Topic: 17 in. wheels on CB 750

[6adan]

I have been thinking about this and  wondering if it will work. I have a 17 in. aluminum rear wheel from a 750A that I am planning to use on my new e bay project. I also have a 17 in. rear from a 77 Goldwing and am thinking of lacing it to the front. I will probably use a 120 on the front and a 130 on the back. I need some thoughts on this, the good or the bad. any info would be great.
Thank Dannie

[Alan F.]

it's been done http://forums.sohc4.net/index.php?topic=50756.0
he hasn't answered any pm's from me though so I don't know if it rode well or not.

I understand MCRider is going with 17's also http://forums.sohc4.net/index.php?topic=36459.0

and I'm going with 17's but I'm one of those modern wheel types...and I won't be riding that one until spring.

-Alan

[Retro Rocket]

I am putting 17's on mine as well, can't really see any problems apart from added stress to the frame and swingarm but i am having the frame braced and i will also be using a much stronger swingarm..

Mick

[simon#42]

im sticking a 17 front in mine but am leaving the rear 18 . trying to get it to turn a bit sharper and it will  give me a much better choice of tyre .  anyone suggest a speedo drive that will work?

[MCRider]

I am putting 17's on mine as well, can't really see any problems apart from added stress to the frame and swingarm but i am having the frame braced and i will also be using a much stronger swingarm..

Mick

We will lose some ground clearance. I got +2" tubes to adjust the front. Longer shocks are easier. Many aftermarket shocks are a bit longer than stock anyway.

I'm anticipating new sidestand and centerstand as well.

[Retro Rocket]

im sticking a 17 front in mine but am leaving the rear 18 . trying to get it to turn a bit sharper and it will  give me a much better choice of tyre .  anyone suggest a speedo drive that will work?

I am going to use the 1100 Suzuki speedo and electronic tacho because i am using the whole GSXR1100 front end as well as the wheel.

I am putting 17's on mine as well, can't really see any problems apart from added stress to the frame and swingarm but i am having the frame braced and i will also be using a much stronger swingarm..

Mick

We will lose some ground clearance. I got +2" tubes to adjust the front. Longer shocks are easier. Many aftermarket shocks are a bit longer than stock anyway.

I'm anticipating new sidestand and centerstand as well.

Hi MC, i have had the internals and tubes in the front end lengthened 2 inches to give me some scope for adjustment as well and already have slightly longer shocks, i also have a mate who is a bike suspension guru and he will set it up properly for me....

Mick

[MCRider]

Mick: Cool!

I will use an inline converter for my speedo cable, or I've been told the internal on the speedo can be modified for the difference, a speedo shop told me.

If it were a scratch bike there are really cool digital modules available with builtin stop watches, weather vanes, divining rods and all sorts of accessories.

I'm mostly worried about my brakes having clearance. I'll know soon.

[Terry in Australia]

One member here who hasn't been around for awhile, Evil Don, built a really nice "highway tourer" running 16 inch hog front and rear rims with "old school" style tires with fairly high profiles and "white walls", and I've gotta say they looked pretty good, although you'd be limited to "rear tire only" tire choices.

The biggest problem aesthetically with installing smaller wheels is the fact that they don't "fill" the gaps like the OEM items. When I first installed the 16" hog wheel on the back of my K1, the gap between the seat and the wheel made it look like a dirt bike, and wasn't fixed until I installed shock lowering blocks.

Similarly, some thought needs to go into how to fix the gap between the front wheel and front fender, keeping in mind that you'll need to run a wider fender to suit the wider front tire. If you're running a complete front end like Mick, that's not an issue, but it is if you're going to "mix and match" various parts to make it work. Cheers, Terry.

[MCRider]

One member here who hasn't been around for awhile, Evil Don, built a really nice "highway tourer" running 16 inch hog front and rear rims with "old school" style tires with fairly high profiles and "white walls", and I've gotta say they looked pretty good, although you'd be limited to "rear tire only" tire choices.

The biggest problem aesthetically with installing smaller wheels is the fact that they don't "fill" the gaps like the OEM items. When I first installed the 16" hog wheel on the back of my K1, the gap between the seat and the wheel made it look like a dirt bike, and wasn't fixed until I installed shock lowering blocks.

Similarly, some thought needs to go into how to fix the gap between the front wheel and front fender, keeping in mind that you'll need to run a wider fender to suit the wider front tire. If you're running a complete front end like Mick, that's not an issue, but it is if you're going to "mix and match" various parts to make it work. Cheers, Terry.

I noticed that on my rear 17" with a 70 series tire. Lots of air. I'm using a K0 rear fender which has slightly less length, but still...

The front, I've got a ZL900 fender which was for an 18", is short and wide, (maybe too wide) and looks like it will serve. I'm using a 110/80 on front so far

[Retro Rocket]

Just wondering what change these wheels will have to the drive train ratios, should we go down a tooth or two on the back?

Mick

[MCRider]

Just wondering what change these wheels will have to the drive train ratios, should we go down a tooth or two on the back?

Mick

I've posted links to several calculators but they elude me at the moment. I ran a 17/48 with a 120/80/18 tire. I loved that, for brisk performance and spirited touring. TO maintain that with a 140/70-17 I calculated 18/48 put me within a few 10ths of the same ratio. With a /80 it was dead on IIRC.

The 140/70-17 with the 17/48 rougghly equaled a 16/48 with the 18" tire. THat's a drag racing setup for some, though many prefer the 15/48.

If you drop the rear you'd go to a 46 which is not easily available and much more expensive than going up one on the front. Going to the more commonly available 45 on the rear, is too far for me.

