Standard brake pads/setup 420
Discussion
Hi All, I have a 420 with quad piston brakes. The car is a self build so there's a possibility of poor brake bleeding (!) but the brakes lack any kind of bite. I'm at Snetterton next week so keen to understand is this is normal and perhaps the brakes perform better as they warm?
The suspension performs badly on the road as the car really fidgets over bumps (rear jumps around a little) so also keen to receive any feedback with regards to setup!
I have the Sports suspension pack.
Thanks, Robert.
The suspension performs badly on the road as the car really fidgets over bumps (rear jumps around a little) so also keen to receive any feedback with regards to setup!
I have the Sports suspension pack.
Thanks, Robert.
I built pretty much the identical car to you.
420 sports suspension and 4 pot calipers. It's even the same colour!
The brakes have always been a pig to bleed properly. Even after having used a pressure bleed system, I always found the old school 2 man job way of manually pumping fluid through was the only way to get all the air out. It was usually the rears which were the main problem. If you have only just built it, they will need bedding in though.
The sports suspension IMO is awful for purely road use and does tend to get easily unsettled on anything less than perfect roads but comes into it's own on track. That's the trade off I suppose.
Even for track use, I run the rear anti-roll bar on a soft setting and if I was only using it on the road, I would remove it altogether.
Andy
420 sports suspension and 4 pot calipers. It's even the same colour!
The brakes have always been a pig to bleed properly. Even after having used a pressure bleed system, I always found the old school 2 man job way of manually pumping fluid through was the only way to get all the air out. It was usually the rears which were the main problem. If you have only just built it, they will need bedding in though.
The sports suspension IMO is awful for purely road use and does tend to get easily unsettled on anything less than perfect roads but comes into it's own on track. That's the trade off I suppose.
Even for track use, I run the rear anti-roll bar on a soft setting and if I was only using it on the road, I would remove it altogether.
Andy
Edited by Gasolina on Saturday 30th July 13:25
Thanks for the replies. Yes, I find the rear fidgets all over the place on B roads, there's plenty of grip but bumps bounce the rear over so I'm just not really bonding with the drive right now. I also think there's not enough heat in the tyres since the rear also steps out quite easily - but also probably brought on by bumps I guess. Anyway, hope the track makes much more sense. I do really like the 420 - I also think the power delivery is a little odd for such a light car with the performance so high on the rev range which is a little manic for the road.
With a solid rear axle, the rear will always be a little "lively" over bumps in corners. I have the much stiffer track spring rates, but I also have the Watts linkage which eliminates rear axle steer, so I don't find it hard to control on the street, though it is very stiffly sprung for a street car. The stiff rates feel great on track though.
Probably not a very useful data point, being a much different car/suspension setup, but I'm always surprised by how compliant my (06/k engined) cat is on the road. Non-sports suspension, but being light it gets away with being softer than (for example) the boxster that preceeded it.
I assume the sports pack isn't adjustable for damping? Maybe it's a get used to it, but they can be very compliant IME.
Rear will always be lively. You never have meaningful tyre temperature road driving and there's a lot of power with little weight. Definitely need to respect the go pedal (or deliberately abuse it for giggles, but on your terms..). Goes double if it's cold / damp.
As for brakes.. what are you comparing them to? IME they will feel a bit wooden and like nothing much is happening if you're used to / coming from a typical modern car that is heavily assisted... but the difference is simply 'shove'. Get used to applying an order of magnitude more pressure and they're devastatingly effective. I can't say I've noticed any real cold brake issues, despite running rather more 'track focussed' pads (ds2500).
Of course, you might have a brake issue, but I think you'd need to compare to another caterham to see on that. If the pedal's firm, I'd start with 'hit them harder'.
I assume the sports pack isn't adjustable for damping? Maybe it's a get used to it, but they can be very compliant IME.
Rear will always be lively. You never have meaningful tyre temperature road driving and there's a lot of power with little weight. Definitely need to respect the go pedal (or deliberately abuse it for giggles, but on your terms..). Goes double if it's cold / damp.
As for brakes.. what are you comparing them to? IME they will feel a bit wooden and like nothing much is happening if you're used to / coming from a typical modern car that is heavily assisted... but the difference is simply 'shove'. Get used to applying an order of magnitude more pressure and they're devastatingly effective. I can't say I've noticed any real cold brake issues, despite running rather more 'track focussed' pads (ds2500).
Of course, you might have a brake issue, but I think you'd need to compare to another caterham to see on that. If the pedal's firm, I'd start with 'hit them harder'.
An update - the 420 was brilliant at Snetterton in every way! Incredibly composed and stable - all of the B road shakes and damping issues vanished! I fitted EBC RPX brake pads in the end which did improve upon the standard AP brake pads - even on the road - but on the track they were really good. There's quite a bit of travel before the brakes kick in so guess they might need bleeding a little more. The only issue I experienced was with the comfort seats we selected - my side is bruised as I wasn't held in too well. Oh and the standard Avon ZZS tyres also performed brilliantly!
Thank you for the replies.
Thank you for the replies.
