Wheel spacers

[dtype38]

Originally Posted by Alan Cherry

Don't forget the blue book ( unless it's changed this year ) limits spacers to 1 per wheel, and 1" max.

If anyone bothers to look that is. One chap I used to race against has a car built to take very wide tyres (14" wide rims I think) but was only allowed 8" wide rims by the series regs. So he fitted 5" spacers to get the wheels to the outside of the wheel arches. Was never challenged about them.

[greenamex2]

We have been checked at least twice for wheel spacers.

[trikesrule]

Meb I'm always looking to reduce drag in what ever I race but in the gravity racers I build and race a lower tyre coefficient is a definate plus. Drag cars could easily benefit from zero SR. You guys that go around corners on the black stuff may find a nice little improvement with reduced SR. The spacers u add to clear what ever may do the job for clearance but perhaps it was just that quick fix that increased your SR. Hence u may find you have to apply the throttle a little sooner to get those times back down. It really is a catch 22.........trikes

[meb]

So, there is a happy place (more subjectivity) between track width and sr with regard to a given plateform, a best scenario compromise.

[dtype38]

Originally Posted by Denis Bassom

We have been checked at least twice for wheel spacers.

Wow, was that at different circuits? I know I've never been checked cos on my car you'd have to take a wheel off to see it.

[greenamex2]

Oulton and Mallory.

I think it was the eligibility scrutineers 'latest thing'.

At least one person got picked up on it, but they just got a 'fix it for the next race' warning rather than a penalty.

[DanFord]

sorry to revive an old thread but I've just got a quick question on the subject as I have just finished a project but not driven it yet -

if you move the complete (mac) strut outwards (adjustable top mounts, extended TCA's and tie rods) instead of using wheel spacers do you encounter the same issues as discussed earlier?

I was under the impression that it wouldn't as the SAI hasn't changed but looking through some of the more technical replies I think I may under estimated the implications

[RandaMk4]

Hi everybody,
this is my first post, so I'll introduce myself: my name is Ottavio, I'm 33 y.o. and I live in Italy.
I'm experienced bad understeer problems with my Honda Prelude 2.2 Vtec. I've changed the original rims 15'' et 45 6,5j with 16'' et 35 8j, widening, as a consequence, the track. Well, the car handles like crap now
It understeers a lot entering a corner, especially at low speed, and oversteers inside the corner, especially at high speeds. The real problem is the understeer, anyway. I've played a lot with angles, but without success.
I think the wider rims and above all the lower offset might have affected negatively the steering geometry because the scrub radius variation. I've thought about an incorrect Ackerman, but can't say it for sure.
By the way, the car has a wishbone front suspension with stabilizer bar , rear suspension with stabilizer bar independent with coil springs. It has four wheel steering.
I run stock suspension. Is there a suspension upgrade I can balance this thing with, reducing the understeer, or my only hope is to return back to the old rims?
Thank you very much in advance.

[dtype38]

Hi RandaMk4 and welcome to 10-10ths.

I'm sure there will be plenty along to give advice on this, so I'll kick off with my take. At first glance I'd say that you don't seem to have made a that big a change to cause so much problem. Going from 45ET 6.5J to 35ET 8J I think only moves the centre line or your tread out by just over and inch (27.5mm). I'd be surprised if your car is so sensitive for that to be the only cause of the problem. first question has to be about your tyre change. Are you using the same type of tyre? Have you increased the tread width in the same proportion to the increase in rim width? Oh, and have you adjusted the profile to keep the same overall diameter? If no to any of these, then that might be the first place to look. Even if you have, though, the new tyre will have a bit less side wall flex than the original, so might need the springs and stabiliser bar softening slightly to give the same responsiveness.

I'd say that in general, unless you are hopelessly over-tyred for the car, then more track and more tread on the ground should give better results. Just a case of getting it all tuned in to take advantage. Good luck.

[RandaMk4]

Originally Posted by dtype38

Hi RandaMk4 and welcome to 10-10ths.

I'm sure there will be plenty along to give advice on this, so I'll kick off with my take. At first glance I'd say that you don't seem to have made a that big a change to cause so much problem. Going from 45ET 6.5J to 35ET 8J I think only moves the centre line or your tread out by just over and inch (27.5mm). I'd be surprised if your car is so sensitive for that to be the only cause of the problem. first question has to be about your tyre change. Are you using the same type of tyre? Have you increased the tread width in the same proportion to the increase in rim width? Oh, and have you adjusted the profile to keep the same overall diameter? If no to any of these, then that might be the first place to look. Even if you have, though, the new tyre will have a bit less side wall flex than the original, so might need the springs and stabiliser bar softening slightly to give the same responsiveness.

I'd say that in general, unless you are hopelessly over-tyred for the car, then more track and more tread on the ground should give better results. Just a case of getting it all tuned in to take advantage. Good luck.

dtype38,
thanks for your reply. I apologise for not having specified it: the original tires were 205 - 55 / 15; the new ones are 225 - 45 / 16. The diameter is the same and the tire fits perfectly the rim.
I thought about the side stiffness and yes, I believe the new tires are much stiffer than the old ones, and not only because the size. Unforunately stock suspension of my car are not adjustable, but I did hope that the higher stiffness of the tires might be counterbalanced by the longer arm given by the new rims.

[dtype38]

You are correct that the increased track should effectively soften the suspension a little. Not an expert of this I'm afraid, so hopefully someone else will have some more ideas. If you don't get any more replies, then it could be because you've tacked onto a thread titled "wheel spacers". You could try starting a new thread with your original post and title it something like "Handling problems after changing wheel size/offset" or the like. That should get more response.

BTW, if you're replying to a post directly above, you can just reply without the quote. Even if there have been more posts, you don't need to quote the whole of a long post... you can use your delete key to reduce it the just the relevent bit and everyone will know what you mean.

[Goran Malmberg]

No problem meb.
Goran

[dtype38]

You keeping up with the thread Goran?

[trikesrule]

The way I see it is if you widen the track at say the rear you loosen the car creating oversteer. Widen the front and you add understeer. The next place I would head is the rear roll centre - raise it and lower the front RC then perhaps add toe out. Then again you could start by adding toe out. That'll help turn in.........trikes

[grichie87]

Originally Posted by andypipe

Whats the pro's and con's of using wheel spacers to bring the rims further out into the arch and clear suspension units?

Andy,
You should use 6inch spacers allround there is no problem, also try using road tyres as they are much better than slicks.

[bdwoody]

165/sr 13 at 65psi should do the trick hey grichie?

[Goran Malmberg]

Originally Posted by dtype38

You keeping up with the thread Goran?

Well, I realized that my response was a bit late. When I opened the side
the other day, page 3 appeared as the last inlay for some strange reason, where Meb explained that he missundertod me.
Sorry.
Goran

[dtype38]

Don't worry Goran, it happens to us all! Seems this thread has taken a less than serious turn anyway...

[RandaMk4]

Thanks to everybody, I'll open a new thread as suggested.

Sorry for the crosspost.