Why did I bother!!!
Discussion
17" wheels on my e39 touring need a refurb so acquired a set of 16" ones to tied me over. Had them balanced and fitted to car. Look brilliant but....car handles like a pig! Thought I could live with it but can't so rang dealer for advice.
Dealer now recommending a. 4 wheel alignment, b. computer adjustment of rear self-levelling suspension ride height plus c. gearbox adaption reset!
They argue a. different set up of car with 16s, b. ride height adjustment needs to be made to rear suspension (but surely rolling radius is the same so no adjustment is necessary) and c. gearbox needs to relearn with the 16s on (thought gearbox was learning adaption system so will adjust after a while).
Does any or all of this make sense to someone, and if so, which, if any, of the recommended work do I actually need done? Their bill would be £449 (plus VAT I assume).
Beginning to think that I will just get 17" wheels refurbed asap!
Dealer now recommending a. 4 wheel alignment, b. computer adjustment of rear self-levelling suspension ride height plus c. gearbox adaption reset!
They argue a. different set up of car with 16s, b. ride height adjustment needs to be made to rear suspension (but surely rolling radius is the same so no adjustment is necessary) and c. gearbox needs to relearn with the 16s on (thought gearbox was learning adaption system so will adjust after a while).
Does any or all of this make sense to someone, and if so, which, if any, of the recommended work do I actually need done? Their bill would be £449 (plus VAT I assume).
Beginning to think that I will just get 17" wheels refurbed asap!
If the wheels are being refurbed not sure why you're too worried. But saying that, if it is a pig to drive it could be for a number of reasons. Firstly, the car will drive differently on 16s to 17s, the side walls of the tyres are bigger so it'll give a softer more compiant ride and probably not as sharp a turn in. Secondly, you didn't mention if the tyres on the 16s are part worn, good quality brand or cheap brand. Cheap tyres can be awful things. As has been mentioned, what are the tyre pressures? If your 17s are going back on and it was fine with them before, I wouldn't make any adjustments to the suspension, as you'll have to put it back when you put the 17's back on.
There's no sense getting 4 wheel alignment on 16's when you'll end up swapping to 17's again once they're back from being refurbed.
If the wheels and tyres have come off another car, they're an unknown quantity. They may need a rebalance. The wheels could be buckled and more importantly, the tyres will have been worn in a completely different way to how your car is set up and may well be a mish-mash of patterns and different tread depths. This along with what has been mentioned above is typical.
I'd do the cheap stuff first; check the tyre pressures, jack the car and check for buckles in the wheels and uneven wear patterns and then look at a rebalance.
If the wheels and tyres have come off another car, they're an unknown quantity. They may need a rebalance. The wheels could be buckled and more importantly, the tyres will have been worn in a completely different way to how your car is set up and may well be a mish-mash of patterns and different tread depths. This along with what has been mentioned above is typical.
I'd do the cheap stuff first; check the tyre pressures, jack the car and check for buckles in the wheels and uneven wear patterns and then look at a rebalance.
Hi
17s are 235/45/17 and 16s are 225/55/16.
The 16s are immaculate and really look the part (type 32), they were balanced before they were put on the car, as a precaution, and they are not buckled and there was not apparent uneven wear to the tyres although they are a mixture of brands. Were it not for the handling I would really like to keep them on for the time being. The 17s are cross spoke split rims and have gone the way of many I have seen and made the car look constantly dirty.
I decided to wait until I needed to get new tyres before I did the refurb and so am faced with a refurb and 4 new tyres versus getting the car sorted with the 16s
Handbook gives pressures for both wheel sizes as 29 F 34 R. I have checked them weeekly since being fitted and they are fine.
Am going to do a battery restart to attempt to sort the gearbox ie disconnect battery for 20mins but I understand that it is alsoo worth holding the battery terminals together to discharge the memory completely.
Regarding the self levelling ride height, is it a indie/dealer thing or is there a way of doing it yourself? I am tempted to buy the softwear and cable off a popular internet site and attempt it myself, it has to be cheaper than a dealer doing it!
17s are 235/45/17 and 16s are 225/55/16.
