FT: Frame (Twin) Suspension and Handling Upgrades

CarlHungness

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Yes it appears that the front wheel moves forward and up at the same time over a bump in an arc as you noted, this was with original geometry.
On fall away it appears to return on the same arc.

When braking the movement was noted to cease at the point the brake was applied.
The detail was poor but he thought the suspension was not returning as it did with no brake on.
Advice was try to ride out the bumps, be careful heavy braking know your limitations brake before cornering avoid brake correction in bumpy bends.
Never brake on fork fall away as the bike will want to ride over as you say.

One interesting thing was hammering into a bend and braking late the fork almost wanted to oscillate the wheel this was apparent with the steering damper turned off.
Turned on and set just over half way this was corrected.



Yoda had said that some subtle changes to the rake could improve this.
Would not be drawn on which way shorter or longer or more attack.

What I failed to mention is I am running twin springs in both spring boxes he had remarked that it would maybe be better to run a softer set up on the front, spring wise maybe one outer on one side and the twins in the other side.
My travel on the spring boxes marked at max compression was 30mm or just over an inch measured from the bottom of the outer box cover.
Al
Any possibility you might post a photo of the Norman Walker steering damper and its attendant brackets, and what it takes to install one? Thanks.
 

timetraveller

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Carl, here is a picture of the kit.
1661414603535.png


and here is a picture of it fitted to a bike.
1661414684594.png

If you want the best from the system then going for the JE stem with softer springs and better damping is the way to go. You will never make the standard geometry as safe. This is not a sales pitch as I am currently waiting for the next batch of twenty steering heads to be machined, promised by mid September but we will see if that date is kept to.
 

CarlHungness

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Carl, here is a picture of the kit.
View attachment 52733

and here is a picture of it fitted to a bike.View attachment 52734
If you want the best from the system then going for the JE stem with softer springs and better damping is the way to go. You will never make the standard geometry as safe. This is not a sales pitch as I am currently waiting for the next batch of twenty steering heads to be machined, promised by mid September but we will see if that date is kept to.
I'm sure I want at least the steering damper and bracket. Not sure what it takes to install the JE stem, so let me know. Need pricing of each too. Thanks so much for posting. I already have longer softer front springs and replacement shock. Have longer springs in the rear as well, ones Justin MacKay Smith made years back, plus I have replacement rear shock as well, and fully sprung rear wheel.
 

timetraveller

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Carl the fitting instructions are too large to put on here or in a PM so I need an email address to send them to. You can have them as either a WORD file or a PDF. The JE stem is tuned with the correct spring strengths and the corrrect length of damper. You might get away with the damper once I know the combined length of the damper plus lower eye bolts but I doubt that your springs would be suitable. The new ones are only £30 for the pair so not too painful. The new steering head complete with stainless steel concentrics to replace the eccentrics and four ball races each side will be about £400 but you do need to get someone to open out the rear eyes in the lower link to take 32 mm diameter bearings. The new springs are actually 16.5" long so you will be able to decide whether you could make your springs work. The rate of the new springs is 36 lbs/inch for middle weight people but I also have 30s, 33s and 45s.
 

CarlHungness

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Carl the fitting instructions are too large to put on here or in a PM so I need an email address to send them to. You can have them as either a WORD file or a PDF. The JE stem is tuned with the correct spring strengths and the corrrect length of damper. You might get away with the damper once I know the combined length of the damper plus lower eye bolts but I doubt that your springs would be suitable. The new ones are only £30 for the pair so not too painful. The new steering head complete with stainless steel concentrics to replace the eccentrics and four ball races each side will be about £400 but you do need to get someone to open out the rear eyes in the lower link to take 32 mm diameter bearings. The new springs are actually 16.5" long so you will be able to decide whether you could make your springs work. The rate of the new springs is 36 lbs/inch for middle weight people but I also have 30s, 33s and 45s.
Hi: e mail is carlhungness@frontier.com and I think a PDF will work. Don't know how to figure if my longer, softer springs will work so will buy yours...need the price on just the steering damper and bracket as I won't be installing the steering head right away. And I am not in any hurry, riding season here is just about over and busy moving into my new shop. Thanks so much.
 

timetraveller

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Price of the steering damper is £125 plus whatever the shipping costs, probably about ten pounds. You will not need the springs unless you go for the JE steering head. I will email the instuctions for fitting the hydraulic steering damper to a standard front end.
 
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Chris Launders

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Carl,
I did quite a bit of the road testing of the stem, bearings, dampers and springs.

The stiff standard springs are fitted to keep the standard forks in the "safe" area of the their travel, venturing out of this causes handling problems, so the geometric problem needs to be fixed (fitting the JE steering stem) before fitting the softer springs that go with the stem kit.

When you say you have softer longer springs do you mean the "D" springs, if so these can be fitted, they are actually the same rating as the shorter springs but don't use the extra internal ones.

Once freed of their geometric constraints the forks become much more sensitive to rider weight, as an indication of the difference, the standard springs are about 57lb/in, with the JE stem fitted I have 45lb/in springs in mine but I weigh 20 stone, most people are using 36lb/in springs, some even as low as 33lb/in.

Chris.
 

CarlHungness

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Carl,
I did quite a bit of the road testing of the stem, bearings, dampers and springs.

The stiff standard springs are fitted to keep the standard forks in the "safe" area of the their travel, venturing out of this causes handling problems, so the geometric problem needs to be fixed (fitting the JE steering stem) before fitting the softer springs that go with the stem kit.

When you say you have softer longer springs do you mean the "D" springs, if so these can be fitted, they are actually the same rating as the shorter springs but don't use the extra internal ones.

Once freed of their geometric constraints the forks become much more sensitive to rider weight, as an indication of the difference, the standard springs are about 57lb/in, with the JE stem fitted I have 45lb/in springs in mine but I weigh 20 stone, most people are using 36lb/in springs, some even as low as 33lb/in.

Chris.
Hi: It's been so long I've forgotten what front springs are in it...I got rears from Justin MacKay Smith, so if he had fronts they are his too...Any measurement I should take to tell? Plus, send me an address. Thanks
 

Speedtwin

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Fantastic film thanks for that I have just returned from Scotland and the Far Far North Rally suspension performed very well keeping the wheels on the road nicely soft enough for touring with luggage no bottom out whole trip very pleased with the AVO set up and the steering damper worked a treat.
I rode from home in Ireland to the rally and home from the rally so got a nice mix of A,B and some roads you should only be on in a tractor.

Happy with the suspension brakes are next which will need another look at the front end geometry and steering head.
Al
 

timetraveller

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The best brakes would probably be twin discs. The next the German made twin leading shoe brakes with their 'hidden' modification. Next, a copy of the sytem I use and discussed on here recently and the photograph of the Vibrac and son racer shows the layout. Glad you found the new suspension to your liking.
 
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