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Discussion Starter #1
Hello all @ hondatwins!

I'm looking at getting some vintage style Coker Diamond tyres.

My question is which dimension tyres do I need to order and how big can I go on the standard 18" rear rim and 19" front rim without having to adjust anything.

Thanks :D

 

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Coker will tell you (as will any tire manufacturer) what rim sizes their tires should be run on.
a quick check of their site says they have two options for a rear tire which will fit your 18x1.80 rear rim their tire is 3.50 x 18

they do not make a tire that will fit your front rim...they make one tire that has the same numeric designation as your stock front tire (3.25 x 19) however Coker says the minimum width you should run this tire on is an 2.15 x 18.

so to answer your question directly, if you want to SAFELY run Coker tires you will need to lace up a wider front rim to run the smallest size they make

lots of people squeeze these tires onto skinny rims, you see them for sale on ebay all the time (just built 50 miles since built!) because they simply don't work and are dangerous to ride on.
 

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Discussion Starter #3
Coker will tell you (as will any tire manufacturer) what rim sizes their tires should be run on.
a quick check of their site says they have two options for a rear tire which will fit your 18x1.80 rear rim their tire is 3.50 x 18

they do not make a tire that will fit your front rim...they make one tire that has the same numeric designation as your stock front tire (3.25 x 19) however Coker says the minimum width you should run this tire on is an 2.15 x 18.


so to answer your question directly, if you want to SAFELY run Coker tires you will need to lace up a wider front rim to run the smallest size they make

lots of people squeeze these tires onto skinny rims, you see them for sale on ebay all the time (just built 50 miles since built!) because they simply don't work and are dangerous to ride on.
Thanks for the info! :) Is it then possible to buy an OEM rear rim and lace it with the front hub, then run the same front and rear (safely of course)? will that fit my forks correctly?

Something like this running 18" front and rear...

 

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that would work...you'd need to get a CB450 front wheel so you could use the spokes (for the 18" rim) and then get an extra 450 rear wheel so you could use the rim (the CB450 front rim is too narrow).

your tires would still be narrower than the one pictured. if you wanted to run something that big you'd need to get much wider rims. see how badly the tires are pinched in at the rim in your picture...not safe
 

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That *might* work, but the spokes would be a bit long. I don't know if you can shorten them the ~1/2 inch, and still have threads left. You may need to have custom spokes made, if you can't find them on the market.
 

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no...it will work just the way I described above, no question.

CB450 front spokes with CB/cl450 rear rim...only thing you are changing from the CB450 front wheel is the width of the rim...diameter is still 18". Spokes don't care how wide the rim is so long as the diameter is the same
 

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John is correct.... the spokes from an 18" front drum 450 wheel will fit the rear 18" rim perfectly.....
Surj is discussing replacing the 19" disc wheel with an appropriate 18" drum hub wheel.....Same tires on both....
Personally, IF I wanted to run the Coker's, (fortunately, I don't), I'd relace both wheels to 2.50 rims at the minimum........
 

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I guess I don't recall that they made the 450 with an 18" front wheel. All the data I have says 19", for both CB and CL.

EDIT: I found a page on the K0 that says 18" on the front. Just my faulty memory, I guess. He'd have to give up the disc brake, though, and the extra braking power that comes with it. Doesn't that also mean the forks will have to change, too?
 

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Discussion Starter #9 (Edited)
John is correct.... the spokes from an 18" front drum 450 wheel will fit the rear 18" rim perfectly.....
Surj is discussing replacing the 19" disc wheel with an appropriate 18" drum hub wheel.....Same tires on both....
Personally, IF I wanted to run the Coker's, (fortunately, I don't), I'd relace both wheels to 2.50 rims at the minimum........
Wow, Thanks for taking all the head work out of this for me. You guys never fail to impress me!

Apologies if I wasn't to clear with my initial question. 66Sprint is correct, I am looking at running an 18" rim with front drum hub, without any major adjustments.

I think I will run wider 2.50 rims at 18" which I hope would allow me to run the larger Coker tyres safely. My next qestions would be to confirm the 2.50 rims would fit the 450 K6 correctly (Though if 66Sprint says they do, I am willing to take it as absolute fact) and ask for any suggestions as to a correct fitting front hub.

Oh and to finally apologise to all the purests for selecting such a controversial tyre! I'm such a philistine! :)

Also considering Dunlop K180 and Continental TKC 80 tyres if anyone has an opinion as to whether these are better for the road?
 

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Do a google search for Dunlop K70's. Run the 4.00 or 3.50 in the back and the 3.25 or 3.50 up front.

I think they look great, and are about as good as you'll be able to do without having to buy different rims. I highly doubt you'll fit a K180 (dirt track) tire to your rims.
 

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I guess I don't recall that they made the 450 with an 18" front wheel. All the data I have says 19", for both CB and CL.

EDIT: I found a page on the K0 that says 18" on the front. Just my faulty memory, I guess. He'd have to give up the disc brake, though, and the extra braking power that comes with it. Doesn't that also mean the forks will have to change, too?
Not if he runs those overly large 4.00 tires pictured..... He'll get that 1/2"+ back in height
 

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Discussion Starter #12
Do a google search for Dunlop K70's. Run the 4.00 or 3.50 in the back and the 3.25 or 3.50 up front.

I think they look great, and are about as good as you'll be able to do without having to buy different rims. I highly doubt you'll fit a K180 (dirt track) tire to your rims.
Hi there sir!

