Tire rim fitment, load rating, speed rating, charts

[gggGary]

Some interesting info here.

Was thinking about putting some wider rims on stock hubs so wanted to see what tires would work best. Note how narrow the metric tires to fit stock rims are.

And some other useful charts RE tire selection.

View attachment Street-Tire-Load-Ratings.pdf

 

[gggGary]

One problem here is there are almost no "sporty tires" to fit our rims or even rims we can stuff in the chassis. I am seriously thinking of using a front tire at both ends. I kinda think a front can deal with the incredible XS650 horse power.
chewing on using the mikes 2.5 x 18 front and rear. maybe run 110/80 tires

Then michelin says nearly all of their sporty rubber cannot be run with tubes. So I would have to launch into no man's land and say well the OLE XS ain't going to run fast enough long enough to create a problem with a tube in a pilot 3. The resto mod is running pilot activs (tubes OK) 100/90/19 on a 2.15 front rim and 4.00x18 on a 2.5 rear rim, it felt pretty good this last year.

 

[gggGary]

I am still trying to educate myself on tires. It appears your best bet is to fit the LOWEST speed rated tire that you can find to fit your rim.
What I think I am learning...
A: our bikes aren't fast enough to challenge even the lowest rated tires in our size range.
B: the higher rated the tire the heavier it needs to be built. lighter thinner tires improve suspension action and improve road contact.

 

[TwoManyXS1Bs]

Here's the Hagon chart:

View attachment 53366

I'm way behind on modern tire technology, but back in the daze, tires had the "3T" code:
Treadwear, Temperature, Traction. And understanding the code values was important.

Are they still marked as such?

 

[gggGary]

Good chart 2M!

Tire pics with a few notes.







These first 6 are the Pilot Activs 100/90/19 on 2.15 rim, 4.00/18 on 2.5 rim.







These 6 are ancient 3.50 front 4.00 rear on stock rims.

 

[gggGary]

More pics





Some used Michelins on stock rims





The 110/80/18 pilot 3s on 2.50 rims These are dual compound radials. I would prefer a P4 with solid edges for better traction when sh'es way over. but in these sizes you buy what you can find. Michelin says NO tubes in the pilot 3s but that's what I did.........





a 130/90/16 on a stock mag

Not sure how much this all shows, but it's what I could get done this morning!

Then once you decide on rims and tires you have to pick tire pressures! And no one has a definitive guide for THAT once you leave the stock tires, rims behind.

 

[gggGary]

I'm hoping to have 2 bikes with 3 sets of rims/tires down in the Ozarks late April for the 650 society rally so we can do some comparing.

 

[gggGary]

Some good info on tires n rims

https://www.motointernational.com/blog/news-and-events/post/sharing-daves-ol-tech-articles-episode-3

 

[grizld1]

Gary, two "sporty" tires for the stock 1.85-19 front and 2.15-18 rear are Pirelli Sport Demons and Bridgestone BT45's. Shinko 712's are a cheap but sticky option (just watch out for bead seating; sometimes one has to be sent back, so buy locally and avoid the BS that will be involved when the party that sold the tire can't examine the installation).

Big, fat rims and tires are fine on modern sport and sport touring bikes, but the steering geometry on those machines is compatible with wide rubber.

I've been very happy with 2.15-18 rims front and rear, with 100/90/18 in front and 110/90/18 in back. Pirelli, Bridgestone, and Shinko all have offerings in those sizes.

 

[gggGary]

Yeah I was going to try these BT45's but they got sold before I could install them. Still waiting on the guys tax refund so they still might be available for the rally....



These bikes were "designed" for hard old Yokahamas or Dunlops with blocky rear tread and straight line front tread. But I ain't puttin' those on my bikes....

 

[grizld1]

Uh, re. what the chassis was designed for, I was referring to little things like rake; steeper angle on the steering head is one of the reasons newer designs can use fat rubber without steering like a truck or a Hardley Ableson. But you're young and strong, so it doesn't really matter--you can pitch that scoot over no matter how hard those big tires fight ya!

 

[gggGary]

Well we will find out and can even do back to backs in the Ozarks!

 

[gggGary]

a blurb about tire pressures, no provenance.

Yes most of the tires I have run on my 650 needs about 28 front and 32 rear. What the manual calls for is factory tires, not made any more. The best way to figure out what pressure works is set them to say 30 front 35 rear. Take it for at least a 15 minute ride at speed, not around town but out where you can cruise at 55-60.
After the 15 minutes pull over and check the hot pressure.
If it goes up 3 lbs, then the pressure is right.
If the pressure goes up 4 or more lbs then the cold pressure was too low.
If it goes up 2 lbs or less, then the cold pressure is too high. Let the tires cool down - 45 minutes to an hour works. Reset the cold pressure as needed.
Do the 15 minutes at speed and recheck the hot pressure.
Do this till you find the cold pressure that gives you a 3 lbs more hot pressure.
Now remember this pressure. Thats the ideal pressure for those tires at the load on them. If you load up for a trip, reset the cold pressures the same way to get the loaded cold pressure.
Write these pressures down. As long as you use the same tires you will know just how to set then for the load and conditions.

 

[TwoManyXS1Bs]

3 lbs, good tip, got it.
And thanx for the chart updates in post #1. Got my copies...

 

[XSLeo]

I have used the 3 lb. formula On tires for years. I was learned this a long time ago, so long ago I can't recall where I learned it. Some with a more precise pressure gauge say 10% increase is right, but 10% of most bike tires is real close to 3 lbs.
I use this to adjust tire pressures on most any thing with tires, any that go 55-60 mph anyway. On the mini bikes and garden tractors I go with what the vehicle owners manual suggests.
Leo

 

[gggGary]

Got the 3 x 18 flange rim from italy. http://www.ebay.com/itm/252275596547 About $150 shipped to my door. This one arrived in 8 days, not bad! Haven't mounted it yet but by looks it is very high quality. It has much better fit finish than the Mike's offerings and the stock DID and Tasago? rims also. After a couple tries I could not find the weld and that's a good thing! It is not size marked, DOT labeled, or branded.

Spoke angles look usable, after just a bit of re-aiming with my "custom ground rejiggering" tool. I think we are lucking into angles that are about half way between front and rear XS650 angles. But this may be over the top wide for a front rim. As is true on (all?) 3" and wider rims the center drop and nipple bulge is deeper than the narrower rims probably about 1/8 to 3/16" closer to the hub. I think I will get it on an XS650 rear hub with the Mikes SS spokes but would probably run out of thread trying to mount it to a TX750 rear hub.(spokes too long). Lacing this will have to wait til April.

I stripped a stock XS650 rear last night for the hub. now I have to get it cleaned up a bit.

 

[TwoManyXS1Bs]

Italy? An unmarked Boranni clone? Like for Guzzis?

 

[gggGary]

Could be, what do you know? Guy has lots of duc and other italian MC parts. I would like to import more of these, wuz thinking 6 at a time or so. would be super to have matching 3x18 and 2.5x18 flange 36 spoke rims! will probably order the flange 2.5 18 when I get back, the mikes 2.5x18 work but aren't flange and for me better quality would be worth the diff in price!

 

[TwoManyXS1Bs]

I know nothing.

Sounds like you've found an interesting alternative...

 

[gggGary]

Got the 3x18 mounted used mikes 18" stainless rear spokes. Had to re angle/drill the spoke holes, about the same deal as the mikes wide rims.
View attachment 62612

View attachment 62613

View attachment 62614

I have a Michelin RP3 110/80 so will probably mount that. This will go on the restomod and get exercised at the Ozark rally.