what is the difference

[Guest]

Ok, I hear all the time here not to put radial tires on a tire that was built to run a bias ply tire. So my question is what is the difference between the two rims? On cars you can make the swap with no problem, but on the bikes people chatter on about it like nuts with the wings. The only place I could see that should make a difference is in the bead of the tire and seating on the rim. That is the only point of contact there is between the two, and willing to bet that there is no difference between the two tires styles.

What I'm wanting is varifiable facts on this.

[SIR tricky]

What’s the difference between radial tires and bias-ply tires?
The main difference between radials and bias-ply tires lies in their construction. Tires aren’t just toroidal balloons, they are reinforced with cords of steel or synthetic materials such as nylon or Aramid. In bias-ply tires, the fibers are wrapped in an X pattern between the beads; in radial tires, the fibers are wrapped perpendicular to the tread. Radial tires have more flexible sidewalls than bias-ply tires, and thus absorb road irregularities better and have a comparatively larger contact patch when leaned over. Because of the flexible nature of a radial, these offer higher mileage compared with a comparable bias-ply for a given rubber compound. Since they absorb small road irregularities better, they ride more comfortably and are less likely to be upset by groovy pavement.
While radial tires perform better than bias tires, some older motorcycles can’t be fitted with radial tires because of differences in rim profiles. You probably won’t notice much of a difference anyway, so stick with bias tires if that’s what the motorcycle was designed for.

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Other than that, we shall have to wait for info from Honda or Dunlop or.....?

[Guest]

Let me say this again, what is the difference between the rims? I don't mean to offend, and if I did I'm sorry, but it's just I hear these wives tails and no substance behind it. If the older rims can not hold a radial then what is that reason?

Exavid pointed out that there is a width difference between the 1800 and 1500 rims. Maybe that's it. Is it that the sides of the rims are too weak to handle the extra flexing of the radials? I'm just the kind of guy that wants to know why, and I see this on the net the contradicts what I know form the automotive and agricultural lines.

[SIR tricky]

I posted a queery on the Dunlop website and here is my post followed by their reply.

****************************************
* Dunlop Tire Contact Form Submission *
****************************************

Sent On : 1/31/2007 8:49:02 AM
From :
Country : Canada.


Comments :
I own a 1985 Honda Goldwing GL1200, Most of the tires I have installed on the bike have been the K491 model tire.
I have installed the newer E3 Bias tire for next years travels but I am curious about one thing, the E3 of course comes in radial and
bias configurations, is there any specific differences in the type of rims required to install a radial tire? Could a radial E3 type
be installed on a rim that normally has a bias tire installed on it. When the GL1200 was designed I don't think that there were radial
motorcycle tires being made, did the radial tire require a specially designed rim?

Thank you

Richard Kirby

Reply

Richard,

Thank you for taking the time to contact us with your motorcycle tire questions. There are no differences in rim flanges when fitting
radial and bias-ply tires. We'll be happy to send a motorcycle tire product brochure out with today's mail.


"Dunlop Tire"
<website@dunlopmotorcycle.com>

From that reply, I would assume that it would be safe to install radials to the 1200 rims.

After I have run through my bias set maybe I shall try them.

[admin]

You can put a radial tire on a GL1200 but it will have a wishy washy feel to the handling almost like driving on a soft tire(s) and that wallowing is why you'd want an extra secure safety bead on the rim to keep it from coming off.

Apparently the GL1800 has an extremely rigid front suspension, frame and swingarm that allows it to make use of radial tires. All you have to do is to look closely at an 1800's frame and you'll see that it's built quite rigid.

Radial tires can twist and distort in the sidewalls in order to keep the tread of the tire flat against the asphalt so the frame of the bike must be rigid.

Bias tires will distort on the tread surface therefore if the frame is flexible it helps make the ride of the bike a little more comfy but the handling will suffer somewhat.

If you're thinking about installing radial tires on your 1200 make sure you obtain race quality riding gear to help protect you if you go down due to the incorrect tires. I know someone who has and I have also sent detailed emails to Dunlop about using radial tires on my GL1200 and they strongly stated to not use radial tires on any GL1200.

Dunlop has a pretty good handle on what works when it comes to tires and I trust them.

[SIR tricky]

If you read again Vic the reply said there was no difference in the rim for bias or radial. This was from DUNLOP

I am not arguing against the people who make the tires.

