wheel size question

[Vagsport]

No sweat. Apart from the wheels, even if I had the correct size, say 8" x 18" ET 35 - 38, I would still have used spacers to give the car the wider track, so the bodywork would look good. Ever since seeing the ABT C5, I always fancied a wide bodied type 89. ABT also built a prototype in 1990, after VAG gave them the task of installing the RR 20V into the newer Coupe q, as a replacement for the Ur. The first car had the early bonnet (pre '91) and bulging arches. VAG accepted the mechanical installation, but not the bodywork, as it was deemed too expensive to mass produce the cars in that form. Another German team, Hoenester Racing (I think I've spelled it right) built a similar car, but with wider Integrale - style arches and a Rieger rear wing, :eek2: and this is what I am replicating. I'll post some pics up when I get some taken.

[Doug_RS2]

Vagsport - heres a pic of the front wheel on mine. As you can see, becasue your overall diameter is 40mm bigger than mine you would hit the spring base. In order to space the wheel out you need to move approx 50mm out. That 50mm plus the offset difference in wheels(5mm) gives you approximatley your 2.5inches your car needs.

You understand that Tom?

[Vagsport]

Cheers for that, Doug. I guess having a narrower spring platform (coilovers may reduce the need to space the wheel out very far. Gonna speak to the bodyshop tomorrow, as you said, Demon Tweeks do spacers.

Siena

[Vagsport]

Doug, just spoken to my bodyshop, also paid him a visit this arvo. The front spacers need to be a whopping 60mm :eek2: (yes, you read that right!), while the back can be the same, or 70mm. I'm having these made, these are being made by a local engineering firm, they are using an S2 hub and OE alloy as a template to get the centrebore and chamfer to match the S8 wheel and my S2 hubs. These are bolt on spacers, at this thickness they need to be! I have the choice of studs or bolts, I reckon I'll go for studs, makes wheel changes in the dark a lot easier. My question is, would you go for steel or aluminium? Obviously, steel is heavier, :frown: but it is unsprung weight and stronger. Any views on this, anyone?

[Lee]

For spacers this big I would use Aluminium otherwise they will weigh a few kilos each. Bolt the spacer to the hub first. Don't use long bolts here and use the stock ones if you can but still make sure you clamp a healthy amount of ally (20mm or so). You'll need a counterbore for this but it might be worth using some Unbrako capheads to retain the spacer to the hub. Threads in the aluminium for the bolts or studs need to be very strong. Most of the decent spacers use a steel insert (something like a Keensert if they do them in M14!). If I was doing it myself I would probably make up some steel inserts with an M20 outer and M14 inner thread. I would then screw 5 of these into 5 M20 holes in the spacer and loctite them in place. Given the size of your spacers I would make these inserts about 20mm long. This would give you a decent load path through the spacer. Don't rely on sending the bolt that retains the wheel into bear ally because a few months down the road you will be crying in your beer. The other option is to bond in studs as you pointed out. These would probably go straight into the ally if they were loctited in but I would air on the side of caution and use some kind of high strength insert even if using studs. Unless you want to take some risks, don't remove material from your spacer to reduce mass as you need to effectively stransfer the loads from the 5 new fixings to the old 5. I would perform some FEA if I was doing these myself to allow some material to be removed. The type of spacer I have losely described is standard on the German tuning scene and meets TUV but not sure you can get 70mm stock ones though. Good ally to use for this is 6082-T6 (or HE30 which is pretty similar)

An important note: moving the wheels out that far is going to move the contact patch quite far away from the strut axis which will drastically affect your steering (centering and stiffness) which may be undesirable.

Spacers this big also offset the wheel cetreline from the hub a hell of a lot. You will increase the bending moments that the wheel bearings have to carry by a huge amount. Not a problem if you treat them as a service item (check them every other service and replace as necessary). I was looking into wider arches and wider wheels on my S2 under RS4 style flares but that is at least 2 years away. When it comes to it I will be completely re-addressing the standard suspension geometry and wheel bearing strength at the same time. Have you looked at using an S8 strut with custom driveshafts and wishbones (assuming these struts are still MacPhearson type)?

I converted my hubs from bolts to studs and the wheel change is far simpler. Wish I did it years ago.

Good luck mate.....looking forward to the piccies already.

Lee

[Doug_RS2]

I was going to say exactly what Lee said

Can't wait to see this beast - Can we have a group meet at your garage?

[Vagsport]

Cheers for that, Lee. S8 struts are not compatible with type 89 / B4 cars, at least not without a lot of work! My spacers ARE being bolted to the hub as you say. I think I have pretty much decided to go for aluminium, due to their much lower weight. The only problem I can foresee is aluminium generally does NOT like steel contact, the different materials tend to react to one another. Still, I'll see what the engineers say tomorrow. I know the wheel bearings will be under considerable strain, but hey, no pain, no gain.

In future, I intend to look into spacing the lower bearing carrier away from the hub, (where the two bolts attach the strut to bearing housing). That way, the bearing carries the same load as standard. Obviously, the driveshafts will have to be lengthened or spaced out from the drive flanges a similar amount, as will the lower ball joints. The steering arms have been taken care of, as I have had some custom items made up in stainless steel, with rose joints rather than standard ball joints. These arms have more adjustment than the standard items, and are less likely to seize, due to their unique construction and adjuster assembly. They do not use locking collars as standard.

Siena

[Vagsport]

Yeah, Doug, am moving soon, so will be after Xmas. Will be nice to chat to the rest of the crew in the flesh over a keg of Britains finest.

[Lee]

I agree, I think an adjustable rose jointed wishbone is the way to go. Stainless isn't really that strong. You may be better off with a high strength steel instead. With regards material compatibility don't forget that the road wheel is aluminium so you've already got ally to steel contact anway.

Looking forward to a good bevvy up!!

Lee

[Vagsport]

Lower ball joint is goint to be high tensile steel, only the steering arm is going to be stainless, should be strong enough, as it's not load - bearing.

[audiman]

Up for a piss up and talking Audi stuff. Be nice to meet up with everyone again. and not have to drive home the same day ie

[Lee]

Yep, stainless would be fine for the steering arm. The wishbone needs to be a bit stronger if you are going to make a new custom one.

[porkkis]

Originally posted by Vagsport
When I get the car back, I intend to increase the track by having spacers made out of solid billet steel, but fitted between the strut and the hub carriers (where the two bolts attach the strut to hub carriers) that way the track is increases without compromising the integrity of the wheel bearings by moving the shoulders outwards. I also have spacers to fit between the inner CV's and drive flanges to compensate for the increase in track.

Errrrm.. You need a completely custom hub carrier that has the bearing more out. As a result you have the wheels turning (when steered) at larger diameter than originally.. And that makes the drive shaft travel a bit more front/back..
With spacers between strut and hub carrier you'd need longer wishbones and then the strut and the ball joint would not be alligned right. Ok as long as you go only straight
Perhaps I've understood something wrong, just my quick thoughts.

[Vagsport]

Might as well leave the wagon at home and train it down! Don't reckon you'll be fit to be piloting an S2 after a bevvy session!

[Vagsport]

Yer definitely missed summat, Porkkis! Summat in tha thread suggest different.