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Buck
Level 2 Member
Victoria
26 Posts |
 Posted - 12 Jan 2008 : 2:51:08 PM
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Hi everyone, need some expert help. My brother and myself have been building our outfit for the past 18 months and we have entered Phillip Island. Had only a few cosmetic things to do. Just took it for a spin around the estate and we have major front end wobble. It is a leading link front end, we have tried shifting the front end forward back etc but has not changed things. We are running 12" Renault steel rims, they came with the chassis when purchased. Does any one have any ideas as to what we can do to get rid of the wobble. This was at about 10 to 15 kph both on acceleration and decelearation. If we cannot fix this we are out of the event which would be a bad thing.
Cheers,
Rob Peters #20
(Buck)
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There is a bear in there and a bundy as well.... |
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Alan
Forum Moderator
Western Australia
353 Posts |
Posted - 12 Jan 2008 : 9:28:35 PM
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Hi,
You will get lots of conflicting suggestions regarding this problem but from my experience changing the trail wont help. What I had to do with mine which had a serious and I mean serious head shake was to change the angle of the headstock, mine was to steep. There are several other factors which come into play and the easiest to check is wheel balance, weight distribution is another especially if there has been a motor change, the toe in/out angle of the sidecar wheel and also the lead of the sidecar wheel can all contribute. One thing you might consider doing is to get to somewhere where you can actually get it going quickly, preferably a race track, a lot of sidecars shake there head until they are going quite quick, you notice it when they are on the warm up lap etc or riding on and off the track, it is a difficult science because everything about sidecars is different and all you can do is to work through the settings one at a time until you eliminate the problem. If you cant resolve it yourself try to get hold of Lindsay Urquart or another frame builder who might be able to shed some light on your problem. Personally I think if you can get the outfit wound up it will go away. maybe you could get up to Broadford during the week if they have weekday practice and try a few things out.
Good Luck
Alan Sidecar 21 WA |
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Jeff
Level 2 Member
New South Wales
32 Posts |
Posted - 13 Jan 2008 : 12:22:30 AM
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I have had similar low speed wobbles on sidecars and agree with Alan that it may go away at speed. I had one that would wobble with too much tyre pressure or the wrong tyre profile. A steering damper may reduce the problem while you ride through the wobbling speed or at least get you through the meeting so you can find out the cause.
Jeff |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 14 Jan 2008 : 05:39:53 AM
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| I suggest you find the cause and fix it before racing. I'd have a talk to Lindsay Urquardt or someone else with alot of experience in frame building. Having the wrong head angle, trail or offset isn't something to try and live with. |
Is your machine authentic or merely eligible? |
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acotrel
Advanced Member
Victoria
2147 Posts |
Posted - 14 Jan 2008 : 05:48:10 AM
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| A few years ago Don and Phil Barlow were big in building sidecars. For everyone else what they built was excellent. Their own short wheelbase sidecar was downright dangerous and should never have been let onto a race circuit! I'd be finding out whether the sidecar chassis you've bought was EVER competitive, and whether it has ever handled OK. |
Is your machine authentic or merely eligible? |
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littledoug
Level 2 Member
Victoria
35 Posts |
Posted - 14 Jan 2008 : 2:35:07 PM
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G,day guys
My front end shackes on the broadford acess road but goes away in race conditions my brother bruce his bike is a shocker and you realy have to get up it to stop it shacking if it will help i have all the front end measurements of my bike and have spocken to lots of people regarding my front end understear so you can ring me 0418316511. Early volkeswagon streering dampers work real good and i have fitted one to my bike
Little doug |
batteling on in the face of shear adversary |
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peen0_0
Level 3 Member
Victoria
224 Posts |
Posted - 14 Jan 2008 : 7:24:58 PM
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Thanks all for the help with the issue.
As Buck said, the problem exists at low speed. With a slight twist of the throttle it eases and I suspect will disappear.
Acotrel, the frame was raced around Mt Gambier in the late sixties/early seventies. Don't know how competitive it was, but it did operate OK. We are lead to believe that it is an Urqhart copy?
We have the opportunity to test it this weekend, so time will tell. I'm sure we will also get more advice at this outing.
Doug, Buck will contact you tonight or tomorrow.
Thanks again, peen0_0 (Tony, the older and wiser brother)
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Edited by - peen0_0 on 14 Jan 2008 7:36:40 PM |
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Buck
Level 2 Member
Victoria
26 Posts |
Posted - 17 Jan 2008 : 6:10:23 PM
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Hi to all again, after getting the info from you guys I have applied the adice. Two other things I have learnt, One, if I bet rid of my brother there will be no more shake, Two, after the first six feet of the maiden voyage of our machine, I relised that Peen had fogoten about me and the sidecar becuase he killed all my solar lights in the drivway, what got me was, " S""" sorry I fogot about the side car." my question is "Should I consider that to be a lesson learnt by Peen or will it hurt at the island next week?" Again thankyou for your help and Think Pink....we have, you will see next week.
Cheers, Buck (dunno how to yous the spell check..) |
There is a bear in there and a bundy as well.... |
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