Author Topic: CB550 Tire Thread (Read 26157 times)

cleveland · « **Reply #50 on:** August 27, 2008, 06:40:38 PM »

So I took in my CB550 rear wheel and the local guy set me up with an Avon. Seems like a nice gummy tire, but I noticed it was smaller then the old rear tire. Turns out I had a 120/90 and he set me up with a 110/90. Then....I decided to have him order a new front tire, same thing! 110/90, and I should have a 100/90.

So my question is, why the bigger tires? Should I have kept the bigger size, or is the stock size the better choice?

kghost · « **Reply #51 on:** August 27, 2008, 06:45:55 PM »

One size bigger...least on the back (talking 120 vs 110) seems to wear a little funny.

Twotired did a post a while ba ck about why...something about pinching the bead and flexing the tire carcass.

Anyways...just from experience the 120 wears in the center faster and gets kinda square there.

cleveland · « **Reply #52 on:** August 27, 2008, 08:05:47 PM »

Quote from: kghost on August 27, 2008, 06:45:55 PM

Anyways...just from experience the 120 wears in the center faster and gets kinda square there.

Now that you mention it, my rear tire was a bit square due to only wearing in the center.

dboblet · « **Reply #53 on:** August 27, 2008, 08:30:34 PM »

I've been thinking about this one a lot lately. My tires are completely stock size on my CB750f and the old tires that came off after 20 years of sitting, were definitely larger. I LIKE the larger look.... but the new tires it the correct one for the rim and is wearing evenly.

There is a lot to tire sizes besides just the tire width. The surface area that meets the road effects the bike handling in curves, and the weight distribution for a bike as you accelerate through a turn. Having too much surface area contact will increase the weight to the rear wheel and consequently decrease the weight on the front tire.... something like 60/40 for most stock superbikes is close to right for a turn and having a larger than stock tire can change that ratio **for the same given roll on acceleration**. Just something to think about.

That fat tire look on many of todays road race cafe style bikes is designed into the suspension system and frame design. I don't think you can go to a really fat rear tire on one of these 'classics' without some serious thought and pehaps other changes as well (shocks and springs for instance).

oops, rambling again.... sorry.

markjenn · « **Reply #54 on:** August 27, 2008, 10:13:30 PM »

Every rim width has a small range of tire sizes where the tire will have the proper profile for good handling. The stock sizes will give you this certainly, and you may be able to go slightly wider, but not much. I wouldn't deviate from this significantly. Given that your front rim is considerably narrower than the rear, I don't think having the same tire widths front/rear is correct.

As I recall, your rim sizes are 1.85/2.15 front/rear and the stock tires were a 3.25" front and a 3.75" rear. In metric sizes, I'd be looking for a 90 (or a 100 in a pinch) for the front and a 110 (or 120 in a pinch) rear tire. That 110 on the front will probably make the bike handle quite oddly.

- Mark

cleveland · « **Reply #55 on:** August 27, 2008, 10:27:43 PM »

Quote from: markjenn on August 27, 2008, 10:13:30 PM

That 110 on the front will probably make the bike handle quite oddly.

- Mark

Been that way since I got the bike. I have probably ridden those tires a season and a half too long.

Now that I have the same size tire in front and back (110) it does feel odd. Next week the replacement front tire will be in. I am sure it will be fine for that short period.

So just to be sure I am reading everyone's posts correctly, the wider tire is for visual effect and not performance........correct? Anyone think differently?

TwoTired · « **Reply #56 on:** August 27, 2008, 11:19:04 PM »

The 550 has 1.85 inch rims front and rear.

The tire manufacturers often state the allowable rim size that works with the selected tire if you look hard enough. Tire salesmen hide this info from you as there is more profit margin is larger tires. Plus, fitting them onto narrow rims helps them wear faster, and has you coming back for replacements sooner. Why? Because the rim is pinched together making a higher sidewall angle that has less rigidity and adding more "crown" the tread area at the same time. To stiffen the sidewall, more tire pressure is required and that adds even more crown to the tire tread, resulting in much more rapid wear in the center of the tire tread.

I don't let them sell me metric "equivalents" anymore. Because they aren't really equivalent.
The old inch size tires for the 550 were/are 100% aspect ratio. A 3.25 front equates to 83 mm width and height. A 90/90 tire is wider and shorter at only 81mm height. The good news is that it will usually work ok for a 1.85 inch width rim. But, it works best with a wider rim of 2.15 inch. And, bikes designed to use metric tires have wider rims than the 550.

