Rear shocks for wideline and slimline

jseng1

jseng1

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Nov 26, 2009
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Do wideline and slimline featherbed frames use the same shocks?

Is eye to eye extended length just under 12" or closer to 13" as with Commando? Maybe 13" length for the wide line?
Specs say about 11-7/8" extended length for the slimline but that seems short. Trying to get the right specs. Do they have 3/8" bolts on top and 5/16" at the bottom?

thanks
Jim
 
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On my Wideline I run the same size Koni shocks I had on my Commando with 19" wheels, with my Slimline the rear Ikon shock are smaller with the 18" wheels, I brought the new Ikon shocks that were made for the Slimline size shocks, I can give them both a measure tomorrow.

Ashley
 
Slimline shocks are 11.875" with 3/8" top & 5/16" bottom bolts. 110 lb spring rate was supplied for road bikes (Red Red Red)
 
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What happens to shock length if you put a 19 inch rear on a slimline? Do then go with the Commando length of 12.9”?
 
jms said:
What happens to shock length if you put a 19 inch rear on a slimline? Do then go with the Commando length of 12.9”?
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Good question, when I brought my Wideline frame it came with a rusty old frontend but no shocks on the rear so converting all my Commando bits to the Wideline, frontend and rear end it just looks right with the Koni's off my Commando, but the Manxman has 18" wheels and had the old Slimeline shocks near 1" shorter difference to the Commando shocks, but I replace the slimeline shocks with a new set of Ikon's for the SL frame.
 
jms said:
What happens to shock length if you put a 19 inch rear on a slimline? Do then go with the Commando length of 12.9”?
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That would depend on the tire aspect ratio and width.
 
Do all widelines and slimlines have 3/8" top bolts and 5/16" bottom bolts?
Shock travel of Girlings and Hagons?
 
jms said:
What happens to shock length if you put a 19 inch rear on a slimline? Do then go with the Commando length of 12.9”?
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Nothing happens to the shock length if you don't change it, but longer shocks raise the back end of the bike (assuming proper spring rate and preload on the shocks), increasing ride height (center of gravity), and steepening the steering angle while decreasing trail. All mentioned changes decrease the stability.

You may not even notice the differences individually, but taken together, the change of 1" longer rear shocks with a tall tire (inch tire dimensions tend to have a rounder ratio) on a taller wheel, might make the bike more twitchy than you'd like. They're extremely responsive when stock.

When you get your project going, you'll find out if it's ok for you or not. Might be great if you've got lots of tight twisties with great pavement. Changing back to short shocks (11.9") would probably have the most impact if you're going to change something.
 
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jms said:
3.25-19 front and rear
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That tire wouldn't last long on the rear but would be pretty close in diameter to a typical 18" rear. I forgot to include manufacturer as one of the parameters. In Avons, the 19 would be smaller than a 120-90/18 by 11mm. Decreasing shock length an inch would make a much bigger difference, like five times as much. In Dunlops, the 19 would be slightly bigger diameter.
 
jseng1 said:
Do all widelines and slimlines have 3/8" top bolts and 5/16" bottom bolts?
Shock travel of Girlings and Hagons?
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Andover Norton exploded view diagrams show Slimline to have a 3/8" top and 5/16" bottom, and shows both are 5/16" for the Wideline.

I know nothing about the travel of those OEM like shocks. Maybe ask British Cycle Supply, Baxter, Walridge or one of the other people selling parts for the old British bikes.
 
After a lot of research I finally found suitable Ikon shocks for Featherbeds. 12.8 length with 2.5 travel for the wideline and 12 length with 2.5 travel for slimlines. Both with good damping rates for Featherbeds.
 
jms said:
What happens to shock length if you put a 19 inch rear on a slimline? Do then go with the Commando length of 12.9”?
Click to expand...
I just finished installing a Commando 19" cush-drive rear wheel on my Atlas. It definitely raised the bike a bit, maybe 3/4 inch. I had extended the center stand by 1 inch when I installed a Commando disc front end, and with the 19" front and rear it's just right. Couple of other things: I had to remove about 3/16 inch from the spacer outside the speedo drive, and I kept the Atlas brake plate since the lever is up, opposite the Commando one.

The handling seems a bit quicker but it's subtle. Since 100/90-19 tires at both ends works fine on Commandos, I have no worries using them on the Atlas.
 
nortonclub said:
I just finished installing a Commando 19" cush-drive rear wheel on my Atlas. It definitely raised the bike a bit, maybe 3/4 inch. I had extended the center stand by 1 inch when I installed a Commando disc front end, and with the 19" front and rear it's just right. Couple of other things: I had to remove about 3/16 inch from the spacer outside the speedo drive, and I kept the Atlas brake plate since the lever is up, opposite the Commando one.

The handling seems a bit quicker but it's subtle. Since 100/90-19 tires at both ends works fine on Commandos, I have no worries using them on the Atlas.
Click to expand...
Just re-reading this thread and was curious what length shock you went with?
 
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