Topic: 18" wheel options for 1978 CB750 K8

[Buster68]

I only recently realized (with dismay) that Honda switched to a 17" rear wheel for the '77-"78 CB750K's, so I won't be able to go with the Dunlop K70 that I wanted to for the rear. Plus, now all I can see when I look at the bike is the "fatter" rear wheel.

I was planning on rebuilding both the wheels and powdercoating the rims anyway, so if I wanted to change to an 18" rear I assume the easiest option would be to buy an 18" rim when I rebuild, figure out the spoke length needed to match it to the stock hub (I have heard Buchanan's are really helpful for stuff like this), and then go from there. Is there any reason that a relaced 18" matched to the stock hub wouldn't fit a K8?

Alternatively, would an earlier CB750K 18" wheel fit the bike? Has anyone done anything like this? I did a search but couldn't find anything. I understand that the swingarm is different on the '77/'78's, so I am not sure if there might be axle issues.

[Don R]

The earlier wheel can be swapped if you keep the cush drive on the same bike. I'd expect someone to make you a swap offer. some guys like the wide 17" wheels. 

I did an  engine swap and used an earlier engine in a 77 frame. The early cush drive worked to line up the chain.

[madmtnmotors]

The earlier wheel can be swapped if you keep the cush drive on the same bike.

+1

I swap between 17" and 18" on my K8 without issue. Just use the K8 sprocket carrier and axle hardware (i.e. spacers). The hubs are the same, it's the supporting hardware that changed.

[Buster68]

The earlier wheel can be swapped if you keep the cush drive on the same bike.

+1

I swap between 17" and 18" on my K8 without issue. Just use the K8 sprocket carrier and axle hardware (i.e. spacers). The hubs are the same, it's the supporting hardware that changed.

That's good to know. So I could either buy and 18" rim and lace it to my existing hub / brake, or if I can find an earlier CB wheel I could do that as long as I swap over the drive assembly - is that right? I guess if I am going to be relacing the wheel anyway, it will just come down to whether i can find a good condition earlier 18" wheel cheaper or faster than I can buy a new 18" rim

[lucky]

I only recently realized (with dismay) that Honda switched to a 17" rear wheel for the '77-"78 CB750K's, so I won't be able to go with the Dunlop K70 that I wanted to for the rear. Plus, now all I can see when I look at the bike is the "fatter" rear wheel.

I was planning on rebuilding both the wheels and powdercoating the rims anyway, so if I wanted to change to an 18" rear I assume the easiest option would be to buy an 18" rim when I rebuild, figure out the spoke length needed to match it to the stock hub (I have heard Buchanan's are really helpful for stuff like this), and then go from there. Is there any reason that a relaced 18" matched to the stock hub wouldn't fit a K8?

Alternatively, would an earlier CB750K 18" wheel fit the bike? Has anyone done anything like this? I did a search but couldn't find anything. I understand that the swingarm is different on the '77/'78's, so I am not sure if there might be axle issues.

 17 inch or 18 inch the outside diameter still ends up being almost the same.
You can get tires better than those 40 year old designed K70's.
Just use the Avon Road Rider 26 tires on the 17 inch wheels.

[754]

 Rim 150 or + ..spokes 70 or +
 Used wheel.....less than that..

[Buster68]

You can get tires better than those 40 year old designed K70's.
Just use the Avon Road Rider 26 tires on the 17 inch wheels.

You can also buy a "better" bike than a 40-year-old CB750. Using that logic we should all be driving Volvos.

I am always amazed when people ignore the question, and instead tell you how what you should or shouldn't do with your bike, based on their own preferences.

[Buster68]

Rim 150 or + ..spokes 70 or +
 Used wheel.....less than that..

Yeah, that's the way I am leaning (provided I can find one here in Canada, otherwise the shipping on a wheel from the States sharply shifts the economics of that argument).

The spokes from Buchanan's are considerably more than that too...

I envy you in Kelowna - some of the nicest riding in Canada right at your doorstep.

[zeech]

I just found an 18" rear and swapped the hub from the stock one (since it was different) and that worked out good.

K70s seem like a small tire for a 750... I have K70s on my 550 and they are good, but can't imagine them on a 750 personally. Just me. I wish they made a 5" and other options.

[Geeto67]

17 inch or 18 inch the outside diameter still ends up being almost the same.
You can get tires better than those 40 year old designed K70's.
Just use the Avon Road Rider 26 tires on the 17 inch wheels.

+1 the 17" rear rim has access to much better tires. the K70 is a pretty marginal tire but I am pretty sure you could ride up a wall with avon road riders. used to be able to get avon venoms for 18" wheels and talk about a superb tire.

