Discussion
Cars with abs are set with negative scrub radius so that if your brakes on one corner fail the car will remain in a straight line under braking.
Modern cars are set with negative scrub radius so that if you have a blow out, the car will be easier to control - the wheels won’t naturally turn to put weight onto the failed tyre, and the car will be easier to keep on a straight line.
Negative scrub radius will reduce bump steer. So spacers fitted will make the steering more fidgety over bumps (though the increased steering feel that also result will probably be welcome).
Negative scrub radius increases braking stability, the car will maintain a straight line better under braking than it will with a positive scrub radius, especially on bumpy roads.
So, I know perfectly well what I’m talking about, thanks.
The dismissal of the claim sounds like someone who doesn’t like the claim making up a reason (‘sounds like someone just parroting without understanding’) to disregard it.
Modern cars are set with negative scrub radius so that if you have a blow out, the car will be easier to control - the wheels won’t naturally turn to put weight onto the failed tyre, and the car will be easier to keep on a straight line.
Negative scrub radius will reduce bump steer. So spacers fitted will make the steering more fidgety over bumps (though the increased steering feel that also result will probably be welcome).
Negative scrub radius increases braking stability, the car will maintain a straight line better under braking than it will with a positive scrub radius, especially on bumpy roads.
So, I know perfectly well what I’m talking about, thanks.
The dismissal of the claim sounds like someone who doesn’t like the claim making up a reason (‘sounds like someone just parroting without understanding’) to disregard it.
GiantCardboardPlato said:
So, I know perfectly well what I’m talking about, thanks.
Each example you've provided is true to a certain degree, but in practical terms somewhat immaterial."Cars with a negative scrub radius have greater stability under split braking or failures" Yes..so what? Are we talking moving from a negative to positive scrub radius, or just reducing the degree of negative scrub? Are we happy to trade a degree of that stability for significantly increased road feel and feedback? I think a lot of people would be.
"Screwing up all the geometry"

d_a_n1979 said:
Which 'silver' is it, do you know?
I wondered this too. So much nicer than a diamond cut finish.HM-2 said:
Are we happy to trade a degree of that stability for significantly increased road feel and feedback? I think a lot of people would be.
"Screwing up all the geometry"
Birds specify spacers for the 140 as part of their handling upgrades for exactly this reason. I think they know what they're doing."Screwing up all the geometry"

It’s been 5 years now since I collected my 340i, it’s the longest I’ve owned a car and I’m still loving it. In that time it’s taken me all over the country & I think 6ish trips to Europe. It’s been fantastic, I’ve commuted in it, done road trips in it, taken it for back road hoons and lapped the odd track in it too, it’s taken it all in its stride.
As I’d always planned to keep it long term I’ve serviced it yearly, on top of that it’s had a set of front pads, a set of rear pads and a set of new tyres a while after getting the wheels. It’s treated me well so far, hopefully by me keeping on top of everything it’ll continue to do so. Total spend on maintaining it is at around £2,500.
I’ve listed the mods as I’ve gone along here so I wont go into too much detail about them all, but I will say as a whole they have enhanced the car hugely for me. The suspension is a huge improvement on the stock stuff and the MPPSK gives the car the sound to go with the performance. The maps (engine and box) have taken advantage of the extra performance the B58 has hiding inside, still very happy with all of those changes. I’ve probably spend about £4250 on modifications over those 5 years (Mrs Pizzaeatingking isn’t a PHer)
I bought the car new and always knew it would be here for a while but I decided to have a little look at the current values touted for similar models. I’m hugely surprised, I know perhaps the COVID thing has effected the prices of used cars but it appears the cars lost around £8k over the 5 years! Bonkers, I think this was helped by getting a very good deal on the car in the first place but the 40i cars in general seem to be doing well.
I’m hoping this summer to finally get the LSD sorted, then get a sports cat and tweak the map. I’ve been reading up on Quaife vs M Perf LSD, then I’ll get looking at downpipes. I dunno how far I’ll go with it, there are loads of B58 engines running decent power with very few issues, even the ones that seem to have a hard life.
I’ve done 40k in it now, mix of everything although since changing jobs a couple of years back it has been used less for commuting and more for fun. It still makes me grin when I get in it, I still get nice looks and comments about it too. I’ve considered changing it but it’s tough to find something that covers all the bases as well as this does. The only thing that really excites me is the Alfa Guilia but I’m not wanting to spend that money at the moment, both in purchasing and running it.
I’m off to Germany again in a few weeks, ironically with my mate in his Guilia, so I’ll have plenty of time to ponder while I following him down the autobahn (lets be honest I’ll probably not pass him!). Later in the year I’ll be driving down to Italy for my brother in laws wedding, followed by a visit to Munich on the way home
Plenty of road trips to be getting on with.




