Race chassis

[Grumph]

I think you are missing what i am saying Michael.
The car suspension pic was to illistrate their is nothing amazing about the concept of either the britten or the Hossac
i just feel the links are at the wrong end.
There is nothing to stop someone adding parallelogram link to a leading link.
Its likely even been down before they were all the rage in the 50's and 60"S. Grumph?
I personally don't see suspended steering as being a great advantage as it has to steer a wacking great gyro anyway.
Front suspension to me needs to be light perferably lighter than a conventional fork adjustable and fixable, but more importanly it needs to feel not funny.

If you want the links at hub height, you're looking at a "headless" frame IMO. It's been done but without noticeable success.
Raises too many packaging problems IMO.

[F5 Dave]

Careful. The feet forward zealots will be along shortly.

[husaberg]

If you want the links at hub height, you're looking at a "headless" frame IMO. It's been done but without noticeable success.
Raises too many packaging problems IMO.

I was more thinking a 4 link leading link steered from the steering head.
with a rocker arms for the shock much like the last RC250's had prior to the Prolink.
I think that orange German MX bikes that used Rotax and i think maico engines had something similar.
KRAMER i can't find a pic of that either.

[guyhockley]

One possible advantage of girder front ends, steered or not, could be variable stiffness between fore'n'aft and lateral? Something like MotoCzysz tried with their front fork, a 6:1 ratio was claimed, I think.

[Michael Moore]

I looked at a 125GP Ohlins fork, must have been 15 years ago, and was impressed at how little friction it had.

But teleforks are one of those things that if a person were starting with a clean sheet and not 70 years of legacy production/development they would probably not be high on the list of good engineering solutions. I can build a Hossack FFE with a good modern damper in my garage, high-quality teleforks would have to be bought in.

Unsprung weight is important, but steered mass is also important, and complexity/ease of construction is important, and wheel path is important and . . . .

As Tony Foale says when he starts his seminars, the only thing you can't change is "just one thing".

I've got a couple of FF projects in the planning/accumulating parts stages, though I don't think I qualify as a zealot quite yet. I want to see if there's a reason for zealotry first.

cheers,
Michael

[F5 Dave]

Ohh, ohh. Is it long wheelbase and rearward weight distribution?
If there's a photo make sure to cultivate a suitable beard.

[Michael Moore]

A track bike a couple inches longer than a MotoGP bike, under 200 pounds, RS125 wheels (Dymag)/brakes (Brembo CNC/billet 4 piston caliper), 50hp KTM 250SX engine, Hossack FFE, probably Penske dampers front and rear. Basically a Gurney Alligator with FFE and a lot less weight. A near 50/50 distribution seems likely, depending on how much an airbox interferes with my nether regions. As usual with my bikes, I'll be the limiting factor on how fast it goes, but I do intend to get someone reasonably fast to give it a try.

My beard is and has been for decades quite suitable, at least as an exemplar of hirsute elegance!

[husaberg]

A track bike a couple inches longer than a MotoGP bike, under 200 pounds, RS125 wheels (Dymag)/brakes (Brembo CNC/billet 4 piston caliper), 50hp KTM 250SX engine, Hossack FFE, probably Penske dampers front and rear. Basically a Gurney Alligator with FFE and a lot less weight. A near 50/50 distribution seems likely, depending on how much an airbox interferes with my nether regions. As usual with my bikes, I'll be the limiting factor on how fast it goes, but I do intend to get someone reasonably fast to give it a try.

My beard is and has been for decades quite suitable, at least as an exemplar of hirsute elegance!

What is the penske actually like? they looked like a nice quaility bit of kit when they csame out in the mid 90's, i remember Rob Muzzy using one, then they sort of faded into obscurity?
Def never seen one in Kiwiland. Did they just go back to just doing car stuff?
Personally teles do a lot of things badly, but i think they looked the part back in the 50's and had room for dampers. The problem is they have now been that highly devleoped replacing them is going to be a big ask even for a better solution.

[Michael Moore]

That's the first time I've heard anyone refer to Penske as having become obscure as that isn't the case in the USA.

FWIW, there's a guy on my chassis list who is a machinist for Penske, mainly on the F1 dampers. Ian Drysdale paid him a visit last summer when he was over here (Dave has one of Ian's V8 engines). Ian is definitely no slouch as a machinist, but he said that the level of work Dave was showing him left him slack jawed.

Sure, the F1 stuff is probably a step or 5 above what we mere mortals can afford. But Dave once told me when I was asking about how Penske compared to some of the other similar big names that "I build these things and know what I've got to do to hold the tolerances I have to hold, and it is not easy". The other brands were OK, but he didn't seem to think their, shall we call them, general public dampers were built to as high a standard as the Penskes aimed at the same market. No castings to save money, everything is machined from solid, etc.

