seat repositioning.

[Challenger392]

I am currently in the process or repositioning the seat in the Howe Mod I just bought. I'm 6’ 2" and as most of you know the previous owner was a little shorter than that. First is there any reason I shouldn't mount a 10 degree layback seat on a slight incline to give me a little more arm room? Also I will need to drill 2 holes in the seat to keep one of the brackets pearallel to the direction of travel, since I am moving the seat down by about 2 inches. Do you tech guys have any suggestions/do’s/don’ts for drilling holes in a seat? The seat is a Kirkey aluminum intermediate 10degree layback if that helps. Thanks in advance.

[walterclark]

I would just try the seat with the added recline to see if it is comfortable - especially for the backs of your legs. I dont think the seat will be any safer or more dangerous for the change.

The Kirkey installation instruction pretty vague on mounting. They just say to mount the seat to the cage (or to brackets that mount to the cage). 4 bolts on the bottom and 2 widely spaced bolts on the back just below the shoulders belt holes.

I would be sure the holes in the seat are reinforced on both sides with extra metal such as large shoulder washers or small plates, or even sandwich the seat bottom and back area of the bolts with aluminum plates to help keep the bolts from tearing thru the aluminum if subjected to a stress that would rip them thru the aluminum seat. Use decent bolts like grade 5 5/16" or larger diameter, or better yet buy AN5 bolts from a reputable source since then you know you are not getting junk. The FIA seat mounting requires M8 8.8. and the 5/16" (AN5) grade 5 is close (except the AN has higher tensile strength, is less brittle and may actually be what it says it is).

Before you mount the seat make sure the shoulder harness holes in the seat permit a proper 0 to -10 degree vertical angle from the harness bar to the Hans with the seat sitting int its future location and you seated in it. You may need to do some fab work on the seat, I think a lot of the Kirkey are cut with low shoulder harness holes. We required that Smokey add a higher bar recently and with your added height it may or may not be in the right place depending on how much lower you fit the seat.

I almost forgot. We are more likely to ding you for poorly located or mounted belts than anything else. Try to be sure each belt leads to you from a solid attachment point such as the cage in your case, is within the angles in all the belt manufacturer installation instructions (except the shoulder harness locations which should be per Hans or your H&NR instructions if not Hans), and nothing that the belt contacts is likely to chafe it or cut thru it in a crash. This includes bending over a seat opening that is sharp or in an uneven manner so one edge of the belt is loaded more than the other when fastened and mounting belt ends (typically on the seat and crotch straps) so the belt pulls at an angle to the end bracket (using clip in ends and forged eyebolts eliminates this problem for the seat and crotch belts). If using clip in ends be sure to safety wire or pin the spring loaded gate after installation so it cannot open once clipped in place - the end usually has a hole in it for this.

[KevinGale]

I'm with Walter about the comfort part. Having a setup where your legs go numb after 10 mins is a real problem when you are stuck in staging for 20 mins and can't get out of the car. You really want it to be a place where you wouldn't mind taking a nap.

[Challenger392]

Ok good to know, Its good to see I'm on track. I don't think comfort will be a problem, with the slight recline I will be putting in my legs should be about perfect since they are long and will be slightly bent anyways. I will make sure to consider the belts when I am positioning the seat. I saw where you had smokey reposition them to, and I think that I will just end up suing the stock belt position that is still there since the seat will be so much lower. I will also be using most of the same brackets, just repositioning/realigning them. Also the seat was orginally only mounted with two bolts on the bottom front and two in the back so I may add a bracket and two more bolts to the bottom of the seat.

[Rabbit Farmer]

You really want it to be a place where you wouldn't mind taking a nap.

I have taken many naps in my car at the tops of all the hills (except Philo)

[Challenger392]

Made some good progress on the seat install today, I got the upper bracket installed so I can actually sit in the seat without it moving around. I found that once I adjust the pedals the car is going to fit great. The next thing I need to figure out is whether or not the current harness attachment points are goin to work for me. I checked them out briefly and found that I shouldn't have too much trouble. The shoulder belts look as though they will be at a good angle if I use the stock mounting possitions. the only thing I notices was that, due to the single fairly narrow opening in the seat (kirkey) I end up with a little bit of an hour glass shape type of thing going on. Meaning that my shoulders and the mount points are about half a belt width wider than the hole the harness goes through. Should I be worried about this? And if so what can I do to rectify the problem? Everything else seems to be in order Harness wise, The lap belts appear to be at a good down/back angle and the crotch belt will need a little rerouting but thats nothing I cant handle. Once I get everything all set up Ill get in the car with a helmet on and take pictures to make sure everything is up to snuff. Thanks in advance for all the help.

[walterclark]

This seat wasnt really designed with the Hans in mind. Seems to mostly be made to fit a narrow space as they have omitted a lot of width in the shoulder area compared to their own road race seat.

You dont want the edges of the belt rubbing against the seat like that. At the very least it will cause chafing and we will be forced to require you replace them sooner than they might need to be otherwise. At the most the seat edges would cut thru the belts in an impact and not properly hold you in place.

If you are using a Hans device there is maybe some good news. Hans has some mounting info here: http://hansdevice.com/Tech and Scroth published a guide the FIA has listed here: http://www.schroth.com/download/HANS_Guide-FIA.pdf that are good to read. At the hanscevice.com site, of particular interest should be the document titled IMIS Guide to Seatbelt Installation. The whole thing is something of an education as well as an installation guide but I want to direct your attention to one illustration in particular:



A better illustration is in the FIA/Schroth document:



Hans recommends the harnesses close toward one another as they approach the harness bar at around 20-25 degrees, and at lengths over 18" the installation should have them cross to achieve this. I know your harness bar is right behind the seat, but my point is that Hans would like you to have the shoulder strap mounting points much closer together at the bar than at your shoulders. This keeps the belts from slipping off the Hans device, and the device itself has an inside lip to keep the belts from coming off and cutting into your neck (even more effective with 2" shoulder harnesses). If you set yours up this way, they may just clear the edges of the seat opening. If they still rub, or could be cut in a crash as you are pushed forward and the belts stretch, you may have to increase the width of the opening. As these seats have no certifications that modification could nullify you should feel free to make improvements as needed and I would suggest that in particular if you need to widen the shoulder belt opening that you add some bracing up the middle to compensate. This is already the case with their "Intermediate Road Race" seat. You may wish to bolt rather than weld in a brace and combine it with the load distributing plate on the seatback for the back brace - whose primary attachment should be located at mid shoulder height.

To keep the harnesses in place on the bar you can use short lengths of the more firm rollcage padding that is then clamped in place. The padding itself prevents the outside edge of the belt at the bar from chafe. I have also seen come ring shaped aluminum clamps that do the same thing.

[Mopar 151w2]

Like usual - I have a thought, Walter already has blueprints...... http://www.mcmaster.com/#6436K152 are the 2-pc.aluminium shaft collars, http://www.mcmaster.com/#6436K25 gets you steel for 1/2 the money

[Challenger392]

Thanks for the info and pictures, I'll see what I can do. Its going to take some creativity as that center position is currently taken up with the seats mounting bracket. But well see what I can come up with.

[Chief Geek]

I think Walter's reply can be used to illustrate to anyone unfamiliar that, if you have something sketchy on a NEHA car, you have to get up pretty early in the morning to sneak it through. You'll be much better served by manning up and asking.

I doubt professional racers get treated this well, especially by a potential competitor.