I suspect you are using the k70 because you like the look of the tread and not because you have any real experience with the tire. I had a set on my GS750 and was not a fan, though they were better than the Cheng Shins that came with a bike I bought once. If it were me and I had to have an 18 inch rear I would go with metzlers.

so to answer your question - it isn't such a bad thing you have a 17" rear rim. If you were planning on relacing both wheels anyway then 18" aluminum rims are easily available (excel makes an excellent quality rim and it is in the race paddock) and you should probably replace the front with an 18" as well.

The cheap "racer" solution is to find a 17" rear alloy wheel off a 1976 CB750A hondamatic. That is a bolt on deal same as an older 18". If it were a choice between a 17" alloy and an 18" steel I would rather have the alloy. In fact I would rather have 17" alloy front and rear.

All modern sportbikes run with 17" rims. This means that the bulk of performance tires are in 17" rim sizes. while most might not be in your width it is still better than the "vintage" performance tires out there which are basically Avon roadriders, Metzler lazertecs, and bridgestone batlaxs. I don't consider the K70 a performance tire.

You can also buy a "better" bike than a 40-year-old CB750. Using that logic we should all be driving Volvos.

I am always amazed when people ignore the question, and instead tell you how what you should or shouldn't do with your bike, based on their own preference

What a terrible attitude. You know, when you obviously have no knoweldge or experence it pays not to be a dickburger to people who obviously have more of both than you. If people just answered your stupid questions and didn't try to give you valuable knowledge you wouldn't learn anything real. Most of the time those without experence don't even know what are the right questions to ask, or if the asked question gets them the most beneficial information.

[Buster68]

17 inch or 18 inch the outside diameter still ends up being almost the same.
You can get tires better than those 40 year old designed K70's.
Just use the Avon Road Rider 26 tires on the 17 inch wheels.

I suspect you are using the k70 because you like the look of the tread and not because you have any real experience with the tire. I had a set on my GS750 and was not a fan, though they were better than the Cheng Shins that came with a bike I bought once. If it were me and I had to have an 18 inch rear I would go with metzlers.
I don't consider the K70 a performance tire.

You can also buy a "better" bike than a 40-year-old CB750. Using that logic we should all be driving Volvos.

I am always amazed when people ignore the question, and instead tell you how what you should or shouldn't do with your bike, based on their own preference

What a terrible attitude. You know, when you obviously have no knoweldge or experence it pays not to be a dickburger to people who obviously have more of both than you. If people just answered your stupid questions and didn't try to give you valuable knowledge you wouldn't learn anything real. Most of the time those without experence don't even know what are the right questions to ask, or if the asked question gets them the most beneficial information.

I am sorry that my attitude disappoints you. But please don't mistake my low post count for a lack of experience with motorcycles, or with motorcycle forums. I have been running "vintage" style tires on my 1953 Harley panhead (and other bikes) for years, and yes, I know what they are like. It is something I choose to do, both because of the aesthetics, and because I don't find the performance that bad, especially on a bike that does not have the power or handling of a modern bike (and yes, I have lots of experience with modern bikes as well).  If I had had asked "what is a good performance tire for a CB750", then I would welcome advice such as the above. What I asked for was specific advice on switching from a 17" to an 18" on the CB750. But instead, I get people telling me what I should and shouldn't do in general, and get called a dickburger and told I obviously don't have any "knoweldge or experence" (sic).

[Roland]

Get any 70's 18" rear wheel and buy new spokes from www.vintagecb750.com (in Canada). They have the spoke sets for cheaper than anyone.  I too like the look of the 18" rear wheel best.

[Buster68]

Get any 70's 18" rear wheel and buy new spokes from www.vintagecb750.com (in Canada). They have the spoke sets for cheaper than anyone.  I too like the look of the 18" rear wheel best.

Thanks Roland - nice to know there is a Canadian supplier for CB750 parts. I ordered some stuff from Dime City (who were great to deal with), but the shipping and duty was a killer.

[Wobbly]

17 inch or 18 inch the outside diameter still ends up being almost the same.
You can get tires better than those 40 year old designed K70's.
Just use the Avon Road Rider 26 tires on the 17 inch wheels.

+1 the 17" rear rim has access to much better tires. the K70 is a pretty marginal tire but I am pretty sure you could ride up a wall with avon road riders. used to be able to get avon venoms for 18" wheels and talk about a superb tire.

I suspect you are using the k70 because you like the look of the tread and not because you have any real experience with the tire. I had a set on my GS750 and was not a fan, though they were better than the Cheng Shins that came with a bike I bought once. If it were me and I had to have an 18 inch rear I would go with metzlers.

so to answer your question - it isn't such a bad thing you have a 17" rear rim. If you were planning on relacing both wheels anyway then 18" aluminum rims are easily available (excel makes an excellent quality rim and it is in the race paddock) and you should probably replace the front with an 18" as well.