Now I expect that if you are a MotoGP team that Penske, Ohlins, WP and probably several others can all supply equally wonderful dampers, but those are limited production to a high standard and probably even higher cost. For a standard 2 way adjustable at around $900 each there seem to be a lot of choices, and I expect that all of them would work well enough that my limited ability wouldn't be able to distinguish between them in a blind test, presuming they are all set up properly to begin with.

I'm probably going to buy Penske because they are made here, every one of them is made to order, they are all run on a dyno to check them before sending out, and lots of suspension shops are familiar with them. I also like that Penske actually encourages owner maintenance of the dampers and provides manuals for that purpose, and it doesn't seem like they need a drawer full of special tools to work on them.

But if my local suspension guru really liked Ohlins, or JRi, or Elka, or Wilburs, or WP or or or . . . . I'd give serious thought to buying what they preferred to work on and felt most comfortable tuning, because at my level any good damper is probably going to be way better than I need.

[husaberg]

That's the first time I've heard anyone refer to Penske as having become obscure as that isn't the case in the USA.

FWIW, there's a guy on my chassis list who is a machinist for Penske, mainly on the F1 dampers. Ian Drysdale paid him a visit last summer when he was over here (Dave has one of Ian's V8 engines). Ian is definitely no slouch as a machinist, but he said that the level of work Dave was showing him left him slack jawed.

Sure, the F1 stuff is probably a step or 5 above what we mere mortals can afford. But Dave once told me when I was asking about how Penske compared to some of the other similar big names that "I build these things and know what I've got to do to hold the tolerances I have to hold, and it is not easy". The other brands were OK, but he didn't seem to think their, shall we call them, general public dampers were built to as high a standard as the Penskes aimed at the same market. No castings to save money, everything is machined from solid, etc.

Now I expect that if you are a MotoGP team that Penske, Ohlins, WP and probably several others can all supply equally wonderful dampers, but those are limited production to a high standard and probably even higher cost. For a standard 2 way adjustable at around $900 each there seem to be a lot of choices, and I expect that all of them would work well enough that my limited ability wouldn't be able to distinguish between them in a blind test, presuming they are all set up properly to begin with.

I'm probably going to buy Penske because they are made here, every one of them is made to order, they are all run on a dyno to check them before sending out, and lots of suspension shops are familiar with them. I also like that Penske actually encourages owner maintenance of the dampers and provides manuals for that purpose, and it doesn't seem like they need a drawer full of special tools to work on them.

But if my local suspension guru really liked Ohlins, or JRi, or Elka, or Wilburs, or WP or or or . . . . I'd give serious thought to buying what they preferred to work on and felt most comfortable tuning, because at my level any good damper is probably going to be way better than I need.

Looking at their distributer map it looks like they have concentrated on the US market.

[Grumph]

They hit the UK market hard in the 90's. V & M used them to win a couple of British titles I believe.

Where I think things fell down was that a lot of the UK magazine projects get shocks on favourable terms for the publicity value.
The Penske distributor apparently didn't want to play at that game. So you very seldom read about them now outside the US.

[Michael Moore]

I suspect that Penske might have a little barrier to sales outside the USA from their "made to order, tested before shipping" business model. I thing it is going to be a lot easier to have a large number of pre-boxed "standard" dampers stored on shelves in another country for sale vs setting up a custom assembly/dyno test operation.

It looks like Ohlins has a "budget line" manufactured in Thailand or similar location, Penske has a higher bottom limit to what they make and a narrower target market/focus.

There seem to be lower barriers to entry in the performance suspension market these days. I periodically run across yet another new brand. If you add in the firms that go only after automotive or ATV markets there are even more people making suspension parts.

[Michael Moore]

http://www.bsaotter.com/scorpion_spo...rch_1963..html

has some photos of the Scorpion fabricated steel sheet frames that I'd not seen before (including one in scrambles trim) and a period article says the frame was made of 16g material. 2" x 5" deep at the head stock tapering out to 4" wide (probably the underseat/vertical box area).

Look around the rest of the site for interesting trials frame info.

[Grumph]

I got into conversation with a guy who I'd known for years about frames a few years back and that one came up. He knew all about it as he'd helped to build the prototype. He's since died but you'd be surprised how many Kiwis were in the UK in the early 60's involved with motocross and trials. One chap I knew had been the welder at the Rickman Bros factory for about 4 years. Apparently it was a job that was handed from Kiwi to kiwi...Another here still active worked for Cheney for a couple of years then moved around as and when the little independents could afford to pay wages - usually when an order came in, LOL. It was all hand to mouth stuff at the time which suited the Kiwis who usually didn't want to be tied down - and wanted time off to ride or do some Continental meetings.

[chrisc]

Does anyone have this book I could borrow? Pleeeeeassssseeee. I've read the first one and loved it.

John bradley
The Racing Motorcycle: A Technical Guide for Constructors: Vol 2