Slimy38
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| posted on 26/5/26 at 06:53 AM |
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Improving seat ergonomics
When I was making my seats I was primarily focused on IVA, so the base is fairly thin and completely horizontal. It turns out this is not comfortable
at all, with only a small area of my back side actually touching the seat. I also have issues with my legs ending up straight, I thought it would be a
good resting position but again it looks like I was very wrong.
I want to increase the padding and change the angle of the base, but I have no idea where to start. Is there some standard 'ergonomic'
position that will get me most of the way there? I only want comfort rather than 'race car like support' so an expanding foam kit is
overkill.
I was looking on Amazon for 'car seat cushion' but they seem to be based on a seat base that is above the pedals, so they are either flat or
slop downwards.
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Sanzomat
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| posted on 26/5/26 at 09:30 AM |
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I guess looking at your daily driver and other cars that you find comfortable is a good starting point. If you make it to Malvern (with a sore rear!)
maybe try sitting in a few - the Kitnet people are very friendly! and see what others have done. I have standard MGTF seats in my GTM and they are
very comfy - can sit in there for hours, but quite heavy and bulky. My Locost has some old fixed back Cobras. They are padded but as they are 23 years
old I think the foam has deteriorated. there is also very little lumbar support but reasonable lateral location. Only used for 15 minutes track
sessions at a time so just about okay but wouldn't want to sit in them for much longer!
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coyoteboy
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| posted on 26/5/26 at 12:15 PM |
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Unless you sit in a similar height and position to a normal daily driver, those seats aren't correct either - their bases are fairly flat too
because it assumes your pedals are a foot lower than the seat. Normally the seat needs to be rotated backwards so the base supports the bent-leg
position properly, but then you're straining your neck forward to stay head-level. TBH you think the foam kit is overkill, I'd say it's
the bare min.
Check out the likes of this
https://www.fcc.chalmers.se/mediadir/2021/01/msc_thesis_proposal-race-car-ergonomics-using-digital-human-models-a-multi-objective-optimization-of-the-
driver-cockpit.pdf
[Edited on 26/5/2026 by coyoteboy]
https://www.fixmystreet.com/
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Slater
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| posted on 26/5/26 at 02:40 PM |
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a fibreglass seat that is mounted tilted back is quite comfy, even without any padding.
linker
[Edited on 26-5-26 by Slater]
Why do they call Port Harcourt "The Garden City"?...... Becauase they can't spell Stramash.
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Slimy38
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| posted on 26/5/26 at 02:57 PM |
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quote:
Originally posted by coyoteboy
Unless you sit in a similar height and position to a normal daily driver, those seats aren't correct either - their bases are fairly flat too
because it assumes your pedals are a foot lower than the seat. Normally the seat needs to be rotated backwards so the base supports the bent-leg
position properly, but then you're straining your neck forward to stay head-level. TBH you think the foam kit is overkill, I'd say it's
the bare min.
Check out the likes of this
https://www.fcc.chalmers.se/mediadir/2021/01/msc_thesis_proposal-race-car-ergonomics-using-digital-human-models-a-multi-objective-optimization-of-the-
driver-cockpit.pdf
[Edited on 26/5/2026 by coyoteboy]
Aha, yes that PDF is the sort of thing I've been after, thanks. You're right, the comparison to tin tops just wasn't working in my
head. My Skoda Superb is proper 'armchair' comfy but it's not difficult to see the pedals are much lower than where the seat base is
pointing.
Changing the angle of the entire seat had occurred to me, but as you say I think for a strictly road going car I didn't want to spend my time
with my chin on my chest. If I can change the angle of the base then I think I'm on the right lines. Just sitting on the floor against a wall
shows that I can preserve the rear angle but have my legs lifted.
For the foam kits are there smaller versions that are just used for the bottom of a seat, rather than trying to envelop my entire mass?
