Tillet TR1 runner in SV with lowered floor

[Apothecary]

I’m trying to decide the best way to fit Tillet B6XL Seats in my SV chassis car. I could go for the fixed fittings on both passenger and driver side as the two usual drivers helpfully are the same size so positioning is the same. However, a shorter occasional driver would require an adjustable runner.

The hole spacing in the seats is slightly different to how the existing leather seats attach to their adjustable runners (315mm front to back and side to side on the Tillets compared to 305mm front to back and 315mm side to side on the existing seats).  

The Tillet runner (TR1) would obviously fit to the seat perfectly but I’m worried that the handle would foul the chassis cross member in front of the seat ( that’s presumably why the Caterham runner has a single handle that slots through cross member). 

Has anyone used the TR1 adjustable runner to mount their Tillet seat in a car with a lowered floor and can comment?

if I go for the Caterham aluminium box section to mount the seat I’m assuming I may have to elongate one of the holes to give me the right distance front to back to match the mounting holes on the Tillets.

Alternatively , if I get the Caterham adjustable runners would I have to also fettle them to align the mounting to the Tillet seat holes? Have others had experience of this?

Search is helpful but not definitive hence a fresh question. I also understand that the B6XL might have different hole spacing to the smaller B6 about which there is more comment in the archives.

Thanks for any advice.

Paul

[elie boone]

Yes the handle can foul the cross member but u can bend it out of the way, but even then be ware of your hand / fingers to get squashed.

[SimonR300]

I have an S3 R300 race car which came with a driver's lowered floor, Caterham adjustable runner and Caterham composite seat.  I had to renew both the runners and seat, fit a passenger lowered floor and seat.

 

Presumably with the SV, you'll have a bit more room, but mine was tight.  The Caterham runners have just the one lever which extends under the cross member in the floor and through the cutout in the vertical plate between the chassis and floor as you've said,  so I'm not sure how you'll get on with the TR1 runners.  Maybe you can't use them with the lowered floor?

I noted here the problems everyone has bolting in Tillet seats from above, so I elected to fit M8 rivnuts to the underside of my runners and bolted them in from below with suitable washers and threadlock.  I keep an eye on them.  Replacing what was there with new runners and a B6 seat was fairly straight forward.

The new lowered passenger floor had to be drilled for the seat bolts.  I used a Tillet W1i and made up my own aluminium box sections as I couldn't get hold of the Caterham one's at the time.  First you bolt the box section to the seat with suitable spacers to angle the seat back as required and to clear the bulge on the seat bottom, drilling though both sides of the box section, opening up the one hole for the cap head.  Again I used shakeproof washers and threadlock for the final fit.

Then I bolted the box section onto the floor, again from below, into M8 rivnuts fitted into the box section.  This is what Caterham do I think.  Just make sure the box section is heavy duty enough and the rivnuts are perfectly fitted.  The slightly tricky thing is working out where to drill the holes.  Various cardboard templates and head scratching required.

The Tillet seat fixings are the same spacing as the Caterham composite seat, so you might not need to move the holes around in the Caterham box section.  The Caterham runners have holes that align with the Tillet seats.  Tillet could tell you if the XL seat has the same spacings to the fixings as the narrower B6 seat I fitted.  I found this photo ( http://www.caterhamr500.co.uk/  )   which helped me.

It shows the the standard Caterham runners and box sections with the opened up holes to access the cap heads into the seat an the rivnuts in the box section.  My previous runners (worn out ) had bolts welded in place so nuts could be fitted from the underside of the floor.

Good luck.

[Apothecary]

Thanks to both EB and Simon for their advice. Simon, your comprehensive reply was very helpful and I appreciate the trouble you went to.

In the end I decided to go for the fixed set up on both sides for weight saving and the fact that both my son and I have pretty much the same seating position. I also found that the adjustable rail didn't actually fit the B6XL (the pre drilled hole spacing in the rail is not in the correct place for the 2018 model year seat it seems) so I needed to exchange the one I had ordered and which had already been delivered for a second set of the fixed position aluminium brackets  - which doesn't have the same issue as there is a 'slotted' hole to accomodate sufficiently for adjustment.

Anyway, with help of the CC parts dept I quickly had what I needed and proceeded to fit the new seats. Thankfully I had plenty of Tillets spacers to hand as I needed several to ensure the brackets both cleared the bottom of the seat and I had the right seating angle. I did have to slightly reposition the holes in the floor to accomodate everything but by very little. If anyone is doing this afresh you will need two packs of spacers.

Everything is now securely in place and done up nice and tight. The B6XL (with cut sides)fits perfectly in an SV chassis car and because the holes for the belts are bigger you thankfully don't have to dismantle the belt fixings as they can just be fed through.

