Topic: new rim / tyre combo for 550?

[flatlander]

i'm on my way to go x-mas shopping for the 550... thinking of getting her some nice new alu rims 

that opens up the possibility to go for a correct pairing of modern, metric size tyres and the matching rim width. i want to have the best possible handling. from what i've heard that's with the relatively slim, original tyre sizes which are:
3.25" 19 front
3.75" 18 rear
on 1.85" wide rims.

so here's what i'm thinking:

the closest metric sizes seem to be
90/90 19 front
100/90 18 rear

generally recommended rim width for these seem to be
2.15 front
2.5 rear

there are nice tyres available in these sizes, including from avon.

an even bigger selection is available in the sizes
100/90 19 front
110/90 rear

the 2.15 / 2.5 rims would still work with these, from what i could find. so i'm thinking of going with these as i guess the original 1.85 rims would pinch the tyres too far and thereby reduce the amount of useable profile.

what do you guys think, does this make sense?
does anyone have experience with modern tyre sizes on the 550?

[seanbarney41]

I don't think going bigger on the front is gonna gain you anything except a more modern look.  Even on a cb750, the 100/90/19 makes for imprecision and extra weight with numb feel and little or no extra grip.  ...just my opinion

For whatever it's worth, I don't think the metric size equivalents ever work out on these bikes.  The profile of metric tires is just "different".  The only time I use them  is if 3.25x19 front and 4.00x18 rear are not available.(I realize the 550 is supposed to have a 3.75 rear, but does anybody make this size?)

I am all for some nice aluminum hoops, though!  The stock chromed steel rims is one area where Honda just "cheaped out", in my opinion.

[flatlander]

yes i'm definitely getting the rims, only question is what sizes.
so based on your experience you'd go for the stock size 1.85"?

i'm definitely not looking for wider tyres just for the sake of it. the wider rims i was considering so that metric tyres of similar to stock size don't get pinched as much as on stock size rims.

[seanbarney41]

I would stick with stock size, especially on the front.  I would put a 2.15 width rim on the rear and run 4.00x18, as they are much more available than the 3.75.  In my experience, the metric tire profiles make these bikes feel heavy and imprecise.

[Darren Jakal]

This is great info. Thanks for the questions and answers.

I’d be interested in knowing what rims you are going to use as I would eventually like to get aluminium ones myself.

Cheers, Darren

[Stev-o]

I would stick with stock size, especially on the front.  I would put a 2.15 width rim on the rear and run 4.00x18, as they are much more available than the 3.75.  In my experience, the metric tire profiles make these bikes feel heavy and imprecise.

I agree with Sean, stick with the stock size on the front.  Plus, a bigger tire may run too close to the fender.

However, I dont find the metric tire profiles making my bikes seem "heavy and imprecise", I just pump up the pressure to 35-36psi.  Have you tried that Sean?

FL - Have you considered Borrani Polished rims?!

http://www.buchananspokes.com/categories/rims_borrani.asp

[seanbarney41]

Yeah, Steve-O, and that does help

[flatlander]

thanks guys!

indeed, i'm not wanting to go bigger for looks. just plain good handling. and metric is not automatically bigger, that's why i tried to find the closest sizes to original. i've only looking at wider rims as from what i understand, metric profiles of similar width to stock need a slightly wider rim to support them in the correct shape.

anyway, the consensus seems to be to stick to stock inch sizes.

stev-o: what metric tyre/sizes have you used?

i'm going to get the wheels done by these guys who are more local to me: https://www.haanwheels.com/
they have excel and morad polished or not, maybe a few more options once i talk to them.
buchanan's will be more of a pain with shipping to NL.

[grcamna2]

I've found the metric sizes aren't exactly equivalent,but most usually wider and not as tall of a profile.
The challenge is finding the stock size tires !

[bryanj]

Continental and metzeller do stock sizes

[Deltarider]

Flatlander, having had Contis before (RB2 and K112 as well as TK22 and TK44) I now have the Bridgestone BT45s and I must say I'm pleased with them. Next time I may try Metzelers because I've read they have a pressure prescribed that is way lower and close to what the original tyres back then had prescribed. I wonder if that could bring some more comfy in my ride. The CB500 is quite Spartan suspensionwise.

[cb550papi]

I'm running Metzler Lazertecs at 3.25" front and 4.00" rear and only run about 28-30psi front and 30-32psi rear on stock cb550 rims.  Ikon 7610's and the progressive wound fork springs with 10wt oil.  Very smooth ride and the handling is so far superior to the stock setup it actually feels like a different motorcycle.  I wonder how much of an improvement (would I even notice) switching to aluminum and running a 2.15" in the rear instead of the stock 1.85"?  The underlying motivation here for me is if I do it, I'll setup a dual disc and get some real stopping power while making the change...

[flatlander]

thanks again for all your inputs!
i'm quite familiar with what tyres are available in stock inch sizes (and that 3.75/18 rear is pretty much unobtainable). running higher than stock pressure wouldn't be an issue, i have upgraded suspension.

i'm trying to keep an open mind towards options as inch size tyres seem to become a bit of a relic of the past in a shrinking market, so if going metric can work well than why not? it's also clear to me that they wouldn't work well on the skinny stock rims but as i'm getting new ones that wouldn't be a problem, either.

anyway, sounds like there's not much experience with this so i either play it safe and go with 1.85" front and 2.15" rear rims, with the available inch size tyres - or take a gamble on the dark (metric) side using slightly wider rims. tough decision.

