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 Post subject: Frame question
PostPosted: April 22, 2021, 11:26 pm 
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I ended up buying this and am too wide in the shoulders to drive it! My question is can I cut those horizontal bars out and relocate them lower? Thanks Rich


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 Post subject: Re: Frame question
PostPosted: April 23, 2021, 7:57 am 
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That may not be the best way to tackle the problem. How about a pic with you in it with helmet?
You should also consider arm clearance. May be better to cut the lateral tube behind the seat then use a bod jack to spread the hoop, then weld in a new lateral.

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 Post subject: Re: Frame question
PostPosted: April 23, 2021, 9:06 am 
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Depending on your seated position with a helmet on, I'd consider moving them up instead of down. Or like MV8 mentioned, widen the main hoop if you have plenty of room to pass the broomstick test.

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 Post subject: Re: Frame question
PostPosted: April 23, 2021, 12:06 pm 
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Not sure those upper bars are structural, there is a node at the front of the bar but none at the rear.

I'd do a torsional analysis before moving forward.

You may be able to fix this problem and increase rigidity (improve the chassis) at the same time.

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 Post subject: Re: Frame question
PostPosted: April 23, 2021, 1:42 pm 
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I'm trying to recall the intricacies of FSAE frame design, but those look to (hopefully) be loaded primarily in torsion. If that's the case, they could likely be moved up or down. As noted though, make sure you have enough elbow room for sawing the wheel if moving down.

I want to say a fairly common alternative designs is to run them from high on the front hoop and triangulated it down to the node on the main hoop. Judging by the bulge in the bodywork, I'm guessing that might also just end up moving the interference point down though.

Perhaps replace with kinked (hockey stick shaped) shoulder tubes that provide better shoulder/elbow clearance? If not too concerned about weight, you could then even triangulate fore and aft to/from the kink. Bodywork would need to be modified too though.

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 Post subject: Re: Frame question
PostPosted: April 23, 2021, 2:54 pm 
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Rich,

there is a plethora of improvements that could be made to this. Are you interested or is this another short term foster care?

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Miata UBJ: ES-2074R('70s maz pickup)
Ford IFS viewtopic.php?f=5&t=13225&p=134742
Simple Spring select viewtopic.php?f=5&t=11815
LxWxHt
360LA 442E: 134.5x46x15
Lotus7:115x39x7.25
Tiger Avon:114x40x13.3-12.6
Champion/Book:114x42x11
Gibbs/Haynes:122x42x14
VoDou:113x44x14
McSorley 442:122x46x14
Collins 241:127x46x12


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 Post subject: Re: Frame question
PostPosted: April 23, 2021, 3:11 pm 
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Those aren't doing much for stiffness. As Bent Wrench said, there is nothing supporting them in the rear. The diagonal that should be below that bar is really needed to make it effective. Otherwise it is just a rectangle that is able to become a parallelogram under load.

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