Incoming 420R, California

[theDreamer]

1 hour ago, Vovchandr said:

This is the way! 

Mmmmm...

Mandalorian you quote,

Words wise these are!

[KnifeySpoony]

Looking good - you gonna get that sucker out to the track? 

[KnifeySpoony]

triple post

Edited April 22 by KnifeySpoony

[KnifeySpoony]

triple post lol

Edited April 22 by KnifeySpoony

[theDreamer]

5 minutes ago, KnifeySpoony said:

triple post lol

Don't you just hate when this happens! I know it has happen to me and I'll be danged if I know what I did wrong, if anything.

[Nocturnal005]

13 minutes ago, KnifeySpoony said:

Looking good - you gonna get that sucker out to the track? 

absolutely! Just ordered a new “ABP” lid. Once the car gets some more wringing out on the back roads she’s headed to Laguna. 
 

speaking of which I am looking for track alignment recommendations. The research I’ve seen so far is 135mm front ride height, 15mm rake, red front bar, 2.8-3 front camber, max caster, and about a 1.0-1.5 front toe out. 
 

currently I am at about -1.8 front camber, zero toe, 135 front height, 15mm rake, and on the orange front bar. Shocks are set at “7” all around (cup 420 shocks). handles ok but tends to push a bit w more steering input (only backroads driving)

[KnifeySpoony]

You are on 888R? Not sure how much camber they like but I am running 3deg with ZZR and wear is good. I might bump to 2.5 and see how you wear - depends on your street/track balance of driving. I run zero toe because I prefer the feel. I run my ride height quite low 119mm/138mm - this puts front LCA parallel with ground. This puts bell housing clearance at 68mm which sounds scary but I've had no issues. I've even driven over a speed bump or two.  Do you happen to know the spring rates on the cup suspension?

 

Your push is probably just because you aren't getting heat into the front tires. I wouldn't judge car setup based on that tbh. Besides, that is easily fixed with a gentle prod of the throttle- rear will come right around, especially on cold tires on the street. These cars really can't do what they were meant to do/are capable of on the street. They are surprisingly fast and capable on track. 

[KnifeySpoony]

Also - re: caster - I'm one washer away from max and steering effort is very high on track. People that have driven my car think it's ridiculous. It is very fatiguing actually, but I enjoy it. I just imaging I'm driving a 70s F1 car. On the street it's fine though. 

 

ARB choice and rear setting will vary on other factors, especially your spring rates. I think I have the orange bar (can't remember actually - whatever comes with the "track" setup) and I'm at one hole from full stiff on rear bar.

Edited April 22 by KnifeySpoony

[Nocturnal005]

36 minutes ago, KnifeySpoony said:

You are on 888R? Not sure how much camber they like but I am running 3deg with ZZR and wear is good.

 

Yes, 888R and 18psi cold as a start point. Are you running the stock de-dion ears in the back? 

[KnifeySpoony]

I think you will find 18psi a bit low for street, but a good starting point for track. I think most aim for 21-24 hot - and you won't get that much gain on street. I start at 17 cold first session usually then bleed off as the day warms up. I'm running 2.5deg ears. On ZZS I had very uneven wear (pretty much entire outside half of tire) with 1.5deg. I swapped to 2.0 ears but also changed to ZZR around the same time. The wear is much better but still some shoulder wear so I recently swapped to 2.5deg ears when I did the race rear brake upgrade. I was concerned it might be too much, but balance still feels good though it's too early to say on tire wear. Gonna get proper tire temps next day out on track and find out.  They make a 2.0 in the race ears so I can always drop back down. They have a 3.0 also but I assume that is intended for slicks only. 

 

 

 

 

Edited April 22 by KnifeySpoony

[empti]

On 4/22/2025 at 10:40 AM, KnifeySpoony said:

You are on 888R? Not sure how much camber they like but I am running 3deg with ZZR and wear is good. I might bump to 2.5 and see how you wear - depends on your street/track balance of driving. I run zero toe because I prefer the feel. I run my ride height quite low 119mm/138mm - this puts front LCA parallel with ground. This puts bell housing clearance at 68mm which sounds scary but I've had no issues. I've even driven over a speed bump or two.  Do you happen to know the spring rates on the cup suspension?

 

Your push is probably just because you aren't getting heat into the front tires. I wouldn't judge car setup based on that tbh. Besides, that is easily fixed with a gentle prod of the throttle- rear will come right around, especially on cold tires on the street. These cars really can't do what they were meant to do/are capable of on the street. They are surprisingly fast and capable on track. 

