Traction, or lack of

[M5 TT]

Originally Posted by DTP1980

I don’t think I have an attitude problem with this matter. I have attempted to guide our fellow member based on information they have given by providing further important information to consider rather than pushing him down a set route, which up to that point was very narrow.

The approach from people is to assume that BMW are somehow wrong, so the answer often seems to be to throw money at the problem rather than looking at it objectively and in a manner that gets to the source of the problem.

The problem described is rarely read on these forums, so we have to assume there are some unknown factors here, which I have tried to address in part.

I don’t believe he said it was tuned, so my approach was to assume not.

We are also assuming there isn’t a technical problem because one hasn’t been indicated. A quirky diff or throttle issue could easily be considered.

Read some books. Altering rear camber towards zero alone will increase understeer because rear grip increases, thus overpowering front grip. This will be quite notable in damp/ wet conditions. In a non AWD M car especially, this is not favourable. And as the camber is set by the highly experienced and qualified technicians at BMW M, I bet almost no-one on this forum is qualified to argue with their setup. Logically, it would come from the factory that way otherwise.

Making tyres wider than default will increase the contact patch which will increase a vehicles tendency to aqua plane. Water skis aren’t narrow, they are fat and wide. This is a simple matter of physics.

Neither did I say that I was against progress or advancing our machinery to meet our goals. I’ve owned tens of cars and enhanced them all in one way or another to my advantage, based on years of reading and learning, not just by mindlessly following the other sheep.

Fair enough.

So far I have not found any increase in under steer but as I said I don't track my car. I have increased rear tyre size and contact patch, I have also reduced rear cornering grip due to rear camber reduction, very doubtful I have actually lost any front end grip.

Reading books will only help give you an idea of what may happen and wont be car specific. All my years of kart racing has given me a very good understand of how traction works and the effects of altering front and rear grip. I am not saying BMW got it wrong. I am saying they set the car up for the best of both world. Road and Track and only 560bhp

What you also have to take into consideration is we live in the UK where ambient temps are rarely above 15 degC and rear traction is a big issue

I am no sheep, I would say I am the exact opposite and always trying to find a way to improve my cars, sometimes I get good results and sometimes not. I been playing with cars more years than I care to remember. My set up is tested (about 3k miles) and am happy with where I am currently.

Hmmm, way to many "I"s in that post lol

[Herofmine]

2015 M5 just a tune and catless downpipes pushing 729wtq and 700whp PS 4s all around and i don't have any problem with traction, yesterday on the highway i had a chance to pull with F90 m5 roll race from 30 mph i just destroyed him owner was shocked.
If your car properly tuned and if you have nice tires you will not have any issues with traction.

[steeve13m]

Originally Posted by Herofmine

2015 M5 just a tune and catless downpipes pushing 729wtq and 700whp PS 4s all around and i don't have any problem with traction, yesterday on the highway i had a chance to pull with F90 m5 roll race from 30 mph i just destroyed him owner was shocked.
If your car properly tuned and if you have nice tires you will not have any issues with traction.

What tune you running?

[Herofmine]

Originally Posted by steeve13m

What tune you running?

Flash tune by Kevin @golabworx

[DannyA]

Yeah I have to agree the power is very hard to get down, but with practice, you can have a much better chance.

Even if you are trying to burn someone off the lights etc, I always find its so much better to get at least some sort of movement before hitting the power (E.g. 10mph+). I would also suggest keeping it in second, if you get the traction at the start you can hammer the whole of 2nd with no spin.

If you are doing a standing start, I did some tests with an ODE reader and it was actually faster to 60 with all settings set to normal drive mode!

Another very strange thing I have noticed is that with the suspension on sport mode, unless the road is perfectly flat (pretty much no UK road) then you get better grip on the softer settings.

My car is 700 BHP+ and although it is easier to light up the rear wheels, the improved acceleration is very noticeable. When I drive it in stock it is a different car.

I moved from an RS6 and one thing I really love about the M5 is when on a motorway the car will squat under hard acceleration, you just dont get that with 4WD

[Advantage]

We primarily do roll racing from 40 mph here. At those speeds in 2nd gear I could never put the power down due to traction. And, as we all know, spinning ain't winning. Heck, I would even break loose at 50 and 60 mph on the freeway which is a little more than scary. That was with new MPSS on 20" stock wheels (295s in back).

