4.5 Inch Rear Rim

[drc]

Hello All.

I’m putting together a RZ350 for a local vintage racing series. Just started into it again after Christmas so I machined down a FZ600 arm over the weekend and will pick the frame up from Powder today after doing a lot of bracing.


They changed the rules and I’m now allowed to run 17” rims which is great as there is a much better selection of tires.   


I was thinking about fitting a 110/140 back and front, but I spoke to the track side tire guy at the bike show at the weekend and he said think about fitting a 4.5 inch in the rear as he has a much better selection in 160’s from Dunlop, Michelin and Pirelli.


I’m still leaning towards the 140 but was wondering if there was a 4.5” rim that was an easy swap for the FZ arm. Bear in mind I’m in Canada so the choice locally will be fairly limited but could grab something from the UK on eBay


Thanks

[midlifecrisisrd]

Think you are right sticking to 140, turns a lot better

160 is a struggle for chain run

Just fitted a tdr hub in an fz arm with a 17 inch rim

The fz arm is still quite narrow so the hub width is the biggest issue

A 140 will go on a 17 x 4 or even a 3.5

Also the fz arm is a 17mm spindle so I've had to sleeve the adjusters for the 15mm spindle on the early tzr/3xc rear wheels

I do have an early xjr400 rear wheel which is 17mm spindle and 17x4 but I'd have to check if it would go in an fz arm

I'm fitting it in an fzr arm

If I get time I'll try and find the sprocket carrier and see how wide it is

FYI the later xjr400 wheel is 20mm axle

Steve

[midlifecrisisrd]

If you are not bothered about it being yam you can use a bandit 400 wheel (4) (not sure on spindle size), gsxr 400 gk76 (4.5) (20mm spindle)

Steve

[jon]

So what size tyre is supposed to go on a 4.5 rim?

Will a 140 go on this rim size?

Jon

[midlifecrisisrd]

Just checked and the xjr wheel with the sprocket and brake caliper bracket is slightly wider than the fz arm

I would hope with a bit of machining it would go

Steve

[midlifecrisisrd]

Jan 20, 2020 19:14:16 GMT 1 jon said:

So what size tyre is supposed to go on a 4.5 rim?

Will a 140 go on this rim size?

Jon

140mm is 5.5 inches so it should go

Gsxr 400 has a 4.5 rim with a 160

Rgv 250 has 4.5 rim with a 150

Gsf 400 has a 4.0 rim with a 150

Gs 500 has a 3.5 rim with a 130

Steve

[jon]

What would you pair them with on the front?

Jon

[midlifecrisisrd]

Jan 20, 2020 19:35:50 GMT 1 jon said:

What would you pair them with on the front?

Jon

130/140/150 I'd go 110/70

160 (150 if you wanted) I'd go 120

The 130 on something lightweight bike could go 100/80. Used that set up on my supermoto

Steve

[drc]

Thanks all. This site is a wealth of information.

I'm going to run an FZR600 front end so it will have a 17x3 rim that should be fine for a 110/70.

I think there is some good advice above and good reasons to stick with the 140.

GS500 and 400 Bandit wheels are plentyfull and cheap and it looks like they both have a 17mm axle. From what I can find the GS500 swing-arm is ~216mm at the axle ( I'll need to confirm) and I just measured the FZ and its ~220mm so it should be a relatively easy install, and the caliper mounts above the wheel the same as the FZ.

The Bandit sprocket carrier looks a lot wider though, maybe a GS500 carrier would fit. The caliper also mounts underneath but it would be easy to put a bracket for a torque arm on the underside of the swing arm.

The 4" rim is probably a little better for the 140, but a 3.5 is also specified as an alternative. It seems like Pirelli would be the best tire choice in this case as they make 140's in Slicks, Wets, Rains and Supercorsa's and seems to be the race tires most commonly used 250 and 300 ninja's with the 3.5" rear.

[midlifecrisisrd]

The caliper mount should be easy

I've got the tdr hub In the fz arm and an xjr in an fzr arm

I checked the disc sizes of fzr's, fz's and rd 500 to find which was the same diameter disc then used ones that fitted

Steve

[drc]

Thanks for everyone's help on this.

Ended up going with a 400 Bandit rim. I picked it and the sprocket carrier up this afternoon from a local breakers.

The sprocket carrier looks wide, but the actual hub is quite narrow. I compared it to a GS500 wheel and the actual hub is much wider with a narrower sprocket carrier

I just held it between the swingarm and I think it should fit with some machining and spacers. It will be interesting to see how the chain lines up

[midlifecrisisrd]

If you look at the sprocket carrier bearing it has an oil seal about 5-6mm thick

If you use a sealed bearing you can omit it and machine that bit off

As for chain alignment there is a lot of meat you can remove. Up to 10mm is possible

Also the gs carrier has less sprocket offset but it may end up with a chain run that hits the tyre

The gs carrier should fit the bandit wheel

Steve

[drc]

Thanks Steve. This is great information