want to ride fast on a flat tire, but I bet you could get where you wanted to go w/o difficulty.
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RadioHowie
I Miss Beemerdons!
:thumbsupsmileyanim: :clapping: :thumbsupsmileyanim:
Back on track....and some awesome info.
I'm goin' Darkside when Silver Streak is brought back from the grave.
Thanks, Eric!
'howie
Back on track....and some awesome info.
I'm goin' Darkside when Silver Streak is brought back from the grave.
Thanks, Eric!
'howie
madmike2
Shtirrenuppenmeister
Great information, Eric.
Please keep us informed as your testing continues. It'll be interesting to see how many miles the tire might last and if traction deteriorates as it does with some motorcycle tires.
Please keep us informed as your testing continues. It'll be interesting to see how many miles the tire might last and if traction deteriorates as it does with some motorcycle tires.
Bustanut joker
Well-known member
Damn it!! Twice in one month I agree with Howie :huh:
I gotta stay away from here... My reputation is gonna be shot ta hell if this keeps up.
Then again if the weather keeps bein' so shitty I won't have to worry about a new tire till next year.
:jester:
I gotta stay away from here... My reputation is gonna be shot ta hell if this keeps up.
Then again if the weather keeps bein' so shitty I won't have to worry about a new tire till next year.
:jester:
Darth Maul
New member
Death Star 2
BF Goodridge G-Sport 205\50 R17
The center stand does clear but I wanted a little more clearance.
A quick adjustment with a die grinder and cover the metal with some paint
No way the rear brake control arm will work.
New one made up from 3/16 steel bar
How does she handle, well like you have a large wide tire on the back, you need more input more force on the bars to start the turn but quite acceptable. Very stable in the corners.
Why do it well I calculate I'm going to need 4 rears on my next trip
Darth
BF Goodridge G-Sport 205\50 R17
The center stand does clear but I wanted a little more clearance.
A quick adjustment with a die grinder and cover the metal with some paint
No way the rear brake control arm will work.
New one made up from 3/16 steel bar
How does she handle, well like you have a large wide tire on the back, you need more input more force on the bars to start the turn but quite acceptable. Very stable in the corners.
Why do it well I calculate I'm going to need 4 rears on my next trip
Darth
SkooterG
Purveyor of Crooked Facts
Take heed FJR masses - The Apocolypse is upon us!
Zorlac
Well-known member
Nice job Darth!
I love the way you posted, here's what I did, here's pictures, and I'm not looking for concurrence, beautiful!
Did you spoon that tire on, or get a machine to do it?
Did it need a lot of balance weight?
Enjoy your long trip!
I love the way you posted, here's what I did, here's pictures, and I'm not looking for concurrence, beautiful!
Did you spoon that tire on, or get a machine to do it?
Did it need a lot of balance weight?
Enjoy your long trip!
RadioHowie
I Miss Beemerdons!
And look, Uncle Skoot....
It's got tread over the sidewall transition and it ain't real square!
The Emperor will be proud of you.
Best 2nd Post for a FNG EVER!
It's got tread over the sidewall transition and it ain't real square!
The Emperor will be proud of you.
I like the looks of that donut. Bet it takes you 2 years to get down to the wear bars!
Best 2nd Post for a FNG EVER!
Bellerophon
Well-known member
With all due respect you car tire guys are nuts. How can you possibly hope to improve on the years of engineering motorcycle tire manufacturers have put into their products? This is simply foolhardy. At best you may gain some miles of wear, at worst..well the worst is not a nice thought.
Good luck in your endeavors, and most of all ride safe.
Good luck in your endeavors, and most of all ride safe.
iCruze
Well-known member
At worst you only buy one rear tire every 30,000 miles? If you know something we dont throw it out there
Bellerophon
Well-known member
Well okay if you insist. The worst is dieing in a horrific accident because the car tire not designed for your bike fails.