I know how rigid the 1800 is, the flexing in the frame caused extensive cracking in the earlier models. that tells me it really isnt any more rigid than its steel counterparts.

[admin]

Tricky, a man would have to be a fool to use a tubeless tire of any type that that did not have a safety bead, especially a radial tire due to its characteristic sidewal flexing.

If the frame and related components were flexible they would not crack, rather it would bend and flex like the single backbone type of frames.

Next time you get a chance observe the frame on an 1800 look carefully and you'll see how the top tubes of the frame actually extend out like a sport or racing bike type of frame. This stiffens the frame dramatically and makes for an extremely responsive bike which it is.

I distinctly remember when the 1800 was first introduced and how taken I was by the structural integrity of its frame. Part of its problem is that it was too rigid for its own good and we all know the outcome. Anything that can't bend will eventually break if enough stress is imposed on it.

Our old wings don't have much frame problems because they bend and sway gradually to soak up the shock loads.

[Guest]

I'm not overly familar with the saftey bead that you talk about, but from what Dunlop said I would say that both tires have it or do not have it. Guessing by your comment if the GL1200 rims don't have a safety bead then they should be thrown in the junk pile.

As to the flexing of the tire I would say that higher pressure should be used to compinsate for some of the change. If memory serves I radials run at higher PSI then bias.

I am by no means an expert on this area, but I do talk to people that know tires from time to time, and alot of the mith around this subject has bothered me. Tricky, thats for emailing Dunlop. Handn't crossed my mind to try that.

[admin]

Dunlop is terrific at responding to technical questions. I am not one to lean towards hearsay instead I prefer to either test the object myself or get actual test results from the manufacturer.

Dunlop actually has a race team of engineers who field questions from the public. Too many times I've seen myths created by guys online and it really sickens me every time I see one of those false myths about tires because it takes so long to dispell the myths and bring the true facts to light.

Radial tires do not belong on a GL1200 because they pose a safety factor that will adversly affect the handling of your motorcycle.

If you modified your GL1200 substantially you probably could run the radials but I don't believe that it would be worth the effort since the Dunlop Elite III bias ply tires perform so well on the 1200.

According to Dunlop the GL1200 frame would need to be reengineered to work with the radials but they said that Honda would need to oversee that project to make it safe and I doubt that Honda would be interested in partnering a modification to one of its 20+ year old motorcycles.

[SIR tricky]

Surely Dunlop in their reply would have stated unequivocally that it would be unsafe to install radials on a 1200 if that was so, considering that was the basis of the question.

[admin]

They did state clearly and emphatically that radials are not to be used on the GL1200.

They also took great exception to my statement about modyfying the GL1200 to accept radial tires and felt that it could only be done by Honda.

Maybe it's time that I write them again to see if their position has changed. When I corresponded with Dunlop it was when they were first engineering the new Dunlop Elite III tires for the GL1200 so that is some time ago.

Once I get their reply I will copy and paste it here. Please add any further questions here and I will add them to my email in order to get one reply.

[SIR tricky]

I have just replied to that email I got from Dunlop with a direct question as to whether or not it is safe.
I shall also post the reply if one comes.

[admin]

I'll just wait for your reply Tricky. No point in wasting their precious time.

[Guest]

Interesting debate i've started here. BTW, I'm not meaning to start a myth, but rather have more information as to a myth that I see here in reguards to goldwings. I did read a thread talking about putting radials on FJ's that were originally built in the 80's. They seem to have no problem with it.

As to the 1800 stiff frame the 1800 really is a sprotbike in many ways, but with the exceptions of dressing and engine.

[SIR tricky]

From the horses mouth.

My post to Dunlop Rep:

Thank you for your prompt reply.

The basis of the question regarding the radial/bias rim differences was to try to clear up a discussion as to whether or not it is safe to use a radial E3 tire on a GL1200.
Is it safe or not to install radial E3's on a GL1200 motorcycle.
Some riders say they are safe to use, others say not.

Thanks


The reply

Richard -

The elite 3, in the correct sizes for use on the GL 1200, are bias-ply and
are recommended for use on this vehicle.


Still it is a recommendation, they still dithered on the safety issue.

I imagine we will only find out when someone gives the radial a true test on a 1200, most of what I have heard is 3rd or 4th hand hearsay.