TIN CHASSIS

[Bob B]

Gents, please The thread is about 'Tin Chassis' not a dissection of the costs of modern racing

[Nick G]

Fascinating though.
Continue on a new thread?

[steve-e]

Will split it when I get to a pc

[Bob B]

Have opened a new topic 'Cost of Modern Racing' in the Sidecar Paddock to discuss, unsurprisingly the cost of modern racing and its ramifications, please carry on there

[tonybsa2008]

The Vmcc is NOT slightly lower standard,if you have a real classic 750 twin outfit,or a proper vintage sitter/kneeler there is oppurtunities to get a lot more track time per meeting,thereby making more value for money.ie possibly 5 races per day,versus 2,and becuase people are not spending stupid amounts of money on thier bikes,or trying to develop beyond what was available in the pre 72 period,its much cheaper and financially viable to be at the front,and if you consult history,much more representative of what people actually raced in period.

[jkr46]

I agree with Bruce and are we now in danger of everyone needing a 1300cc BMW to be in with a chance of winning, or are we going to insist on all BMWs being Rennsport replicas, including right hand sidecar.
Whilst I agree with Eddy that TZs were really a bad thing, surely they were just another evolution, as were Imps, as were twins, as were overhead valves, if it was built and raced in the period, it should be allowed.

Who's got a 1300cc BMW then? I still think a 1200 Vincent and 900 Weslake would beat a BMW on power, its just the BMW is the most cost effective route (i looked into them all!). I think what your forgetting is the two BMW's that are so successful with the crmc have the two best drivers in the classic club aboard them! Put Houghton on his weslake the result will be the same.

If the cut off for two strokes is 1967, does that not make the chassis cut off for them 1967?

[Eddy Wright]

I doubt if anyone in the CRMC runs a 1300cc BMW !

[Phil Davies]

Eddy wrote, "The CRMC rules are spot on. They were formulated to give proper classic bikes, classic racing where they could be competitive racing against bikes of their period. I know you will remember what TZ 700/750s did to every other outfit on the grid. I use the TZ as an example."

Well my 2d (I'm that old),
Unless I have this well wrong, surely if you want to TZ750 (and I do) then you support the post historic club/series, which is where they belong, classic surely is for the old clunkers.

I ran a Vincent (sitter) in both VMCC and CRMC and loved it (still would do) and will do again, then went modern (at the time) with a TZ750 (because I wanted to go faster) and was respectable with it.
Which was cheaper to race? - the TZ, yep, by miles .
I have never understood why people complained about the cost of TZ750 racing, if you built them properly from the outset with proper parts (NOT yamaha) they are fabulous and reliably predictable. In my experience most wallet explosions were self caused, by neglect or sheer mechanical ignorance/incompetence.

The Vin on the other hand, was a 50's road bike cooking engine racing against lots of modern (by comparison) race developed componented(!!) engines - Wessies, Pumas, Commandos (bit like racing a classic against a TZ - !!!!), to make a Vin go properly fast against that lot required one off parts developing, which to me was/is part of the fun, but NOT cheap by any standards (unless you own a tool room - and I didn't and still don't :cry) but I accepted that as "what you want to do".

So any argument about cost of racing is fundamentally flawed from the outset.

Classic should only be of that period (otherwise what ARE we actually racing exactly?) with start and stop dates determined and fixed, because ones man's "classic" is another man's "post-classic".
Post classic is exactly that.

AND how did single sided swing arms ever get into "classic" please - repent ye and cast out these demons I say??

[tonybsa2008]

Phil,What youve said is spot on.

[sidecarracer51]

The reference to 1300 BMW, was because that is what would be allowed but who raced a 1300 BMW in the period?, at some point down the line, someone will throw silly amounts of money at a BMW engine and that will become the new TZ, just as all the modern incarnations of period engines have had serious developement and are not the engines that were used in period, so why all the fuss about a chassis rail, which is what the thread was about from the start.

[Eddy Wright]

Lets face it there are BMW outfits that have a fabricated (box section) cross member already competing in CRMC event's.

It makes no difference to the performance of the bike. What's all the fuss about ? Box section has been used for ages.

[Bob B]

I think the point being, Eddie, that the' tin chassis' has no tubes anywhere in it as the construction is of a stressed skin box tha size of the sidecar platform and bottom frame tubes with vertical box sections for the forks, swinging arm and chair wheel. Sorry, there are two tubular bits - the handlebars

as for 'making no difference to performance' this chassi certainly does by comparison to other 16" machines of the same period. Mallory 1967 this thing swept past us on the outside around Gerards with Dane kneeling next to rear wheel with her right arm languidly draped over the rear wheel disappearing into the distance. Allied with mini wheels it was technically a great step forward.

[Eddy Wright]

Bob, Are you referring to a complete tin chassis, or just the box section from the bike to the sidecar wheel ?

[Bob B]

Yes Eddie, a complete stressed skin box section as was used F1 GP cars at the time where a number of them constituted not only the chassis but the whole car with an outer skin rivetted over them, a bot like the old Keil Kraft model aeroplane kits. What I do not mean is just a "beam" on which the sidecar wheel is hung.

I believe that in the originating thread Mike was asking about a complete chassis as described above rather than than the later development of a 'beam'. This design was run by Rudi Kurth in 1967 using a Honda Black Bomber 440cc engine and put many good 16 inchers to shame

[Eddy Wright]

Then I agree with you Bob.