Edited by hooneyrob on Friday 5th August 22:18
Edited by hooneyrob on Friday 5th August 22:33
BertBert said:
Very pleased it all came together on track. Are the brakes better on the road after a proper use on the track?
I could tell straight away that the EPX had more bite vs the AP pads, there's less of a wooden feel if that makes sense. I'd never used the AP pads on track so don't know if they would have performed similarly.I had a live axle Caterham for many years. I sold it in 2019 & bought a 420R.
When I test drove the 420, I loved the car generally, but assumed the brakes needed a good bleed, as the pedal travel was so long.
But bleeding the brakes didn’t improve matters. Initially, I assumed it was my brake bleeding technique that was at fault, particularly as I’d done a bit of research online & had come across a lot of allusions to the rear calipers being a pig to bleed.
After a lot of repeated bleeding & no improvement, I took the car to a a Caterham race prep specialist who told me that the pedal travel was ‘normal’ & suggested I fit a ‘high ratio’ race spec brake pedal.
That sorted the problem for me, giving the pedal a much shorter travel & a much more positive feel. Heel & toe was more repeatable & intuitive & in general, the pedal had the familiar feel of my old Caterham.
I’d recommend trying one.
When I test drove the 420, I loved the car generally, but assumed the brakes needed a good bleed, as the pedal travel was so long.
But bleeding the brakes didn’t improve matters. Initially, I assumed it was my brake bleeding technique that was at fault, particularly as I’d done a bit of research online & had come across a lot of allusions to the rear calipers being a pig to bleed.
After a lot of repeated bleeding & no improvement, I took the car to a a Caterham race prep specialist who told me that the pedal travel was ‘normal’ & suggested I fit a ‘high ratio’ race spec brake pedal.
That sorted the problem for me, giving the pedal a much shorter travel & a much more positive feel. Heel & toe was more repeatable & intuitive & in general, the pedal had the familiar feel of my old Caterham.
I’d recommend trying one.
Hi Hooneyrob
is yours an S spec car which you then added the sports suspension as an option? I am guessing its missing the LSD too?
How are you finding it without the LSD on road and track? I am close to locking down the spec on my 420 which will be mainly road use so wondering if S will be better choice, although most specialists I speak to recommend getting the sport suspension for the adjustable platforms
is yours an S spec car which you then added the sports suspension as an option? I am guessing its missing the LSD too?
How are you finding it without the LSD on road and track? I am close to locking down the spec on my 420 which will be mainly road use so wondering if S will be better choice, although most specialists I speak to recommend getting the sport suspension for the adjustable platforms
Coolcatshaft said:
Hi Hooneyrob
is yours an S spec car which you then added the sports suspension as an option? I am guessing its missing the LSD too?
How are you finding it without the LSD on road and track? I am close to locking down the spec on my 420 which will be mainly road use so wondering if S will be better choice, although most specialists I speak to recommend getting the sport suspension for the adjustable platforms
Mine is a 420 spec car but with the comfort seats which was a mistake for track use - they don't hold you in enough which means your core stability has to be strong! So mine does have LSD - I've not driven one without LSD so difficult to comment. What I will say is that the 420 on the Sports suspension is a terrible road car because the rear is so jumpy over B road bumps. It depends what you want though because if you're looking for a raw experience then the Caterham doesn't get much better. With this said, you can of course try and soften the sports suspension as much as possible which might improve things - I haven't tried.is yours an S spec car which you then added the sports suspension as an option? I am guessing its missing the LSD too?
How are you finding it without the LSD on road and track? I am close to locking down the spec on my 420 which will be mainly road use so wondering if S will be better choice, although most specialists I speak to recommend getting the sport suspension for the adjustable platforms
I'd also try and drive one with the standard suspension if you're mainly driving on the road. As I said in my earlier post, the 420 on Sports suspension was amazing on the track. The standard Avons didn't grip as well when used on a second track day but the weather was cooler. And that's the other thing, the Avons do need heat to work well which you'll not generate on the road - the rear will step out. And lastly, the 420 power delivery doesn't suit the road for me because you have to thrash it which becomes a little annoying if the 40 in a 60 SUV's get in the way.
AFAIK the standard and sport suspension have the exact same spring rate and dampers - the only difference is the adjustable spring perches on the sport. There will be no difference in ride quality. Going up to the "track" suspension increases the spring rates significantly, especially at the rear. The "race" suspension as the same rates at the "track", but has better quality dampers.
Blue 7 said:
After a lot of repeated bleeding & no improvement, I took the car to a a Caterham race prep specialist who told me that the pedal travel was ‘normal’ & suggested I fit a ‘high ratio’ race spec brake pedal.
That sorted the problem for me, giving the pedal a much shorter travel & a much more positive feel. Heel & toe was more repeatable & intuitive & in general, the pedal had the familiar feel of my old Caterham.
I’d recommend trying one.
Late to the thread here, but I had exactly this many years ago in my 1600 k. The higher ratio brake pedal was much better.That sorted the problem for me, giving the pedal a much shorter travel & a much more positive feel. Heel & toe was more repeatable & intuitive & in general, the pedal had the familiar feel of my old Caterham.
I’d recommend trying one.
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