Swinging arm thread.

[matt glascock]

A cool idea occurred to me after reading the recent rear suspension thread posted by Dal Aymond. I would be willing to donate a swinging arm if anyone with legit welding skills would be willing to extend and reinforce it properly. I'd even throw in a chain. Then, the kit could be passed around among club members interested in having their swinging arms extended so the modification could be trialed before modding their own swinging arms. Probably less important for street and light trailing as opposed to racing but at least people could check it out before committing to the mod. Let me know if there is any interest in putting this notion together

[MTrat]

Sounds like an obvious candidate for a Resonator article.

[matt glascock]

For sure. I have a pumped up toaster tank Super Rat that was nearly unraceable until I got the swinging arm extended. I couldn't keep the front wheel on the ground unless I was practically sitting on the tank. The extension really makes a difference.

[Dal Aymond]

I'd love to see a side by side comparison of a stock CW swingarm (or a Rat swingarm) and an extended one. I had heard of extending one inch, but not two inches. Maybe a pic of each of the three side by side. I could only imagine that a couple of inches longer swingarm would have to smooth out the ride and control some.

[Bullfrog]

Interesting project idea - but I think it would need to be somewhat model specific. As an example, that toaster tank Super Rat was produced with a 49.6" wheel base (which was significant part of the er, um, easy wheelie habits of the first Super Rats). Adding 2.4" to the swingarm would result in a new wheelbase of 52", and would tame the wheelie tendency by a bunch! But even this extended wheelbase Rat would be shorter than the 53" wheelbase of the Wombat and Combat Wombat . . . and a fair number of folks have extended Combats to get to 54" or 55" or even 56" wheelbase.

The concept of a "share-able" extended swing arm would likely have to focus on frame "families". The Ace era 100's could all accept the same test swing arm (I think). But that test swing arm wouldn't fit up right in the model 94/95/96 frame - so another custom swing arm would be needed to share amongst owners of those later models.

Ed

[Dal Aymond]

I just ran across a good article, on extending the swingarm, in the Resonator Volume 2 Number 20, by Max Good.

[dirty_rat]

Ed,

You are right about needing different swingarms for the early 100's (up to the last 92's and 93's) and the model 94 Wombat, model 95 Combat Wombat and model 96 Dirt Squirt. As noted, this is because of different frames.

But, you might also need two seperate swingarms from the early 100's as they used two different size rear axles. The early ones (before the cushioned rear hub came out) used 12mm rear axles. The later ones with the cushioned hubs used 15mm axles. The swingarms at the axle were also wider on the cushioned hub models. So, you would either need a 12mm axle swingarm and a 15mm axle swingarm, or go with the 15mm swingarm and use a wheel with the cushioned hub.

[matt glascock]

Just from memory, I know I have several of those and would be willing to donate them to the cause if there is any interest. I believe the test swinging arms would be of most value to those interested in setting up a bike for racing or at least more heavy-duty trailing. By my way of thinking, if I wreck spectacularly enough to roach a swinging arm, my riding days are likely to be over

[viclioce]

... By my way of thinking, if I wreck spectacularly enough to roach a swinging arm, my riding days are likely to be over

Wow Matt! I sure hope that never happens.

I’m about to unwrap my hand and get cleaned up. I’m less than an hour from the time they took me into surgery 4 days ago. It will be good to have the bandages off!!! Victor

[taber hodaka]

I have and use the extended swing arm on my old ace 90 it has 3 axle positions I can use. Quick change, quick align, and quick tension. ----------------- Clarence

[matt glascock]

Cool Clarence. It would be really groovie if you could post a picture of that swing arm. Sounds snazzy.

[Dal Aymond]

A cool idea occurred to me after reading the recent rear suspension thread posted by Dal Aymond. I would be willing to donate a swinging arm if anyone with legit welding skills would be willing to extend and reinforce it properly. I'd even throw in a chain. Then, the kit could be passed around among club members interested in having their swinging arms extended so the modification could be trialed before modding their own swinging arms. Probably less important for street and light trailing as opposed to racing but at least people could check it out before committing to the mod. Let me know if there is any interest in putting this notion together

Matt, I now have an "extra" Combat Wombat swingarm, that I would like to donate to this endeavor.

[Vintagenut]

Here is a pic of a nicely modified Ace 100 swing arm. Works well.

[matt glascock]

Excellent Dal. We're starting to get a decent collection. I just unearthed a blue swing arm which I hope came off a Super Combat or painted tank Rat. I don't think it is off an SL250. Now we need a craftsman-level welder and some input from a pro regarding the best length to add.

[Vintagenut]

I have a Swenco swingarm on my Super Rat. I will measure the length and post. I believe it is 1 inch longer.

[matt glascock]

Sweet bike. I have one of those Bassani pipes that will need a header mod. How do you like it on a 100cc motor? Mine was off a 250, but it is the same as what I can see in your picture. Cool bike, by the way.

[Vintagenut]

Tha Swenco swingarm is 1 1/2 inches longer.