Much easier to jump the front from 17 to 18 and back again. Doesn't require any change to the chain or much wheelbase change.

[Retro Rocket]

Thanks MC, i would much rather go up one tooth at the front anyway. I will be using a 150 - 160 on the back and a 120 on the front.

Cheers     Mick

[MCRider]

Thanks MC, i would much rather go up one tooth at the front anyway. I will be using a 150 - 160 on the back and a 120 on the front.

Cheers     Mick

By my calculations a 160 will hit the brake stay arm. I had my arm mount moved out in case I want to go that wide.

Otherwise... party on Garth!

[Retro Rocket]

No probs with the brakes mate as i am using the GSXR discs and modified gsxr swingarm, shortened and braced with the mono shock removed on the back as well....


Mick

[MCRider]

Now that's kewl!

[Retro Rocket]

Now that's kewl!

You think it will be strong enough....     Its probably overkill but it sure looks cool...

Mick

[Terry in Australia]

Hey Mick, how are you going to go about chain clearance? My chain just clears the 150 rear tyre on my K1, are you going to offset the rear sprocket? Cheers, Terry.

[Retro Rocket]

Hi Terry, the gsxr wheel sits the rear sprocket further out than the Honda one, i will have to use one of cycleX's offset front sprockets to get the chain close and maybe i might have to shave a little of the rear sprocket carrier to get it all lined up. The slick thats on it at the moment is a 160 and it just clears now and that carrier has already been machined down, i tried to get it as close as i could by just machining the rear carrier but it still doesn't line up, hence the offset front sprocket. It will all be tight but will fit in just...
I have another stock Suzuki carrier to use so i was just experimenting with the one that currently on it.


Mick

[Terry in Australia]

Sorry Mick, I meant "are you going to offset the front sprocket, but you knew what I meant. Cheers, Terry.

[Retro Rocket]

Sorry Mick, I meant "are you going to offset the front sprocket, but you knew what I meant. Cheers, Terry.

Yeah, after a short scratch of the head i figured it out.....

Mick

[754]

retro. If you welded them shock mounts on the arm, they may be a bit soft, from the welding, if not re heat treated..

 If anyone wants to build a Honda with a wire 16 on the front, I found a cool rim.. it is off a Honda 400 I think with a belt drive, and has the same profile as a 77/78 750 K. It had a 120 on it and does not look like a hog rim..
 They must make 16 in front street rubber as I have a couple japanese sportbike wheels that are 16 inch.

[Terry in Australia]

Yeah you're right Frank, in the early 1980's just about everyone dabbled with 18cinch rear and 16 inch front wheels but they realised that it was a dumb idea and moved up to 17 inch wheels front and back, but nowadays 16 inch front tires are virtually impossible to find because there's no market for them.

I did an internet search and I did find one 16 inch front tire from Cheng Shin, and while I've only had CS tires on a CB750 once (and actually thought that they were OK) I couldn't find any 16 inch front tires from the better quality tire manufacturers. Cheers, Terry.    

[Retro Rocket]

Yeah you're right Frank, in the early 1980's just about everyone dabbled with 18cinch rear and 16 inch front wheels but they realised that it was a dumb idea and moved up to 17 inch wheels front and back, but nowadays 16 inch front tires are virtually impossible to find because there's no market for them.

I did an internet search and I did find one 16 inch front tire from Cheng Shin, and while I've only had CS tires on a CB750 once (and actually thought that they were OK) I couldn't find any 16 inch front tires from the better quality tire manufacturers. Cheers, Terry.  

Hi Guys, i had a mate that was a very successful racer and raced a GPX-750 Kawasaki in the 80's with the 16 inch front. Back then you could get plenty of front 16 inch tyres but Greg ran comp K metzler 16 inch rear tyre reversed on the front and it was also a 130, everyone said it wouldn't work but he was just about untouchable on that bike and won many races and titles including his section of the Castrol 6 hour endurance race, i bought the bike and registered it on the street and left the tyres exactly the same way he had them and man that thing handled like a dream. I also let another racer mate ride it on the road and he said it was one of the best handling bikes he had ever ridden, he was racing a FZR1000 Yamaha at the time. I have an old frame at home that i am going to make a bobber with and will be using 16 inch wheels front and back..

Mick

[754]

 Yup, I was actually thinking bobber, but this thread was more on sportbike use..

 The cool thing is it would be Honda rim, could mate with a matching 17 rear, or a conventional 16 rear.. at least the front would not look HD in the rim dept and may fit into stock forks... altho I have a WideGlide, I could use with a the non HD style 16" rim, just to be different..

[Yoshi823]

With the extra traction afforded by the 17" choice of rubber that you put on the bikes nowadays,I would suggest bracing an older steel frame in several places first.
When I modified my 750F2 frame I placed a horizontal tube across the frame where the frame tubes bend from the rear tank mount down to the swing-arm pivot.I then brazed in fillets of tube to stop the frame twisting here.
I also inserted a bracing tube across the front down tubes just above the front engine mount points.
Also,where the tubes come down from the rear tank mount into a 'V',below where the oil tank and electrical bits are,I placed a tubular fillet at the bottom of the 'V'.
When I cut out the cross member for the centrestand, I brazed in a piece of 531 tube to replace this.

I fitted replacement wheels in the same sizes as a 1988 GSXR1100J ie.a 110x18" Metzeler CompK Me33 with a 140x18 CompK ME1 on the rear.The standard F2 swingarm was modified using phosphor bronze bushes only.