Commando Rear Shock Length

Classic Norton Commando Motorcycles.

Commando Rear Shock Length

Postby mschmitz57 » Thu Oct 24, 2013 8:18 am

I ordered a new set of NJB "Classic" shocks for my `73 Commando and when I went to install them I noticed they were a half inch longer than the old stock Girling shocks which ar 12.9".. I asked the seller and he told be that Norman Blakemore was supplying the 13.4" shocks for Commandos. I e-mailed Norman and he verified that he's been supplying 13.4" shocks for Commando's without a problem.
I realize it's only .5" difference. I'm a little worried the extra free length might cause the swing arm to contact the muffler brackets when the swing arm becomes unsprung. Anyone run 13.4" shocks on their Commando's?

Thanks,
Mark Schmitz
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Re: Commando Rear Shock Length

Postby concours » Thu Oct 24, 2013 8:23 am

12.9 is very commonly available. Simply go to another supplier.
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Re: Commando Rear Shock Length

Postby pete.v » Thu Oct 24, 2013 8:33 am

I don't think 1/2" will matter too much. It's really all about the ride. It is not that they were long, it's just that the springs on the particular set that I had were to darn stiff.

The effect they had on the center stand was also an issue.

In some areas of my garage floor, I would need a block under the stand so the bike wouldn't teeter.
There seems to be so much involved with maintainance and having the rear wheel off the ground that having the right length shock makes my life easier. I fiddle fart alot.

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Re: Commando Rear Shock Length

Postby mschmitz57 » Thu Oct 24, 2013 9:04 am

Thanks. I thought I posted here before but apparently not.

Yes, the center stand will be an issue as well. The bike is currently on my lift (just finishing up a top end rebuild, Dave Taylor head steady, new paint, fork rebuild, etc) so I wasn't able to install both shocks and test the center stand.

I have an Atlas Cafe Racer and the center stand is annoyingly short as well. Probably due to non-stock DOT shocks I fitted.
I have to use wood blocks to jack it up enough to spin the rear tire.

`73 Commando
`63 Atlas Cafe Racer
`64 BMW R50/2
`84 GPZ550
`05 DL-650 V-Strom
`00 KTM 300EX-C

Some pics:
Commando:
http://s646.photobucket.com/user/mschmi ... t=3&page=1

Atlas:
http://s646.photobucket.com/user/mschmi ... t=6&page=1
Mark Schmitz

`63 Norton Atlas Cafe Racer
`73 Norton Commando 850
`64 BMW R50/2
`84 Kawasaki GPZ 550
`05 Suzuki 650 V-Strom
`00 KTM 300 EXC
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Re: Commando Rear Shock Length

Postby hobot » Thu Oct 24, 2013 9:36 am

Many racers will fit 1" longer shocks for better handling, though not likely noticed if not risking tire limits and the 'hinged' wobble-weave onset. Don't want to rub swing arm much as the tubes are rather thin. Tire fix on side of road may mean a hunt for objects to put under stand to get tire off. Could weld an arc of tube section on stand feet to gain clearance.
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Re: Commando Rear Shock Length

Postby Towner » Thu Oct 24, 2013 10:19 am

Hi,

I have NJB shocks on mine which are 13". I got them from AN. Hagon and Ikoni for Norton Commando are 13" as well. I think that's because they made them in metric length (13"=33cm).

Ralf
1973 Norton Commando 850 MK2
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Re: Commando Rear Shock Length

Postby lcrken » Thu Oct 24, 2013 10:49 am

I ran 13.5" rear shocks on my Commando PR race bike for many years with no problems. I liked them because they quickened the steering a bit and also gave more ground clearance. I wasn't running a center stand or stock exhausts, so I can't say if that would cause a problem.

Ken
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Re: Commando Rear Shock Length

Postby acotrel » Thu Oct 24, 2013 11:13 am

What you've been offered could be better or worse for your application. If the springs are softer on the long shocks, you have more suspension travel. A lot depends on how you intend to use the bike. The rear shocks affect the steering head angle, so if they are wrong in height, spring rate or damping, you feel it at the front of the bike.
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Re: Commando Rear Shock Length