The cheap "racer" solution is to find a 17" rear alloy wheel off a 1976 CB750A hondamatic. That is a bolt on deal same as an older 18". If it were a choice between a 17" alloy and an 18" steel I would rather have the alloy. In fact I would rather have 17" alloy front and rear.

All modern sportbikes run with 17" rims. This means that the bulk of performance tires are in 17" rim sizes. while most might not be in your width it is still better than the "vintage" performance tires out there which are basically Avon roadriders, Metzler lazertecs, and bridgestone batlaxs. I don't consider the K70 a performance tire.

You can also buy a "better" bike than a 40-year-old CB750. Using that logic we should all be driving Volvos.

I am always amazed when people ignore the question, and instead tell you how what you should or shouldn't do with your bike, based on their own preference

What a terrible attitude. You know, when you obviously have no knoweldge or experence it pays not to be a dickburger to people who obviously have more of both than you. If people just answered your stupid questions and didn't try to give you valuable knowledge you wouldn't learn anything real. Most of the time those without experence don't even know what are the right questions to ask, or if the asked question gets them the most beneficial information.

You have to admit though: Only looking at the opening sentence of your thread, it initially sounds a little odd that you want to replace the wheel to fit the tire. Customarily, it is done the other way around. And since I already cruised off topic, I like to mention that the BATTLAX BT-45 is the best “performance” tire for that bike. Yes, only my opinion, but I arm-wrestle you for it.
P.S.: When all is done, post some pics for us. Thanks!

[Geeto67]

I am sorry that my attitude disappoints you. But please don't mistake my low post count for a lack of experience with motorcycles, or with motorcycle forums. I have been running "vintage" style tires on my 1953 Harley panhead (and other bikes) for years, and yes, I know what they are like. It is something I choose to do, both because of the aesthetics, and because I don't find the performance that bad, especially on a bike that does not have the power or handling of a modern bike (and yes, I have lots of experience with modern bikes as well).  If I had had asked "what is a good performance tire for a CB750", then I would welcome advice such as the above. What I asked for was specific advice on switching from a 17" to an 18" on the CB750. But instead, I get people telling me what I should and shouldn't do in general, and get called a dickburger and told I obviously don't have any "knoweldge or experence" (sic).

If you have so much exprience then act like it. Or at least act like you have manners. You can't control the universe, sometimes you ask a question and good helpful people are going to try and give you more information than you feel you need. Try not to be ungrateful, you should be so lucky someone wants to help you at all.....or have you forgotten the bad old days when it was hard to get any kind of question answered in person without a visit to a shop or a long rambling spiel by an "oldtimer", usually prefaced with a "wadda you want to do that for, you stupid or sumptin?"

I agree with wobbly, the Battlax is an excellent tire.

[Don R]

 I'm still surprised no one wanted to trade for the 17".  I predicted wrong.

[Bankerdanny]

See Geet, I think it's you and the others showing poor manners, not Buster. He asked a very straight forward question and said why he wanted to know.

He wants to use a particular tire to achieve a particular look, which is a perfectly legitimate reason and does not require comments from others to 'educate' him on 'superior' options.

Sometime people ask silly questions or propose cosmetic changes that can seriously compromise safety, and I have no problem asking them why or pointing that out. But changing from a 17" back to the older 18" size and wanting to run a K70 is neither of those things.

[Geeto67]

I'll have to remember that providing useful information to you is considered bad manners.

[Geeto67]

He wants to use a particular tire to achieve a particular look, which is a perfectly legitimate reason

clearly you and I have a different opinion on what consitutes a legitimate reason. I'll concede that it can be a consideration but it shouldn't be the only one.

At least we aren't talking about those crappy firestone repops. Then it would be a safety consideration.

[Bankerdanny]

Who named you chief of the style police?

And your suggestion was useful how? Did you think he didn't know that there were 17" tires available for his bike? Why would you think that? He didn't say he couldn't find 17" tires, he said he wanted to run a particular 18" tire. And the K70 might be a low performance tire by modern standards, but it has provided reliable every day performance on tens of thousands of bikes for decades. It is a perfectly reasonable choice that requires no second guessing from you or anyone else.

In this contect you answered a question that wasn't asked.

I'm not saying an answer like yours never has it's time and place. It absolutely does, I've done it myself.

I'm just saying in this particular case he explained in advance why he wanted to change to an 18" so telling him that  staying with 17" wheels offered better tire options WASN'T actually useful, it was presumptuous.

You seem to assume he didn't know better without having any reason to think that. That pissed him off, and I think his reaction is perfectly understandable, and his reply was firm, but not rude.

[Bankerdanny]

Geet, I am with you on the Firestones. They are the hipster equivalent of the 315mm monster tires on choppers. A look that makes yoour bike handle worse, not better.

