Race chassis

[guyhockley]

Just to add that there have been twin shocks with linkages - Maxton and others.

[monkeyfumi]

Until you fit pressurized twin shocks in the old-fashioned position near the rear axle; the gas pressure alone already gives too much preload.

Yep, you can achieve up to 15% progressiveness that way, which is enough for road racing.
Omitting the linkage saves weight and components, and avoids wear and extreme forces acting on the frame.

Try searching for "Suspension Smith". I haven't got a link handy but I will post it when I find it.

http://pbmagforum.co.uk/index.php?/t...93366612351673

This is Laurie's build thread (you will have to sign up to the PB forum to view) It started as a hossack conversion to a modern Fireblade (he has done several evolutions of girder/hossack style front ends) then progressed into looking at lateral damping. He is a clever cookie.

[Grumph]

Wonder if carefully though out rubber swingarm bushes might not be a better idea. Far lower maintenance and real easy to change for tuning.

Ever ridden a featherbed with slogged out swingarm rubber bushes ? I have and most surprisingly it wasn't bad at all...

At the time I raced a good manx and a friend turned up with a 650SS. Try this he said....There was about an inch of sideways movement at the rim.
Nice bumpy uphill curve past home - and it stayed on line. Weird.

[Ocean1]

Ever ridden a featherbed with slogged out swingarm rubber bushes ? I have and most surprisingly it wasn't bad at all...

At the time I raced a good manx and a friend turned up with a 650SS. Try this he said....There was about an inch of sideways movement at the rim.
Nice bumpy uphill curve past home - and it stayed on line. Weird.

Don't think so. But now that I think about it I did rebuild a minibike with rubber swingarm bushes, originally built by the old man with bronze.

Had all of 4" travel, wheels made out of Caterpillar pistons and wheelbarrow tyres, so I can't say whether the rear suspension improved at all or not.

I do recall that the telescopic forks were held together by the springs, you just screwed them onto bosses at either end, a feature that eventually caused me to lose the front wheel on a jump, (and several hours consciousness).

[husaberg]

Huh? You google, dressed in miniskirt and high heels? Does it help?

Come again , What sort of website did I just log into......

[philou]

Hand-formed sheet on wooden die

[WilDun]

That is a good looking chassis - and made without dies (ie expensive steel press dies).

[husaberg]

Hand-formed sheet on wooden die

That is a good looking chassis - and made without dies (ie expensive steel press dies).

It is a thing of beauty
This one has 28 diferent hand formed pieces in the head stock alone
Which formed a forced air system along with one of the frame rails
https://www.kiwibiker.co.nz/forums/s...post1130228408

These ones were also hand formed, plus judious use of a press too i think
https://www.kiwibiker.co.nz/forums/s...post1130228780

[Flettner]

Hum, I have the 'book'

[Grumph]

Hum, I have the 'book'

Well there's your tea breaks and lunchtimes spoken for, for some time.....

[philou]

Hum, I have the 'book'

Hello,

Is it really good?

Can you describe the method of forming the frame spar ?

[guyhockley]

We moved back to the UK after 28 years abroad a while ago. For various reasons, incompatibility with british stuff, helping my son etc. I left a lot of gear behind, so almost starting from scratch. Currently (not really started) using a 3m square workshop attached to the house. Apparently, it's dashed bad form, what, to store acetylene in a residential area. Has anyone advice, experience, caveats to offer on using propane for bike frames (say; 3/4" or 19mm to 4"(!) 100mm x 16swg or 1,6mm steel), please?

(Also posted this on the Ask an engineer thread)

[EssexNick]

I think the problem is more "workshop attached to the house" than anything else. A separate building made of brick or concrete should be ok but it's a gray area.

[Grumph]

My local (rural..) engineering co uses oxy/lpg - but only for cutting and pre heating/bending. They glue everything electrically.

I've seen them use it and asked at the time about any advantages. Price is the big one, much cheaper than acetylene.
Disadvantage seems to be somewhat higher gas usage than acetylene for the same heat.
I'd assume that once tip sizes and pressures were sorted, it would be usable for bronze welding.
No idea how compatible an in-line fluxer would be.

[WilDun]

My local (rural..) engineering co uses oxy/lpg - but only for cutting and pre heating/bending. They glue everything electrically.

I've seen them use it and asked at the time about any advantages. ........... No idea how compatible an in-line fluxer would be.

I bet the Vapoflux would cost an arm and a leg even if it was compatible with LPG and cancel out any savings! - then I could be wrong, I only used the stuff (way back), I didn't have to buy it.