Low Profile Tyres

K

kfpg

Registered User
Messages
182
Can any car experts tell me why it seems like my new car gives an unusual drive. I have gone from a 318i with regular tyres to a 318d with low profile tyres.
The car seems to 'pull' all over the road and it really is not a nice drive. All I can think is that it is the effect of the low profile tyres and their wider contact surface with the road. A friend confirmed to me that it is his experience that low profile tyres do give a strange feel to the drive.

Can they be changed easily to regular tyres, would the alloy itself need to change along with the tyres, OR maybe my problem has nothing to do with this???
 
have the wheels and tyres been balanced? Is your tracking ok?? what about camber ??? all these will affect the driving feel from wheels
 
Thanks Ronan that is the first thing I did i.e. fully balanced, tracked and camber adjusted. It made no difference.
 
You are probably experiencing tramlining, see [broken link removed] for a brief explanation. Larger wheels in combination with lower profile tyres have a number of effects, while they can be more aesthetically pleasing and improve cornering and handling they also reduce the ride comfort and have a diminished ability to handle rough surfaces and potholes.

It'd also be worth checking your tyre pressures. While debate can vary on what you should be running i've found 30/32 or 32/34(front/rear) to be an adequate compromise.
 
Eurofan - thanks - "Tramlining" I would say that is exactly what is happening especially noticable on secondary roads where there is wear from heavy trucks and general poor maintenance of the road.

Does anyone know if I can just change the tyres or does the alloy need to change also. I really don;t like this tramlining sensation!
 
Lakeview said:
Does anyone know if I can just change the tyres or does the alloy need to change also. I really don;t like this tramlining sensation!
Click to expand...

Nope, you don't have to change the alloys. Go to any tyre "shop" and they'll have you back on the road in 10 mins.
 
If you change the profile, i.e. depth of the tire, you will also have to change the rims in order to preserver the outer diameter.
 
smcgiff said:
Nope, you don't have to change the alloys. Go to any tyre "shop" and they'll have you back on the road in 10 mins.
Click to expand...

The above is incorrect, Leo is bang on. Changing the profile without changing the size of the alloy will completely throw out the diameter of the overall tyre/wheel and will have other implications including underreading on your speedo.

You shouldn't experience this upto about 16" alloys with 50 or 55 sidewall. I currently have 17"s on my own car with a 45 sidewall and tramlining is present but not too bad. 18" alloys or above can experience bad tramlining depending on the kind of roads you tend to drive on.

I would emphasize checking your tire pressures though, it's amazing what a difference this can make.
 
Lakeview,

Check with your garage. Chances are they wont recommend a change in alloys - You can get 17" alloys with 55m depth.
 
smcgiff said:
Lakeview,

Check with your garage. Chances are they wont recommend a change in alloys - You can get 17" alloys with 55m depth.
Click to expand...

With all due respect please stop misguiding the chap. The information you are providing is way off the mark and shows a profound lack of understanding of how tyres/wheel combinations work.

While you can get 17" alloys with 55m depth that is not a correct size for bmws. I am currently running 17" with tyre size 245/45/17. In order to get a 55mm sidewall you'd have to reduce the width of the tyre to 185 in order to maintain the correct rolling diameter overall (absolutely vital).

He hasn't mentioned what size alloys he's using but i suspect they are 17" minimum. He could get away with 205/50/17s which would help but if he's finding the tramlining to be that disconcerting (and some people do) he's much better off dropping to 16" or even 15"s.
 
Eurofan,

I've advised him to get advice from a garage and not an anonymous poster.

You've recommended he gets new alloys. If he gets BMW alloys he's going to pay well over a thousand euro. If he doesn't go with BMW alloys he's going to lose €€€ in trade in value. He definitely should seek advice from a garage before making such a decision.
 
Eurofan said:
He hasn't mentioned what size alloys he's using but i suspect they are 17" minimum.
Click to expand...

The Standard alloy (according to BMW's website) for the 318d is 16" and the standard tyre is 205/55 R16.

