Race chassis

[Grumph]

This thread is a goldmine of information but it seems a lot of people have moved on from modifying/building race bikes... anyway i'm curious if builders always endeavor to have their tyre central to the swingarm pivot bearings - i'm (slowly) building up a bike and have noticed some sport bikes dont always have everything symetrical. from an engineering perspective i like the idea of equal loads throughout ,maybe the marketing people have so much sway we end up with things like an R1 or cbr swingarm . maybe i need to measure some GP bikes - i suspect they give a better insight .

I've never seen that detail mentioned in any of the recognised source books. I suspect that where an offset single sided arm is used the bearings are simply sized to cope. FWIW my last few frames I've used angular contact ballraces as the bearings - and with the wheel central.

[Flettner]

Within reason, does it matter?

[diesel pig]

I would have to agree with the last two posters. As long as the rear wheel centers lines up on the front wheel, does it matter?

[Grumph]

Within reason, does it matter?

In theory, it would be possible by bad choices or design to have a chassis handle quite differently when turning left vs right.

i have seen somewhere that the reason for Honda going back to a conventional swingarm on the RS250 was consistency of response.
And it was slightly lighter.

[jato]

To be more specific a trellis chassis with one swingarm pivot 85mm from centre while the other is 105mm from centre would surely put different loads into the supporting tubes... maybe its quite ok on a streetbike but i expect no racebikes would entertain the concept

[Grumph]

To be more specific a trellis chassis with one swingarm pivot 85mm from centre while the other is 105mm from centre would surely put different loads into the supporting tubes... maybe its quite ok on a streetbike but i expect no racebikes would entertain the concept

You'd need a structural engineer and possibly a computer running a FEA programme to put numbers to that scenario.
I'll go along with it being undesirable practise.

[husaberg]

I don't remember ever making tubular sub frames .Some RS125 Sub frames on the 450 like Jason's. Mostly Carbon or alloy sheet

Hi Anyone know what Loctite glue Dave used in the Tigcraft frame he did that MZ productionised without the glue?

[IvanJuggins]

wow

been a few moons but remembered kiwibiker stumbled across it and found its still active!

great to see this thread still going i switched back to start and saw my old account were I was talking about my frame build sadly it never got completed, we sold everything up and that bike frame went to a guy in Welington dunno what ever happened too it probably scrapped to be fair


I ended up moving away not long after this chat started and moved to Western Australia got out of bikes all together and become a dad and husband

then recentley I just had the urge I missed tinkering with buckets so ended up buying a 2009 Kymco Quannon 125


me and my young fulla are building it up first thing is to build that bike and get it running but a custom chassis build is on the cards down the track

sadly there is no bucket scene here and I am now too fat and old haha


Im literally building a racing spec bike with no intentions to ever see a track call me crazy but I definatly remember the love of it and its once you have been away from something for so long I realise you kiwis are bloody clever