[AbhiJ]

Hi,

So my uncle had a knee replacement surgery recently is currently unable to bend his knee without significant pain. He owns a Creta and sits in the front seat during his commute to work.

He is a tall guy and has major problems while getting in and out of the car.

If the cars front seat went just a little further back, maybe 2 inches more, it would have made his life much easier.

Is there a product which can safely accomplish such a thing?

I have access of a milling center and can fabricate something to move the seat further back, but am concerned about functionality and safety aspects.

[Traveler]

I had the exact same requirement and I did a DIY to increase the leg space in my Pajero. See the pictures in this post. It should be a simple DIY. You just need 4 inches of steel bars with holes on either ends. Use them as extensions to mount the original seat rails.

DISCLAIMER: I am not a safety expert and cannot comment on the safety aspect of this. It worked for me however do this at your own risk.

Here is the link to my post http://www.team-bhp.com/forum/showthread.php?p=2491901

[AbhiJ]

Originally Posted by Traveler

I had the exact same requirement and I did a DIY to increase the leg space in my Pajero. See the pictures in this post. It should be a simple DIY. You just need 4 inches of steel bars with holes on either ends. Use them as extensions to mount the original seat rails.

DISCLAIMER: I am not a safety expert and cannot comment on the safety aspect of this. It worked for me however do this at your own risk.

Here is the link to my post http://www.team-bhp.com/forum/showthread.php?p=2491901

Thanks. I had something similar in mind, but just concerned about the safety aspect in event of a crash.

[Traveler]

The other option I considered was to drill new holes in the floor and move the entire seat back. I did not go that route since ai did not want to drill holes in the car. That may be a safer option since you are moving the whole seat back but in the same floor. Safety comes first so consider that before you make any changes.

[Rahul Bhalgat]

Originally Posted by Traveler

The other option I considered was to drill new holes in the floor and move the entire seat back. I did not go that route since ai did not want to drill holes in the car. That may be a safer option since you are moving the whole seat back but in the same floor. Safety comes first so consider that before you make any changes.

Instead of drilling the holes on the floor, drill new set of mating holes on the adjuster frame. To take the seat 2" towards the rear, the new holes shall be 2" towards the front.

[sridhu]

Perhaps he can try this one out:

https://www.team-bhp.com/news/turnpl...seats-disabled

[Durango Dude]

Originally Posted by AbhiJ

Hi,

So my uncle had a knee replacement surgery recently is currently unable to bend his knee without significant pain. He owns a Creta and sits in the front seat during his commute to work.

He is a tall guy and has major problems while getting in and out of the car.

If the cars front seat went just a little further back, maybe 2 inches more, it would have made his life much easier.

Is there a product which can safely accomplish such a thing?

I have access of a milling center and can fabricate something to move the seat further back, but am concerned about functionality and safety aspects.

A knee replacement is done to ease pain and increase mobility; I think rather than trying to increase the front leg room of the car, I'd suggest you go back to the doctor who operated. My hunch is the operation hasn't been a success and may be the implant is loose: that may be the source of the pain.

[GTO]

100% possible in most cars, especially if rear seat legroom isn't a consideration. Also, in some cars, manufacturers intentionally restrict the front seat's travel range to impress customers in the showroom.

I just increased the legroom of my Jeep and its usage has increased by 50% - link to post. Am no longer in my 20s (or even 30s!!!), hence comfort is a priority.

Originally Posted by Traveler

The other option I considered was to drill new holes in the floor and move the entire seat back.

This is what I would do. Just ensure the right treatment of the new holes (to prevent rust) and covering up the old ones.

[jinojohnt]

If you are ok travelling in the back seat, you could as well remove the front passenger seat to create that 'royal' leg-room. Ingress can be tricky, though. (Would be easier if only your right knee has the issue, because you can easily side your right leg in without bending). Please try this out once, any car accessories shop can remove/refit the seat for you.

[AbhiJ]

Originally Posted by Durango Dude

My hunch is the operation hasn't been a success and may be the implant is loose: that may be the source of the pain.

The surgery was done about 45 days ago and the doctor says that recovery will take time.

Thanks for your concern.

Thank you all for your replies. Decided to do the modification myself today. Its done and it turned out great. Will be posting pictures and details of the mod soon.

[wildsdi5530]

Originally Posted by AbhiJ

The surgery was done about 45 days ago and the doctor says that recovery will take time.

45 days is still too short a time to think of loosening. I'm a joint replacement surgeon in Bangalore. Most patients are back to normal by 45 days, but some take upto 3 months. So don't jump into any conclusions.

[AbhiJ]

It was a slow work day and I decided to take my uncles car to my workshop (I have access to my CNC milling machine there)

Removed the front passenger seat and found it bolted down using 25 mm Thread Length Bolts (M10 x 1.25)

Quickly designed a spacer which will on one side be bolted on to the floor of the car and on the other side of the spacer will be tapped so the seat can be bolted onto the spacer.

Below is the basic design and dimensions of the spacer.







CNC Machining of spacers from Steel



Finished Spacer with bolt arrangement.

I used the original seat bolts to fasten the spacer to the floor of the car and M10 Allen bolts to attach the seat to the spacers.



All 4 Spacers installed and bolts torqued.



Rear Bolts tightened.



Front bolts tightened.



Conclusion

The spacers moved the seat back 75 mm and increases the seat height by 16 mm. The height increase is not a problem in this case since there is plenty of headroom.

There was no modification / drilling done to the car. If tomorrow one needs to go back to stock, it can be done in 15 mins.

[Gannu_1]

Oh man, that looks like machining porn right there! Beautifully and intricately cut (not surprising because it was done in a CNC machine). How did you get that final finish? The final pics look like it is made of Aluminium!

[AbhiJ]

Originally Posted by Gannu_1

Oh man, that looks like machining porn right there! Beautifully and intricately cut (not surprising because it was done in a CNC machine). How did you get that final finish? The final pics look like it is made of Aluminium!

You have a good eye. I sprayed it with an aerosol of silver paint with the primary intention to avoiding rust.

[Joe-Ker]

Great work, but next time avoid the sharp change in section at the OE bolt, In the event of a crash you are 100% guaranteed to get the failure at that change of section, just smoothening it out adding a largeish chamfer will solve the problem, Easiliy doable in a CNC.

The load in a frontal crash will cause the seat+passenger (~100kg) to rotate around the mounting on the floor, the new piece is rigid so it will fail around the place where the section of the part changes sharply. on the rear mounts it will pull at 45% angle an failure likely at the same area but less likely as the weight transfer happening to the front.

But on the whole the part is overengineered and should last in a crash. At some speed however the rigid part would fail at at the sharp change in Cross section and the passenger will hurtle towards the front. In normal case the mounts, floor etc will bend within limits and absorb and dissipate a lot more of crash force before anything fails.

A far safer alternative from crash point of view is to do it without modifying the load path. i.e to extend the rails the seat slide on to a couple of nothches back without touching the mounting points. the stress on the mounting points will only increase slightly in that case and should be within limits and may even be compensated for by the additional survival space created by the seat moving back.