A 3.75 rear equates to 95mm width and height. A 100/90 width tire is wider and shorter, and is optimized for an even wider rim than the 90/90.
Actually a 4.00/18 rear is far easier to get and has a 102mm equivalent width. But, to get close to that height, you have to go to a 110/90 (99mm height) which works best on a 2.50 rim width that the 550 doesn't have.
A 120 metric tire is simply too wide for the 550s 1.85 inch rim width. It will center wear far faster than the proper tire, and require much earlier replacement.

That's why I still use inch size tires, which the tire hawker will order for you if you insist. But, they will try their best to sell from what they stock at the store using what are convincing arguments for the uneducated.

Finally, I think the the 550 simply handles better with the proper inch size tires.

Cheers,

See also:
http://www.dkebay.com/jsp/tpl/tire/tiresizeexplain.jsp

pdxPope · « **Reply #57 on:** August 28, 2008, 12:06:08 AM »

Wow, TT. I applaud your restraint, sir.

-JP

cleveland · « **Reply #58 on:** August 28, 2008, 05:57:22 AM »

Thanks TT!!!

bggann · « **Reply #59 on:** August 28, 2008, 06:20:32 AM »

I just went through a very similar transformation on my CB400f - which by the way has 1.85 front and 2.5 rear rims.

The PO²- who I have found was a very competent mechanic, but primarily a Haley rider, had put on larger tires. Front was 120/80, rear 130/70. They looked pretty - though that front one was really stuffed in there.

Anyway - the rear was pretty worn - and I took it right on down. In fact PO was really surprised how quickly it wore out - he had not ridden the bike much and I'm using it as daily driver.

I decided to go back to closer to stock size for that bike. Put Metzler Lasertek 90/90 on the front, ME-77 4.00-18 on the rear.

The bike has changed.
- Before - I had to 'hold' it in the corners - consciously - if I relaxed, it straightened out.
- Now - it is almost perfectly neutral in corners, will hold the line, or perhaps drop in more just a bit.

This has impacted my driving posture too. Before, I found myself doing the old "bike leaned in- I'm leaned out - style. Now, my body pretty much doesn't move - stays right in line with the bike.

In short - the bike handles better, quicker, smoother.

BG

TwoTired · « **Reply #60 on:** August 28, 2008, 10:56:08 AM »

I just rechecked my CB550K3. Stamped into the rims is 1.85 x 19 Front, and 1.85 x 18 rear.

Quote from: bggann on August 28, 2008, 06:20:32 AM

I just went through a very similar transformation on my CB400f - which by the way has 1.85 front and 2.5 rear rims.

Is this a modification? The stock 400s I've encountered all had the same rims as the 550.

Quote from: bggann on August 28, 2008, 06:20:32 AM

The bike has changed.
- Before - I had to 'hold' it in the corners - consciously - if I relaxed, it straightened out.
- Now - it is almost perfectly neutral in corners, will hold the line, or perhaps drop in more just a bit.

This has impacted my driving posture too. Before, I found myself doing the old "bike leaned in- I'm leaned out - style. Now, my body pretty much doesn't move - stays right in line with the bike.

In short - the bike handles better, quicker, smoother.

This parallels my experience as well. But, it should be noted that when the metric tires are still new, and have their original tread crown without wear, they handle much better than when they have worn center treads after a bit of use. The handling gets progressively worse with the high rate of center wear. It's insidious.

Cheers,

kghost · « **Reply #61 on:** August 28, 2008, 10:57:38 AM »

Thanks Lloyd....couldn't find your other post.

Sorry to make ya repeat yourself.

andy750 · « **Reply #62 on:** August 28, 2008, 12:45:16 PM »

Quote from: kghost on August 27, 2008, 06:45:55 PM

Anyways...just from experience the 120 wears in the center faster and gets kinda square there.

+1 - I had 120s (Dunlops GT501) on the back on my CB750K4 and it squared off - just replaced with the correct size with a Bridgestone BT45 and much happier in corners...no more "straightening out" as described above.

And thanks TT for adding the usual science part to the thread.

cheers
Andy

dboblet · « **Reply #63 on:** August 28, 2008, 01:13:00 PM »

Just curious but isn't it possible that for 'some' of us, squaring off, or excessive center tread wear could be (mostly) a product of riding style. Up here in the mountians, I do a lot of riding on the edges and consequently, have pretty even tread wear (or so it seems).

It occurse to me that If I were riding mostly on the highway or more urban settings, I'd be on the center of the tire tread most of the time and wear the centers our a whole lot faster thus 'squaring' off the tires.

kghost · « **Reply #64 on:** August 28, 2008, 01:33:12 PM »

Quote from: dboblet on August 28, 2008, 01:13:00 PM

Just curious but isn't it possible that for 'some' of us, squaring off, or excessive center tread wear could be (mostly) a product of riding style. Up here in the mountians, I do a lot of riding on the edges and consequently, have pretty even tread wear (or so it seems).

