wheel spacers ~ worth it?

[ScottEgg]

I used to run a 205 track day car with spacers, helping with turn in and providing even more stability through quick bends (not much notice when she did let go tho!). DOes anyone here use spacers and what are your thoughts? are they worth it, how much did you pay, what size offset etc etc? thanks Scott

[UweM3]

Personally I don't like spacers. If you have the rims with the correct offset, why bother?
They also need to be machined to high quality otherwise you buy in all sorts of other trouble (wheel wobble)

[GeoffBob]

Spacers should only be fitted in order to achieve the correct offset (with rims that don't already provide this). That is to say, to bring the wheel centreline back in line with the bearing centreline (as viewed perpendicular to the wheel axis). Every effort should be made to achieve this in order to keep the wheel load over the centre of the wheel bearing.

Fitting spacers to front the wheels (reducing the effective wheel offset) increases the scrub radius, which results in brake steer, a tendency of the front wheels to straighten out (to work against your steering effort) while simultaneously turning and braking.

For more information, refer to page 9 of my brake upgrade document which can be downloaded here:
ftp://ftp.csir.co.za/DPSS/Landwards_Sci ... radeV5.pdf in which I discuss the importance of fitting wheels with the correct offset, and sizing spacers in order to achieve this.

[ScottEgg]

Cheers for the feedback. I'm running the original BBS 15" so the spacers are a no-go! many thanks

[furbster]

Sorry to Hijack the thread but it's on the same subject.

I purchased a set of wheels shop with wets. They were off of an E30 but as I have Leda Coilovers the front wheels catch rub the coilovers (rear are fine).

A 10mm spacer clears them with a couple of mm to spare but just to be on the safe side I am considering buying some 15mm Eibach Hubcentric Spacers to give that little but extra clearance.

My question is will having spacers on the front and not on the rear have an adverse effect on the handling?

Many tanks!

[GeoffBob]

Furbster, I can relate to your problem. I was in exactly the same situation with my coil-overs when I cut my struts down by 30mm. I could only get around the problem by changing my rims.

I would advise against fitting wheel spacers for the same reasons as those presented in my last post (see above). Your biggest problem will be with brake-steer as a result of increased scrub radius. You'll also move the wheel centre-line to the outside of the bearing centre-line, which will increase the load on your wheel bearings, and thus shorten their life-span. However, given that they are so easy to change (I basically treat them as a maintenance item) I wonder if life-span is really such an issue, so long as they don't fail critically while you are out on the track.

If you have no other choice, and there is nothing else that you can do to solve the problem, then as a last resort I would say fit the spacers, but keep them as thin as possible. The fact that you won't have the same track-width on the front and rear of the car will not be a problem. Brake-steer, however, will be. But this has nothing to do with the difference in front and rear track-width.

For more information on sizing rims and wheel-spacers to fit an application, refer to page 9 of my brake upgrade document which can be downloaded here:
ftp://ftp.csir.co.za/DPSS/Landwards_Sci ... radeV5.pdf

[furbster]

Thanks GeoffBob,

Bearing life is not really an issue and as these particular wheels will only be used in extemely wet conditions (I have three other sets road, dry track and drift) that do not suffer from this issue I will go ahead and order myself a set.

Top Man!!

[UweM3]

GeoffBob, there are plenty of E30 people using wheel spacers out there without wheel bearing problems. I have not measured it myself but from what I have read over the years E30's do not suffer much from brake steer either. Your reply reads like using some wheel spacers will result in drastic results in very little time.

The one thing I would watch out for when using spacers is the hubcentric lip. With a thin spacer there is not much left of the centre lip and some rims feature really big chamfer and the rim isn't touching the centre lip and only centred on the hub by the screws. Can work but can also cause a lot of wheel wobble.

So if it would be me, I would rather use a quality hubcentric wheel spacer and have my rims properly centred and live with the 5mm too much thickness (which I believe doesn't cause havoc for the Joe Bloggs weekend warrior anyway)

Furbster you didn't give any ET numbers to determine how "bad" the problem will be. Can you fit shorter springs? ( I guess the spring platfromes are the problem??)

[furbster]

There is no ET written on those wheels that I can see.

Uwe you are correct in your assumption that it is the spring platforms that foul the tyres but I do not think that I can go any shorter with the springs.

