Adjustable seat versus adjustable pedals?

[ahaidet]

For the teams that have tried adjusting the seat versus adjusting the pedal plate what did the judges say in design? We are looking at doing that. It seems silly to me to adjust the whole pedal plate with brake hydraulics and all mounted on it. When we adjust ours we loose our throttle pedal adjustment and it doesnt move easily or have much adjustment but it is there and the judges do seem to like it. Looking outside the norms of FSAEdom I thought that this sounds like a better solution as thats what most street cars do. A team mate also mentioned that for big time endurance racing ALMS and such that the seat, pedals and steering wheel are set to the tallest driver and the shorter drivers all have individually fitted pads that fit the seat to push them closer to the steering wheel and pedals. The judges last year like the adjustable pedals but noticed that the steering wheel was not adjustable. So logically I think we could loose weight, make the plate stiffer, actually have an adjustment that would make the car more drivable, and it could be adjusted in endurance in the 3 mins with a quick change of seat padding. To adjust the pedals on our car this year you had to, remove the nose cone, loosen 3 quick releases and pull a pin slide the plate (with minimal adjustment), adjust the throttle and reattach the nose cone. WAY TO MUCH for 3mins with a driver change. This solution with adjustable seat ala padding makes sense in the real world (i.e. ALMS.. etc) But in the judges eyes I am not to sure. What kind of flack has your team recieved for an adjustable seat in design if your team has tried it? Or any other concerns that we may be overlooking? Just an idea right now...

[Alan]

How much would moving the seat change your CoG?

[Jersey Tom]

There's much easier ways of adjusting the pedals without having to move any of the hydraulics. Its a 60 second change on our car.

[Ppada]

If that is your problem put some pilows to adjust the seat. 0 time change.

[Marshall Grice]

How much would moving the seat change your CoG?

how much does putting a shorter/taller driver in the car change your CoG?

[RKemmet]

You pedal tray takes wayy too long to adjust. ours is literally a 10 second thing, actually less, it takes as much time as it takes the driver to extend their legs.

[kwancho]

Originally posted by Marshall Grice:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> How much would moving the seat change your CoG?

how much does putting a shorter/taller driver in the car change your CoG? </div></BLOCKQUOTE>

I think he's talking forward or backward, like weight distribution. Really, from tallest to shortest driver, you're moving how much, 6"? Would it be that bad?

[Cement Legs]

Originally posted by Alex Kwan:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by Marshall Grice:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> How much would moving the seat change your CoG?

how much does putting a shorter/taller driver in the car change your CoG? </div></BLOCKQUOTE>

I think he's talking forward or backward, like weight distribution. Really, from tallest to shortest driver, you're moving how much, 6"? Would it be that bad? </div></BLOCKQUOTE>

yes.

[Marshall Grice]

6" movement of the heaviest part of the car (or second heaviest) is significant. also taking 50-100 lbs out of the car is a big difference as well.

[ahaidet]

Out of curiosity some of the guys that are mentioning they can adjust there pedals in 10 seconds, 30 seconds etc. What sort of trick mechanisms are you using to adjust so quickly? It would take us that long to remove and replace the nose cone. So perhaps your not removing the nose cone? And if so at what weight cost? Seems to me I can think of some different mechanisms to allow for quick and easy adjustment and still have it robust enough to withstand pedal use, however at a significant cost of weight.

[Chris Boyden]

How about a single shear pin connected to a button locked aircraft control cable from aircraft spruce? Also
put a detent mechanism that "clicks" in place
when ever pin holes line up. 1" resolution should be enough.

Push the button, pull the handle, move your feet, push the handle back in place all from inside the cockpit without requiring help from the outside.

Make everything move with the pedal plate, throttle cables, master cylinders, etc...so that no adjustment needs to be made afterwards. Use braided cables for the brake lines.

[Homemade WRX]

on our 04 car we used the pad method but the seat sucked...in 05 we did adjustable pedals...nothing else...
for 06 we are doing adjustable pedals and telescoping column...
I had debated the moving seat but couldn't find a light weight easy to adjust method with our parameters...

[D-Train]

Monash had a sweet pedal adjustment system - the whole assembly is on rails so it can slide in and out, and it's sprung so that when pins that locate the box are removed (by pulling a handle in the cockpit - very cool) they move towards the driver. Change pedals in no time with no outside help. Nice work on that one guys. Care to share any pics?

[Frank]

advice to those considering sliding pedal box

1 It is a good idea if you need a large range of adjustment (much better than moving toe pads)

2 Be fastideous about the throttle cable

[C.Casper]

Just a few thoughts on this subject(not the pedal guy on our team, but still curious)

Fastidious: having high and often capricious standards : difficult to please OR showing or demanding excessive delicacy or care.

I guess I'm just trying to figure out what you meant by this. It seems logical to be careful when designing a moving pedal assembly of course. But it seems to me that the entire assemble could not be moved w/o operating the throttle or causing slack in the cable depending on the direction of travel. The same would go for the clutch if said car has one.

Perhaps a solid link would be needed to achieve this? Not that anyone should completely layout a how to on this, but it would be interesting to see a little bit of how some teams have achieved this.

[Homemade WRX]

But it seems to me that the entire assemble could not be moved w/o operating the throttle or causing slack in the cable depending on the direction of travel. The same would go for the clutch if said car has one.

its quite simple...the support for the cable(where it meets the housing) is also mounted on the pedal assembly so that the distance between the pedal and the mount for the casing stays the same and the "slack" is just in the housing bending.
I'll post pics of our pedal assembly from last year

[Skooter327]

Originally posted by Marshall Grice:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content"> How much would moving the seat change your CoG?
how much does putting a shorter/taller driver in the car change your CoG? </div></BLOCKQUOTE>
When taking 4-corner weights from our 2004 car, we found that replacing a 160 lbs, less than 6-feet tall driver with myself at 230 lbs and 6'5" moved our CoG about 3/4" forward. It is worth noting that my legs weigh much less than anyone else of similar height and weight, which implies that the difference would be even greater with a more average 6+ footer in the car.
Our 2004 car has a 69-inch wheel base, and is fairly heavy at 605 lbs. I know most of you have shorter, lighter cars, so the CoG shift from lighter-to-heavier/shorter-to-taller drivers whould be even more significant.


I remove both the back and butt seat pads to fit into our car, and the weights we measured were with these pads removed for both drivers. It would make sense that adding the back pad for the 160-pound driver would move his weight forward, and bring the total CoG closer to where it is with me in the car. For this reason, I am a proponent of changing seat pads to suit different drivers. However, changing seat pads is part substitution, which goes against the spirit of the rules. I have never been to an F-SAE competition, but vetran teammates tell me that the judges like to see adjustable pedals.

[Marshall Grice]

we've normally done adjustable pedals but we still need seat inserts so the shorter people can reach the wheel and see out of the car. By that point we pretty much all use the same pedal location...so why adjust the pedals? I suppose we could build the car to fit the small people and then try to cram the taller ones in there, or just don't let tall people drive (like f1).

btw, the rules allow seat insert changes during the driver change.