The 16s are immaculate and really look the part (type 32), they were balanced before they were put on the car, as a precaution, and they are not buckled and there was not apparent uneven wear to the tyres although they are a mixture of brands. Were it not for the handling I would really like to keep them on for the time being. The 17s are cross spoke split rims and have gone the way of many I have seen and made the car look constantly dirty.
I decided to wait until I needed to get new tyres before I did the refurb and so am faced with a refurb and 4 new tyres versus getting the car sorted with the 16s
Handbook gives pressures for both wheel sizes as 29 F 34 R. I have checked them weeekly since being fitted and they are fine.
Am going to do a battery restart to attempt to sort the gearbox ie disconnect battery for 20mins but I understand that it is alsoo worth holding the battery terminals together to discharge the memory completely.
Regarding the self levelling ride height, is it a indie/dealer thing or is there a way of doing it yourself? I am tempted to buy the softwear and cable off a popular internet site and attempt it myself, it has to be cheaper than a dealer doing it!
Edited by Scamp's Walker on Friday 6th May 18:13
Have you got different tyres on front and rear??
That kills BMWs handling wise.
For a start, ride height does not need adjusting, the car should be riding the same, you should have 225.55.16's to be the same, but 235.55 will make sod all different.
Alignment? I doubt it, unless it was out before and the tyres wore unevenly to comspensate and now you really notice with decent ones on?
What tyres are they?
Correct load rating for that car?
Not something that is out of date? Tyres only last 5 years.
More info needed.
That kills BMWs handling wise.
For a start, ride height does not need adjusting, the car should be riding the same, you should have 225.55.16's to be the same, but 235.55 will make sod all different.
Alignment? I doubt it, unless it was out before and the tyres wore unevenly to comspensate and now you really notice with decent ones on?
What tyres are they?
Correct load rating for that car?
Not something that is out of date? Tyres only last 5 years.
More info needed.
Buy a matching set of 16" tyres - they'll be a fair chunk cheaper than 17's. Match the rolling radius properly - I notice a comment above that you really should have 225's (which will be cheaper than 235's - more common). There are wheel size calculators online if you want to check.
Once you're on matching rubber if you've still got problems then start looking at suspension setup etc, but also consider increasing the tyre pressures (within the limit written on the sidewall) if you just want things a little firmer.
My Volvo felt more sloppy when I switched from 17's to 16's in October, but less comfortable and more jittery when I swapped back to 17's in March so it's probably as much a case of getting used to the different ride. I'm seriously considering a second set of 16's for the summer because on balance the ride was probably better and the tyres are so much cheaper.
Once you're on matching rubber if you've still got problems then start looking at suspension setup etc, but also consider increasing the tyre pressures (within the limit written on the sidewall) if you just want things a little firmer.
My Volvo felt more sloppy when I switched from 17's to 16's in October, but less comfortable and more jittery when I swapped back to 17's in March so it's probably as much a case of getting used to the different ride. I'm seriously considering a second set of 16's for the summer because on balance the ride was probably better and the tyres are so much cheaper.
Just to clear up, they are all 225s, which is the recommended BMW size and are all the correct speed rating or above.
Are they really that sensitive to mixing tyres? Does it really make that much difference? Only ever replaced pairs or like for like before but just went with what they were this time.
So all the other potential recommended work would be unnecessary?
Are they really that sensitive to mixing tyres? Does it really make that much difference? Only ever replaced pairs or like for like before but just went with what they were this time.
So all the other potential recommended work would be unnecessary?
Sorry - just re-read your earlier post on sizes. According to this link you should be on 215/55/16 to match the 235/45/17's you took off, although the difference isn't great.
Your best option is just to get the refurbishment done quicker and then buy some winter tyres for the 16's in September ready for when the bad weather hits in November. If you're thinking of using the 16's long term then get some decent matching tyres fitted before you commit any money to making it all work - the car is bound to handle badly with different handling characteristics on every corner. Would you go out wearing a dress shoe on one foot and a wellington boot on the other?
