Topic: Widest wheel/tire combination on a CB500K1

[gschuld]

I'm a fairly big guy(6'3" - 235lbs)on a mid sized bike.  I absolutely LOVE my 500K1 but I look borderline silly on it(and I'm told that alot- including vintage Honda guys).  And yes I am in the market for a  K1 or K2 750, but I will keep and ride my 500K1 forever!  My interest in wider tires and wheels is admittedly 110% aesthetic.  FWIW, I fully realize and agree that extra(or unnecessarily) wide tires on these vintage bikes is widely accepted as a hinderance on handling performance rather than an improvement.  Especially when crammed on the 1.85" front and rear factory rims on the old 500s.  Clearly, a good set of 110 front/120 rear avons on the factory rims would be FAR more capable in the handling department that I could rationally ask for.   

That being said, I need new rims/spokes and tires.  I want to take this opportunity to make the bike look a little more in my wife's term "beefy" to fit my size.  This plan would include swapping in a gl1000 front fork assembly with it's larger fork spacing and dual disc brakes.  I currently run a 130/90/16 challenger on a Harley 16x3 rear rim laced up to the factory hub.  This tire is 5 1/4" wide(just measured it) on that rim and only 24 3/4" tall.  I have a shade over 3/8" clearance on either side up forward.  The front is a 100/90/19 Challenger on the factory rim (3 7/8" and 26 1/4").
The chrome on both rims were going seriously south so I have both rims painted black.  A desperation move.

So I'm looking at going for a good set of tires (Avons probably) in 130/140 or -perhaps- 150 section in the rear with a 120-130 section up front.  I imagine new chrome rims in 3-4.5 wide out back and 2.5-4 wide up front would make sense. Perhaps 18" tall front and rear?  And of course new stainless spokes to match.

Another thought was to use a pair or GL1000 rear rims on BOTH front and rear.  I do really like the idea of using as many vintage Honda parts as possible.  These rims are 2.5" wide and aluminum, but are 17" tall.  Any idea if using these would be feasible with say 120/130 fronts/130/140 rear taller section tires?

For the GL1000 2.5x17 rims front and back there are for example:

Avon Roadriders

tire            tire section width     suggested rim width   tire height
 
120/90/17   5.0"                      2.5"+                                 26.6"             universal
130/80/17   5.4"                      2.5"+                                 25.4"             rear tire
130/90/17   5.5"                      2.5"+                                 26.4"             rear tire
140/80/17   5.6"                      2.75"+                               26.2"             universal

As a side note, a custom bike shop owner gave me a great offer on a pair chrome 40 spoke drop center rims in 18x4" and 18x4.5" that he was has sitting on his shelf for a year as one of his customers bailed on a bike build.  Brand new, not a nick on them, and 75 bucks for the matched pair!  VERY tempting!

Avon Venom

130/70b/18    5.1                      3-4                                 25.1            front    1.2" wider than my current
150/70b/18    5.8                  3.5-4.5                               26.2            rear     1/2" wider than my current

The crazy thing is that I am about certain that these rims/tires will fit on the bike as long as I use the gl1000 forks! Would it look wierd though?
 
I haven't up till now shown a huge interest in pushing the deep corner handling characteristics of this bike too much. Most of my riding has been longer road trips and around town cruises.  But spending an evening blasting through Piedmont Park with the 'Chin on the Tank' vintage Honda cafe racer club    http://www.chinonthetank.com/category/cb500t/ has convinced me otherwise .   I spent the last 3 days putting over 500 miles on the bike with Godzilla riding shotgun on my headlight.  Some of which was northwest NJ with some great windy roads with nice elevation changes.  I was LOVING it, but yearning for my bike to be better set up for the turns.  So as I was riding I was planning some changes.

Style wise I will be modding the bike with clubmans at first then likely a set of custom made clip ons, a 750 tank and 500 side covers painted to correct 500K1 colors, (likely, not decided yet) a new Honda seat cover mounted a bit lower to a factory seat pan using high quality seat foam.  Oh and better rear shocks.  I am not against selective frame reinforcement/modification if it is deemed worthwhile.

I will be giving  http://www.buchananspokes.net/ a call in the morning to ask him these questions, but I'd love to get some feedback from you guys regarding how such wheel/tire combinations would/could adversly affect the handling.  I will NOT be racing this bike or anything close to it.  But I do plan on getting into a bit more cornering in my future.