It occurse to me that If I were riding mostly on the highway or more urban settings, I'd be on the center of the tire tread most of the time and wear the centers our a whole lot faster thus 'squaring' off the tires.

I hardly ride conservatively....mine still squared

TwoTired · « **Reply #65 on:** August 28, 2008, 01:53:22 PM »

Quote from: dboblet on August 28, 2008, 01:13:00 PM

Just curious but isn't it possible that for 'some' of us, squaring off, or excessive center tread wear could be (mostly) a product of riding style. Up here in the mountians, I do a lot of riding on the edges and consequently, have pretty even tread wear (or so it seems).

It occurse to me that If I were riding mostly on the highway or more urban settings, I'd be on the center of the tire tread most of the time and wear the centers our a whole lot faster thus 'squaring' off the tires.

Do you have over size tires, mounted on narrow rims, with higher than recommended tire pressures?

eldar · « **Reply #66 on:** August 28, 2008, 02:18:17 PM »

You will wear whatever part of the tire you ride on the most. Cant really dispute that. In my area, corners do not exist, so it does not matter how you ride, it will square just because there is a lack of corners. Simple as that. The only thing is, how long will it take.

I must say, I love the larger rim the 78K has. A 130 is a great size for the back and 110 works perfect on the front.

bggann · « **Reply #67 on:** August 28, 2008, 03:00:20 PM »

Quote from: bggann on August 28, 2008, 06:20:32 AM

I just went through a very similar transformation on my CB400f - which by the way has 1.85 front and 2.5 rear rims.

Quote

Is this a modification? The stock 400s I've encountered all had the same rims as the 550.

Probably is, but it was a PO² mod. The rims are sligtly gold - so not stock. No issues with fit tho. The rear may be 2.25 - I have to look - but it is certainly not 1.85.

BG

75-550 · « **Reply #68 on:** February 08, 2009, 09:13:48 PM »

Hello,
I have a 1975 CB550 that is in need of new tires. I will be traveling about 50/50 on gravel/pavement so I was thinking about dual sport tires. Does anyone have any recommendations on this? The current tires are 3.25-19 front and 4.00-18 rear, I don't really know how the tire sizes work, so I am also wondering what sizes will fit on my bike. So if anyone has thoughts on if this is a good idea or not, what specific tires would run good on this bike and what sizes will work I'd appreciate it.

Thanks

Alan F. · « **Reply #69 on:** February 09, 2009, 06:52:32 AM »

I haven't run them myself, but there's been some buzz on the forums here about Michelin Anakee, it's a dual sport tire and I understand that it's available as a radial and as a bias ply.

For tire size explanations check out http://www.motorcycleproshop.com/tires/tireinfo.asp

75-550 · « **Reply #70 on:** February 10, 2009, 05:41:55 AM »

Those look good, I'm not sure they make them to fit my bike though. It looks like the rear tires are all 17" for the Anakees.

Has anyone tried Dunlop K70's, those look like the originals and have a bit more tread than normal street tires. I'm looking for something that will run ok on gravel as well as the street.

It would really help me if I could find out what size tires people are running on these bikes. I've read so many different things on tire sizes, I guess I'm wondering what is the closest size to the original.

Thanks

Alan F. · « **Reply #71 on:** February 10, 2009, 06:03:09 AM »

if you know the stock size, like 4.0x18, this page will help you to convert it to a metric equivalent.

http://www.motorcycleproshop.com/tires/tireinfo.asp

I've read many posts pointing dualsport tire questions to a forum called http://www.advrider.com/forums/

Maxacceleration · « **Reply #72 on:** February 10, 2009, 06:28:02 AM »

Heres a pair that would fit.
http://tiresunlimited.com/ALL%20TIRES/AVON/AVON%20MC/avon_distanzia.htm

For adventuring around some DS tires would be pretty beef.

75-550 · « **Reply #73 on:** February 10, 2009, 06:33:45 AM »

Those Distanzia's look good. From the link posted above it looks like 100/90H19 for the front, for the rear my two choices are 110/80S18 and 120/80S18. The link recommends 110/90, so would I go with the 110/80S18?

Thanks again

Maxacceleration · « **Reply #74 on:** February 10, 2009, 06:44:48 AM »

Ya, I would do the 110's although the 120 would be pretty burly.
Ask to see if 120's are fitting on the 550's.

(BTW I'm putting a 120/80 on my 550 (not stock!), hope there is clearance...)

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Author Topic: CB550 Tire Thread (Read 26157 times)

bggann

eldar

bggann

75-550

75-550

75-550