I was intreagued by your comment regarding the small spacers though as the standard 15" BBS's need a 5mm spacer to stop the R888's fouling and I have exactly that issue (have to centre the wheel using the bolts) which takes a bit or fiddling to get it spot on.

Would you recommend using the 15mm hubcentric spacers that I will be purchasing for the wet wheels instead or do you think that would be too much?

I could just get some 10mn hubcentrics but there is only about 2-3mm clearance between the tyres on the wets and the spring platform and I am worried that the tyre could make contact on high speed corners!

Any advice greatly appreciated.

[UweM3]

furbster, you can use hubextenders from Turner Motosport in the US.
They replace the dust cap on your hubs and extend the lip and centre the wheel with thin spacers.

I don't know if this is a universal E30 or M3 specific part, so please check



http://www.turnermotorsport.com/html/de ... TWH9905001

[GeoffBob]

GeoffBob, there are plenty of E30 people using wheel spacers out there without wheel bearing problems. I have not measured it myself but from what I have read over the years E30's do not suffer much from brake steer either. Your reply reads like using some wheel spacers will result in drastic results in very little time.

No Uwe, I certainly never said anything drastic would happen, so kindly refrain from putting words in my mouth. And reducing the bearing life, say, by half, is likely to go unnoticed. And if it's so easy to replace the bearings, then in fact, who cares?

As for the effects of increased scrub radius upon the steering geometry, well these are very real and can be measured. Whether the person concerned chooses to live with the consequences (brake-steer, etc) is another story altogether, and unless measured properly, perceptions of these effects can be quite subjective, and I do not work in a world of subjective opinion.

Uwe, I suggest you pick up the book Racing Chassis and Suspension Design, edited by Carroll Smith.

[UweM3]

GeoffBob, there are plenty of E30 people using wheel spacers out there without wheel bearing problems. I have not measured it myself but from what I have read over the years E30's do not suffer much from brake steer either. Your reply reads like using some wheel spacers will result in drastic results in very little time.

No Uwe, I certainly never said anything drastic would happen, so kindly refrain from putting words in my mouth. And reducing the bearing life, say, by half, is likely to go unnoticed. And if it's so easy to replace the bearings, then in fact, who cares?

As for the effects of increased scrub radius upon the steering geometry, well these are very real and can be measured. Whether the person concerned chooses to live with the consequences (brake-steer, etc) is another story altogether, and unless measured properly, perceptions of these effects can be quite subjective, and I do not work in a world of subjective opinion.

Uwe, I suggest you pick up the book Racing Chassis and Suspension Design, edited by Carroll Smith.

GeoffBob not everything in live needs to be solved on PhD level.

[jaistanley]

I have an automotive engineering degree and still own a bloody big hammer. Make of that what you will......

[GeoffBob]

GeoffBob not everything in live needs to be solved on PhD level.

No, but a bit of common sense would help.

I have an automotive engineering degree and still own a bloody big hammer. Make of that what you will......

Degreed at Loughborough by any chance? I know it well. I have a hammer too, but that doesn't stop me from applying a little theory before I use it. Measure twice, cut once, and all that.

This isn't rocket science gentlemen. Most of the above is common knowledge.

[Ziggy]

Degreed at Loughborough by any chance? I know it well. I have a hammer too, but that doesn't stop me from applying a little theory before I use it. Measure twice, cut once, and all that.

This isn't rocket science gentlemen. Most of the above is common knowledge.

Did you study at Loughborough, or do/did you have some other involvement with the course? I still wonder whether I should have done Auto eng...

[GeoffBob]

Did you study at Loughborough, or do/did you have some other involvement with the course? I still wonder whether I should have done Auto eng...

No, I was invited to present some of my work and had some research interaction with them. I lost contact with Loughborough when I changed jobs in 2004. I had no involvement or experience of the undergraduate courses whatsoever, but superficially they looked OK.

At post graduate level they seemed pretty involved in fluid dynamics and general analysis of engine VE using fluid dynamic techniques. But that was about all I picked up on.

Was your experience not good Ziggy?

[UweM3]

GeoffBob not everything in live needs to be solved on PhD level.

No, but a bit of common sense would help.

I have an automotive engineering degree and still own a bloody big hammer. Make of that what you will......

Degreed at Loughborough by any chance? I know it well. I have a hammer too, but that doesn't stop me from applying a little theory before I use it. Measure twice, cut once, and all that.