As I’d always planned to keep it long term I’ve serviced it yearly, on top of that it’s had a set of front pads, a set of rear pads and a set of new tyres a while after getting the wheels. It’s treated me well so far, hopefully by me keeping on top of everything it’ll continue to do so. Total spend on maintaining it is at around £2,500.
I’ve listed the mods as I’ve gone along here so I wont go into too much detail about them all, but I will say as a whole they have enhanced the car hugely for me. The suspension is a huge improvement on the stock stuff and the MPPSK gives the car the sound to go with the performance. The maps (engine and box) have taken advantage of the extra performance the B58 has hiding inside, still very happy with all of those changes. I’ve probably spend about £4250 on modifications over those 5 years (Mrs Pizzaeatingking isn’t a PHer)
I bought the car new and always knew it would be here for a while but I decided to have a little look at the current values touted for similar models. I’m hugely surprised, I know perhaps the COVID thing has effected the prices of used cars but it appears the cars lost around £8k over the 5 years! Bonkers, I think this was helped by getting a very good deal on the car in the first place but the 40i cars in general seem to be doing well.
I’m hoping this summer to finally get the LSD sorted, then get a sports cat and tweak the map. I’ve been reading up on Quaife vs M Perf LSD, then I’ll get looking at downpipes. I dunno how far I’ll go with it, there are loads of B58 engines running decent power with very few issues, even the ones that seem to have a hard life.
I’ve done 40k in it now, mix of everything although since changing jobs a couple of years back it has been used less for commuting and more for fun. It still makes me grin when I get in it, I still get nice looks and comments about it too. I’ve considered changing it but it’s tough to find something that covers all the bases as well as this does. The only thing that really excites me is the Alfa Guilia but I’m not wanting to spend that money at the moment, both in purchasing and running it.
I’m off to Germany again in a few weeks, ironically with my mate in his Guilia, so I’ll have plenty of time to ponder while I following him down the autobahn (lets be honest I’ll probably not pass him!). Later in the year I’ll be driving down to Italy for my brother in laws wedding, followed by a visit to Munich on the way home





Congrats on the 5 years. Have loved reading through the posts.
If your getting a sports cat you may want to get a cold start delete. A sports cat + mppsk = loud cold starts.
And if your getting a sports cat fitted, might as well get the B58TU high pressure fuel pump fitted too. That will complete the performance mods for “full bolt on” aka stage 2+.
Maybe worth thinking about the ZF gearbox oil service at some point too.
Hope my suggestions don’t hurt the wallet too much!
If your getting a sports cat you may want to get a cold start delete. A sports cat + mppsk = loud cold starts.
And if your getting a sports cat fitted, might as well get the B58TU high pressure fuel pump fitted too. That will complete the performance mods for “full bolt on” aka stage 2+.
Maybe worth thinking about the ZF gearbox oil service at some point too.
Hope my suggestions don’t hurt the wallet too much!
On the LSD, I wouldn't agonise about what type to get - it's not a racing car. I took my 340i to Birds and let them loose with the suspension, diff and remap - during that process I read a lot about the M Performance diff and the Wavetrack, with people crowing about how the Wavetrack is superior because it stays locked when one wheel is in the air etc. If it's a track car I get it, but for a road car that kind of thing is entirely unnecessary to worry about so just crack on with the one you want.
For what it's worth, I've never wanted for anything more than the Quaife diff in mine. It's transformative when you have 400+ bhp in these cars.
For what it's worth, I've never wanted for anything more than the Quaife diff in mine. It's transformative when you have 400+ bhp in these cars.
bumskins said:
Lovely looking car OP, perfect illustration (as if any were needed) that black/'diamond cut' wheels look s
t and hide the best features of a good wheel design.
RE: your LSD agonising, I always thought the M Performance LSD was an item manufactured by Quaife?
I agree on the wheels, most look much better in a lighter shade than black.
RE: your LSD agonising, I always thought the M Performance LSD was an item manufactured by Quaife?
I don’t think so, they’re a plated diff vs the quaife type.
Bobupndown said:
Stunning looking car.
Re your magnetic plates, what do they actually 'stick' to?
Is it just the metal behind the presumably plastic outer face of the bumper?
The kids come with a set of small magnets that stick behind the bumper. Nice and strong too! Re your magnetic plates, what do they actually 'stick' to?
Is it just the metal behind the presumably plastic outer face of the bumper?
Pizzaeatingking said:
I don’t think so, they’re a plated diff vs the quaife type.
The M Perf diff is made by Drexler. Plate type with 30% lock-up. I'll be getting mine fitted soon (also on a 340i, caused in no small part by this thread). Pizzaeatingking said:
The kids come with a set of small magnets that stick behind the bumper.
I'll have to try this for my 3-year-old daughter. It'll stop her kicking my seat. Edited by HM-2 on Wednesday 17th May 21:57
Survived Germany. Lovely drive there and back with my mates, done one lap of the ring in a thunderstorm. It was lovely, only saw 2 other cars!

Before that we stopped at a hotel that has car lifts to allow you to park on your hotel rooms balcony. I think this is my favourite picture of my car yet, taken from my hotel bed!


Pretty cool, staying again later in the year but with the mrs.

Before that we stopped at a hotel that has car lifts to allow you to park on your hotel rooms balcony. I think this is my favourite picture of my car yet, taken from my hotel bed!


Pretty cool, staying again later in the year but with the mrs.

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