Going to the Dark Side

[exskibum]

I'm not sure about the shaping of the edges of the tires. In the old days shops used to 'true' up tires by shaving some rubber off the sides. I suspect there isn't a whole lot that could be removed and that it may prove detrimental to tire life to do that. I will never be riding on the side walls, just less than full width of the tread at times. You know, like motorcycle tires do in a lean.

I might be mistaken, but it's lodged somewhere between my ears that the contact patch on a motorcycle tire actually gets BIGGER when the bike is leaned over than when it is upright. Of course, it's also dealing with increased sideways loading (and taking up more of the available "traction points") when it's turning, but that's my recollection of the physics of leaning it over on a MC tire.

Just sayin'.

Good luck on the quest. Most of my riding is in twisties, so I'll read with interest but that's all.

 

[Fencer]

This should FINALY put the 190 rear tire on an FJR debate to bed :lol:

As far as handling/ turn in. If you have an after market shock that allows for height adjustment, raise it all the way up and it will help with turn in.

Good luck in you endeavor

 

[BugR]

this will be great when someone builds a FJR-worthy sidecar.

Here's one

Chris

 

[Warchild]

And another.....

Sure looks like a car tire there on the front....

 

[BugR]

So uh... What makes this NEPRT? While I've not been around here forever, I've been around a while and I don't ever recall this topic previously.

Mostly just because it's a tire thread. Tire threads are so argumentative that they all go to NEPRT.

BugR - I'm still looking at specs, but the Goodyear Eagle F1 all season and a Yokohama are at the top of my list. Hell, I'm considering the Blizzak too. Looking to keep the tread width under 8". The Cooper Zeon just fit, I need to check it's specs, but I believe it's over 8" like most of the summer performance tires.

Thanks for that info, This rules out the BF Goodrich g-Force™ Super Sport A/S 205/50ZR17, The specs indicate 8.43 section width (on a 6.5 wheel)

You mentioned the Blizzak, Do you think you still get the tire life with a snow tire?

They melt on our cars here above 15C.

Chris

 

[dcarver]

I'm going to the other dark side -

I'm installing FJR take-off tires on the dually 1 ton truck!

 

[user 213]

this will be great when someone builds a FJR-worthy sidecar.

Actually, there are some very nice kits already, though spendy. No link off the top of my head, but do a Google search and they should come up.

BugR - From what I can tell, anything more than 8.4 section width is going to rub. However, it's been pointed out that the published specs aren't always gospel. There are tolerances and variations.

That is my concern with the Blizzak too, but it might be great for this time of year.

One of the current leaders in my search is the Bridgestone Potenza RE-750. 8.1 section width and a smaller tread width that most. There is a Yokohama in 195/45-17 that looks promicing though it's not rated for a 5.5" rim and has a smaller diameter, so would put the speedo off more.

 

[user 213]

I suppose that you've already tried all the regular hard compound motorcycle specific tires. If so, you could compare the feel of the car tire to those.

I have tried to. I did draw the line at running a ME880 Bias ply though. The ME880 radial only went 10k for me, and considering the loss of wet traction over a more conventional ST tire, I didn't think it was worth it. 'Course, at the time, I was getting and easy 10k or more from Avon Azzaros.

Any suggestions on other hard compound radial moto tires in our size?

 

[ian]

I'm watching this with interest. I only get about 6,000 on a rear tire unless I'm in the twisties which halves the mileage. I run a Shinko (the horror) on the rear and get a lot of negative comments but it seems to work OK for me and I get an additional 1,000-2,000 miles. I'm keeping an open mind, it'd be nice to take a 10,000 mile trip without having to change the rear.

I remembered this on youtube, interesting. I assume the sounds are the pegs scraping. Ian, Iowa

https://www.youtube.com/watch?v=Ay3ZVmORDl4

 

[exskibum]

I remembered this on youtube, interesting. I assume the sounds are the pegs scraping. https://www.youtube.com/watch?v=Ay3ZVmORDl4

Interesting vid, but I don't think the sounds can be the pegs scraping (even if it is a Wing), because the same sounds continue at much lesser lean angles, and even when the tire is perpendicular in a couple places. No question the rider does get it leaned over pretty good a few times.