There was no mention of larger wheels, but presumably they would be available.
 
You advised him he wouldn't have to change alloys, i (and others) pointed out you can't just arbitrarily change profile without affecting rolling diameter.

If he's downsizing alloys then he will have a set to sell and will not have to pay a fraction of what you suggest, there's always a willing market for 17"s and above on the various bmw boards and the bmw Ireland Club.

He specifically said originally he was running low profiles (but neglected to say what size alloys), that's not going to be 16" with a 55 sidewall but would be a good size to move to.

As for 'anonymous' advice on the internet a/you're the only one providing incorrect info and b/it is, at least, without bias which you cannot guarantee from a garage with something to sell to him.

I can heartily recommend www.bmw-driver.net and www.bmwcarclubireland.com for further advice along these lines along with options (if you so choose Lakeview) for disposing of whatever alloys you may have if you decide to downsize.
 
Hi ,


I work for a vehicle importer at technical level and if I had a euro for every time Ive seen this Id be retired today.

Firstly some backround questions ....

Are the alloys & tyres on your new car a factory factory fit?
If not what was fitted (alloy?,rim & tyre size pls)?

Were the tyres & wheels on your old beamer a factory fit? (alloy?,rim & tyre size)

Sorry for the questions , but its impossible to answer without these vital items of info.
Put very simply choosing wheels & tyres is all about compromise and achiveing an acceptable balance ie. road holding VS vehicle comfort/ride. Manufactures spend millions in the design/field testing in order to get the perfect wheel/tyre/suspension compromise or combination.
If youve fitted a wheel or tyre outside of spec youve have probably undone all that the manufacturer intended you to have with regards to road holdoing & comfort.

Dave
 
Eurofan said:
“If he's downsizing alloys”
Click to expand...


There’s no suggestion that he is.

If he has standard 16” alloys then the previous car could have had lower profile tyres, such as 45. He wouldn’t need to change alloys to put on 55m tyres. They would in fact be standard.

Is my above comment correct or not?

Eurofan said:
As for 'anonymous' advice on the internet a/you're the only one providing incorrect info and b/it is, at least, without bias which you cannot guarantee from a garage with something to sell to him.
Click to expand...


This from someone who, in another thread, advised someone to conduct themselves in a manner that would void their insurance cover. And, now, you’re advising someone to take anonymous advice over that of a garage. Next you’ll be advising on the wearing of tinfoil hats when taking a car in for a service.
 
smcgiff said:
If he has standard 16” alloys then the previous car could have had lower profile tyres, such as 45. He wouldn’t need to change alloys to put on 55m tyres. They would in fact be standard.

Is my above comment correct or not?
Click to expand...

No, you cannot just change the tire from a low profile to a 55mil without changing the rim diameter by the corresponding amount. The combined diameter of rim and tyre must remain constant.

Otherwise speedo readings will be rendered inacurate, and the ratio of wheel turns to drive shaft revolutions will change, throwing out the gearing ratios BMW presumably spent some time tuning.
 
There has been a fair bit of confusion going on in relation to this.

The facts are as follows.

1. Car manufacturers fit a wheel/tyre combination to give a certain fixed finished wheel diameter. The gears and speedometer and even such basic things as wheel clearances are calculated using this fixed figure.

2. Any subsequent changes must reflect this and the wheel/tyre combination must maintain the same overall diameter.

3. Tyres have three dimensional statistics width ,depth and wheel rim diameter.

A 225/55R17 is a tyre which has a tread width of 225mm an "aspect ratio" of 55% (i.e. the sidewall height is 55% of the tread width. "R" means it's a radial ply tyre and 17 is the diameter in inches of the hole in the middle which defines the appropriate rim.
So if you change the rim diameter calculate the required change in tyre wall height to suit and the closest fit is the correct tyre to use
 
HighFlier said:
So if you change the rim diameter calculate the required change in tyre wall height to suit and the closest fit is the correct tyre to use
Click to expand...

But what if you don't want to change the rim diameter? :)
 
You must log in or register to reply here.
Back
Top