Topic: Aftermarket frame - group purchase

[simon#42]

really is price the biggest factor ?

[Tintop]

really is price the biggest factor ?

I've been asking myself that question since this tread started Simon.

[livefast_dieold]

really is price the biggest factor ?

I've been asking myself that question since this tread started Simon.

I don't understand the sense of this comment.
Price is definitely a factor, as it varies widely without much explanation from one manufacturer to another. I got quotations for backbone egli-style frames from 10.000 €, to this one of 900 €. So what is driving this massive difference? It's not the quality of the steel, nor the cost of labour, as the lowest quotation comes from Finland, not exactly a cheap labor country.

My understanding so far is that the difference is driven by experience: a manufacturer that regularly does frame is able to offer them at the lowest price (as JL Meccanica and George Martin himself) as it has already cover its tooling cost (jig, welders and so on) and he also knows how to do it efficiently.

[simon#42]

do you think all replica frames are the same?  do you think they all have the same geometry ? do you think the builders all have the same skill ?
do you think they have all been tested the same ? do you think they all can lap at the same speed?   .... no you dont and that is the sense of that comment .   in racing i have found that the people only sell things cheap because they know its not very good . price should be a factor but a long way behind quality and function .

[slikwilli420]

Agreed, performance is the top consideration. Having said that, there are already world class frames available with the price tag to match. If I can already buy world class at X price, then this other option (which may be better, the same, or worse than known builders) needs to have a price to match. CMR for example, has a long track record of world class performance and without that factor included, the price needs to reflect the chance I am taking on an unknown builder.

[eli]

As many over here, I moved from Europe to this (US-) forum because of reasons like size of community, collective experience and competence of many members and, I must add, the polite and friendly ways of conversation over here at SOHC4.net.
This discussion begins to lack one of the three.
Obviously, there are some arguing from the point of "racing" and others from the point of "high performance" or let's say "higher performance as stock". I understood that this part of the forum is for both. Maybe I'm wrong with thinking like that and what for example I'm doing is only "amateurish tinkering with a bike for the good looks and a few mph more" or "cafe-racer-building" or something like that. I personally admit that I will never race a bike in my live. But I know that the information I'm looking for can be found in the "High Performance and Racing Forum" and not in "SOHC/4 Bikes" or somewhere else.
Which brings me to the point. From what I read I get two ideas what is possibly happening:
A) People are arguing about two different things (a nice performance aftermarket frame vs. the one best racing frame). Why argue then? The thread was started with the first idea in mind (correct me if I'm wrong).
or
B) People that are simply interested in performance and trick knowledge for the bike should not comment here, because they are not competent enough/they are no racers.
As a humble (relatively new) member of the forum I would like to know what the intention of the "High Perfomance And Racing" forum is, so that I know where to comment.
eli

[Leino]

FIM Vintage 7A class 2015 European Champion seems to think JLM frames work pretty well. Just one example.

[turboguzzi]

simon, although there are some people here with deep pockets, there are also folks who have less means, me included. So, an improved frame (not hard to do) over the stock one that fits the budget you have to spend is a totally acceptable choice.
Brent has just sent me a link to nice close ratio gearboxes for my 500/4 at only 1600 euro or something. No question that it could make my bike lap quicker, but don't that have that kind of sum to spend, so will continue with my humble stock box.
It's all a value for money thing and JL's makes total sense to me too. Even if it's just 5% stiffer and lighter than stock, it would be well worth that price.   

[simon#42]

im used to modern prices yossef , with suter or kalex chassis costing the thick end of seventy grand .  you dont go racing to save money !
i still dont see the point in buying a less crap frame when you could save up and buy a good one though.

[simon#42]

dont worry call they only sell them to good riders  .

[livefast_dieold]

do you think all replica frames are the same?  do you think they all have the same geometry ? do you think the builders all have the same skill?
do you think they have all been tested the same ? do you think they all can lap at the same speed?   .... no you dont and that is the sense of that comment .   in racing i have found that the people only sell things cheap because they know its not very good . price should be a factor but a long way behind quality and function .

In racing I also found out that people sell expensive things because they know they'll find the sucker that is going to buy it, without questioning the substance. Surprise surprise, marketing gimmicks apply here too!

Anyhow, I've tried to compare apples with apples, i.e. backbone style frame, and the price differences are staggering. We are talking 10x at the extremes of the range. Interestingly enough, the best prices come from the companies that have been in the market longer and with more frames out there actually racing.

[scottly]

Has anyone inquired as to how much one of Roger's Seeley frames cost? When I bought my Seeley in '79, I had been told that the PO had paid $1200 US for the Seeley "kit", which included the frame/swing-arm, fuel tank, and seat/rear cowl.

[simon#42]

FIM Vintage 7A class 2015 European Champion seems to think JLM frames work pretty well. Just one example.

A three round championship with only two people doing all the rounds .

[Leino]

FIM Vintage 7A class 2015 European Champion seems to think JLM frames work pretty well. Just one example.

A three round championship with only two people doing all the rounds .

You really are on a mission . Good luck with that.

[livefast_dieold]

Has anyone inquired as to how much one of Roger's Seeley frames cost? When I bought my Seeley in '79, I had been told that the PO had paid $1200 US for the Seeley "kit", which included the frame/swing-arm, fuel tank, and seat/rear cowl.

You can get the frame and swingarm from CMR for 3000 €, aluminium gas and oil tank is another 1000 €.

[simon#42]

FIM Vintage 7A class 2015 European Champion seems to think JLM frames work pretty well. Just one example.

A three round championship with only two people doing all the rounds .

You really are on a mission . Good luck with that.