 

[v65]

I remembered this on youtube, interesting. I assume the sounds are the pegs scraping. https://www.youtube.com/watch?v=Ay3ZVmORDl4

Interesting vid, but I don't think the sounds can be the pegs scraping (even if it is a Wing), because the same sounds continue at much lesser lean angles, and even when the tire is perpendicular in a couple places. No question the rider does get it leaned over pretty good a few times.

Yeah really interesting.

1) Very little contact patch when leaned over. Have you seen how much contact patch a good bike tire has when leaned over?

2) I suspect if I was riding that bike it would be on its side. I twist the throttle coming out of a turn, listening to that vid the rider doesn't.

 

[rocketdoc]

This might be a useful Long Distance option, ie IronButt, probably more puncture resistant as well. As said above OC is a pretty handy and careful guy, he is also providing some novel entertainment. Thinking outside the box so to speak.

 

[madmike2]

this will be great when someone builds a FJR-worthy sidecar.

Actually, there are some very nice kits already, though spendy. No link off the top of my head, but do a Google search and they should come up.

Here's a place to start.....https://www.hannigansidecar.com/content/hpsidecars.html

I had other websites but they were hosted by AOL's Hometown which has been shut down by the owners (Imagine AOL acting like that!).

 

[exskibum]

1) Very little contact patch when leaned over. Have you seen how much contact patch a good bike tire has when leaned over?

So you're of the same impression as I am (posted above at end of last page) that the contact patch actually INCREASES in size on a MC tire when leaned over?

2) I suspect if I was riding that bike it would be on its side. I twist the throttle coming out of a turn, listening to that vid the rider doesn't.

Good point and astute observation.

Still, I was surprised at how well it SEEMED to smoothly transition (so far as I could tell from that ground level camera perspective) when the bike was put up on the corner of the car tire tread. I assume it flattens there to grip the road more than I would have guessed.

I'm still not even thinking about this dark side application for myself . . . until the economy takes us to a real Mad Max scenario where ANY useable tire will probably be desirable.

 

[user 213]

2) I suspect if I was riding that bike it would be on its side. I twist the throttle coming out of a turn, listening to that vid the rider doesn't.

Interesting comment. A good reason you might not like the car tire. I on the other hand, don't twist the throttle coming out of corners. In a nut shell, I set my corner speed before the corner and maintain that speed all the way through. I'm not going particularly slow, often twice the posted corner speed, but I'm not wearing the tire as much as accelerating out would. It's one of the reasons I can get 10k from a moto tire.

I'm not sold on the moto tire having a larger contact patch when cornering. I think it depends on the tire to some degree. A rounder profile would seem to indicate a more or less equal contact patch as you roll over to the side. You're losing the same amount on one side as you gain on the other.

The car tire does obviously lift on the outside. Still, the remaining amount of tire on the ground is significant, especially considering the wider tread section.

I'm sure you're capable of overwhelming the contact patch with your current tire coming out of a corner. The car tire likely has lower limits in that regard. What I want to find out is if this is lower than my normal riding or not. If not, I don't lose anything, traction wise. If it is lower than my normal riding limits, then that would be less than desirable!

 

[canyonman]

Maybe one of our resident video guru's could set up a camera on your bike aimed from behind at the contact patch to record the tire's behavior while you ride. might be surprising to see all the dynamic forces coming together.

just a thought

 

[exskibum]

I'm not sold on the moto tire having a larger contact patch when cornering. I think it depends on the tire to some degree. A rounder profile would seem to indicate a more or less equal contact patch as you roll over to the side. You're losing the same amount on one side as you gain on the other.

Not positive, but somehow I think the source of my recollection that a moto tire has a larger contact patch when leaned over is Keith Code. But I can't find it anywhere right now. Maybe someone else has read the same thing.

EDIT TO ADD: Doing a Google search, I can't actually locate Code saying it, but do find references to him having made this claim at track schools (and others reciting the same relationship as an assumption, but without attribution), and one guy noting that Code told him this at a track school also posted this jpg and caption from an unverified source:

For what it's worth and no more -- can't verify that it (greater lean angle = greater contact patch) applies to all motorcycle tires, in all conditions or even that it's an accurate representation of what actually happens. I note that the picture is 2 and not 3 dimensional, and have also found detailed discussion that even if larger contact patches result from being leaned over, there are other factors at work such that a larger contact patch doesn't necessarily mean that greater grip results (especially past a certain lean angle). OTOH, none suggest that smaller contact patches yield greater grip absent other factors (like tire compound).

