Front vs rear wheel base

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JDaly
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Front vs rear wheel base

Post by JDaly » Mon May 28, 2012 7:54 am

My 7 has an mx5 rear-end, and will your more conventional custom built front suspension and steering. It is looking like the rear wheel base will be wider than the front. How normal is this? I have been through the manual and can't see anything which specifically says this is not OK. I checked the ackerman geometry stuff, and it seems like I can keep within the Ackerman limits ok with less wheel spacing at the front than the rear. Anyone know more about this, or have experience in this area?

Thanks. Jason.

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heavyseven
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Re: Front vs rear wheel base

Post by heavyseven » Mon May 28, 2012 3:41 pm

What I've heard is that a slightly wider track is desirable at the front.
But I may be talking out of my rear.

bzrse7en
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Re: Front vs rear wheel base

Post by bzrse7en » Mon May 28, 2012 5:40 pm

I believe more front track promotes understeer, could be wrong thou. How much difference is there?
If this is the car I am thinking of that uses the older Mcgregor A arms, you might consider wider front A arms.

Patrick

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feckn7
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Re: Front vs rear wheel base

Post by feckn7 » Mon May 28, 2012 6:25 pm

Most 7's have a narrower front track than rear as standard

A wider front track will(should) reduce understeer and promote oversteer - depending on many other factors (tyre width etc)

Caterham (and Fraser's) have wide track options for the front for this purpose.

David

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JDaly
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Re: Front vs rear wheel base

Post by JDaly » Mon May 28, 2012 8:13 pm

Thanks guys. Spoke to Mark at McGregors today also, and he said a few percent difference in track (I think he said 7%), between front and rear, is normal. McGregors are wider at the front. yes, I think there is scope to make my a-arms longer. Also, can look at spacers for the wheels, or having different pair of wheels on the front c.f the rear. At the end of the day, as long as the car stays on the left side of the road, I'm happy.

bzrse7en
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Re: Front vs rear wheel base

Post by bzrse7en » Mon May 28, 2012 8:18 pm

feckn7 wrote:Most 7's have a narrower front track than rear as standard

A wider front track will(should) reduce understeer and promote oversteer - depending on many other factors (tyre width etc)

Caterham (and Fraser's) have wide track options for the front for this purpose.

David
Yea, you are right, silly me.

Reading stuff about Lotus F1 cars a while ago, Chapman made the comment that he realized he didn't know much about car dynamics when his drivers didn't notice any real differences in quite big suspension geometry changes, but they did notice a change in track, particularly increasing track increased cornering potential at the slight trade off of top speed.

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