This isn't rocket science gentlemen. Most of the above is common knowledge.

there is something called Common sense and this is to take into account that SMALL deviations from the ideal are acceptable for most of the intended use.

GeoffBob I do agree with what you are saying and for sure you have a more studied background than me in car design etc. But you remind me of somebody else I know very well and who's approach is quite similar to yours (not trying to put words in your mouth or discredit you or whatever, nothing is meant offensive)
Said person is spending thousands and thousands of £££ on his car just to make it perfect. You haven't got AP 6 pistons front and 4 pistons rear? Your brakes are shite then. Engine hardware not the maximum which can be had, no conrod bolts safe to 10.000rpm? That can't work. And the list goes on and on. What said person has probably forgotten (and he is a highly educted professional with a PhD) that having fun doesn't mean chasing every last tenth or hundredth (and spending ££££ on the way to achieve it). On a certain race track in Germany starting with an N said person is probably 20-25 sec faster than me (that on a 13miles long course and I guess 10 sec of that is down to a much more risky approach than I am willing to go) and his mega ££££ Grp A replica engine didn't (to my very surprise I have to say) pull away from me 'that' much on a long uphill straight section.
Not bad methinks with a car that has sinlge piston sliding calipers from the scrapyard and a DIY coil over suspension and has cost not even a 5th of above mentioned car. (and is probably setup very bad if compared to Caroll Smith book)

What I am trying to say is, yes things can be measured and are different from what could/should be. But that doesn't mean they need to be corrected straight away. Not for Joe Bloggs having some fun at the weekend. If you race in BTCC or DTM fair enough.

just my 2p

[GeoffBob]

Fair comment Uwe, I have no problem with what you have said, in fact I tend to agree with you. I'm certainly not out to spoil anyones fun for the sake of perfection. Keep in mind though, a little bit of knowledge is a powerful tool that can save you a lot of money and often offers a superior result to boot. Contrary to what you may think, I'm not into mega ££££ builds. My preference is generally for the simplest and cheapest solution that provides optimum performance on the track. I work a lot with second-hand parts, so I understand your point.

[UweM3]

Contrary to what you may think, I'm not into mega ££££ builds. My preference is generally for the simplest and cheapest solution that provides optimum performance on the track. I work a lot with second-hand parts, so I understand your point.

I was a bit scared when I typed my reply that it may come across the wrong way. I do not know you in person and I really don't want to imply anything related to your person or what you do. From past posts about your stuff and past projects I have read, I can see that you are a very hands on person and not the "open the wallet" builder.
It is very difficult to participate in a "conversation" sitting behind a keyboard and with english not beeing my first language I have come across in the past the wrong way unintended, so I am always a bit worried when I open my loud mouth

But I promise to keep learning and if I ever have a real problem to solve I know who to ask.

I remember the days when my car was more or less stock. I turned the key and just drove it every day and a few trackdays here and then. such a nice time that was. Then I bought a AFR gauge......

[GeoffBob]

furbster, you can use hubextenders from Turner Motosport in the US.
They replace the dust cap on your hubs and extend the lip and centre the wheel with thin spacers.

I don't know if this is a universal E30 or M3 specific part, so please check



http://www.turnermotorsport.com/html/de ... TWH9905001

Uwe, I just had a look at these. They wont fit the E30 four lug hub, but I take your point. They are a good idea for use with non-hubcentric spacers. I should imagine that it is possible to have something made up by a local machine shop from a piece of aluminium round bar machined down to the correct diameter and then parted off to the required thickness (at not too high price). I only work with hubcentric spacers (to avoid the problem you described above), but for use with spacers that don't self-centre I think this would be a good idea.

If anyone wants a drawing I am sure I can throw one together fairly quickly. I would however recommend putting something in the centre of the hub-extender to aid in its removal if you ever want to pull it out (to release the bearing, say).

