53 replies to this topic

[Nev]

Does anyone know what the Roll center height is on std VX 220 for front and rear

And how this is effected with a 30mm lowering, with same outer tire diameter?!

 

Br, Per

 

I don't know the OEM roll centre height, but with the stubby wishbone arms a 30mm lowering will make a big difference. Try using an online geo calculator (eg https://www.racingas...try-calculator/) and see.

 

Edited by Nev, 29 October 2017 - 07:11 PM.

[Aerodynamic]

If someone doesn´t have the  answer, I will have to start measuring everything when I start the winter working for the car for real.

[Exmantaa]

You'll have to Google on Elise specs for this, but beware that there is a lot of crappy info on the net:

 

This is from Lotustalk:

 

Lotus Elise  (could be S1 data...)

 

Front suspension roll centre height 30mm travel 50mm bump / 60 mm rebound camber gain in bump 0.31 degrees per inch frequency 90cpm KPI 12.0 degrees Castor 4.25 degrees Trail 4mm Scrub radius 10.5mm

Rear suspension roll centre height 75mm travel 50mm bump / 70 mm rebound camber gain in bump 0.45 degrees per inch frequency 98cpm

 

It appears that many preformance cars have roll centers in the 30 to 70mm range.

[Aerodynamic]

Is there someone who have there A arms easy available and can measure?

 

My car is still on its wheels and not so easy to measure on right now.

 

Br, Per

[Doctor Ed]

Mines sitting pretty to measure all of this. Just need to get to the shed... sometime on the weekend I'm guessing

[Exmantaa]

Is there someone who have there A arms easy available and can measure?

 

My car is still on its wheels and not so easy to measure on right now.

 

Br, Per

 

More important are the hard chassis- and upright pivot points. The A-ams just ty everything together.

Small issue; measuring in 3D space with the front and rear wishbone bushes...

[Aerodynamic]

Do you feel like you want to measure this aswell, then your more then welcome.

 

I thought if someone can measure the A-arm lengths then I can measure the chassie ad upright pivot Point myself

But if someone wants to help with this aswell I´d be happy.

 

If/ when I have all information collected I can make a easy CAD model to show RCH at different height settings.

 

Br, Per

 

 

 

Is there someone who have there A arms easy available and can measure?

 

My car is still on its wheels and not so easy to measure on right now.

 

Br, Per

 

More important are the hard chassis- and upright pivot points. The A-ams just ty everything together.

Small issue; measuring in 3D space with the front and rear wishbone bushes...

 

 

[Aerodynamic]

1. The hub carrier bolt threads are only aluminum, so the HCB mechanical grip (which I like to overtighten with 12.9 bolts) are a weak point. Their advert implies these have steel threaded inserts, but they don't.

 

This is not true, The bolt will be threaded in the hubcarrier not the upright.

 

Br, Per

 

I think the main reason for buying these hubs is that you can lower the car by 4cm without affecting the wishbone angles. This means the roll centres stay the same as designed and the suspension sits in the centre of the bump curve as designed. Both these functions are important (best to read about elsewhere if you don't understand them). Also it means you can make these changes without having to buy new (shorter) dampers + springs.

 

There a couple of disadvantages too though:

 

1. The hub carrier bolt threads are only aluminum, so the HCB mechanical grip (which I like to overtighten with 12.9 bolts) are a weak point. Their advert implies these have steel threaded inserts, but they don't.

 

2. The front hub carriers will need approx 1 CM of spacers to get 0 degrees (ie OEM) camber. This is designed with intent, but you need to be aware of it.

 

 

 

[Tonie Pettersson]

The HCB's are threaded in the upright.

What Nev mean is that in EP´s upright it´s just a simple thread in the aluminium, no insert (like a Helicoil / timesert for example).

Edited by Tonie Pettersson, 13 November 2017 - 06:43 AM.

[Aerodynamic]

Thought the hub was the bearing. Wouldnt it then be called upright carrier Bolt? :-)

[Tonie Pettersson]

 

4 CARRIER,BALL JOINT,UPPER (NLS.- USE 9198483 48 01 530)

 

 

So hub carrier bolt is a quite nice word for it (hub = upright, same sh*t just different names ).

Edited by Tonie Pettersson, 13 November 2017 - 07:23 AM.

[Spitfire Engineering]

It's probably so much easier just to use the correct names for everything!

 

1.  Hub carrier (or upright)

2.  Hub

3.  Hub mounting bolts (as opposed to the wheel bolts which go in from the other side)

4.  Ball joint carrier (or ball joint plinth)

5.  Ball joint carrier to Hub carrier bolts (hence they are usually referred to as HCB's)

 

 

The point that was made was Lotus uprated these to 10.9 as it was considered the 8.8's were not strong enough and there is plenty of bent bolts to confirm this, however this upgrade was not available for the Lotus aluminium uprights as the material was considered incapable of taking the extra torque required along with all the margins needed etc.

 

So with a new aluminium upright you would expect to see either:

A component locking system whereby the shear forces applied under extreme braking are carried directly from component to components relieving the bolts of any significant shear forces, or

The capability to accept 10.9 specification bolts including all the stress/fatigue considerations of the softer material.

 

[Tonie Pettersson]

It's probably so much easier just to use the correct names for everything!

 

1.  Hub carrier (or upright)

2.  Hub

3.  Hub mounting bolts (as opposed to the wheel bolts which go in from the other side)

4.  Ball joint carrier (or ball joint plinth)

5.  Ball joint carrier to Hub carrier bolts (hence they are usually referred to as HCB's)

 

No more misunderstanding .

 

The point that was made was Lotus uprated these to 10.9 as it was considered the 8.8's were not strong enough and there is plenty of bent bolts to confirm this, however this upgrade was not available for the Lotus aluminium uprights as the material was considered incapable of taking the extra torque required along with all the margins needed etc.

 

So with a new aluminium upright you would expect to see either:

A component locking system whereby the shear forces applied under extreme braking are carried directly from component to components relieving the bolts of any significant shear forces, or

The capability to accept 10.9 specification bolts including all the stress/fatigue considerations of the softer material.

 

 

It sure is very complex, so many variables to take into consideration.

 

I´m really excited to see what you are working on, can we get a sneak peek of what is is perhaps?

[FLD]

Lotus moved to a larger hub carrier block on the back. Is there any benefit to this other than sharing the front shims (ie cost)?