I recently moved to NT05's (305s in back) and have no issues with traction even at 40 mph in 2nd gear. These things just stick and go.

[Dwaynos]

Yeah I have problems at 50 and 60 also. I'm going to have to go for Michelin 4s 305s and hope for the best as the weather here in the UK won't allow the likes of nittos or r888rs.

[Advantage]

Originally Posted by Dwaynos

Yeah I have problems at 50 and 60 also. I'm going to have to go for Michelin 4s 305s and hope for the best as the weather here in the UK won't allow the likes of nittos or r888rs.

We've had a very wet start to summer here in Minnesota. I have to say I am impressed with the NT05's in the rain thus far. The far superior grip in the dry far exceeds the minimal loss (if any) in the wet when compared to Michelin's IMO.

[Barry_S]

Originally Posted by Dwaynos

Yeah I have problems at 50 and 60 also. I'm going to have to go for Michelin 4s 305s and hope for the best as the weather here in the UK won't allow the likes of nittos or r888rs.

This is a very interesting thread. After 5 months now with my MY15 I'm ready to put new boots on the rear and have been considering everything discussed in this thread.

I'm curious to know what you actually went with. 305 MP4S? Spacers?

What is your impression?

Thanks,
Barry

[Dwaynos]

Originally Posted by Barry_S

This is a very interesting thread. After 5 months now with my MY15 I'm ready to put new boots on the rear and have been considering everything discussed in this thread.

I'm curious to know what you actually went with. 305 MP4S? Spacers?

What is your impression?

Thanks,
Barry

I have 5mm spacers for cosmetics only. I am running the 305 MPS4s and wouldn't go back to anything else. (Other than r888r)

The grip is night and day compared to the 295 MPSS that were fitted before. You will still struggle sometimes though, the only way around this is toyo r888r but then you would lose the daily driveability of the car, especially is wet conditions.

[Barry_S]

Originally Posted by Dwaynos

I have 5mm spacers for cosmetics only. I am running the 305 MPS4s and wouldn't go back to anything else. (Other than r888r)

The grip is night and day compared to the 295 MPSS that were fitted before. You will still struggle sometimes though, the only way around this is toyo r888r but then you would lose the daily driveability of the car, especially is wet conditions.

Thanks for the feedback. This exactly what I’ve been planning to do. Did you put any spacers on the front or leave stock?

Any profile shots you can share that illustrate the outside edge of the tire to the fender?

Barry

[Dwaynos]

Originally Posted by Barry_S

Thanks for the feedback. This exactly what I’ve been planning to do. Did you put any spacers on the front or leave stock?

Any profile shots you can share that illustrate the outside edge of the tire to the fender?

Barry

I currently do not have spacers on the front, I have 275 MPS4s on there. I'm currently looking into making from mudflaps for the front to keep stone chips to a minimum. Once I've done that i will most likely put 5mm on the there aswell.

Shots of the rear tyre? I'll take some tomorrow if I remember.

[Barry_S]

Originally Posted by Dwaynos

I currently do not have spacers on the front, I have 275 MPS4s on there. I'm currently looking into making from mudflaps for the front to keep stone chips to a minimum. Once I've done that i will most likely put 5mm on the there aswell.

Shots of the rear tyre? I'll take some tomorrow if I remember.

Thank you. Your feedback has been very helpful.

I'm running the stock 265's on the front and am planning on mounting 305's on the rear with a 5mm spacer as you've done. This may create some understeer as others have suggested, but I'm ok with that. My goal is the same that yours was. More traction.

I look forward to any pics you're willing to share.

Barry

[schrickm5]

I've been running 305 PS4's on the rear now, no spacers.... is anyone else finding them a bit "wobbly" on higher speed turns?
I am running 3.0 psi....do I need more to prevent this?

Honestly right now - I feel like switching back to 295's.
Car is a CP pack, if that makes any difference.

[M5Rick]

Originally Posted by schrickm5

I've been running 305 PS4's on the rear now, no spacers.... is anyone else finding them a bit "wobbly" on higher speed turns?
I am running 3.0 psi....do I need more to prevent this?

Honestly right now - I feel like switching back to 295's.
Car is a CP pack, if that makes any difference.