Your best option is just to get the refurbishment done quicker and then buy some winter tyres for the 16's in September ready for when the bad weather hits in November. If you're thinking of using the 16's long term then get some decent matching tyres fitted before you commit any money to making it all work - the car is bound to handle badly with different handling characteristics on every corner. Would you go out wearing a dress shoe on one foot and a wellington boot on the other?
so you have 4 different tyre treads on all 4 tyres 
willing to bet that's your problem.
it's ok having different tyres front and rear, but both front tyres should be the same, and both rear tyres should be the same. i don't just mean same brand...same tread pattern! i thought just about everyone knew that!?
willing to bet that's your problem.it's ok having different tyres front and rear, but both front tyres should be the same, and both rear tyres should be the same. i don't just mean same brand...same tread pattern! i thought just about everyone knew that!?
Hi, thanks for the kind advice. Have always swapped like for like or axle by axle in the past. As it was only supposed to be a temporary fix I wasn't particularly bothered when I swapped them over. However, I have decided that they do make the car a lot cleaner etc and just thought I would leave them on whilst I decided what to do.
My handbook, and tyre pressure sticker on the car, suggest that the tyre size I have is BMW recommended.
Just going to the refurbishers now for pricing.
My handbook, and tyre pressure sticker on the car, suggest that the tyre size I have is BMW recommended.
Just going to the refurbishers now for pricing.
i think you'll find (somewhere!) that the handbook will also say not to mix and match tread patterns on a given axle. there is no other reason why it should suddenly handle terribly. how many millions of people in the world change wheel sizes on various cars and don't have problems. there is no reason why your car should be any different, it's just you have 4 different treads on the car!!! i'm not surprised it's handling very oddly. imagine when it's wet, all 4 tyres will be dispersing water at a different rate....that'll be fun! 
E21_Ross said:
imagine when it's wet, all 4 tyres will be dispersing water at a different rate....that'll be fun!
Have to agree with everything said already, it's the multiple different tread patterns that are causing the problem. Can't possibly understand why the ride height of the rear suspension would need to be reprogrammed when you're only moving to 16" wheels. Also, like you, I thought the gearbox should reprogramme itself based on your driving - why did BMW say you needed to have it reset?
Scamp's Walker said:
Had them checked over before they were balanced. There are 4 different brands on there, from recollection a Pirelli, a Bridgestone, a Continental and a Dunlop but all above minimum and noyt more than 5 years old.
Hmmm, I always thought this would make an interesting sidenote in a tyre test - put a different tyre make on each corner and see how performance compares to the matched setsBMWs hate having mixed tyres, I had my suspension changed on my M3, then the control arms, rear trailing arms, rear bushes, and then had two 4 wheel alignments done, and still it was a twitchy mess.
The back end came out overtaking on the motorway at 60mph in nothing more than damp road.
I got a call from my dealer to say someone was in that races CSLs and would take my car out for a spin to test it out. I took it down there and on the second corner he pulled over and said "You've got mixed tyres on!"
I swore I didn't and they were all Pilot Sports, but he bet me £50 they were mixed.
We got out and sure enough he was right Pilot Sport 1s on the front and Pilot Sport 2s on the back, drove back, stuck a pair of PS2s on the front and the car was then amazing, just so planted it was unreal.
I then had Kumho KU31s on my 18" track wheels on the fronts with PSports on the back for a week while waiting for stock of PS2s to arrive and they were not that bad.
So it is a gamble, they may be OK, they may be lethal.
Always put matched tyres on if you like to drive at any pace faster than plodding around, mixing them just isn't worth the risk of ruining the car.
The back end came out overtaking on the motorway at 60mph in nothing more than damp road.
I got a call from my dealer to say someone was in that races CSLs and would take my car out for a spin to test it out. I took it down there and on the second corner he pulled over and said "You've got mixed tyres on!"
I swore I didn't and they were all Pilot Sports, but he bet me £50 they were mixed.
We got out and sure enough he was right Pilot Sport 1s on the front and Pilot Sport 2s on the back, drove back, stuck a pair of PS2s on the front and the car was then amazing, just so planted it was unreal.
I then had Kumho KU31s on my 18" track wheels on the fronts with PSports on the back for a week while waiting for stock of PS2s to arrive and they were not that bad.
So it is a gamble, they may be OK, they may be lethal.
Always put matched tyres on if you like to drive at any pace faster than plodding around, mixing them just isn't worth the risk of ruining the car.
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