I want to get this all done fairly quickly, so a decision will be made soon and I will be ordering a whole bunch of parts  very soon.

ALL suggestions and comments are welcome.

George

[haill]

Thinks it will come down to what you can fit in between the stock swing arm, which max would be a 130 and if your keeping the front fender then a 100.
why don't you post a picture of yourself and bike.
Allot of times you see pictures of bikes and think "what a great looking piece of machinery" then one includes the rider and the image fades away cause the two don't fit together. Like an ill fitting suit.
Things that interact with humans, chairs, cars, motorcycles, clothing, have to fit each other to be comfortable and look smart. 
You may be better off getting a larger bike. You both, the motorcycle and yourself, will benefit.
Your idea of larger tires might end up looking like big shoes on a little guy. Just a little guy with big feet.
Shop around and find something, most likely a CB750 that is designed for someone more your size.
Think in the end, it's the only way, for porportion and scale won't change, just for the sake of it...

[Bankerdanny]

You and I are basically the same size. Other than having to remove my seat strap because of where I have to position myself on the seat, I really don't feel to big on my bike.

I went with the stock tire sizes, which are more than capable of supporting our weight. Of course if we wanted to have another adult as a passenger we would both be in trouble since we are about 70lbs from fully loaded with just ourselves.

Plus bigger tires won't make the bike any bigger. I wouldn't bother with the effort and expense.

FYI, the GL1000 has a 19" front wheel just like the CB's, only the back is 17". The simplest (though not cheapest) route is to have wider rims laced to stock hubs. This avoids the need for any fabrication hassles.

[gschuld]

I just ran across this recently done cb500.  I am not sure what his wheel/tire combination is, but I'd like to find out.  I'd guess around a 130 series front, 150 series rear tire width.  It looks like it has roughly a 4-4.5" rear rim width.

Does anyone know the details of this build?

George 

[gschuld]

http://www.youtube.com/user/wnegrini#p/a/u/1/eSnNyQY7Nck

Video of it running.

The owner's name is Negrini Wilson I believe.

Anyone know this guy?

[chris mcshifty]

So a 130/17 will fit on a stock cb500 front end with no mods. How wide does the rims have to be

[Retro Rocket]

So a 130/17 will fit on a stock cb500 front end with no mods. How wide does the rims have to be

That rear tire is a 140, and i'd say probably a 120 on the front, maybe a 130. If you are going to fit wide tires and want the bike to handle then you , if you have a 140 rear, would want no more than a 100-110 on the front. I am kinda confused reading your posts mate, it sounds like you want a good handling bike but you are looking at killing handling with crap over sized tires that will make it handle like a pig, not trying to be an arse but fat firestones are for looks only. I think you need to decide what you actually want or expect out of your bike before going any further....  I should also mention that a 130 front will require modification, especially to the brakes...  Fat tires on the front do look cool but i would only put them on a bobber, something that isn't built to handle well....

[chris mcshifty]

So a 130/17 will fit on a stock cb500 front end with no mods. How wide does the rims have to be

That rear tire is a 140, and i'd say probably a 120 on the front, maybe a 130. If you are going to fit wide tires and want the bike to handle then you , if you have a 140 rear, would want no more than a 100-110 on the front. I am kinda confused reading your posts mate, it sounds like you want a good handling bike but you are looking at killing handling with crap over sized tires that will make it handle like a pig, not trying to be an arse but fat firestones are for looks only. I think you need to decide what you actually want or expect out of your bike before going any further....  I should also mention that a 130 front will require modification, especially to the brakes...  Fat tires on the front do look cool but i would only put them on a bobber, something that isn't built to handle well....

I didn't know what I wanted at first cafe hardtail bobber the I saw the brats and that's what I want. I'm not looking for all out speed jus a cool ride that handles descent

[gschuld]

Chris Mcshifty,

     I'm the one who started this thread a while back.  Just for the record, for me the idea of putting fat tires on a cb500 died out for just the reasons that Retro Rocket stated.  I spoke with a few heavily experienced people in the position to answer my questions and they all steered me away from overly fat tires if a good handling bike means anything to me.  People have put all kinds of tire/wheel combinations on these bike and ride them.  Just be careful of how you changes affect the rest of the bike and how it handles.  Sometimes seemingly minor changes can make very detrimental steering geometry changes to a bike, especially when you start having fun a lean the bike hard over in a turn . 

George