Commando Swing Arm Travel

For a stock Norton Commando, what is the swing arm travel at the rear axle?

This is relative to the shock absorber. I am sure there are geometric limits and changes in handling characteristics at the ends of the travel, but what ever they are, there is no reason not to shoot for ideal.

Sorry for the SD'ish responce. :mrgreen: I am sure hobot will have what you need.

With Hagon/factory scale shocks/springs its about 4" total. The real limit is the rear tire fouls the fender underside on bottoming out with stock range shocks. To get more means swingarm must move further downward at base sag loaded and then must watch out for oil filter fouling and extra chain slack in unloaded hi sitting position. Its long been a standard for racers to lift the rear an inch for better handling, but that's only because regular isolastic chassis or very rigid solid chassis can not take corners on full rear thrust like linked Ms Peel so must depend on front tire traction to get on around w/o crashing. Its like shooting one's own foot to me because if the chassis can take it the power will squat whole bike mass on rear tire only while lifting the front out of effective traction and then fighting with the rear's aim for THE Hinge onset in 'un-tammed' cycles of in Peel's case even off the surface for pure unicycle turns w/o a hint of tire conflict upset. I can GUARANTEE you can not corner this harsh if still in counter steering slow motion mode on front patch, SPLATT! Ms Peel must earn her keep so 150 lb of two feed sacks and couple/3 cases of beer is 2nd reason her butt will sit higher unloaded.

Dances with Shrapnel said:

For a stock Norton Commando, what is the swing arm travel at the rear axle?

Click to expand...

Up and down or side to side? :mrgreen:

Sorry...

Dances with Shrapnel said:

For a stock Norton Commando, what is the swing arm travel at the rear axle?

Click to expand...

There is also an issue with the drive chain. I have heard of people who had the tension on the drive chain a little to snug and when riding two up the gearbox gave way. That thought should keep you awake.

Ok if you want to get that nit picking then the two planes of 'obvious' swing arm freedoms, when combined with the iso mounts gives a skewed asymmetric torsion twist spring that allows Cdo's to fling-fall over faster sharper to the L than the R. Most evidence for this on an "un-tammed" Cdo's is I can tear out the RH lower shock mount on side loads but not the LH, so far. Drive chain loads tend to lock in the straighter DS swing arm 'stability'. Clever engineering to get chain clearance and not kill off pilots and bikes till the warranty ran out. Each single improvement adds a bit more speed load handling to invite ya into better practice and skill in recovering THE HInge, which will hit every bike ever fielded but one in a row. The must be some downside to the more solid state of McRee's swash plate racer as I don't see or hear him besting the solid chassis in cornering - just equaling them, which is great but not enough to take on purpose made balloon tire bikes. Dances when ya get over my obnoxious bedside manner might try hobot insights and see what you are missing out on. If ya still feel the the front tire turns the cycle near traction load limits then got a fair ways to go to catch up in leaned flings. I know better than expect much of solids or rubber baby buggies so don't press them no more.

BTW carrying a passenger or cargo don't hurt handling corners hardly at all, just slows up the acceleration and De-acceleration ability.

So is that 4" vertical travel or 4" along the shock centerline?

Thanks ludwig.

I'd agree that the shock-absorber stroke is in the three-inch range.

I have standard-length Hagon shocks built to give a firm ride for 225 lbs at the softest setting, with two-inch risers on the swing arm (I'm 6'6").

My tall 18-inch tire still has lots of daylight between the fender even with a full-sized passenger. Before this modification, with standard shocks and the highest preload I would routinely scrape the rear tire against the fender on just about any dip in the road--even riding solo.


Tim Kraakevik
kraakevik@voyager.net
'72 Combat, '74 RH10 850

Hi Tim, any chance of some pics of your set up including tall 18" rear tire , make and model
Regards Mike

I sent an e-mail, Mike--feel free to share text and photos with forum members



Tim Kraakevik
kraakevik@voyager.net
'72 Combat, '74 RH10 850

Ok will do
Regards Mike

Here are the pics kraakevik sent me with the shock extension/offset to allow for his height , and the 18 " rim and rear tyre (tire).
Regards Mike

Mike

There's a reason racers have shod their steeds with huge back tires for
decades.

I confess I don't understand the controversy when it comes to classic
bikes--my Norton with 18-inch tires handles well--and the back tires last
twice, three, four or five tmes as long.

I've got Cheng Shin V-Max and Kenda tires in the 130/18 configuration

Tim

I know the reason for bigger meats in back on vintage cycles, it takes more power than the old bikes have to break loose on leans and on hi powered moderns it spreads the heat loads more before melting. Extra inch rear height racers told me made easier to turn, apparently d/t decrease in fork trail &/or more load on front tire traction. There must be a sweet size of tires vs power even in our old steeds - too narrow = too easy to over heat and too wide = too much mass to spin and swing. I found my lifted special could lay over more w/o fouling and a bit wider 120 allowed more grip that far over but took more head start on throttle to feel the response as on lighter narrower tire. Mileage better on wider tires. My special has a need for sand paddle and flat drag slick so 16x5 in the works but not for road race type play.