This has got to be old stuff but........ My '66 Bomber is running 3.50x18 up front and 4.00x18 rear. The tires are 2008 issue, so I'm going to replace. I think originals are 3.25 and 3.50. Is the 4.00x18 too big for the rear rim that measures the same as the front rim?
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AD
Tire sizes??
- Thread starter Kasindy
- Start date
On the stock rims for a 450, a 4.00-18 for the rear is actually too large but it will work. Many 450 owners have used 4.00-18 on the rear because there are/were no 3.75-18s. A 3.50-18 on the front is only 1/4" larger and though it would make the steering feel a bit slower, it would work as well. The main issue is the footprint, when a slightly larger tire is used on stock rim width it causes the tread surface area intended to be fully touching the pavement a bit more rounded due to the sidewalls being sucked inward slightly because of the narrower rim width. I put the metric equivalent of a 4.00-18 on the rear of my 450 (100/90-18 = 3.94" wide) yet it looks a little smaller than the previous 4.00-18 that was on it. I have a 90/90-19 on the front, 100/90-18 on the rear and it handles wonderfully.
WintrSol
Veteran Member
So you know the math: A 100/90 gives a height of 3.54", with the greater width of 3.94", so similar rpm in gear and somewhat less clearance on the sides, and only a small increase in curvature. The 90/90, that AD uses, is only a 0.3" wider profile but almost the same height as the 3.25", so the speedo wouldn't be off that much more, while the extra width does affect turn in some. So, choose what is most easily available, with a good tread pattern. There are many more choices in metric sizes, if you can't find what you want in Imperial units. I run a 100/90 rear when I can't find a good 3.50" or even 4.00". A lot if those 'vintage' tread patterns look good in a show, but I like a better ride.
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Mydlyfkryzis
Supporting Member
I had a nifty chart showing what size tires go on what size rims. Ah Here:
Also this:
When I restored my CB360, I went up one width on the front and back. Even the stock size tires benefit from a wider rim. Stock used the minimum size. My CB360t handles better now with stock tires and wider rims than it did in 1979 with stock rims and tires. I
attribute the improvement to the better tire cross section and contact patch with the one size larger width rim.
Also this:
When I restored my CB360, I went up one width on the front and back. Even the stock size tires benefit from a wider rim. Stock used the minimum size. My CB360t handles better now with stock tires and wider rims than it did in 1979 with stock rims and tires. I
attribute the improvement to the better tire cross section and contact patch with the one size larger width rim.
bilbikek411
Veteran Member
subscribed
Mydlyfkryzis, That is a nifty chart and I will copy it. I briefly thought of wider rims just because (IMO) bigger tires look better. The original rims are in very good shape and decided to keep it factory correct. Metzler Block C was my choice because they offered a 3.25x18 front. It should be on the road soon.
Mydlyfkryzis
Supporting Member
The issue with the stock rims on most Honda's is that they are the minimum acceptable size and not the standard size for the tire. The profile of an inflated tire is affected by the width of the rim. The right size rim on the right size tire will make the tire behave as intended , usually giving the best grip and predictable handling. Since the rims/wheels on Honda are already small for the size/width tire, even going up one size on tires puts you outside optimum profile/handling for the wider tire. As I said, I went up one size on the wheel width and kept the stock size tires. It has improved handling. A wobble problem I had since 1979 went away, the bike feels more planted. If you go up a size on the tires, you need to go up at least one size on the rim for best results. Under or oversize tire/rim combinations will still hold air and roll, but the handling and traction will be less at least to some degree. These old Honda's were never the exemplar of great handling, so diminishing any aspect is not so great an idea. People will do it even it is detrimental (Ever see cars with those extreme camber setups?) but I like to make sure people are informed before doing something less than ideal. I always like improvements on handling and reliability, looks coming in a distant third.
bilbikek411
Veteran Member
Hi Richard,I certainly Do appreciate your reply;solid tire/rim size information.
I remember you have always helped people be aware of these valuable facts,for years on the forums.
thanks again,Bill
Mydlyfkryzis
Supporting Member
Trying to get back in the groove. I collect things (wife says "Hoarder") and as you are aware, as we gain years, we collect experience and hopefully some wisdom. Hopefully I can inform without drama, as this always seems to be the most productive. I believe this site was formed from the best minds on the internet that own or love these old bikes. I am happy to support that. I will always try to back up my information with data and facts, and I will try to be clear on what is opinion too. While many people learn from their mistakes, smarter people learn from other's mistakes. I made a few of them over the years (ask my wifeHi Richard,I certainly Do appreciate your reply;solid tire/rim size information.
I remember you have always helped people be aware of these valuable facts,for years on the forums.
thanks again,Bill
)and hopefully can guide some younger riders and let them avoid the mistake I made.
JustinF25
Well-known Member
What is an “affordable” way to purchase or build wider rims? I’ve reached out to a vendor and due to the 40 spoke rim on the 450, i think it was around $750 a rim to have them made. That was with me providing the hub.
ballbearian
Veteran Member
Probably a little over half that much to buy new alloy rims and tires for both wheels. Reuse the spokes and do it all yourself.
Mydlyfkryzis
Supporting Member
Google is your friend. A search for 40 spoke rims leads to a lot of Harley Specialty rims. Harleys are like BMW, they charge 4 times the value of the part. I did find this: Buchanan's . While not cheap, they do have a variety of rims that have no holes and will punch holes to order up to 40. Search around the site and look at the different brands. Then call. They are pretty knowledgeable about Honda's (The Owners Son has a CB350, I talked to him for my spokes). They can recommend a rim that fills your needs. They look to be about $200-300 each, but cheaper then $750. They may have a cancelled order, or something that may reduce cost. I am not sure the size on the CB450, but Buchanan's will have something that fits. Try finding other boikes other than Harley that have the 40 spoke rims and see if you can find something like MikesXS, they may have a less expensive alternative.