As I said previously..good luck in your endeavors. I sincerely hope this project works out for those who try it. That said it is indeed foolhardy, why would you risk your life over tire wear. Again good luck, I really do hope it works out for the best.
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madmike2
Shtirrenuppenmeister
One assumes you've read the entire thread including all arguments pro and con. That would mean that you've also read and understand the premise which Eric (ocfjr) stated in his opening posts. One would also, then, know that Eric started with disclaimers that this wasn't for everyone and the reasons why Iron Butt rally riders are looking for maximum mileage rather than maximum cornering performance parameters.
Again....one assumes....
[SIZE=8pt]Erk, yewer gonna dye en soe is Dart. Yewer gunna prolly mek summa them otheren foller yew en yewer gunna bee thuh reeson theys gunna dye, tew.[/SIZE]
Bellerophon
Well-known member
I clearly fall in the "not for everyone" category. And yes in fact I did read much of the thread.
It may come as a surprise to some of you, but motorcycling is an inherently dangerous activity. Really. In all fairness, I should suggest that each and every one of us promptly give this activity up. You know, in the effort to be as safe as possible. It's for our own good, don't cha know?
Naawww, that ain't gonna happen, is it?
BTW, you can die in a horrific accident with very nice moto specific tires too.
At this point I have 13k trouble free miles on the CT with no indication of any kind of issue. Yes, I actually do carefully examine my tires, (both of them), before every ride. No blisters, no wrinkles, no uneven wear, (ok, you got me on that one, the Avon front tire is wearing poorly, cupping and generally being an Avon), and no punctures. The tire is probably less than half worn, according to the mark I eyeball.
The CT at 13k miles.
Camera viewscreen died, so hard for me to get a better pic at this point in time.
Naawww, that ain't gonna happen, is it?
BTW, you can die in a horrific accident with very nice moto specific tires too.
At this point I have 13k trouble free miles on the CT with no indication of any kind of issue. Yes, I actually do carefully examine my tires, (both of them), before every ride. No blisters, no wrinkles, no uneven wear, (ok, you got me on that one, the Avon front tire is wearing poorly, cupping and generally being an Avon), and no punctures. The tire is probably less than half worn, according to the mark I eyeball.
The CT at 13k miles.
Camera viewscreen died, so hard for me to get a better pic at this point in time.
And that's just fine too. There just isn't much point in crying doom at this stage. Now go kill a chimera and come back and we'll discuss it some more.
I appreciate that you took the time to read the thread. We, (motorcyclists), do lots of things that someone, somewhere, didn't intend us to do. And somehow we survive. People have been putting car tires on bikes for a very long time. This is simply a first time for the FJR, at least on this forum. I realize you believe it to be a bad idea, and that's fine. Just understand that you don't actually have experience trying it for yourself. Perhaps you might just consider keeping an open mind to new things. Engineers work for companies, and do what they are told, designing things for narrow applications. Sometimes it takes someone outside the loop to discover other applications.
If you get the chance, take a bike with a car tire on it for a ride. It will broaden your experience, if nothing else.
Bustanut joker
Well-known member
That seals it! damn naysayers got my goat...
Ta hell with waiting for my azoo to wear out, I'm getting ahold of tire rack this afternoon.
:jester:
Ta hell with waiting for my azoo to wear out, I'm getting ahold of tire rack this afternoon.
:jester:
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What's that I see on that tire?
A chicken strip? Holy cow, Eric. You're not even using all the tread that is available to you...
Color me surprised.
Oh, and I do like the BFG G-sports. Had them on a couple of 4 wheel vehicles and they are good performing, Z-rated, reasonably priced tires.
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Darth Maul
New member
You need a machine, the tire walls are extremely stiff on this tire (one of my selection criteria).
The balance is almost perfect I have a ~1/4 ounce on it to counter the valve stem
Oh as for price $135 Costco.
Again I am trying this specifically because finding and replacing 4 rears on the road in next 2 months is going to be a major pain, there are not lot of m/c dealers or UPS stores to mail to north of Yellowknife.
Darth
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