mrxmn
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| posted on 22/5/10 at 09:37 PM |
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MK Lowering and Optimum Wheel's
Just bought an Indyblade second hand and its come with 17" Team Dynamics Rim's. I took it for a first track day last weekend and two
things were very apparent.
The ride height was a lot higher than other comparable se7en style cars and the rim's were far too large.
Firstly I'm looking at selling the 17"ers and replacing them with some 14" as this is supposedly the smallest diameter that will fit
the sierra hub. The main advantages of this seem to be that it will lower the car a little because the extra 20mm of profile will not make up the
3" lost from the rims and the fact that the tyres are almost half the price is a big plus for track days.
My first question is that 14" rims will generally be much narrower e.g. ~185 vs 205 on my 17's how will this effect the performance (grip
in corners).
Secondly obviously the rolling diameter will be smaller due to the reduction in wheel size and therefore the speed of the car at a given RPM will be
reduced, what kind of hit will that have on the performance?
My second problem is that of lowering the car. Even with the smaller wheels it will still be pretty high but the normal method of using lowering
springs doesn't look like its going to be feasible because of the double wishbone suspension. As far as I can see the only effect of smaller
springs will be to raise the wheels relative to the chassis which could potentially ruin the handling? What is the best way to lower the car?
Any help much appreciated
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mangogrooveworkshop
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| posted on 22/5/10 at 09:42 PM |
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Welcome newbie to mad house
If you dont ask
want to swap your 17" inch wheels for these 14" inch wheels one season old
http://www.locostbuilders.co.uk/viewthread.php?tid=134398
On your question of lowering the spring seats just get turned down and the ride height will alter.
Secondly check your spring rates as mk generally gave all cars 325 in the fronts and 250+- at the back.
[Edited on 22-5-10 by mangogrooveworkshop]
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Gordy
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| posted on 22/5/10 at 09:59 PM |
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Im running with 14" rims and 185 048r yokos, excellent grip but not keen on standing water. Wouldnt worry about losing a few mph at top end
cause you'll get better acceleration out the corners
[Edited on 22/5/10 by Gordy]
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austin man
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| posted on 22/5/10 at 11:03 PM |
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17's look good but handle crap, you should be able to drop the car to around 4" by backing of the spring platform, just check the sump
clearance as the previous owner may have raised the height rather than cut the sump.
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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dhutch
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| posted on 22/5/10 at 11:48 PM |
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quote:
Originally posted by austin man
17's look good but handle crap....
I dont even like the look, multiple sets of 13" ford lasers for me!
- but yes, i would say what your doing i very sensable, and if had bought that car, would be what i would be doing.
Im un familuar with the intreces of the chassis geometry setup on the indy but typically your aiming for the effective front wishbone to horizontal
(thats from bush center to balljoint center, not with the tubes flat). Then with the live rear i assume the same again (im live rear) which should
hopfully see the car flat, or if anything, factionally higher at the rear.
Daniel
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Angel Acevedo
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| posted on 23/5/10 at 03:50 AM |
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quote:
Originally posted by mrxmn
.... The main advantages of this seem to be that it will lower the car a little because the extra 20mm of profile will not make up the 3" lost
from the rims and the .....
Secondly obviously the rolling diameter will be smaller due to the reduction in wheel size and therefore the speed of the car at a given RPM will be
reduced, what kind of hit will that have on the performance?
.......
mrxmn,
You will not lose 3" from going down to 14" you will lose only 1.5"
Welcome to the forum.
AA
Beware of what you wish.. for it may come true....
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locostbuyer83
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| posted on 23/5/10 at 06:38 AM |
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I've got sierra hubs and discs all round and have 13's fitted. 205/60/13 rear 185/60/13 front
IMHO 13s are the best size as they are really light and look great
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whitestu
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| posted on 23/5/10 at 07:37 AM |
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Anyone know which 13" wheels will fit over Sierra discs, other than standard ford wheels?
Ideally team dynamics 1.2s for me, but don't want to buy some and find they don't fit!.
Stu
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Humbug
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| posted on 23/5/10 at 07:37 AM |
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quote:
Originally posted by Angel Acevedo
quote:
Originally posted by mrxmn
.... The main advantages of this seem to be that it will lower the car a little because the extra 20mm of profile will not make up the 3" lost
from the rims and the .....
Secondly obviously the rolling diameter will be smaller due to the reduction in wheel size and therefore the speed of the car at a given RPM will be
reduced, what kind of hit will that have on the performance?
.......
mrxmn,
You will not lose 3" from going down to 14" you will lose only 1.5"
Welcome to the forum.
AA
Is there 20mm of extra profile all the way round, or total? The exact amount will depend on what width/profile tyres you are copmparing. As Angel
says, losing 3" of diameter only loses 1.5" (c 38mm) of height so if the profile is 20mm all round, you are only losing 18mm of height or
about 3/4 of an inch. You should be able to live with that!
btw, I have got 14" wheels with Yoko 185/60/14s which seem to be OK and look failry in proportion for the car.
[Edited on 23.05.2010 by Humbug]
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mrxmn
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| posted on 23/5/10 at 04:18 PM |
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thanks for all the info and quick relies,your right humbug that the rims will drop the ar about 38mm but the extra 20mm profile will lower it 18mm
overall, im going to wait till the new rims are fitted before adjusting the springs platforms becaue that may be enough of a drop, especially for road
use
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Davegtst
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| posted on 24/5/10 at 05:39 PM |
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Tyre profile is not measured in mm. It's the ratio of the tyre width.
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davestarck
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| posted on 24/5/10 at 05:39 PM |
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I had exactly the same problem when I purchased my MK Indy R1. Looked the nuts but handled like a sack of potatoes!!
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