 

[jride]

I understand why someone might mount a car tire on a cruiser even though i believe it to be a bad idea. However it makes no sense what so ever to mount a car tire on a bike which uses a sport touring or sport tire. The whole purpose of a sport type tire is to achieve better handling and a car tire would totally eliminate the good handling characteristics of a sport type motorcycle. So the obvious question is Why would you want a fjr that handles worse than most cruisers?????

 

[trmn8er]

2) I suspect if I was riding that bike it would be on its side. I twist the throttle coming out of a turn, listening to that vid the rider doesn't.

Interesting comment. A good reason you might not like the car tire. I on the other hand, don't twist the throttle coming out of corners. In a nut shell, I set my corner speed before the corner and maintain that speed all the way through. I'm not going particularly slow, often twice the posted corner speed, but I'm not wearing the tire as much as accelerating out would. It's one of the reasons I can get 10k from a moto tire.

OC, I too can get 10,000 miles out of a set of tires, and I do ride mostly all mountains. If I was only getting 3,000 miles out of my tires, perhaps I would try something esle like a harder tire. A car tire? Probably not for me, but to each their own. I do not baby the tires, but subscribe to the idea that smooth is fast, while some others seem to brag that they only get 3-4k out of their tires, as if this eludes to them being a faster rider or pushing harder. I am not light at 6'3 and 240 either, yet get great mileage out of the stock tires as well as the Pilot 2's I have now. I will tell you I check proper inflation often, and believe this makes a huge difference in tire wear. I am very easy of my brakes as well, and prefer to focus on being smooth and fast, not trying to be something I'm not or riding as if I'm on a true hyper-sport bike (like my R1). I salute you for your trying something new. Have a great Thanksgiving!

 

[Walden]

I bought a used Cooper Zeon ZXS summer performance tire for cheap to test fit and today with DougC's help we mounted the tire and installed it on the bike. ...

And a 205/50-17 does fit on the FJR's 5.5" wheel, and fits on the bike, JUST. I think it just barely rubbed off the tops of some of the lettering on the sidewall with the brake caliper arm. There was about 1/8" clearance to the side stand legs as well. FYI, it rubbed a little when flat. :-( But not so much you couldn't push the bike around.

...

Eric Vaillancourt

Oregon City, OR

Eric,

:clapping: Kudos for outside of the box thinking and for having the cajones to post such an idea to an overwhelmingly accepting crowd!

I think it is an interesting approach to low mileage m/c tires. I have put about 1000 miles on my used FJR since I got it 2 months ago and have done my best to correct the chicken strips it arrived with. Spirited riding is going to cost me quite a bit in tire costs, I can see.

Your car tire idea makes sense to me, but not with a 205 mm tread width. 205 mm is about 8 in. wide, meaning about an inch of tread overhangs the wheel on each side. A 5.5 in. wheel equals about 140 mm. Theoretically, if you put a 140 series tire on it, your sidewalls would be at 90 degrees to the ground. With a 205 series, that is less than 90 degrees, and will have a much smaller contact patch to the ground. If you go the other direction, with say a 130 series, your cornering patch will be much larger because the sidewall angle to the ground will be greater than 90 degrees.

For an example of the 130 series, I am picturing an old school lowrider with 100 spoke Daytons. The owners seem to like to put a much skinny-er tire on a wider wheel. I think it looks ridiculous on cars, but it might work for your application. Gangsta, I know...

Also, try to find a tire with a higher max PSI than 35. Some are up in the 40's. This will give you more of a crown in the center of the tire and will make the tire more round, rather than square.

:dance: On a completely unrelated note, have you considered mounting a tire that is made for a heavy touring bike, like the aforementioned Goldwings? Those tires are made for long distances and heavy weight (2-up, trailer with sleeping quarters and toilet), so the tread compound is going to be much harder. As an added plus, the contact patch is round too! If you're to the point of mounting car tires, you've probably already thought past this idea. I'm curious why you abandoned this in favor of a car tire.

Overall, a very interesting read!

-Dubyuh