Suspension - please explain.

Howard

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VOC Member
I may have been in the VOC a very long time, but until I bought the Comet 7 years ago I've had nothing to do with standard cycle parts.

My Comet does about 500 miles a year ( Egli does most of my miles), it gets ridden and put away until it's needed again and only needs minimal maintenance. So during lockdown it's become my quest to change as many things as possible (as you do) and look how things work, rather than just putting them back as they were.

The rear suspension has always been a pain in the neck, and all points south, so that's got a good looking at. Everything seemed ok, apart from a bent damper rod and the stud that goes through the top damper eye was also bent - so I made a new stud and damper rod complete with Paul Ennis mods.

Now then, can someone explain to me why the damper has 2" of travel, plus 1/2" each end of hydraulic bump stop, but the spring will only travel 2" and is coil bound before it reaches the compression bump stop? Or is there something wrong with my suspension.

I feel the suspension is missing a trick. Using a spring with more travel, and longer threads on the eye bolts would (I think) allow a less vicious stop at the end of travel, and would allow pre load adjustment.

As they say in exams - discuss.

Cheers
Howard
 

timetraveller

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VOC Member
Pettiford springs allow more travel but you might have to compress them in order to fit them even with the damper fully extended. Are you sure that there is a hydraulic bump stop in the damper? I am not saying that there isn't but I have never noticed it and how would a hydraulic bump stop work? Is that part of the Paul Ennis modification? Fully sprung is a major improvement, hence the Series 'D's. AVO coil overs are a good way to go. At the front then the John Emmanuel mod with my mod for the springs and the Greg Brillus mod to the Oilite bushes makes a dramatic difference to front end comfort and I am currently out of stock so I am not trying to sell you anything.
 

BigEd

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VOC Forum Moderator
The original damper has a hydraulic stop created by the porting being closed as the damper nears the end of the stroke.
 

Bill Thomas

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The Comet rear springs were thinner, A lot of them have been changed to Twin ones over the years.
Maybe OK with a fully floating seat ?.
I like to keep my Old Comet looking Standard, Don't Laugh,
So have kept the seat stays, But changed one spring to a Twin one, I am about 200 lb without all the riding gear = Rides not too bad.
Are the bearings in the RFM OK ?, Free ?,
And the seat pivots free ?
I also don't like high tyre pressures, I run about 26 lb.
I now put oil or something on the lower rear seat pivots, No tension on the knobs, Bit of loctite to stop them from coming off !, Because we now have the hydraulic damper we don't need anymore stiffness.
 
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Howard

Well Known and Active Forum User
VOC Member
Pettiford springs allow more travel but you might have to compress them in order to fit them even with the damper fully extended. Are you sure that there is a hydraulic bump stop in the damper? I am not saying that there isn't but I have never noticed it and how would a hydraulic bump stop work? Is that part of the Paul Ennis modification? Fully sprung is a major improvement, hence the Series 'D's. AVO coil overs are a good way to go. At the front then the John Emmanuel mod with my mod for the springs and the Greg Brillus mod to the Oilite bushes makes a dramatic difference to front end comfort and I am currently out of stock so I am not trying to sell you anything.
Maybe I'm reading too much into it, but the ends of travel look like they could be intended as a primitive bump stop. If I was using the Comet regularly and for a reasonable mileage, I'd have all the great mods you suggest, but I'm just trying to get the best out of the original setup with a few tweaks - A bit of improvement and a bit of DIY hobby while all our lives are restricted.
 

Howard

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VOC Member
Bill, Can't remember the wire diameter now, but apparently the Comet had two spring sizes and the first ones were superceded by thicker ones, mine are the later ones and they're 6 3/4" long so I assume (hmmm? ) they're still good. Oiling a friction damper is the last thing I would ever think of doing, but I see where you're coming from and I'll have a shot at that. All pivots are now good - can't vouch for how they were, because I wasn't looking for problems when I dismantled them.
 

Bill Thomas

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VOC Member
It was not me Howard, I think I got the idea from Vincent Speet, He does a nylon insert, But it's a Turning job and He's too far away, It just made sense to me, I am always willing to learn new tricks !.
 

Howard

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VOC Member
Nylon insert? Now you're talking. That's a lockdown DIY job, I might even have some HDPE bearing material big enough.
 
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