Chassis Design?

[Guest youngsterS3]

Hi,

 

I'm on the hunt for a new already built car, knowing that my series 3 is written off by the insurance company.

 

I have been looking at anything really, but want a bit of practicality, a lockable boot of some size would be good and the cockpit area must be able to accommodate me at just about 6ft.

 

I saw a tiger cat e1 last night and although the same size as the 3, the engine bay has the extra space and I couldn't get my foot up and over to the brake pedal, so no good.

 

So I think I am possibly back to the 2b, or a locost.(as most locosts have a boot, not sure about their size tho. now the question:

 

over on the locost forum there is some mention about he 2b chassis not being great, the stainless version being made from exhaust pipe tubing and for either the mild steel or stainless version there is no triangulation.

 

now I am not a chassis expert at all and from what I had read, I thought the the 2b was over engineered and was stronger than most.

 

can anyone with such experience comment on the locost chassis design, vs the 2b also vs the quantum xtreame monocoque..

 

thanks for any advise

 

Chris

[speedtripledan]

I,ve got a 2B and its strong as you like! that strong that when i spun up a 5" curb sideways at 40mph the only thing that broke was the lip of the wheel.

I use it on occasional track days and when pushed to the limit on corners i can feel a bit of flex between the front and the back but this is the rear sub frame rubbers not the chassis.

i,m 5ft 9 and i have had to modify the pedal box forward and get the seat as far forward as i can to reach the pedals properly so at 6ft you will have no worries

[Guest mower man]

Hi,

 

I'm on the hunt for a new already built car, knowing that my series 3 is written off by the insurance company.

 

I have been looking at anything really, but want a bit of practicality, a lockable boot of some size would be good and the cockpit area must be able to accommodate me at just about 6ft.

 

I saw a tiger cat e1 last night and although the same size as the 3, the engine bay has the extra space and I couldn't get my foot up and over to the brake pedal, so no good.

 

So I think I am possibly back to the 2b, or a locost.(as most locosts have a boot, not sure about their size tho. now the question:

 

over on the locost forum there is some mention about he 2b chassis not being great, the stainless version being made from exhaust pipe tubing and for either the mild steel or stainless version there is no triangulation.

 

now I am not a chassis expert at all and from what I had read, I thought the the 2b was over engineered and was stronger than most.

 

can anyone with such experience comment on the locost chassis design, vs the 2b also vs the quantum xtreame monocoque..

 

thanks for any advise

 

Chris

Hi you mention the Quantum mono, did you know it's an evo of the RH mono? my car was veiwed measured etc while it was being built by Ian Pettinger in Pudsey and Quantum developed it further with different front suspension and numerous other details I have covered 30k ish in it and other than reducing the front spring rates and fitting tie bars to the front have had noprobs whatsoever,as to your question speak to Martin at MK he has been known to build longer ,wider chassis as one off's ,hope this has been of interest regards mower man

[Guest chris brown]

I don’t know where person on the locost forum got his info from but it is all wrong. The 2B chassis is probably the strongest of all the 7's seeing as it uses tube rather than square section and the fact that it is cornerless in that all the chassis rails are curved at the ends and sleeved to the opposite side rail at the back and down to the lower rail at the front I know what I would choose to be in for safety

[Guest Dan_Beeston]

Hi Chris,

 

The 2B chassis is not particularly well triangulated, so it's probably not particularly stiff compared to a well-built locost/westie/Caterham etc (note the Locost book chassis is not very well triangulated either, most people build in a lot of extra triangulation)

 

The 2B chassis is strong however, but it is also heavy to make sure it's up to the job. If ultimate strength to weight ratio or stiffness to weight ratio are your goals, then the 2B won't be the best, but it's better than a lot of people give it credit for a first glance!

 

The facts in this post belong to everyone, the opinions belong solely to the author, the distiction is for the reader to draw

[agent_zed]

I haven't driven any other 7 to be honest but iam pretty pleased with my 2b. I can't detect any twist in the chassis/scuttle shake. When i used to drive my renault laguna over the lip of my drive at an angle i could feel it flex slightly so its certainly better than that.

 

Maybe iam wrong but to me i like having a 38mm x 2mm tube (not exhaust tube as far as i know) protecting my side instead of 1inch box (most likely 16 swg = 1.63 mm!), along with the extra space you get with it being a bigger chassis. You also get a nice big bar up under the scuttle protecting you, which you don't get on locost style chassis. Iam sure i read somewhere that the 2b chassis was developed/checked with birmingham university or something along those lines, not sure if someone can confirm that?

 

Iam certainly not a chassis engineer but looking at the chassis there is definite triagulation (although not as obvious as a locost) coupled with a higher sides (than a traditional 7) giving more strength.

 

The (book) locost chassis is also not perfect from what ive read and can be improved further, but there as you are probably aware are many similar chassis which may or may not be better. They are generally smaller than the 2b from what ive seen.

 

Ive read the quatum have a very high twist rating (forgotten the technical term) and i have sat in one and is comparable in size to the 2b (but a lot more expensive).

 

 

hth and i haven't said too much rubbish...

[Guest youngsterS3]

thanks for the constructive opinions.

 

I'll be going to Detling tomorrow, so I will hopefully be able to scrounge a sit in someone's 2b !

 

I just hope it stays dry!

 

cheers

 

Chris

[Guest chris brown]

No problem there Chris i'l be there if you find me then take mine for a drive and see how you fit in a 2B