GPZ 750/550 replacing rims

First Post
Hi all,
I 'd like to replace the rims on my 2 bikes a 85 gpz 550 & gpz 750.  Will the rims off a Ninja zx7r fit my bikes?   Is this going to be moderately easy job or a royal pain?
I'm thinking I'll use a 200/50-60/17 rear and a 120/70/17 front tire.  Will the bike's handling  be any better or worse?

thanks

of course this is a wish list project at this point, i need to take measurements before buying parts.  just want to chat with others who have done this and how their experience was
 

toddbailey wrote:

First Post
Hi all,
I 'd like to replace the rims on my 2 bikes a 85 gpz 550 & gpz 750.  Will the rims off a Ninja zx7r fit my bikes?   Is this going to be moderately easy job - NO  or a royal pain? YES
I'm thinking I'll use a 200/50-60/17 rear and a 120/70/17 front tire.  Will the bike's handling  be any better or worse?

thanks

I would suggest you look at a lot of the "project" threads ref what you are talking about. You would need to "re-engineer" the bike with different front end, swingarm, offset gearbox sprocket and even then I would think a 180 rear would be your limit on the 750 (smaller on the 550) with both you may have frame to chain clearance issues etc to overcome !!!!! remember the catchphrase "if it was easy everyone would be doing it"

Good point,  maybe a 150x17 rear. might be the easier choice, the zx7r uses a 6 inch rear rim so it might be too much for the bike and a 150 tire
 

There are at least a hundred variables. The wider you go, the more complicated it gets. Using the suspension, brakes and wheels from a donor bike, can reduce the number of headaches, but you will still have to fit the new parts to your frame. 

And that is why I was asking if anyone has done this before.
As fas as tire sizes go I plans to stick with the oem sizes, but maybe go with a slightly larger rear, pretty sure the swing arm will be a issue if I try to go much larger than the stock size.
 

Here's a write up for the 750    ZX6R rear wheel swap, by Mik B - 750turbo.com

riturbo wrote:

Here's a write up for the 750    ZX6R rear wheel swap, by Mik B - 750turbo.com

need to register to gain access. is it a long writeup? too long to post here? thanks.

To the op. the smaller diameter wheels should give quicker steering. but there are drawbacks. less stable at speed. less ground clearance. possibly a harsher ride; less sidewall to absorb road imperfections. another consideration. the smaller wheel uses a smaller speedo drive gear. so for a more accurate speedometer. either swap gears or use the ZX7 speedo drive gearbox. strangely. the zx550 has a 25T speedo drive gear. while the zx750 has a 26T. same size wheels and tires but different speedo gears? strange. the 93 zx7r is a 24T.

H1Vindicator wrote:

the smaller wheel uses a smaller speedo drive gear. so for a more accurate speedometer. either swap gears or use the ZX7 speedo drive gearbox. strangely. the zx550 has a 25T speedo drive gear. while the zx750 has a 26T. same size wheels and tires but different speedo gears? strange. the 93 zx7r is a 24T.

Sorry if this derails the thread too much, but what is the effect of using a speedo drive with a different tooth count? Like say you go up one tooth, does the speedometer now read higher or lower?
All of the aftermarket gauges just say that Kawasakis use a “2240:60” ratio, so I always assumed that every speedo drive was setup the same. Had no idea they came with different tooth counts.

Stereordinary wrote:

H1Vindicator wrote:

the smaller wheel uses a smaller speedo drive gear. so for a more accurate speedometer. either swap gears or use the ZX7 speedo drive gearbox. strangely. the zx550 has a 25T speedo drive gear. while the zx750 has a 26T. same size wheels and tires but different speedo gears? strange. the 93 zx7r is a 24T.

Sorry if this derails the thread too much, but what is the effect of using a speedo drive with a different tooth count? Like say you go up one tooth, does the speedometer now read higher or lower?
All of the aftermarket gauges just say that Kawasakis use a “2240:60” ratio, so I always assumed that every speedo drive was setup the same. Had no idea they came with different tooth counts.

I would question whether there is a decimal point missing in quoted ratio (37.333:1 would mean a 925 tooth gear in the speedo - even by the time it went through a bevel gear the gear wheel would be huge !!) the ration between the wheel and the speedo is determined by the expected "distance travelled" for one revolution of the wheel, so a wheel with a smaller "rolling radius" would travel less distance for one revolution so would read "high" as the speedo would expect you to have travelled a greater distance against time. With a smaller wheel you would need to spin the cable slower

H1Vindicator wrote:

riturbo wrote:

Here's a write up for the 750    ZX6R rear wheel swap, by Mik B - 750turbo.com

need to register to gain access. is it a long writeup? too long to post here? thanks.

To the op. the smaller diameter wheels should give quicker steering. but there are drawbacks. less stable at speed. less ground clearance. possibly a harsher ride; less sidewall to absorb road imperfections. another consideration. the smaller wheel uses a smaller speedo drive gear. so for a more accurate speedometer. either swap gears or use the ZX7 speedo drive gearbox. strangely. the zx550 has a 25T speedo drive gear. while the zx750 has a 26T. same size wheels and tires but different speedo gears? strange. the 93 zx7r is a 24T.







Mik b on the turbo site wrote this   


This applies to the 5” ZX6R Rear wheel and using a 170/60x17 Macadam 90X tyre.

No need to machine any part of the wheel itself, all machining is done to the sprocket carrier, eccentrics and spacers. With the wheel installed centrally I had 11mm chain line run out which I overcame by using a ZX750A front sprocket which is 6mm offset and got the other 5mm from the sprocket carrier.

Spacers
The sprocket side Spacer needs to be 6mm wide, the Disc side is 42mm overall between the s/arm and the Bearing .Keep in mind the caliper mounting arm which will have to be accounted for within this 42mm dimension.

Sprocket carrier
You will need to remove the seal and machine the outer face back to within about 2mm from the bearing circlip; it will have to be able to clear the swinging arm when the 6mm spacer is in place.
The bearing is a stock 6205, best bet here as the seal wont fit now is to get a bearing with either a shield or seal built in.
The sprocket mounting faces need to be machined down by 5mm, when added to the 6mm offset sprocket achieves the 11mm to get the chain inline.
I removed the M10 studs and used ordinary M10X1.5 bolts to mount the sprocket, the studs have a fine 1.25 pitch threads for the nuts but 1.5mm pitch in the carrier so stock bolts will fit.

Eccentric adjusters
These will need to be bored out to take a 20mm spindle.

Torque arm
A flat torque arm will have to be made as the tubular one will rub the tyre! I used 25x6 stainless flat bar and drilled lots of holes in to lighten it.

530 or 630?
Hmm that old chestnut!...well simple really the 630 will fit but will rub the inner face of the air filter housing! 
 

Wookie58 wrote: I would question whether there is a decimal point missing..., so a wheel with a smaller "rolling radius" would travel less distance for one revolution...

Thanks Wookie, that sort of clears it up, but I have follow up questions. I'll ask them in my own thread where the issue may apply.