I think recent shipments all came with 888Rs. Mine has 888R as well. 

[empti]

@Nocturnal005 @KnifeySpoony I am wondering how far back/forth your seats can slide? I noticed mine can probably can only slide 2 inches forward from all the way back. Is this the case on yours ? 

[KnifeySpoony]

No, can definitely slide more than that. Although the rails get really full of grit over time and become hard to operate. 

[Nocturnal005]

58 minutes ago, empti said:

@Nocturnal005 @KnifeySpoony I am wondering how far back/forth your seats can slide? I noticed mine can probably can only slide 2 inches forward from all the way back. Is this the case on yours ? 

Mine also moves back and forth more than 2". I can measure it later. Initially it didn't, more like one or two clicks max. What I found was that one of the screws attaching to the rails (don't recall if it was the rail to seat or rail to chassis) was too long and interfering with the rail movement. Once I fixed that i got a larger range, however i can't get the seat further back than the fixed position of the passenger side. I can get it much closer to the wheel, but that doesn't help me. When it's all the way back it's about perfect (i'm 5'10"). However I'd like to explore one click back to see if it would even be better. A project for later.

[CBuff]

I think my seat rails didn’t get installed perfectly straight so the drivers seat doesn’t slide easily. I have leather seats so I take the squab out and use my foot on the front cross bar of the seat frame to muscle it forward. (While holding up the release lever).  I rarely move it so not too worried.  

[empti]

2 hours ago, Nocturnal005 said:

Mine also moves back and forth more than 2". I can measure it later. Initially it didn't, more like one or two clicks max. What I found was that one of the screws attaching to the rails (don't recall if it was the rail to seat or rail to chassis) was too long and interfering with the rail movement. Once I fixed that i got a larger range, however i can't get the seat further back than the fixed position of the passenger side. I can get it much closer to the wheel, but that doesn't help me. When it's all the way back it's about perfect (i'm 5'10"). However I'd like to explore one click back to see if it would even be better. A project for later.

Thanks! I'll refit the seat later. I am 5'7" so I can only barely reach the pedals. If the seat can be adjusted more forward I will not try to adjust the pedals. 

[empti]

4 hours ago, KnifeySpoony said:

No, can definitely slide more than that. Although the rails get really full of grit over time and become hard to operate. 

Sounds good. Thanks! 

[Anthem]

Even though this is my first Caterham it is far from my first convertible. I always degrease the factory grease from the rails and other moving bits then use a dry lube, use to use a Finish-line mountain bike dry chain lube, I switched to DuPont Non-Stick Dry-Film Lubricant Aerosol first car I tried this on was my '18 AMG GT C Roadster and it has ingress & exit seat movement so it gets movement every time it's driven. On my Caterham the one rail (the floater) will slide with gravity, easy as a hot-wheel car on a hot-wheel track when the seat is removed you have to be carful as the rail is kind of sharp and could scratch something -I use a rubber band.

 

If you find you want to move forward more even after pedal adjustments (mine doesn't allow this) you can flip the rails. Note: as you move more forward your belts may become out of proper alignment to your body so their anchor point needs moving. There is seat belt hardware for doing this.

 

In the picture you can see written on the floor in pencil  "OE and Flipped +1"", the rails will actually hit the frame, you can see the locking rail is at the most forward lock position before it hits the frame -it could go farther if the rails where spaced higher to clear the frame.  The whitish haze stuff on the rails is the dry lube.

[Nocturnal005]

12 hours ago, empti said:

@Nocturnal005 @KnifeySpoony I am wondering how far back/forth your seats can slide? I noticed mine can probably can only slide 2 inches forward from all the way back. Is this the case on yours ? 

I measured it. In the farthest back location the front of the seat (carbon bucket) is just behind the cross beam on the floor. From that position it is able to slide 3" total towards the front. I also noticed I cant' really get the seat further back than it is because the headrest of the seat is already getting close to the trackday roll bar. Hope that helps

[MV8]

The seat to track mounting can be offset forward as needed without new holes or changing the rails. Fully rearward positioning of the tracks without a seat, setting the seat on the track with the headrest/seat back touching the rear firewall, then marking the track through the seat mounting holes would determine how far the forward the offset could be. I don't think two inches would be an issue.

 

You can use 1/2x1-1/2 aluminum plate and thread inserts with 1/2" lightening holes or a lighter version using two bent mounting plates and 1/2" wide rails, all made of .080-.125" steel sheet/strip and require a little more hardware in four bolts or nuts.

 

If the rails contact the cross beam, thin washers can be added to between the track and the frame at the front.