How large of a rear tire will fit a KZ650?

Does anyone know how large of a tire will fit a stock 79 KZ650 rear wheel? It currently has a 110/90/18 on it and I'd like to run something wider and taller, as it is now a cafe racer and the 18" wheel looks a little diminutive compared to the 19" stock front.

130/18 is probably as big as youll be able to squeeze into stock arm.

79cafe wrote:

...I'd like to run something wider and taller, as it is now a cafe racer and the 18" wheel looks a little diminutive compared to the 19" stock front.

Just an FYI:

As you go to progressively wider profiles, you actually get *less* tread on the pavement as you increase the lean angle because of the greater "to center" radius of the tire profile.

It's not a big deal if the tire is mostly for looks, but if big lean angles and showers of sparks are what you're after, going above a 120 might get you more than you're bargaining for...:woohoo:

Post edited by: Pterosaur, at: 2006/06/05 13:14

after thinking about the same thing, i drove to my shop to see what's on my other 2 bikes. my driver is a 110 also and the other b has a 130/90/18 on it and it fits fine. my d parts bike has a 140/90/16 on a mag but it looks like it shaved a little tread on the caliper arm. so i'm lookin for a 130 myself.

130 fits no trouble, mine had one, but i went to 190 with the zx conversion

I am running a 140 Dunlog GT501 on my stock 78 KZ650 SR.

Every brand of tire is a little different. The first problem is crowning on too large of tire for the rim as already mentioned. Otherwise the limiting factor is the stock chainguard. A 120/90-18 is the biggest that will usually fit and even they may slightly rub the chainguard. A 130 in some brands fit too, but will just be because the dimensions are slightly different for that brand or the tire is more crowned on the wheel vs other brands which is no advantage because you just ride on a V part of the tread and wear the center of the tire out. I've used 120/90-18 for yrs, went to 110/90-18 last time but I think 120/90 is still the best choice.

I have a swingarm in my storage with a mono shock and a 14in rim with a 185X14in nobby tire on it, I took it from a yamaha 125 dirt machine, not in great shape but OK, I doubt I will ever put it on anything as is, but it will take any tire I've see yet...as far as bigger tires on a KZ I don't prefer it

I'm running a Dunlop 130 on the rear of my 1978 KZ650 - I have about 1/4 clearance on each side of the swingarm.

I'm running a Dunlop 130 on the rear of my 1978 KZ650 - I have about 1/4 clearance on each side of the swingarm.

I'm running a Dunlop 130 on the rear of my 1978 KZ650 - I have about 1/4 clearance on each side of the swingarm.

lets see here 1/4+1/4+1/4=3/4" that must be one hell of a swingarm ya got!:S