The seating position is lower and I feel much more 'in the car' than 'on it' now without jeopardising my view (of the nearside front wheel). If they are anything like my old CSR CF Tillets they are going to be extremely comfortable too. Hopefully out at the weekend to try them out properly rather than just sitting in the garage 

 

 

[SimonR300]

Glad it helped a bit and hopefully will give some guidance to others in the future.

Just out of interest, were the box sections supplied with rivnuts and bolted down from under the floor as I did?  The adjustment slots are certainly an improvement to the above.

[Apothecary]

Yes Simon, the box section is fitted with Rivnuts so that’s much easier than fiddling with the caphead bolts from above while trying to tighten a nut from below.

Paul

[SimonR300]

Hi Paul and everyone else,

I'm no expert and not wishing to give advice to someone else about a subject of which they are already familiar (and probably more so than the first person)......but in the interest of safety and sharing my experience....

When you said "done up nice and tight", it got me thinking.  I described using shake-proof washers and threadlock to stop the M8 hex head bolts coming undone, especially because if they did, they could drop out onto the road,  but mainly because I didn't do the bolts into the rivnuts nice and tight.  (Or the bolts into the seat because that has bonded threaded inserts too.)  Rightly or wrongly, I used aluminium flat head round body splined rivnuts and tightening a steel M8 bolt into one obviously needs caution as it it easy to rotate the rivnut, deform it or strip the thread.  Being a race car, I will be taking the seats in and out quite a bit too, so the prospect of a rivnut coming loose inside the box section doesn't bear thinking about.

I've used steel rivnuts a couple of times but they were small, M4 I think, and very hard to set with a hand tool.  So using aluminium M8 rivnuts set into the 35 x 35 x 2 mm aluminium box section seemed physically possible without buying a pneumatic setting tool.  I don't know if Caterham use steel rivnuts but clearly they are preferable.  It is the seat belts/harness that holds you into the chassis in the event of a crash and not the seat.  However you don't want the seat coming adrift in a crash either.

So anyway, I've done a bit more googling and found a couple of rivnut manufacturer's data sheets.  If I understand them correctly, it is as I thought, you can't do an M8 bolt up to the usual 20-25Nm or more.  I didn't use a torque wrench on mine and just went with feel.  The highest torque setting I've seen for aluminium is 23.5Nm but these two data sheet are similar, 17-18Nm, which isn't very much.

These figures below are for the various aluminium rivnuts from their range...

Another way to use box section without rivnuts would be to cut an acute angle at each end, so you can drop a bolt down through the floor and put the nut on the underside.  If that came undone, the bolt might stay in place until you turn the car upside-down, but you'd need a very long extension on the ratchet to reach down behind the seat to the cap head and another person hanging onto the nut.  You could probably get to the front ones ok.

The bottom line is to use Caterham supplied box section and use an appropriate torque value for the rivnut material used!

 

Edit***

Turns out I used Stainless Steel M8 rivnuts.  Still don't want to mess up any rivnut thread or find them turning .

[Apothecary]

That’s very comprehensive Simon and I’m sure helpful to all. My ‘done up nice and tight’ was not using a torque wrench but, like you, done by ‘feel’ as I’m always cautious with aluminium and rivnuts not to over stress. I regularly check fixings like this anyway so I’m content with how it’s all been installed.

Having driven the car for a couple of two hour sessions on Sunday (great Open day at PGM by the way) it was clear my co pilot did need to have the seat slightly closer and if I’m honest it would have been slightly more  comfortable for me too towards the end (slightly overstretched arms and leg syndrome).

So, I ordered the TR1 adjustable runners and have just spent a good two hours trying to get the right fitting of the drivers seat. Unfortunately the TR1 uses the same unhelpful approach of a bolt through the floor from above which means lots of cursing when you can’t quite reach underneath and above at the same time (exhaust not helping) and the runners don’t quite align with the holes in the floor (again) and not wanting to over enlarge anything. A second pair of hands made it quicker and less painful.

Anyway, it’s in and it’s much better! I can confirm that on an SV car the handle on the adjuster does not foul the cross member in front of the seat PROVIDED you don’t have the seat all the way forward ( lowered floors). It’s also a higher quality runner than the standard item.

I have been dealing with Nationwide as supplier of the seats and fittings and they have been superb. Efficient, friendly and very professional, so thanks to them for a prompt service (24hrs turnaround).

[elie boone]

If you tape one of the 1/2"  extension bar of your ratchet to the handle of the ratchet you can reach all the bolts, better even to weld the bolts to the runners that makes the job so much easier. runners that lock on both sides are much better than a single runner with a lock.