Topic: Honda CB 500 Four 18 inch front and rear. (Possibly wider rims aswell)

[Andy2000531]

Hi everyone, i need to replace my wheels, as they are not in good condition.
I really like the look of 18-inch wheels for the front. If it’s not too much trouble, I’d like to go with that size.
I believe the original type of spokes will fit the rear wheel, but I’ll need custom spokes for the front. Can anyone recommend where I can find these custom spokes?
And i would also like to change the width of the rims. Is this as easy as finding 40H rims with the size i need, or are there different types of 40H rims ?

Andreas

[Alan F.]

Spoke holes in the rims are drilled at different angles for different diameter hubs. Compare your bikes front and rear rims for instance. So if you're choosing a used rim, narrow your choices to rims that originally came with similar size hubs to yours.

Spokes can be had from many different custom wheel shops, Woody's in Colorado, Buchanan in California, these shops can do and supply all.
There are also some comparable shops in the UK.

Ebay, If you're cheap and like to experiment like me, there are custom spokes made to length in stainless or zinc plated, j-bend or straight pull, but those sellers are outside the USA so if that's not your thing, it's not your thing. Quality on the sets I've used is high.
Edit: I see you're in Norway, I've had good success with spokes from ebay seller kingstar-cn https://www.ebay.com/usr/kingstar-cn

I've been involved with the current breed of Royal Enfield models for a few years now and have found Ebay to be a good source of 36 hole aluminum rims in useful sizes from the current models, and I've also found very good prices on chromed steel 40 spoke rims from their earlier bikes (mid 20th century to ~2018) for very attractive prices, these may be worth a look. Shiping from most of these India based sellers is very quick except during their rainy season... Their prices are generally very good and their communication is very good. Let their Ebay feedback number speak for them.

My favorite websites to help understand how and why spoked wheels are built and function as they do are:
https://earlymotor.com/spoke-length-calculator/
And
https://blackjackwheels.com/spoke-calculator/

[HondaMan]

If you use a smaller wheel on the front, maybe consider also either shorter shocks on the rear, or longer forks up front (hard to find for this bike). Shortening the front forks will reduce trail even more than it is from the too-soft springs to begin with, and the handling gets quicker and "twitchier" as the result. This can become trouble on rough roads at high speeds, like here in the Rockies, or on other twisties.

[Alan F.]

@Hondaman would a 1/2" spacer beneath the fork damper, secured with a 1/2" longer bolt and new copper washer do that job?

[Andy2000531]

Thanks for the answer guys. I think forking out nearly 500 bucks per wheel (spokes and rim) from buchanan is not worth it.
I have reached out to a couple of wheel shops for spokes and rims so i can achieve 18x2.50 front and 18x3.0 rear wheels.
If anyone have a sugestion for a specific rim that has the correct hole pattern/angles, i'm all ears.

[jonda500]

Finding longer forks is actually very easy for this bike - just use 750 forks!
John

[HondaMan]

Finding longer forks is actually very easy for this bike - just use 750 forks!
John

You're right!

[HondaMan]

@Hondaman would a 1/2" spacer beneath the fork damper, secured with a 1/2" longer bolt and new copper washer do that job?

If I understand what you're mentioning, that would make the forks bottom out 1/2" sooner? The 500/550 already bottoms out often with payloads over 150 lbs. on rough roads. The least that should be done is to pack 1" spacers in the upper ends of the fork tubes to try to lift the fork tubes off the bottom of the fork dampers: this won't stop the problem, but will add a [small] amount of trail to the front to help cope with the loss of it from the smaller wheel.

[Alan F.]

@Hondaman would a 1/2" spacer beneath the fork damper, secured with a 1/2" longer bolt and new copper washer do that job?

If I understand what you're mentioning, that would make the forks bottom out 1/2" sooner? The 500/550 already bottoms out often with payloads over 150 lbs. on rough roads. The least that should be done is to pack 1" spacers in the upper ends of the fork tubes to try to lift the fork tubes off the bottom of the fork dampers: this won't stop the problem, but will add a [small] amount of trail to the front to help cope with the loss of it from the smaller wheel.

I'm saying add a 1/2" spacer beneath the "oil lock piece" and the inside bottom of the fork lower.

This will raise the forks, recovering the 1/2" of axle centerline height that was lost moving from a 19" rim to an 18" rim without changing anything else or costing very much.

[Andy2000531]

https://www.ebay.com/itm/186295657323

Do you guys think this rim will fit ? It is same hole number, but possibly wrong angles on the holes.