[Black 750K8]

I only recently realized (with dismay) that Honda switched to a 17" rear wheel for the '77-"78 CB750K's, so I won't be able to go with the Dunlop K70 that I wanted to for the rear. Plus, now all I can see when I look at the bike is the "fatter" rear wheel.

I was planning on rebuilding both the wheels and powdercoating the rims anyway, so if I wanted to change to an 18" rear I assume the easiest option would be to buy an 18" rim when I rebuild, figure out the spoke length needed to match it to the stock hub (I have heard Buchanan's are really helpful for stuff like this), and then go from there. Is there any reason that a relaced 18" matched to the stock hub wouldn't fit a K8?

Alternatively, would an earlier CB750K 18" wheel fit the bike? Has anyone done anything like this? I did a search but couldn't find anything. I understand that the swingarm is different on the '77/'78's, so I am not sure if there might be axle issues.

Buster I have a 78 and thought about some of the same things I think you first thought would be the way to go just lace a 18" wheel now about Buchanan's some people have had issues with the spokes fitting just right you may want to think about sending your hub and let them lace it. There stuff is good I think you just have to force them a little something about the angle is not just right. I have not read this entire post so thought I would point out that the main thing about the  sprocket carrier is a 10mm offset so keep it so it will line up with the front sprocket.

EDIT
Here is a good pic from http://www.cyclexchange.net/index%20pics/picture%206.JPG that shows the different sprocket carriers. plus they have 10mm offset sprockets if your carrier is no good.

[Stoli]

... about Buchanan's some people have had issues with the spokes fitting just right you may want to think about sending your hub and let them lace it. There stuff is good I think you just have to force them a little something about the angle is not just right...

+1  Buchanan's quality is top notch (as are their prices) but I did have some problems with the angles on a set of custom rear spokes they made for me. They did make it right in the end, and it just cost me some extra time and shipping. They said there were some minor inconsistencies in the rear hubs of the 70s Hondas. Something about different thicknesses of the flange where the spoke holes are. Always best to send them a pair of original spokes from the hub if you can, even if you will be getting a different length. That way they have a template to work with. 

Buster - Don't get discouraged that your first thread went so sour.  Most of them stay civil. Geeto is full of good info and experience, he just can't seem to post a reply without insinuating that the rest of us are morons. As you come across the threads that he has posted in, you'll see what I mean. 

[Geeto67]

You seem to assume he didn't know better without having any reason to think that. That pissed him off, and I think his reaction is perfectly understandable, and his reply was firm, but not rude.

Well I have to assume something, this isn't like real life where you can size up someone and get a feel for how savy they are about stuff. I assume if that there is one question then there are 10 more questions behind it that the person hasn't asked yet and I try to anticipate those questions as well. I may take some liberties in assuming things based on the thought process illustrated in the question, but everybody does that. I personally tend to hold people who put form before function in lower regard because that is the world I come from - it works good first it looks good second. If that comes out in my answers, so be it - I am not going to change who I am because someone gets a little but hurt and complains about too much information, that's like complaining you have too much pu$$y.

I am a big fan of informed decision making, so to that end too much information is always better than not enough. If you put something out there on the internet you don't really get to have control over who replies and what they say. These aren't active conversations, you don't get to steer them where you want to go.

I just thought it was rude for buster to chastise anybody who was trying to be helpful to him even if he didn't feel the information was necessary to him specifically. It is selfish to think that a question exists on a public forum just for the purpose of the original poster - really it is here for anyone who has a similar question, any lurkers who want to read, and people who search the archive and find this days/months/years later looking for the same info. To that end, it is a benefit for the community as a whole to have as much info in one place surronding the subject. Sure it may not be helpful to buster but maybe it is helpful 6 mos later to "camaroguy12" (a made up name not meant to single anybody out) who finds the post while google searching the site. So to sum up....shut up, be grateful this place exists in the first place, that there are people who want to be helpful, and try to accept you are not the center of the universe.   

and now that we have filled this thread with useless pontification about who is rude and who isn't...I am going find something better to do.

[Buster68]

I'll have to remember that providing useful information to you is considered bad manners.

Hmmm....

What a terrible attitude. You know, when you obviously have no knoweldge or experence it pays not to be a dickburger to people who obviously have more of both than you. If people just answered your stupid questions and didn't try to give you valuable knowledge you wouldn't learn anything real. Most of the time those without experence don't even know what are the right questions to ask, or if the asked question gets them the most beneficial information.

Where I come from, calling someone you have never met a dickburger, and saying they obviously have no knowledge or experience (that is how those are spelled, by the way) is considered bad manners. In fact, in real life, it would normally get you more than just an internet chastising. But don't worry, there are self-righteous pricks like you on every forum - people that have to tell others what to do to show off their "knowledge", and then try to desperately justify it when they get called on it. I'm not letting it bother me at all. Some other members of the forum were very forthright and helpful in answering the question and providing useful information, and for that I am grateful.