[Edited on 26/5/26 by Slimy38]
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Slimy38
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| posted on 26/5/26 at 02:59 PM |
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quote:
Originally posted by Slater
a fibreglass seat that is mounted tilted back is quite comfy, even without any padding.
linker
[Edited on 26-5-26 by Slater]
It's that sort of seat that made me wonder whether I could get away with very little padding, but actually looking at those pictures I can see
both the base and back are at quite severe angles. Well, they're not severe for their intended application, but they're very wrong for mine.
Having said that, perhaps the base does need to come up that far before it's supporting correctly?
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Slimy38
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| posted on 26/5/26 at 03:13 PM |
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quote:
Originally posted by Sanzomat
I guess looking at your daily driver and other cars that you find comfortable is a good starting point. If you make it to Malvern (with a sore rear!)
maybe try sitting in a few - the Kitnet people are very friendly! and see what others have done. I have standard MGTF seats in my GTM and they are
very comfy - can sit in there for hours, but quite heavy and bulky. My Locost has some old fixed back Cobras. They are padded but as they are 23 years
old I think the foam has deteriorated. there is also very little lumbar support but reasonable lateral location. Only used for 15 minutes track
sessions at a time so just about okay but wouldn't want to sit in them for much longer!
Did you do anything special with your GTM seats? Thinking about it though, I might expect an MGTF to have similar pedal positioning to the GTM,
relative to the seat?
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coyoteboy
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| posted on 26/5/26 at 07:51 PM |
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For foam kits, we always made do with a genuine 7 quid tin of expandy foam and a black binbag, and a little experimentation, if it helps!
https://www.fixmystreet.com/
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Slimy38
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| posted on 27/5/26 at 08:27 AM |
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quote:
Originally posted by coyoteboy
For foam kits, we always made do with a genuine 7 quid tin of expandy foam and a black binbag, and a little experimentation, if it helps!
Hmm, 7 quid is better than some of the seat kits I've seen... perhaps I should try that process if only to gauge what sort of angle it needs to
be.
Any brand recommendations or just whatever Screwfix has on offer at the time?
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adithorp
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| posted on 28/5/26 at 07:19 AM |
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Its difgicult without seeing what you have now.
I'd suggest checking out what seats people have in thrir cars at Malvern and asking to sit in a variety of them. I think you'll be surprised
how much the base needs to slope back. Can you experiment with your existing seats to wedge the seat base angle up a bit and/or add padding at the
front edge with rolled towel or similar to support the back of you thighs and on the backrest as a lumber support?
Personally I have GRP seats with just thin pads and they are comfortable for long days driving. If the seat fits you it doesn't need much
padding. I've also seen many self made seats that people are happy with.
[Edited on 28/5/26 by adithorp]
"A witty saying proves nothing" Voltaire
http://jpsc.org.uk/forum/
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Slimy38
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| posted on 28/5/26 at 08:45 AM |
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quote:
Originally posted by adithorp
Its difgicult without seeing what you have now.
I'd suggest checking out what seats people have in thrir cars at Malvern and asking to sit in a variety of them. I think you'll be surprised
how much the base needs to slope back. Can you experiment with your existing seats to wedge the seat base angle up a bit and/or add padding at the
front edge with rolled towel or similar to support the back of you thighs and on the backrest as a lumber support?
Personally I have GRP seats with just thin pads and they are comfortable for long days driving. If the seat fits you it doesn't need much
padding. I've also seen many self made seats that people are happy with.
[Edited on 28/5/26 by adithorp]
I tried that last night, a couple of rolled up towels on the front edge of the seat. Even just one rolled up towel makes the seat a lot more comfy,
although I still seem to have too much weight on my coccyx. And you're right about being surprised at the angle. The towel added four inches of
height to the front edge and actually looks really high, but it's the sort of angle I think I need.
I will take a look on the weekend, particularly for sevenesque cars as they're the sort of car that has the expected pedal height compared to the
seat.
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