[seanbarney41]

@Hondaman would a 1/2" spacer beneath the fork damper, secured with a 1/2" longer bolt and new copper washer do that job?

If I understand what you're mentioning, that would make the forks bottom out 1/2" sooner? The 500/550 already bottoms out often with payloads over 150 lbs. on rough roads. The least that should be done is to pack 1" spacers in the upper ends of the fork tubes to try to lift the fork tubes off the bottom of the fork dampers: this won't stop the problem, but will add a [small] amount of trail to the front to help cope with the loss of it from the smaller wheel.

I'm saying add a 1/2" spacer beneath the "oil lock piece" and the inside bottom of the fork lower.

This will raise the forks, recovering the 1/2" of axle centerline height that was lost moving from a 19" rim to an 18" rim without changing anything else or costing very much.

no  it won't   

[Alan F.]

@Hondaman would a 1/2" spacer beneath the fork damper, secured with a 1/2" longer bolt and new copper washer do that job?

If I understand what you're mentioning, that would make the forks bottom out 1/2" sooner? The 500/550 already bottoms out often with payloads over 150 lbs. on rough roads. The least that should be done is to pack 1" spacers in the upper ends of the fork tubes to try to lift the fork tubes off the bottom of the fork dampers: this won't stop the problem, but will add a [small] amount of trail to the front to help cope with the loss of it from the smaller wheel.

I'm saying add a 1/2" spacer beneath the "oil lock piece" and the inside bottom of the fork lower.

This will raise the forks, recovering the 1/2" of axle centerline height that was lost moving from a 19" rim to an 18" rim without changing anything else or costing very much.

no  it won't

I agree, the only thing that'll restore 1/2" of front wheel radius subtracted is adding it back.

But wouldn't raising the damper 1/2" from the inside bottom of the fork lower cause the suspension to behave similarly to the way a 1/2" longer fork tube would? 

Ok, 1/2" of spring preload spacer would have to come out.

[seanbarney41]

Alan, think about it this way... with standard telescopic fork (and really, usd forks too) all of the travel has to fit inside he lower fork case, right?  If you take away half inch of the inside volume of the lower, that will do nothing to increase the extended length of the assembly.  It's only gonna use up 1/2" of the space that was available for travel.

err hmmm, I think I see how you are getting this idea and have confused myself.  Not going to the shop right now to tear down a bunch of stinky old forks to resolve this question.  ha ha  Anyway, that would be a really backwards way to extend the length of a fork, if it does work.

CB350/4 comes with 18" front wheel and the same (or really damn similar) hub.  Since you are going with wider rims, you can fix any twitchy geometry problems with tire aspect ratio...say 90 series in front and a 70 or 80 in back. It might take a few tries to get things truly dialed.  Hardly anyone rides these bikes enough to notice these subtle differences anyway...."ohh it's just for looks.  1970's japanese motorcycles all just handle bad..."

[MRieck]

I've run wider, 18" rims for almost 35 years on my 750. No problems at all. Use good components from Buchanan's and somebody that knows how to lace. Bigutah on the forum does very nice work.

[pekingduck]

Stock rim width is 1.85" wide on the front, 2.15" rear.  Wider tires really affect steering input/feel.  I'd stay with narrower rim and tire widths for the light feel, with a 100mm front tire, and a 110mm rear. 

While a 140mm wide tire is 30mm wider than a 110, the difference in the actual contact patch width is probably only a couple mm.

[seanbarney41]

I've run wider, 18" rims for almost 35 years on my 750. No problems at all. Use good components from Buchanan's and somebody that knows how to lace. Bigutah on the forum does very nice work.

Mike, I don't know if you have ridden a 500/550 much.  They turn MUCH quicker than any 750.  My first 750 had 550 forks on it.  I didn't know until I had a 550 to compare parts a couple years later.  With the shorter forks it would head shake scary on a bumpy downhill or decel.  I can remember a couple "moments" that were quite alarming. 

[Don R]

 The 500/550 triple tree offset is less than the 750's. My K2 750 "Rat Race" bike came with modified 500 triples in it (welded longer stem) I assume for road racing type riding.
 Random info, not a suggestion or anything.

[scottly]

The K7, K8, F2, and F3 750s had the same offset as the 500/550. (I don't know about the F0 and F1.)

[Deltarider]

[...]
I really like the look of 18-inch wheels for the front. If it’s not too much trouble, I’d like to go with that size.
[...]

Having read all the replies, I have made my conclusion. How about you?