Postby hobot » Thu Oct 24, 2013 11:25 am

I've run into hi centering and lean fouling too soon for my thrills so will try 2" longer rears to match the 2" taller front stance on Peel to see how that works out but am fudging with air muscles that can pull both end down at least an inch lower than stock. This instant issue is on stand and muffler issues so being lazy and cautious on un-tamed Cdo i'd get the 12 3/4"-ish shocks with spring rates in my general weight- need zone. If ya do like to test fouling and tire limits then longer shocks with squaty spring rate sure helps it hook up more power sharper, unless of course you still depend on full front traction to turn, as this combo unloads front grip in trade for rear grip, so gotta be going in pretty hot on power [not just speed] to take advantage of it if or front may scoot right out from under on a one tank slap cycle SPLAT. A steering damper in this condition will hinder the fork freedom to road follow by snap into straight steer so will just take ya down in one half a tank slap even faster than ya know what went wrongSPLAT, so nothing for it but do it some more till the reality pains sinks into bike and pilot fractures.
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Re: Commando Rear Shock Length

Postby mschmitz57 » Thu Oct 24, 2013 12:02 pm

Well, running taller shocks wasn't my idea. I ordered NJB shocks for a Commando from Walridge and this is what I got.
When asking Mike about the shocks he says Norman has been supplying 13.4" shocks for Commando for some time.
An e-mail to Norman confirms this. I was just wondering if anyone here bought NJB shocks from Walridge for their Commando.
To Mike's and Norman's credit, they both offered swaps for 12.9" shocks. I thought I'd check before sending them back.
Maybe this was the hot setup. This is just a street ridden Commando, mostly stock.

Mark
Mark Schmitz

`63 Norton Atlas Cafe Racer
`73 Norton Commando 850
`64 BMW R50/2
`84 Kawasaki GPZ 550
`05 Suzuki 650 V-Strom
`00 KTM 300 EXC
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Re: Commando Rear Shock Length

Postby DogT » Thu Oct 24, 2013 2:04 pm

I ordered the NJB directly and I'm pretty sure I got the 12.9" ones with the chrome shroud for the 70 'S'. I just measured them with the bike on the sidestand and it measures around 12.75", so I don't think they are any where near 13.4". I got them in 2010.

You might want to email Norman, not Mike.

Dave
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Re: Commando Rear Shock Length

Postby Biscuit » Fri Oct 25, 2013 6:48 am

lcrken wrote:I ran 13.5" rear shocks on my Commando PR race bike for many years with no problems. I liked them because they quickened the steering a bit and also gave more ground clearance. I wasn't running a center stand or stock exhausts, so I can't say if that would cause a problem.

Ken

My stock MK3 has 13.4 and I'd never go back to the shorter length. Used to ground early, now it doesn't. Two up particularly was no fun. Steering is quicker, but not at all twitchy, so that's better. Center stand is not an issue, I consider it a + that the bike almost jumps up on the center stand by itself. True, the back tire lightly touches the ground so I use a 1/4 " piece of plywood under the stand if I want to free up the wheel or once on the stand you can rock it to right, stick a piece under the left leg and visa versa. The inconvenience with the center stand is more than offset by the benefits gained with a longer shock.

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Re: Commando Rear Shock Length

Postby Bernhard » Fri Oct 25, 2013 6:59 am

mschmitz57 wrote:Thanks. I thought I posted here before but apparently not.

Yes, the center stand will be an issue as well. The bike is currently on my lift (just finishing up a top end rebuild, Dave Taylor head steady, new paint, fork rebuild, etc) so I wasn't able to install both shocks and test the center stand.

I have an Atlas Cafe Racer and the center stand is annoyingly short as well. Probably due to non-stock DOT shocks I fitted.
I have to use wood blocks to jack it up enough to spin the rear tire.

Some pics:
Commando:
http://s646.photobucket.com/user/mschmi ... t=3&page=1

Atlas:
http://s646.photobucket.com/user/mschmi ... t=6&page=1


Standard Featherbed framed Atlas was fitted with 18 inch rear wheel in place of 19 inch rear wheel for all other F/b.
The Atlas was also fitted with a 1 inch longer re shocks because of this, centre stand should not be a problem unless you have also fitted 19 inch wheels.

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Re: Commando Rear Shock Length

Postby xbacksideslider » Fri Oct 25, 2013 1:11 pm

Longer is better, as Ken said, lifting the rear quickens the steering and helps with ground clearance.
You can go wider/more contact patch up front but still get quick turn in.

Too long is not good though, I had some long shocks, I forget how long they were; at full extension the swing arm hit the oil filter.
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Re: Commando Rear Shock Length

Postby Torontonian » Fri Oct 25, 2013 1:46 pm

I use those NJB "classic" shocks and am happy. 13.4 is no problem as I camp and carry gear.
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