Sorry Leino that did come across a bit harsh !   

[Tintop]

Has anyone inquired as to how much one of Roger's Seeley frames cost? When I bought my Seeley in '79, I had been told that the PO had paid $1200 US for the Seeley "kit", which included the frame/swing-arm, fuel tank, and seat/rear cowl.

You can get the frame and swingarm from CMR for 3000 €, aluminium gas and oil tank is another 1000 €.

So a single CMR 'kit' would cost $4550 US and include handmade alloy tanks.  It would also have the tabs for things like coils.  I know Denis likes to do runs of x5, so in the spirit of the group purchase theme what kind of discount would / could be offered??  A frame kit from Denis would certainly fulfill Simon & Silki's requirements regarding racing competitiveness, and legality.  However, would a price of say $4000/kit (a guess) entice eli and enough others as a high performance street frame??  One tidbit, in 1973 Denis built a couple of mono shock frames for the SOHC Honda that raced in the Superbike class in Canada.  They were competitive until the Suzuki & Kawi motors came into their own.

[gschuld]

Last time I was at Dennis’ shop (3yrs who) he mentioned those monoshock CB750 frames and made sure I knew he had what was needed to duplicate it exactly.  I think he still has one of the CB750 frame/swingarm/monoshock chassis on hand still.  I saw what a I thought was a little twinkle in his eye suggesting he would be pleased if a few more could be built and raced again.

George

[slikwilli420]

If I jumped to the formula class I'd have something like a twin shock xr69 frame made for a cb750. Looks like sex and is a well proven design. No mono shock though for the majority of AHRMA.

[turboguzzi]

un proven, not a race winner, no pedigree, who is he anyway?

very nice nevertheless

http://www.baldes-auspuff.de/rahmen/rahmen.htm

[MWR]

did anyone go ahead, I am happy with the Martin?
can I order one?
murraywestracing@gmail.com

[livefast_dieold]

Hi everyone!

So, I haven't completely forgotten about this, it was always on the back of my head. I may have found someone to make an Egli frame here in Italy at a decent price, so I've started to analyzed possible frame geometries and to update to the egli frame with more modern dimension. I already had the Egli design, I also found the stock design and 3D model of the stock frame (attached).

I've tried to compare the two and so far the main difference is engine position, which is approx. 1.5 cm forward and upward and rotated approx 6 cm (!) upward in the egli frame. My guess is that the egli frame is designed with a 18 inch wheel and they had to move it up in order to avoid scratching the alternator case on left corners (as you can see in the attachments the rear an front engine mounts are aligned in the Egli frame). Considering that I don't have the alternator in my racebike I could potentially keep the engine at the same height as the OEM frame. I also think that the engine was moved 1.5 forward to increase the weight on the front wheel. Keep in mind that the egli design doesn't have many measurements so most of them were derived

As for modernizing the Egli frame: the original design has a wide rake and long trail (27.5° and 147mm !!!), probably because tracks back in the days were much faster than today and also to make it more usable for the street user. Different tyre performances may have a big role on this as well.

I did a bit of benchmark on modern superbikes and I found this:



At the moment my bike is close to R1 numbers, I'm running a 25° rake. Quite interesting Suzuki and BMW numbers: suzuki's are extreme IMHO, BMW's are at least balanced by the longer wheelbase.

I was aiming to 25°/24° rake and 100 trail with a 1415 mm wheelbase, hoping to get 52% front weight? At the moment it's 50,5%.

Any thoughts? I wonder how the bike would behave with suzuki's geometry 

[turboguzzi]

adding to Calj comment, remember reading that some new norton manx featherbed replicas were designed to match current Supersport 600 geometry. kind of makes sense, on the other hand what works well with 130hp and slick 17" tires might not  necessary apply to a 90 hp cb750 racer with skinny 18"...

to say that there are magic numbers that apply to anything from 50hp to 200hp seems wishful thinking to me
I think the most important feature in a new frame is to build into it good adjustability so you can play with set ups. an adjustable height swingarm pivot for instance

[grcamna2]

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[livefast_dieold]

adding to Calj comment, remember reading that some new norton manx featherbed replicas were designed to match current Supersport 600 geometry. kind of makes sense, on the other hand what works well with 130hp and slick 17" tires might not  necessary apply to a 90 hp cb750 racer with skinny 18"...

to say that there are magic numbers that apply to anything from 50hp to 200hp seems wishful thinking to me
I think the most important feature in a new frame is to build into it good adjustability so you can play with set ups. an adjustable height swingarm pivot for instance

Sure adjustability is key, I've already an adjustable triple three, I can change forks offset as much as 7.5 mm (from 40 mm until 47.5 mm). By raising and lowering forks and rear shocks the range of rake/trail/wheelbase dimensions is quite substantial (for example, by lowering front forks by 10mm, and raising the rear by 10mm you get almost one degree less of rake angle, 5 mm less of trail and 7 mm less of wheelbase!).

I was trying to get an idea of a good starting point: power is absolutely not comparable obviously, but the weight (unfortunately) and overall dimensions are comparable, which is why I was using modern 1000cc sportbike as a reference.

Anyhow, even by using modern 600cc or modern 350cc sportbikes the "magic numbers" appear to always be the same:

> 24° rake
> 100mm trail
> 1400mm wheelbase

And they are always within a +/- 10% range among radically different bikes (although in the supersport category).

What I can't exactly understand at the moment is what difference in frame geometry does having 18' wheels entail, as no sport bikes have those kinds of rims nowadays...
Currently, this is simply reflected by a longer steering offset, to reduce the trail due to a larger tyre size.