Topic: Ordered tires in a rush at lunch

[zanorak]

Long story, but my back tire looks too dangerous to ride now so I ordered Bridgestone Spitfire S11 tires in the 5 minutes I had at lunch. I ordered the size of tires that are on the bike now...
110.90.19 and 120.90.18. (F/R)

However, after reading some more it sounds like my early rims might not be good for these tires. I had missed the fact that the early CB's had narrower rims?

Can anybody shed the light on this? If necessary I can find wider rims this winter and put them on.

THanks ahead of time! I hate to lock my best buddy up in the garage and the sooner I mount these suckers the better. I think we have another two weeks of riding weather here in MI~!

Also, read some posts about head shake due to modern tires on these suspensions. Will the larger tire sizes amplify this? (guessing yes...) What should I expect?

[Stev-o]

what model bike?!!?

[nancy]

Didya post this at lunchtime too?

[BeSeeingYou]

The wider tires will fit the rims but the sidewalls get pinched in and eventually cause the tires to wear poorly.  People do it cause they like the look of the larger tires but the bike will handle better and the tires last longer with the proper size.  I am guessing that 100/90/19 and 110/90/18 may be closer to the correct size.  The Spitfires are also one of the wider tires in a given size.  I have seen 100/90/19 tires that range from 3.9-4.2 inches wide depending on make and model.

[zanorak]

Sorry!!! Classic mistake.
1972 (really built 71) CB500!

No, posted this tonight between housework! :/

[dave500]

i have a 110/90 spitfire on the rear,i like it,i did have the next size up bt45 but it wore out at 7000kays and it turns better now with the correct size.,i have the correct size bt45 front,i dont get any head shakes or anything else.

[BeSeeingYou]

I would eat the shipping and send them back and get the proper size.

[dave500]

is it too late to change or cancel the order?

[TwoTired]

They will handle ok when brand new. You'll have to over-inflate to keep the sidewall stiff.  And that will cause the tread center to wear fast ans the tires will "square-off", which will lead to fighting the bars during the turns to hold your line.
Under-inflation will retard the square-off.  But, then the bike will feel squirmy as the unsupported sidewall won't keep the tread properly aligned with the rim.

Wider than stock tire are a bit harder to seat evenly on the rim, which will cause the tread to wander around the circumference, which will generate "head shake".

Bigger tires also weigh more.

Trucks have bigger tires, too.  They aren't usually referenced as good or exemplary handlers.

Cheers,

[zanorak]

Lots to think about! Thanks everybody.
The tires are listed as "on order" right now on the BB website. So much for "usually ships within 24 hours" huh?

I like the way the big tires look on the bike, but I think I'll go down one size like srust suggested - 100/90/19 and 110/90/18.

That being said, I've never had too much issue with handling problems with this setup as it is. Maybe I just don't know? I'll be BLOWN AWAY! by the correct tires! It does wander, and squirm on grates and grooves...

UPDATE: the order is being shipped from a remote warehouse. BB says they can't change it now, I would have to return them after receipt or refuse the package. :/

I'll decide what to do when I get them, since I'm sure they'll be delivered while I'm at work.

So, back to my question - ARE there wider rims on the later 550's with the 19/18 inch wheel combo? It appears I might be in the market...
Twotired I'm sure you're right but I think I can live with the extra tire if I lived with the old worn out tires. Time will tell? (Ignorance of youth)

[TwoTired]

That being said, I've never had too much issue with handling problems with this setup as it is. Maybe I just don't know?

With the stock size tires, you don't need to fight the bars at all in the turns.  The bike kind of steers itself just by leaning your body weight slightly toward the turn.  Your hands just allow the bars to move where needed for the turn. 
Squared off tires will require you to hold the bars with adverse pressure while in a sweeping turn (any turn actually, it is just more noticeable in the sweeper).

While the new tires still have the new tread crown, it may still be neutral pressure on the bars.  You will adapt your bar pressure as it wears, (and then be so admirable about how well the next news tires feel on the bike with their original tread crown).

"Looks" don't determine "function".  Physics does.

Cheers,

[zanorak]

Damn. And see, I was going to put aesthetics and physics in a room with a rusty knife and see who came out alive. 

I'm a heavy guy twotired. Will that affect the tires much?

[Stev-o]

If they are the same size as you currently have, I'd bet you'll be fine.

[zanorak]

Bike Bandit is astounding! Got the tires today! They don't look too big right now, but I think I'll have to mount them and measure etc. Thanks everybody for your input!