Gsx750fm kat ratt

[H3l1x]

I'm looking to spred the frame to accept an oversized and extended swingarm. 200-220mm. Any thoughts, criticisms, or quandries?
I have a few tricks up my sleeve but information is power!!!

[scottynoface]

You want to mess with the frame to put a bigger swingarm on? I don't get it.

[gobigorange189]

You want to mess with the frame to put a bigger swingarm on? I don't get it.

i think he may mean spread the swingarm??

[Kreylyn]

I'm looking to spred the frame to accept an oversized and extended swingarm. 200-220mm. Any thoughts, criticisms, or quandries?
I have a few tricks up my sleeve but information is power!!!

What swingarm, off another bike or from scratch?

What would the purpose of spredding the frame be for?

Initial thoughts... alot of work for no real gain unless your answers are pointing towards something extreme for the entire bike. If your looking at just wanting a swingarm stretched and widened, you don't need to mess with the frame at all. There are many, many options without changing the frame.

Krey

[H3l1x]

Chain clearance

Well, as I examined the stock configuration it would appear to me that in order to place a 200 or possibly 220mm tire on the bike, that the chain alignment would be moved and the frame would interfere.
Are there work arounds for that? I've been trying to research this for a couple weeks and haven't had any luck, hense I bow to the Katana Gods!

[Kreylyn]

Well, as I examined the stock configuration it would appear to me that in order to place a 200 or possibly 220mm tire on the bike, that the chain alignment would be moved and the frame would interfere.
Are there work arounds for that? I've been trying to research this for a couple weeks and haven't had any luck, hense I bow to the Katana Gods!

I'm not so sure your going to run into frame issues if your top tire size is 220.

First, let me show you what chain clearance is using a 180 tire mounted on a 5.5 rim mounted on a 93 Kat 750.



From this you can see there is still a bit of room between the chain and the frame. You could easily offset the front sprocket by 5mm out and clear just fine.

Unless your going custom wheels, the max size suzuki wheel I know of is 6" rims, and those you can squeaze in a 220 tops I believe. It's going to pull that tire in a bit though, so I don't think your going to have a full 220mm cross to worry about.

But, lets look at the measurements your dealing with.

First, the rim size. The tires stick out quite a bit more than the rims. Your looking at only .5" difference, and that is split between center, so 1/2" or about 13mm. I don't think just upping the size of the rim is going to have much of a difference from what you see pictured with a 5.5 rim. So primarily I'm going to focus on the avg tire sizes and differences.

Pictured is a 180 sized conti-force tire (assuming it actually is a full 180 across straight edge to edge, I measure it at around 177mm) and you want to run 220 max.

220-180= 40mm difference. Split that on either side of center, so you have 40/2= 20 mm difference chain side.

Measuring my setup as is right now, I have aproximately 20mm clearance between the chain and tire edge with no offset of the chain. Since the chain is to one side, any offset will be for the full amount. As mentioned, easily could do 5mm out giving plenty of clearance between the chain and tire edge. Again, this is assuming a 220 tire is actually going to be a full 220 across, and not pulled in by the 6" rim (which I think is what will happen).

My bet would be you could do 220/50 or 220/55 on a 6" suzuki rim without offsetting the chain, but with tight clearances. Add a 5mm offest sprocket on the front, and your golden. Run just a 200 tire, and I have no question it will fit just fine.

You will have more issues with swingarm and brake arm clearances to deal with than chain I feel. One thing I will suggest on that, if you modifiy the Kat arms like I did, you know you have no fitment issues for the suspension linkage, frame, or subframe. If you didn't notice, check my signature for a walkthru on what I did to widen my arm and fit the 5.5" rim.

Krey