longer rear shocks

Forums

I am grounding, I think the centre stand and probably need new shocks but read about fitting these 2" longer and wondered if anyone has tried this? To make the most of grippy modern tyres, or maybe longer knees??

Yeah, they do if you chuck …

Yeah, they do if you chuck 'em in.

Should be pretty obvious what you're touching down from the scuff marks. If centre stand, then try fitting a new spring and checking it retracts fully. If exhausts, find some pipes that sit closer in to the frame. If side stand, fix the sloppy pivot.

If none of that helps then hang off, knee out.
https://i.pinimg.com/originals/b6/a1/a3/b6a1a358643333ccdaf00ff46ee65206.jpg

But to answer your question, I have 20mm longer Hagon rear shocks on mine and it's fine. I have 18" wheels though so your experience might be different. Always thought Commandos drooped down at the back so it looks better too.

Things to watch out for:
If you go too long, and 50mm is pushing it, the swinging arm cross brace will run into the engine plates at full extension.
There will be more variation in chain tension.
The chain will rub even more against the chainguard mounting bracket.
The seat will be higher.

All Stans comments are valid…

All Stans comments are valid. Question, how heavy are you? What model of commando are you riding? The riding position is different between interstate and roadster thus affecting the ride height at the rear. You need to measure the spring rate on your current shocks and the compression on the shocks when your sat on the machine. If the shock dampers are still ok a change of spring could help if the current springs are saggy
Fitting 2" longer shocks could in theory cause the chain to lock the rear wheel or come off the sprocket/s The variation in chain tension would be huge.

thanks Stan and Peter

A facebook post prompted the question but I know now that the bike had a 17" wheel and was set up to maximise lean. My Interpol Mk2a with interstate (level) silencers has Hagons on max preload and I'm over 6' possibly not unlike its previous owner. I got the bike many years ago one step removed from decommissioning, with around 45k miles, so it hasn't had much use since and unlike some bikes, been well looked after. However, I only got my license more recently though its been brilliant to go from long term project bike to 'hard' rider (trying to keep up.) I will investigate further and thanks for your advice, as grounding, usually at roundabouts is unnerving - I came off my 250 Crusader Sports in my youf, and following a Honda at a roundabout but the square rear tyre didn't help?! I would rather touch down on a flexible part like the exhaust than on the centre stand with the leverage it could exert. Incidently, using this stand means leaning the bike quite far over (away) to touch both sides down but when its up on the stand it seems vertical, so something may be twisted possibly from kick starting on the stand? Also the side stand with new bushes is still a bit sloppy so that probably needs an oversized bush made for the arm, and I imagine pulling over to issue tickets it got plenty of use? Long to-do list this winter, like cam chain tension, sticky gears/clutch, before investing in new shocks but I would try 20mm longer, so thanks again. Mike

Had a 17" rear wheel or Has…

Had a 17" rear wheel or Has a 17" wheel? How does fitting a 17" wheel maximise lean?... With the width of the swing arm limiting how wide the rear tyre can be, a 17" tyre that would fit in the swing arm will be quite a bit smaller in diameter than the original 19" tyre. I re-rimmed my 19" rear wheel to 18" so i could use a dedicated rear tyre.
A 4.00 x 18 Avon road rider has the same outside diameter (671mm) as the 100/90 x 19 road rider but has more tread depth
A 120/80 x 17 road rider has a 629mm outside dia, maybe this is where some of the lost clearance has gone? plus the speedo reading will be whoafully inaccurate.

Sorry my mistake

This was an Australian commando on Facebook with raised pipes, no stands I could see and 'everything tucked up' and at a wicked lean in the picture! It was only after my initial comment that the owner explained his 17" rear wheel but not why he fitted it. My bike is stock and will remain so, but I am tall and heavier than the average rider.. so probably would fit a slightly longer shock when I get round to it if it helps clearance. I also think my center stand should be examined to track down where my enthusiastic lean angle hits tarmac first. It's too tempting to chuck it in to turns and fun to come back up onto the fat of the tyre with all that torque, only it's spoilt by a crunch moment.

4.00 x 18 RR

"I re-rimmed my 19" rear wheel to 18" so i could use a dedicated rear tyre.
A 4.00 x 18 Avon road rider has the same outside diameter (671mm) as the 100/90 x 19 road rider but has more tread depth"

Peter - I have to replace my rear rim anyway, and was thinking of the same.

Did you change the rim width - I was thinking of using a WM3? What's the clearance like with the swinging arm?

I upped the rim width to WM3…

I upped the rim width to WM3 to meet the minimum recommended width that Avon stipulate for the 4.00 x 18" road rider. Incidentally the WM 2 rim width is not on Avons list of rec rim sizes for the 100/90 x 19 RR
Clearance wise get the rim built dead in the middle of the swing arm and you should have approx 4mm a side (using a 4.00 x 18 RR)

When i have grounded the…

When i have grounded the bike in a corner it has been the exhaust and the spring lug on the side stand, so much so that the spring has pinged off and the stand has then swung out. Stopped that happening with a tie wrap around the stand and spring.

Grounding out.

I had the opposite problem with my cheap replacement rear shocks bought some years ago being too hard and jolting my back over bumps.
I bought a new set of NJB shocks 2 months ago with softer springs and its much better now.
You sound like you need harder springs to stop it bottoming out.

On the subject of ground…

On the subject of ground clearance, if you're touching the centre stand down then there's a lot of room for improvement by reworking the bend in the arm, even allowing for the silencer flapping around in the breeze:

grounding in corners

definitely over enthusiasm on my part, the springs seem ok and only real problem is trying to ground it consciously, to investigate further. I am learning (leaning) on faster, longer corners now eg to keep over to the side of the road to see further into the bend, but now chicken out on my roundabout for grounding! Plus sorted clutch slip (actually read Haynes again) which adds another level of performance to enjoy this superbike of the back roads. New 19" front first. Thanks for responses and enjoy a nice autumn!

Norton Owners Club