jon200
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| posted on 8/10/12 at 08:27 PM |
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What effect does track width have on handling?
What difference does it make to have a wider from track or a wider rear track?
I have just fitted some new wheels to my Locost and I have removed the rear wheel spacers that were used on the original wheels as they were 30mm slip
on's! I though that as I have the same offset all round and the originals were too I'd need to keep them on there to keep the track the
same ratio as it was but having measure the track with the new wheels on there is only 32mm difference between the front and back(back narrower).
This what I have.
Fronts
7J et37 front 195/50 r15
New 8J et-8 195/50 r15
Inner clearance +33
Outer clearance -59
Track width 1520mm
New track width 1638
Rears
7J et 7(inc 30mm spacer) rear 195/50 r15
New 8J et-8 195/50 r15
Inner clearance +2
Outer clearance -28
Track width 1550mm
New track width 1606
A lot of people on the net say wider front and narrower rear gives better corner exit grip but to what extent? 1",2"? Whereas some say
just have wider rear tyres and the same or wider rear track.
Do I buy some spacers or stay as it is? I have longer studs anyway so no problem there.
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Daddylonglegs
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| posted on 8/10/12 at 08:40 PM |
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Not sure what's right or what's wrong, but my Locost has a rear track which is about 35mm wider than the front, and I don't feel
it's unsafe when I'm driving. That's not to say it's not going to be better with the front equal to or more than the rear, but
I don't think it's a major issue unless you're on the ragged edge.
Just my 2p's worth, I'm sure a much more knowledgeable person will be along soon enough 
It looks like the Midget is winning at the moment......
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NigeEss
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| posted on 8/10/12 at 10:25 PM |
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Mate of mine has a Tiger with wider rear track, he said the only issue is having to place the front wheel away
from the kerbs or the rears clout them.
Time is an illusion. Lunchtime doubly so.................Douglas Adams.
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chillis
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| posted on 8/10/12 at 11:08 PM |
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Crab tracks as they're called were popular in the '50s and '60s and the '70s for that matter with the citroen SM
An increase in track vs wheelbase can make a car more twitchy or oversteery as the chassis will 'turn' more easily.
Doubt the amounts your talking about will have a noticable effect unless your car is already sensitive to suspension geometry already. main thing to
be concerned with is how the track change affects ackerman but thats often a compromise on kit cars anyway.
Why do you need 8" wide wheels? especially when your using tyres meant for 6" wheels? Unless you tube them they'll be popping of the
rims on hard cornering.
Never under estimate the ingenuity of an idiot!
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rodgling
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| posted on 8/10/12 at 11:11 PM |
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Wider track reduces roll and improves lateral grip.
Apparently you've gone from 30 mm wider at the back to 30 mm wider at the front if I read your post right? So I would expect your car to be more
oversteery.
I guess whether that's a good thing or not depends on how you like it set up and how the balance has ended up (if it was really understeery
before then that might be an improvement). Or it might not be enough to make a big difference. Anyway, I would think if the grip balance now feels
good to you and you can get both oversteer and understeer when you expect/want them then it is probably a decent setup?
Go and cane it round some roundabouts and report back ;-)
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jon200
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| posted on 9/10/12 at 03:53 PM |
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quote:
Originally posted by chillis
Crab tracks as they're called were popular in the '50s and '60s and the '70s for that matter with the citroen SM
An increase in track vs wheelbase can make a car more twitchy or oversteery as the chassis will 'turn' more easily.
Doubt the amounts your talking about will have a noticable effect unless your car is already sensitive to suspension geometry already. main thing to
be concerned with is how the track change affects ackerman but thats often a compromise on kit cars anyway.
Why do you need 8" wide wheels? especially when your using tyres meant for 6" wheels? Unless you tube them they'll be popping of the
rims on hard cornering.
195 on an 8 will be fine, ive had a 225 40 18 on a 9.5J for 5 years with no issues at all an that's on track. I appreciate the higher profile
will allow more sidewall movement but that combined with the less weight will negate it.
It's going to be a stiffer ride anyway so the roll etc will be reduced so the extra track width should have too much effect on the handling
it's the different track front to back I'm not sure about.
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jon200
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| posted on 9/10/12 at 03:58 PM |
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quote:
Originally posted by rodgling
Wider track reduces roll and improves lateral grip.
Apparently you've gone from 30 mm wider at the back to 30 mm wider at the front if I read your post right? So I would expect your car to be more
oversteery.
I guess whether that's a good thing or not depends on how you like it set up and how the balance has ended up (if it was really understeery
before then that might be an improvement). Or it might not be enough to make a big difference. Anyway, I would think if the grip balance now feels
good to you and you can get both oversteer and understeer when you expect/want them then it is probably a decent setup?
Go and cane it round some roundabouts and report back ;-)
Initially I fitted the fronts so it was a lot wider at the front and it did feel like the rear wanted to overtake me when cornering fast. I
haven't tried with the rears as they are, maybe I can try it tomorrow and see what it's like. You say it's almost down to preference
so there's not really a right or wrong? It's rather have a little under steer that easy oversteer.
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MRLuke
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| posted on 9/10/12 at 04:28 PM |
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In its simplest form the wider end will have the most grip purely from a stability point of view.
If you stand with your legs together you are more wobbly then if you stand legs apart.
Cannot see the tyre width being an issue on that size wheel as 8 inches is just under 205mm.
What I dont understand is how you have increased the front track by twice as much as the rear. Either your old wheels were not the same size and
offset or there is an error in your measurements :s
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phelpsa
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| posted on 9/10/12 at 05:35 PM |
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Simple weight transfer. Wider track = less weight transfer = more grip. It is why circuit cars will maximise the track to the regulations.
Along the same lines, cars with a higher CoM at the back than the front will benefit more from a wider rear track.
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jon200
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| posted on 10/10/12 at 06:36 PM |
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quote:
Originally posted by MRLuke
In its simplest form the wider end will have the most grip purely from a stability point of view.
If you stand with your legs together you are more wobbly then if you stand legs apart.
Cannot see the tyre width being an issue on that size wheel as 8 inches is just under 205mm.
What I dont understand is how you have increased the front track by twice as much as the rear. Either your old wheels were not the same size and
offset or there is an error in your measurements :s
I had 30mm spacers on the original wheels and have removed them when i put the new ones on there so the rear was wider originally by 30mm. Take the
60mm of spacers off and you get the 30mm narrower. I can't use the 30mm ones because they aren't hubcentric!
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MRLuke
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| posted on 10/10/12 at 09:07 PM |
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quote:
Originally posted by jon200
quote:
Originally posted by MRLuke
In its simplest form the wider end will have the most grip purely from a stability point of view.
If you stand with your legs together you are more wobbly then if you stand legs apart.
Cannot see the tyre width being an issue on that size wheel as 8 inches is just under 205mm.
What I dont understand is how you have increased the front track by twice as much as the rear. Either your old wheels were not the same size and
offset or there is an error in your measurements :s
I had 30mm spacers on the original wheels and have removed them when i put the new ones on there so the rear was wider originally by 30mm. Take the
60mm of spacers off and you get the 30mm narrower. I can't use the 30mm ones because they aren't hubcentric!
Sorry OP stated
"7J et 7(inc 30mm spacer) rear 195/50 r15 "
Which I took to mean the spacer was included in there. My bad.
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