[grcamna2]

I like to go one size larger than stock rims:up from OEM,for my bikes.

[PeWe]

Use a too wide tire on a rim was not a "problem" back in the 80's.
We used 130mm rear tires on CB750 stock 2.15" rim which should have 4.0-18. (closer to 110/90-18)

I have mounted a 120/90-18 tire a few days ago.
It really look fat on that rim. Same tire in 4.0 looked as a better match.
I'll see how it will handle next season. If it will flatten out earlier with bad handling.

2.15" rim and 4.0-18 seems to be a possible combo on several bikes of the 70's.

[flatlander]

thanks pewe, that also confirms the 2.15 rim with 4.0 tyre for the rear.
did you ever try a 110/90 on the same rim?

[PeWe]

No, smallest is 4.0-18 that I realised was the best choice for my bike with 2.15 rim after reading here and on BMW forums where handling was up.
Last purchase affected by the price. 4.0-18 cost much more and I'll try again with 120 tire rear. It looks better too.

The racers goes wider on rims.

Here differences on my bike.
4.0-18 early June, 120/90-18 a few days ago.
I like that tire. Metzeler Roadtec 01.

Rim 2.15"

[Flyin900]

I am looking at replacing my tires on a stock 1978 CB550K and would like to keep the tires as close to the correct original size as possible. After following this post there a lots of opinions and options. So what would be the best tires that will meet the OEM spec? I see that the front tire should be kept to the correct 325-19 size, yet the rear seems to be non existent in a 375-18 size. I did see the Metzler lazertech model and it has a 400-18 special size that is quite a bit more expensive, yet cost isn't a issue for me.

What about the profile height too on both tires, as there are 325-19 in 90 and 80 profiles and the rears too offer a range of profiles.? The stock sizes didn't offer a profile spec only the 325-19 or the 375-18 sizes.

[flatlander]

for the rear, the original 3.75-18 is pretty much unobtainable. you'd need to go for 4.00/18 which is available from bridgestone, conti, avon, metzeler (and a few cheaper brands that i don't care about or for). these four brands also have matching front tyres in 3.25-19.

inch sizes don't usually give the option of different aspect ratios (i.e. "profile hight"). i think they'd be around "100" aspect ratio in metric terms, meaning they're a bit taller than the 90 metric tyres.
at least that's my understanding after doing some research and listening to this discussion.

i guess you see where i'm coming from: support for inch sizes is much more limited than metric, and i'm pretty sure it's a shrinking market because there's less and less of these old bikes riding around.

[grcamna2]

I would like to find more '100 percent aspect ratio' size tires.. The 90 changes the handling a bit.I would like to try a 90/100x19 front..

[Flyin900]

I narrowed it down to the Conti ones or the Metzler Lazertec ones. Both are O/S at my supplier, so I have time to keep an open mind on other options too. I think the Metzler Lazertec appeal to me compound wise and they do have a correct front size of the 325-19 size offering and a 400-18 rear.
The Conti's look old school tread wise and their description of the rubber isn't really inspiring either, as they refer to them as ideal for rigid frame bikes?

Anyone familiar with the Heidenau brand as they too have some vintage tires in the K34 and K36 brand that offer a correct sizing. There is just not much info on the brand on the internet.

[flatlander]

i had heidenau tyres once on a 50cc moped. they were ok, but that's not a very demanding application.
when i replaced them with metzelers on the same moped, i found those stickier on wet pavement although they wore faster. so overall i preferred the metzelers over heidenau.

[PeWe]

Both my bikes have used Heidenau.
K44 3.25-19 front, K36 4.0-18 rear.
Work fine with stock like pattern. Look good on a stock bike from the 70's.

My K6 got the rear replaced last summer when the K36 was too worn.
I replaced it with Metzeler Roadtec 01 4.0-18 that is a better tire. Really stable when crossing lane markers, lines indents in asphalt. It has longer life too, at least 20-25% more.
See photo above.

I like the K44 front tire thread pattern that most likely will grab on slimy mud in asphalt better than modern patterns. It look like early Metzeler ME11. (Rear reminds of ME77)

My front wheel slided very sudden when turning bike when parking on a wet strip with mud.
That front tire was a Dunlop Streetsmart. No thread pattern for that.

So, the front Roadtec 01 might not go on since it has same style, nothing that can grab in mud when leaning the bike.

Maybe I'll change my mind since the later Roadtec 01 is available in 3.25-19 and has got good reviews. I like the rear. I have to be careful when turning bike in very low speed on muddy surface.

[Flyin900]

I am definitely leaning towards the Metzler brand and wonder what the difference is between the Lazertec and the Roadtec models. Both offer a front tire that is the correct spec of 325-19 and the 400-18 rear is off slightly, yet seems to be the best compromise option in sizing.

Can you give me your impression on these two choices, as the Roadtec is a little less expensive for the rear tire and seems like the series maybe a newer Metzler model in their line up.
Also since this is a 1978 CB550K with both a front and rear rim width of 1.85 vs the CB750 width of 2.15, is there an issue with putting the 400-18 on that skinny rear rim?

[jlh3rd]

here's this.....