[UweM3]

I don't know how Turner gets round that problem but I have measured various M3 wheel hubs (different manufacturers) and found quite a bit of variation in the dimension of the inside bore where the dus cap sits. Not a problem for the flexible dustcap but if you machine these hub extenders to fit within a tight tolerance to suit a particular wheel bearing brand, they may sit loose on another brand (or via versa)

[jaistanley]

I did my degree at Coventry uni. Looked at the Loughborough course when I applied. Both very good. Coventry (at the time) leant the course more toward the Mech eng and Production eng side of things rather than absolute technical specifics of design so suited me more (I've worked in various engineering jobs now and am doing a management consultant graduate training scheme now for a company that happens to supply the auto industry as one of its business streams). Of course the Loughborough course looked cooler as they had more budget. Class sizes were very large there though. Cov did give me a good understanding of design, it often amazes me how little supposed 'engineers' often know. Not sure if that is a credit to my Uni, or what a smart arse I am...

I always have this little engineer with a halo sat on my shoulder telling me how I SHOULD be doing things, and another on the other shoulder that (as an engineer) knows what I can get away with. Like you say, a little knowledge is a dangerous thing! lol. I do have to resist the urge to get everything perfect or it just never gets done. I've been a little guilty of that whilst doing my S50 swap, hence it over-stretched my budget and took ages. I hate to think where I'd have gone with it if I hadn't reined myself in!

Uwe: I admire you approach, get your hands on and use your knowledge to make descisions that fit both your requirement and budget.

GeoffBob: I also agree with the more hard line engineer approach. This is the eternal internal struggle of an engineer playing with his own car on his own budget!

[Ziggy]

Was your experience not good Ziggy?

My experience was great! I did the Systems Engineering Meng course at Loughborough, largely because I was able to get sponsorship that I couldn't have done for Auto (or Jai's course, which I also considered!). I certainly don't regret any of it, but it'd be nice to already be in the automotive industry, rather than be looking to make the jump from defence at some point!

That said, it might not be a bad thing to have cars purely as a hobby...

[furbster]

Blimey!

Thanks too all who commented! Loads of excellent advice!

[GeoffBob]

My experience was great! I did the Systems Engineering Meng course at Loughborough, largely because I was able to get sponsorship that I couldn't have done for Auto (or Jai's course, which I also considered!). I certainly don't regret any of it, but it'd be nice to already be in the automotive industry, rather than be looking to make the jump from defence at some point!

That said, it might not be a bad thing to have cars purely as a hobby...

Sorry, when you said you wondered if you should have done Auto Eng I thought you meant you had done it, but were having regrets. I figured it might have something to do with the current climate in the auto industry (GM filing for bankruptcy, and all that). Glad to hear you had a good time at Loughborough.

it often amazes me how little supposed 'engineers' often know. Not sure if that is a credit to my Uni, or what a smart arse I am...

Possibly the latter .... Just kidding. I know what you mean though. I think I have said this before, common sense isn't as common as it used to be.

Sorry everyone if I come across as such a hardliner. I'm not actually. I just can't bring myself to advise someone else to do a job the way I might actually do it myself I publicly advocate doing a job properly, but in private I can screw anything up with the best of them.

I'll post up a drawing of a hub-extender for anyone interested when I get a chance. Not essential I guess, but they might be of use to someone who wants to use wheel spacers that are too thin to be hubcentric.

[furbster]

I'll post up a drawing of a hub-extender for anyone interested when I get a chance. Not essential I guess, but they might be of use to someone who wants to use wheel spacers that are too thin to be hubcentric.

That would be fantastic!

Thanks Geoffbob!

[GeoffBob]

Furbster,

Here, as promised, is a drawing of a hub extender, good for use with non-hubcentric wheel spacers smaller than 10mm thick. I have 10mm hubcentric spacers on my front wheels, which I think is about the limit of hubcentrics.

I would recommend that you have two of these made up from a length of 2-inch diameter 6082 aluminium round bar. They really don't have to be that strong as they are only there to centre your spacer and your wheel as it all goes together. Once your wheel nuts are torqued up, its the friction between the hub face, spacer faces and wheel centre, that stops the whole lot flying off, and the hub extender plays no part in all of this.

Note, however, that the hole in the back of the hub extender is required so that it fits over the nut on the end of the stub-axle. You'd fit these by tapping them in place of the standard dust-caps with a plastic mallet. To remove them, just slot the edge of a flat screwdriver down behind the shoulder and pry out.

I really don't think these will cost a lot to have made up. You'll just need to find someone with a lathe who has the time to make them.

Regards
Geoff

[furbster]

Thanks Geoff you are an absolute star!

I'll get these made up and let you know how I get on.