Mine is a non CP with the 305's and 5mm spacers,none at the front and I have absolutely no problem with wobbling on fast curves using the standard tyre pressures. Driving to Goodwood for an event took many curves fast in sport mode suspension and steering with g/box in soft mode.

[lotus49]

Originally Posted by Dwaynos

I value my driving licence so I don't disregard speed limits.

If by this, you mean you always stick to the speed limits, why on earth did you buy a car capable of 190MPH with 5 times the power of a normal family car?

If you are driving around on the roads that are typical of the UK, particularly near towns, you probably will get blown away by cars like the Focus RS, Civic Type R etc. but you could have established that before you bought it.

As you will have gathered by now, the M5 is far too powerful for anyone to be able to use all its performance often. I tend to make special trips out onto quiet roads where I can be reasonably sure that I won't attract the attention of the Police nor encounter many other cars. When I do that, the car is mind-blowing. The rest of the time, it's over the top. So much so that I have decided to buy another car for commuting, going to the shops and so on.

Many years ago, Autocar did a group test of a bunch of supercars against the Clio 16V. Their conclusion was that most of the time, the supercars were quicker but on normal roads, only just. Not much has changed.

PS I just realised that I joined in a bit of necroposting. I hadn't realised that your initial post was last year. Since you appear still to have your M5, what changed your mind?

[Dwaynos]

Originally Posted by lotus49

If by this, you mean you always stick to the speed limits, why on earth did you buy a car capable of 190MPH with 5 times the power of a normal family car?

If you are driving around on the roads that are typical of the UK, particularly near towns, you probably will get blown away by cars like the Focus RS, Civic Type R etc. but you could have established that before you bought it.

As you will have gathered by now, the M5 is far too powerful for anyone to be able to use all its performance often. I tend to make special trips out onto quiet roads where I can be reasonably sure that I won't attract the attention of the Police nor encounter many other cars. When I do that, the car is mind-blowing. The rest of the time, it's over the top. So much so that I have decided to buy another car for commuting, going to the shops and so on.

Many years ago, Autocar did a group test of a bunch of supercars against the Clio 16V. Their conclusion was that most of the time, the supercars were quicker but on normal roads, only just. Not much has changed.

PS I just realised that I joined in a bit of necroposting. I hadn't realised that your initial post was last year. Since you appear still to have your M5, what changed your mind?

When I first got my M5 I was let down by the lack of traction although I knew it was an issue before I bought it.

The 305s have made it better but that's not the reason I kept the M5. I still own it because I absolutely love the car, despite its issues. It's a lot of fun even though you can't even use half of its power on most roads. Theres something about owning an M5 that gives me satisfaction although I commute to work like it's a 520d.

I can honestly say I've never fully stretched the M5s legs but a trip to Germany will hopefully sort that some day.

When I mentioned speed limits I mean, I don't race numpties because they keep going after 100mph and that is going to get me banned.

[Ickdeep]

When I first got my M5, it had Pirelli P zero's which were okay but I had issues losing traction 2nd and even 3rd great. And if it was wet out (like at all), bang like no traction at all. Then I switch to Michelin Pilot Sport 4s and they are soo much better all the way around. Even in the wet, they work pretty well. Zero complaints with these tires.

[Barry_S]

Originally Posted by Ickdeep

When I first got my M5, it had Pirelli P zero's which were okay but I had issues losing traction 2nd and even 3rd great. And if it was wet out (like at all), bang like no traction at all. Then I switch to Michelin Pilot Sport 4s and they are soo much better all the way around. Even in the wet, they work pretty well. Zero complaints with these tires.

Are you 295 or 305 on the rear?

[Ickdeep]

Originally Posted by Barry_S

Are you 295 or 305 on the rear?

295

[M5Rick]

May be some are probably putting too much throttle on the bends and curves causing the rears to hick up, a trailing throttle with full power when just out of the bend works for me.

[schrickm5]

Originally Posted by M5theonlyone

Mine is a non CP with the 305's and 5mm spacers,none at the front and I have absolutely no problem with wobbling on fast curves using the standard tyre pressures. Driving to Goodwood for an event took many curves fast in sport mode suspension and steering with g/box in soft mode.

What is the tyre pressure you run on the rears?