I had been thinking of the K70s too actually, so thank you for the sizing advice (this is what I am after most, as I've never rebuilt a bike before). As I'm a bit of a sucker for brat styling, I'm looking to safely go as big as I can. I know this will definitely compromise the ride and handling, but as long as they are safe I will try to achieve the particular look I'm after.

Thanks again, I'll definitely be considering the K70s when I come to purchase this bikes first new pair of boots in 40 years!
 

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Wow, Thanks for taking all the head work out of this for me. You guys never fail to impress me!

Apologies if I wasn't to clear with my initial question. 66Sprint is correct, I am looking at running an 18" rim with front drum hub, without any major adjustments.

I think I will run wider 2.50 rims at 18" which I hope would allow me to run the larger Coker tyres safely. My next qestions would be to confirm the 2.50 rims would fit the 450 K6 correctly (Though if 66Sprint says they do, I am willing to take it as absolute fact) and ask for any suggestions as to a correct fitting front hub.

Oh and to finally apologise to all the purests for selecting such a controversial tyre! I'm such a philistine! :)

Also considering Dunlop K180 and Continental TKC 80 tyres if anyone has an opinion as to whether these are better for the road?
I don't believe you'll have much clearance, so a stock fender is probably not a possibility, although I would suggest an "exterior-loop" type fork brace to reinstate the "stiffening" of the forks......You WILL have to find a suitable brake drum (preferably from a 450 with an 18" wheel so the speedo drive gearing is correct), but the hub from any CL 450 would also work if you change the speedo drive unit to one from an 18" wheel and get spokes for the 18" rim.......Actually, a CB77 (305 Superhawk) front wheel would also work, and it only uses 36 spokes so is easier to find a rim for....(the 450 hub is 40 spokes)....
Either way, the wheel from which you obtain the drum will be expensive....(a couple hundred $) and you'll still have to get a rim and lace and true the wheel......

I have BOTH the CL450 drum assembly (no spokes) and the CB77 assembly with a new 36 spoke kit.....Phone me to discuss......540-525-5199....Steve
 

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Discussion Starter #15 (Edited)
I don't believe you'll have much clearance, so a stock fender is probably not a possibility, although I would suggest an "exterior-loop" type fork brace to reinstate the "stiffening" of the forks......You WILL have to find a suitable brake drum (preferably from a 450 with an 18" wheel so the speedo drive gearing is correct), but the hub from any CL 450 would also work if you change the speedo drive unit to one from an 18" wheel and get spokes for the 18" rim.......Actually, a CB77 (305 Superhawk) front wheel would also work, and it only uses 36 spokes so is easier to find a rim for....(the 450 hub is 40 spokes)....
Either way, the wheel from which you obtain the drum will be expensive....(a couple hundred $) and you'll still have to get a rim and lace and true the wheel......

I have BOTH the CL450 drum assembly (no spokes) and the CB77 assembly with a new 36 spoke kit.....Phone me to discuss......540-525-5199....Steve
Thank you kindly for the advice. I have to refurb the wheels anyway as the bike has sat for years. I was planning to run it with out the stock fenders too, so no probs there. I think the CB77 sounds like a good option for me, especially if a rim is easier to obtain. (Will I need a different brake master cylinder?)

The CB77 drum looks stunning, and I would like to take you up on your kind offer. Though please be advised beforehand that I am in the UK. Although I'm not too concerned about shipping fees, the last thing I would want to do is create any hassle for you regarding shipping if we were to sort something out.

If you don't see this as an issue, could you please PM me with what would be included and what you are after price wise.

Oh and advice on what else I would need to complete the front wheel build would be greatly appreciated too. I'm such a Newb! :)
 

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With a drum brake, you will NOT be using the front master cylinder.....It is a cable operated set-up......

I plan on visiting the UK later this summer....I wonder if I could just carry it along in my luggage ....PM me your phone number......
 

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With a drum brake, you will NOT be using the front master cylinder.....It is a cable operated set-up......

I plan on visiting the UK later this summer....I wonder if I could just carry it along in my luggage ....PM me your phone number......
Sent PM, hopefully it got through as it's not showing in my sent box :shock:
 

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Discussion Starter #19
No master cylinder would also clean up the look on the handle bars, and remove the large front brake cable junction mounted in the centre of the fork brace. That would then allow me to run a centrally mounted headlight (also on the bike pictured) so I could also remove the chrome headlight mounts too.

This option is getting better and better for me!

But apologies once again to the purests who will no doubt will be cringing after reading what I've just written :) I wont be chopping the frame, and I'll be keep all original parts, so you can sleep easy knowing it can be returned to its original state at any time! :)
 

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I guess I don't recall that they made the 450 with an 18" front wheel. All the data I have says 19", for both CB and CL.

EDIT: I found a page on the K0 that says 18" on the front. Just my faulty memory, I guess. He'd have to give up the disc brake, though, and the extra braking power that comes with it. Doesn't that also mean the forks will have to change, too?
The CB450 K0, K1 and K2 all used 18" drum brake front wheels. A well adjusted front drum brake is IMHO as good or better than the early stainless steel disc brakes.




no...it will work just the way I described above, no question.

CB450 front spokes with CB/cl450 rear rim...only thing you are changing from the CB450 front wheel is the width of the rim...diameter is still 18". Spokes don't care how wide the rim is so long as the diameter is the same
The spokes from a front 450 drum brake wheel is 3 to 5 mm shorter than the rear wheel spokes and also thinner. There is a risk that you don't get enough thread in the spoke nipples.

I did this the other way around, used rear wheel spokes for a drum brake 18" front wheel and I had to dremel off 3 to 5 mm off the spoke ends.
 
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