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Need help, ordered the wrong tire size.

daddykevin

daddykevin

Moped
I just ordered the wrong tire size for my '01 Concours. I ordered the Avon Storm 2 in 110/80R18 and it should have been a 120/70R18. What will happen if i install this tire? Should I return it and wait for the proper size? Or, will this difference be largely insignificant.  :'(

I'm a total idiot, just trying to get good tires at a reasonable price.

Thanks,
 
Shouldn't be a problem as running the 110/80 was common among us Michelin fans. Quickened up the steering a little.

 
That's the correct size actually.  Most of the 120/70's are recommended for a wider wheel than ours.  The Dunlop OE is narrow for our narrow wheel.
 
Bill said:
That's the correct size actually.  Most of the 120/70's are recommended for a wider wheel than ours.  The Dunlop OE is narrow for our narrow wheel.
Click to expand...

This is correct. A 110/80 is 4.33 inches wide. A 120/70 should be 4.72. IF you look at Avon website it says 4.7 and min wheel width is a 3.5 inches. Connie wheel is 3.0 inches. Too Narrow for a 120.  And if you check Dunlops website you'll see a 120/70 in something like a D205 is 4.7 inches. But if you look at the stock K701 dunlop says its 4.37 inches wide. Thats only .04 inches wider than the 110 and no where near a REAL 120.

And mounting a REAL 120/70 on our narrow wheen does pinch it down.  Kinda like this.

IMGP5355.JPG
 
This was a D205 at 12K and cupped pretty bad. Once that tire was removed here is what it measured. Calipers at 4.72 and the tire measures out. It was pinched that much mounting on the narrow wheel.

IMGP5583.JPG
 
Wow! Completely changes the curvature or shape of the tire. Appears to be a significantly smaller contact patch once the tire is mounted on a smaller width rim.

Thank you Sly, very informative.

Thank you everyone.
:beerchug:
 
True, if you put the same size tire on a smaller rim... But, what we are talking about is a smaller tire on the same size rim.

The larger tire, on the correct rim will have a larger contact patch.

If you put that larger tire on the same size rim as a smaller tire, yes, it will have a smaller patch than if you had put it on the correct size rim, but will it have a smaller contact patch than a smaller tire on the same sized rim? I don't think so, but I can't say for sure.
 
WillyP said:
True, if you put the same size tire on a smaller rim... But, what we are talking about is a smaller tire on the same size rim.
The larger tire, on the correct rim will have a larger contact patch.
If you put that larger tire on the same size rim as a smaller tire, yes, it will have a smaller patch than if you had put it on the correct size rim, but will it have a smaller contact patch than a smaller tire on the same sized rim? I don't think so, but I can't say for sure.
Click to expand...

Whut he say??? I are confused!!  :'( :truce:

IF the contact area on a (120 vs 110) is "in fact" smaller, it is minimal.
If you want the area back,, reduce the air pressure a bit...  (38 psi instead of 40). Problem solved,....  :-[
"Let the flames begin"...........

NOTE: I've heard that the 110/80 is a better choice for our bikes because of the rim size.
But I had the 120/70's on mine prior to hearing that. Works fine for me...

Ride safe, Ted
 
connie_rider said:
WillyP said:
NOTE: I've heard that the 110/80 is a better choice for our bikes because of the rim size.
But I had the 120/70's on mine prior to hearing that. Work fine for me...

Ride safe, Ted
Click to expand...

    Same here. So far I like it.
Click to expand...
 
Some quote misalignment there...

Anyway, what I was saying is in response to the notion that putting a tire on a rim smaller than that for which it was designed, will reduce the contact patch slightly. This may be true but in this case is irrelevant. Because the tire in question is larger than the smaller tire, the larger size of the tire counteracts the reduction or contact patch due to pinching the tire.
 
Well I'm still confused.... Let me see if I get this.

The contact patch of a 120/70 non-OEM Dunlop designed for a 3.5 inch wheel is larger when installed on said 3.5 inch wheel than when installed on our 3.0 inch wheel, due to the tire being pinched on the wheel.

However the contact patch of a 120/70 non-OEM Dunlop installed on a 3.0 inch wheel is the same as the 120/70 OEM Dunlop installed in the same wheel. Even though one is pinched on the wheel the other is a smaller tire. So it works out the same.
 
Ok let me add a lttile more confusion to the mix.

No matter which size tire you use the contact area on the ground does not change, only its dimensions, ie..length vs width.  That assumes air pressure and weight are the same.  Tid bits from my Porsche/Audi days
 
Contact patch aside, so far I like the 110/80 better. My last 120/70 radial was a Dunlop D205 and now using Bridgestone BT45V in the 110/80 size. To me the D205 always felt kinda nervious twitchy feeling. Like I always had to make constant tiny corrections. Steering effort is the same. I didnt not notice any real change in quick steering or anything like that. BT45 just more stable, no twitchy, ride. Still nice light steering and track, stick well.

Not quite apples to apples since they are two different tires and not a back to back 120 versus 110, but I like the 110 better from what I have experianced.
 
Other factors include tire specs and liability issues and more.

I think many places recommend the 120/70 because thats what it says in the manual.  I am seeing dealers in my area will only install MFG listed tire size and thats it. I believe this is out of Liability concerns.

I have not seen this but it was once reported that someone was getting denied a claim from the insurnace company because they had non stock size tires.

I assume the spec's on the tires are there for some reason. It says right on Avon site for example a 120/70 Storm 2 has a min wheel size of 3.5", with a max of 3.75" with 3.5" also being the recommended size. Is it unsafe not staying with in the specs? Dont really know, but there are tons of Connie owners who have been using 120/70 radials intended for 3.5 wheels for year and years. So I think its not bad, but we are exceeding the specs. -- From this point of view I always find it interesting that the tire MFG's always recommend the manuals stated tire size, and recommend a tire that does not meet their own specs.

Lots of factors to consider.
 
Don't do it man!  :-\  Send that tire immediately to me (postage paid please) and then buy a new tire!  >:D

Nothing wrong with mounting a 110/80 on the front. But if the naysayers are convincing enough, well then I'll be happy to accept your kind and generous gift........

I've run the 110/80-18 Michelin 89X/90X and 100X tires for about, I don't know maybe 70k???  and would still be running them but Michelin decided not to be a friend of COG anymore.... :'(
 
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